Enviornmental Assessement report for tiruvarur STP - Municipal ...

ENVIRONMENTAL IMPACT 

ASSESSMENT REPORT 

For Proposed 

SEWAGE TREATMENT PLANT 

6.92MLD CAPACITY 

At 

Kekkarai Village, Thiruvarur Municipality 

Thiruvarur District 

TamilNadu

CONTENTS 

CONTENTS 

CONTENTS

Table of Contents 

EIA EIA FOR FOR 6.92 6.92 6.92 MLD MLD MLD STP STP STP AT THIRUVARUR 

1. INTRODUCTION .............................................................................................................................. 1 

1.1 INTRODUCTION ..................................................................................................................... 1 

1.2 PREAMBLE ............................................................................................................................... 1 

1.3 PROFILE OF THIRUVARUR ................................................................................................ 2 

1.4 NEED FOR THE PROJECT.................................................................................................... 2 

1.5 THIRUVARUR SEWERAGE SCHEME .............................................................................. 3 

1.6 PROJECT BRIEF ...................................................................................................................... 6 

1.7 PROPOSED PROJECT SITE .................................................................................................. 6 

1.8 NEED FOR EIA ......................................................................................................................... 8 

1.9 OBJECTIVES OF THIS REPORT ......................................................................................... 9 

1.10 SCOPE OF THE REPORT ................................................................................................... 10 

1.11 CATEGORIZATION OF PROJECT ................................................................................... 10 

1.12 ENVIRONMENTAL LEGISLATIONS .............................................................................. 11 

1.13 WORLD BANK POLICIES .................................................................................................. 13 

1.14 LEGAL/REGULATORY CLEARANCES FOR THE PROJECT ................................... 15 

1.15 AGENCIES RESPONSIBLE FOR PROJECT IMPLEMENTATION .......................... 16 

2. PROJECT DESCRIPTION ............................................................................................................ 17 

2.1 PROJECT PROPOSAL ......................................................................................................... 17 

2.2 LAND REQUIREMENT ....................................................................................................... 17 

2.3 PROCESS DESCRIPTION ................................................................................................... 19 

2.4 STP PIPELINE AND BYPASS ARRANGEMENT ......................................................... 23 

2.5 RAW SEWAGE CHARACTERISTICS .............................................................................. 27 

2.6 TREATED EFFLUENT QUALITY .................................................................................... 27 

2.7 DISPOSAL OF TREATED EFFLUENT ........................................................................... 27 

3. BASELINE ENVIRONMENTAL DATA ................................................................................... 28 

3.1 METHODOLOGY .................................................................................................................. 28 

3.2 BRIEF DESCRIPTION OF THE PROJECT SITE .......................................................... 28 

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3.3 CONNECTIVITY ................................................................................................................... 31 

3.4 LAND USE .............................................................................................................................. 31 

3.5 RAINFALL & CLIMATE ...................................................................................................... 33 

3.6 GEOLOGY ............................................................................................................................... 33 

3.7 AIR ENVIRONMENT ........................................................................................................... 34 

3.8 Noise Environment ............................................................................................................ 36 

3.9 WATER QUALITY ................................................................................................................ 37 

3.10 SOIL QUALITY ...................................................................................................................... 41 

3.11 SOCIO-ECONOMIC DATA ................................................................................................. 44 

4. PREDICTED IMPACTS AND MITIGATION MEASURES .................................................. 55 

4.1 INTRODUCTION .................................................................................................................. 55 

4.2 IMPACT EVALUATION ...................................................................................................... 55 

4.3 PROPOSED MITIGATION MEASURES ......................................................................... 58 

4.4 CONCLUDING REMARKS ................................................................................................. 62 

5. PUBLIC PARTICIPATION .......................................................................................................... 63 

6. ENVIRONMENTAL MANAGEMENT PLAN ......................................................................... 65 

6.1 INTRODUCTION .................................................................................................................. 65 

6.2 EMP DURING CONSTRUCTION PHASE ...................................................................... 65 

6.3 EMP DURING OPERATION PHASE ............................................................................... 72 

6.4 ENVIRONMENTAL MONITORING PROGRAM .......................................................... 73 

6.5 GREEN BELT DEVELOPMENT PLAN ........................................................................... 77 

6.6 SAFETY TRAINING & HEALTH MONITORING ......................................................... 79 

6.7 EMP BUDGETARY ALLOCATION .................................................................................. 87 

6.8 PERMISSIONS FROM VARIOUS DEPARTMENTS WITH PRESENT STATUS ...... 

88 

7. CONCLUSION ................................................................................................................................. 98 

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LIST OF TABLES 


Table 1-1 Agencies responsible for Project Implementation ....................................... 16 

Table 2-1 Raw Sewage Characteristics ....................................................................... 27 

Table 2-2 Treated Effluent Quality ............................................................................ 27 

Table 3-1 Surrounding Features of the Project Site .................................................... 28 

Table 3-2 Existing land use of Thiruvarur Town ........................................................ 31 

Table 3-3 Land use distribution in Tiruvarur Local Planning Area ............................. 32 

Table 3-4 Proposed Land Use Plan ............................................................................ 33 

Table 3-5 Mode of collection of Ambient Air Quality Parameters .............................. 35 

Table 3-6 Techniques used for Ambient Air Monitoring ............................................. 35 

Table 3-7 Air Sampling Locations ............................................................................. 36 

Table 3-8 Ambient Air Quality Data ......................................................................... 36 

Table 3-9 Noise Level Data Sheet .............................................................................. 37 

Table 3-10 CPCB standards for Noise ......................................................................... 37 

Table 3-11 Sampling Locations in the Study Area ...................................................... 38 

Table 3-12 Ground Water Quality in Project Site ....................................................... 39 

Table 3-13 Soil Sampling Stations ............................................................................. 42 

Table 3-14 Soil Quality data ...................................................................................... 44 

Table 3-15 Population Statistics ................................................................................ 45 

Table 3-16 Literacy Statistics .................................................................................... 46 

Table 3-17 Literacy of Thiruvarur District ................................................................. 46 

Table 3-18 Literacy Rate of Thiruvarur District......................................................... 46 

Table 3-19 Land use Pattern ..................................................................................... 47 

Table 3-20 Agriculture in the District ........................................................................ 49 

Table 3-21 Livestock Census 2004 ............................................................................. 51 

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Table 3-22 Fishery Production .................................................................................. 51 

Table 3-23 Industries in the district ........................................................................... 52 

Table 3-24 List of Educational Institutions ................................................................ 53 

Table 3-25 Workforce in the District ......................................................................... 53 

Table 3-26 Health care facilities in the District .......................................................... 53 

Table 6-1 Environmental Monitoring Schedule .......................................................... 75 

Table 6-2 Cost for Environmental monitoring ........................................................... 77 

Table 6-3 Safety Measures for the operation of the STP ............................................. 80 

Table 6-4 Steps to be taken during Trouble shooting .................................................. 83 

Table 6-5 Environmental Budget .............................................................................. 88 

Table 6-6 Authorities Clearances ............................................................................... 89 

Table 6-7 Construction Phase Impacts & Mitigation Measures ................................... 90 

Table 6-8 Environmental Enhancement measures ..................................................... 95 

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LIST OF FIGURES 


Figure 1-1 Thiruvarur Underground Drainage Scheme Plan ........................................ 5 

Figure 1-2 Satellite Image of the Site Location ............................................................ 7 

Figure 1-3 Current Status of the Site ........................................................................... 7 

Figure 1-4 Layout of Sewage Treatment Plant ............................................................. 8 

Figure 2-1 Layout of STP .......................................................................................... 18 

Figure 2-2 Process Flow of STP ................................................................................. 20 

Figure 2-3 Bypass Arrangement for STP ................................................................... 25 

Figure 2-4 Flow Representation for the Proposed STP ............................................... 26 

Figure 3-1 Surrounding features around Project site .................................................. 29 

Figure 3-2 Satellite Imagery of the Project Site - 10 Km Radius ................................. 30 

Figure 3-3 Geology Map of Thiruvarur District .......................................................... 34 

Figure 3-4 Water Sampling Locations ....................................................................... 41 

Figure 3-5 Photographs during field survey ............................................................... 43 

Figure 3-6 Population Distribution of Thiruvarur District ......................................... 45 

Figure 3-7 Literacy Rate of Thiruvarur District ......................................................... 47 

Figure 3-8 Land Utilization Pattern of the Thiruvarur ............................................... 48 

Figure 3-9 Cropping Calendar ................................................................................... 50 

Figure 6-1 Green Belt Development Plan ................................................................... 79 

LIST OF ANNEXURE 

Annexure -1 Basic Information on Proposed project in Thiruvarur 

Annexure -2 Consent to Establish 

Annexure- 3 Compliance Status of Consent 

Annexure-4 List of Activities 

Annexure-5 Reply to Query 

5

EIA EIA EIA REPORT 

REPORT

1.1 INTRODUCTION 

1. INTRODUCTION 


Tamil Nadu Government made a policy announcement of providing Under 

Ground Sewerage scheme in all urban local bodies in a phased manner at 

District Head quarter towns. The Municipal Sewerage collection network 

systems are implemented and the household sewage are collected and moved 

to the collection chamber of STP. 

The STP consists of various unit operations and processes to treat the raw 

sewage into the final treated effluent quality as per the stipulated standards. 

The project will have construction phase and operation phase impacts 

which have been assessed and the Environment Impact Assessment has been 

prepared. 

1.2 PREAMBLE 

The proposed sewerage system was designed for the targeted population 

of about 60,000 people. The project has the following components: 

Sewerage network consisting of the main sewer line, branch sewer 

line and manholes; 

Construction of a sewage pumping station; 

A sewage treatment plant 

For the purpose of sewage system the project area divided in to 5 zones 

each having a separate pumping station. There will be 5 pumping stations and 

16 lift stations. The scheme contains provisions for sewer laying for a total 

length of 71.679Km and construction of 2846 manholes. 

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The Sewage Treatment Plant having a capacity of 6.92 MLD is proposed at 

Kekarai, Thiruvarur District, Tamil Nadu. 

1.3 PROFILE OF THIRUVARUR 

Thiruvarur Municipality is located at a distance of 60 km from East of 

Thanjavur town. The latitude of the town is 10〫77” and the longitude of the 

town is 79〫15 “. As per 2011 census, the population of Tiruvarur is 1268,094. 

Males constitute 49.5 % of the population and females 50.5%. The 

decadal growth rate is 8.43%. Tiruvarur has an average literacy rate of 83.26%, 

male literacy is 89.65%, and female literacy is 77.02%. 11.98% of the 

population is under 6 years of age. 

1.4 NEED FOR THE PROJECT 

With the rapid growth of the population in Thiruvarur district, the lack of 

proper drainage system and sewage treatment facility has become an ever – 

larger problem for public and from environmental point of view. Therefore, 

Government has decided to provide an Underground Sewerage Scheme with 

STP at Kekarai as a part of urban development project for Thiruvarur 

Municipality. 

M/s. Hindustan Dorr-Oliver Limited has been assigned for Design, 

construction, erection and commissioning, startup and operation of the sewage 

treatment by Tamil Nadu Water supply and Drainage Board (TWAD). 

In order to assess the impact of the proposed STP on the environment, 

M/s. Hindustan Dorr-Oliver Limited, Chennai studied the environmental 

scenario of the existing situation and the probable impacts that could arise 

from the proposed sewage treatment plant at Thiruvarur. Suitable mitigation 

measures have also been suggested based on the impact assessment. 

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1.5 THIRUVARUR SEWERAGE SCHEME 


Administrative Sanction was accorded vide G.O No. 16 MAWS dated 

1.09.2006 and action was initiated in the year 2007 by TWAD. Sewerage 

treatment plant site was selected at Kekkarai Village. (Proposed treatment 

plant) About 8.87 Acres of land was identified for this purpose. The location of 

Sewage Treatment Plant and the underground drainage scheme plan is shown 

in Figure 1-1. The pumping Station is divided into 5 zones. Zone I 

(Srinivasapuram), Zone II (Chettikulam), Zone III (Kulunthankulam), Zone IV 

(Arasankulam) and Zone V (Ramagaye Muni). 

The sewage from the residential area is discharged into the corresponding 

underground sewerage system. All the sewerage zones are interconnected 

with the sewerage network, ultimately collecting into the main pumping station 

(Zone V), where sewage will be pumped to the Sewage Treatment Plant. The 

treatment system adopted is Activated Sludge Process (ASP). 

1.5.1 Zone -I 

This pumping station at Srinivasapuram covers an area of 1200 m 2 

comprising 1000 housing service connections. The length of sewer is 7398 m 

and the sewage from this Zone is pumped to Zone II. 

1.5.2 Zone -II 

This pumping station at Chettikulam covers an area of 2750 m 2 

comprising 3100 housing connections with the sewer length of 16068 m. The 

sewage from Zone II is pumped to Zone III which is further pumped to the main 

pumping station at Zone V. 

1.5.3 Zone III 

This pumping station at Kulunthankulam (located in HR & CE land at 

Thirumanjana veedhi) covers an area of 1950 m 2 includes 4600 housing service 

connection with the sewer length of 17722 m. The sewage from Zone III is 

pumped to the main pumping station at Zone V. 

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1.5.4 Zone IV 


This pumping station at Arasankulam covers an area of 1240 m 2 

includes 3760 housing connections with the length of 19314 m. The sewage 

from Zone IV is pumped to the main pumping station at Zone V. 

1.5.5 Zone V 

This is the main pumping station located at Ramagaye Muni. covers an 

area of 1144 m 2 includes 2079 housing connections with the sewer length of 

11177 m. All the sewage from this zone is pumped to the Sewage Treatment 

Plant at Kekarai village, Thiruvarur Municipality. The entire treated effluent 

will be disposed into Sukkanar drainage canal. 

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Figure 1-1 Thiruvarur Underground Drainage Scheme Plan 

EIA EIA FOR FOR 6.92 6.92 MLD MLD STP STP AT THIRUVARUR 

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1.6 PROJECT BRIEF 

Project Town : Kekkarai Village, 

Municipality : Thiruvarur Municipality 

District : Thiruvarur District 

State : Tamil Nadu 

EIA EIA FOR FOR 6.92 6.92 6.92 MLD MLD STP STP AT THIRUVARUR 

Technology used : Activated Sludge Process (ASP) 

Capacity of the Plant : 6.92 MLD 

The project involves the construction of Sewage Treatment Plant with an 

intermediate capacity of 6.92 MLD and an Ultimate capacity of 8.55 MLD. 

Basic Information on Proposed project in Thiruvarur is enclosed as Annexure-I 

1.7 PROPOSED PROJECT SITE 

Thiruvarur Municipality is located at a distance of 60 Km from East of 

Thanjavur town. The satellite image and the current status of the project site 

are shown in Figures 1.2 and Figure 1.3 respectively. With the rapid 

expansion and urbanization of Thiruvarur Town, an underground sewerage 

scheme has been formulated for the town and the collection system works are 

in progress/ nearing completion. The final sewage from the Zone V will be 

redirected to the proposed Sewage Treatment Plant for final treatment and the 

treated effluent will be redirected to the downstream flow of Sukkanar (a 

channel formed by the drainage of the agricultural lands in the village) which is 

about 100 m from the proposed site. 

The sewage treatment plant covers an area of 8.87 acres. The STP with 

selected modern technology has a capacity of 6.92 MLD. The layout of STP is 

shown in Figure 1.4. 

6

Proposed 

Project 

Site 

Figure 1-2 Satellite Image of the Site Location 

Figure 1-3 Current Status of the Site 


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1.8 NEED FOR EIA 

Figure 1-4 Layout of Sewage Treatment Plant 


Environmental Impact Assessment (EIA) is a study of the possible impacts 

that a proposed project may have on the environment, which may affect 

natural, social and economic aspects in and around the project area. 

The purpose of the assessment is to make the project proponent to 

enhance the environmental quality of the project site during planning and 

execution of the project. The International Association for Impact Assessment 

(IAIA) defines an Environmental Impact Assessment as "the process of 

identifying, predicting, evaluating and mitigating the biophysical, social, and 

8


other relevant effects of development proposals prior to major decisions being 

taken and commitments made." 

As per the World Bank policy, the project is categorized under F1. A 

proposed project is classified as Category F1, if it involves investment of Bank 

funds through a financial intermediary, in subprojects that may result in 

adverse environmental impacts. Hence an assessment study is mandatory as 

per the funding agency. 

The proposed project is categorized under E1 (as per ESF of Tamil Nadu 

Urban Infrastructure Financial Services Limited, Chennai) since it includes 

sewerage network, pumping station and sewage treatment plant. Hence an EIA 

study is required for the proposed work. 

This Present report elucidates the existing environmental scenario of the 

project site and the predicted impacts due to installation of the proposed 

Sewage Treatment Plant. It evaluates the impacts during the pre construction, 

construction and operation phases of the project. Both positive and negative 

impacts are being considered and reported. The Environmental Management 

Plan (EMP) is also aimed at mitigating the possible adverse impact of the 

project and ensuring the existing environmental quality gets enhanced. 

1.9 OBJECTIVES OF THIS REPORT 

The objectives of the report are 

To identify and assess any potential negative environmental and 

social impacts and to facilitate the planning of preventive and 

remedial measures. 

To identify possible environmental enhancements in the project 

setting and lay down the action plans. 

To develop a set of environmental monitoring and management 

plans compliant with the relevant codes, statutes & social norms. 

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1.10 SCOPE OF THE REPORT 


To assess the baseline of air, water, land, soil and noise environment 

around the proposed site in relation to the town by collecting the 

samples of air, water, soil and noise in the project setting and 

analyzing for the recognized parameters as per local statutory 

regulations and prepare the baseline document and to predict the 

potential impacts 

To identify the potential impact by the STP on related environmental 

issues like wildlife, bird sanctuaries, flora & fauna, public health, 

social uplift, archeological monuments, heritage structures and 

bring up the appropriate preventive & remedial procedures without 

compromising the objective of STP. 

To develop a set of practices to be followed during preconstruction, 

construction and post construction periods in order to avoid the 

foreseeable negative impacts. 

In keeping with the operational policy of the World Bank 4.01, go 

through a process of public consultation and transparently 

apraising the public of the foregoing and securing their concerns, 

evolving mutually agreeable measures to all the concerns, document 

the same and ensuring a periodic and continual follow up with 

project persons and the public. 

1.11 CATEGORIZATION OF PROJECT 

The proposed project is categorized under E1 since it includes sewerage 

network, pumping station and treatment plant as per Tamil Nadu Urban 

Infrastructure Financial Services Limited, Chennai. 

As per the MoEF Notification S.O. 1533, notification under sub-rule (3) of 

Rule 5 of the Environment (Protection) Rules, 1986, dated 14 th September 

2006, the Sewage Treatment Plant is not categorized in the schedule. 

10


As per TNPCB Industrial Categorization, the present project is categorized 

as Orange Category. 

1.12 ENVIRONMENTAL LEGISLATIONS 

below 

Salient features of some of the major laws that are applicable are given 

1.12.1 Water (Prevention and Control of Pollution) Act, 1974 

The basic objective of this Act is to maintain and restore the 

wholesomeness of the country's aquatic resources by prevention and control of 

pollution. Consequently, the Water Act, a Central law, was enacted under 

Article 252(1) of the Constitution, which empowers the Union Government to 

legislate in a field reserved for the States. All the States have approved 

implementation of the Water Act. As during operation, it is likely that the 

ground water quality and surface water quality may be altered. Therefore this 

act is applicable to the proposed project. 

1.12.2 Air (Prevention and Control of Pollution) Act, 1981 

The Union Government under Article 253 of the Constitution passed this 

Statute. This Act provides for the prevention, control and abatement of air 

pollution and confers powers to the Central and State Pollution Control Board 

with a view to carry out the aforesaid purposes. This act is applicable to the 

proposed project. 

1.12.3 Environment (Protection) Act, 1986 

The Union Government under Article 253 of the Constitution passed this 

Statute. The Environment (Protection) Act, 1986 seeks to achieve the objective 

of protection and improvement of environment and for matters connected 

therewith. This legislation enables the co-ordination of activities of the various 

regulatory agencies; setting up of an authority or authorities with advocate 

powers for environmental protection etc., This Act is applicable to the proposed 

project. 

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Objective of this Act is to provide the protection and improvement of 

environment (which includes water, air, land, human being, other living 

creatures, plants, microorganism and properties) and for matters connected 

therewith. 

1.12.4 Public Liability Insurance Act, 1991 

The Act, provides public liability insurance for the purpose of providing 

immediate relief to the persons affected by accident occurring while handling 

hazardous substances. Hazardous substance means any substance or 

preparation which is defined as hazardous substance under the Environment 

(Protection) Act 1986, and exceeding such quantity as may be specified by 

notification by the Central Government. 

1.12.5 Municipal Solid Waste (Management & Handling) Rules, 2000 

This notification by Ministry of Environment & Forest lay down the 

methods of handling Municipal Solid Waste (MSW) and its scientific disposal. It 

bans incineration of MSW. 

Municipal Solid Waste (Management & Handling) Rules, 2000 are 

applicable to every municipal authority responsible for collection, segregation, 

storage, transportation, processing and disposal of Municipal Solid Waste. The 

Rules contains four Schedules namely; 

Schedule Activity 

I Relates to implementation schedule 

II Specifications relating to collection, segregation, storage, transport, 

processing and disposal of Municipal Solid Waste 

III Specifications for land filling, indicating site selection, facilities at site, 

specifications for and filling, Pollution prevention, water quality 

monitoring, ambient air quality monitoring, Plantation at landfill site, 

closure of landfill site and post care. 

IV Indicate waste processing options including; standards for composting, 

treated lactates and incinerations 

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1.12.6 The Noise Pollution (Regulation And Control) Rules, 2000 


The Union Government has laid down statutory norms to regulate and 

control noise levels to prevent their adverse effects on human health and the 

psychological well being of the people. Under the new regulation, different 

areas and zones are to be identified as industrial, commercial, and residential 

or silence areas and anyone exceeding the specified noise level would be liable 

for action. In industrial areas, the noise level limit during the day time (6 am to 

10 pm) is 75 decibels and during night (10 pm to 6 am) 70 decibels. 

Similarly, for commercial areas day time limit is 65 decibels and night 

limit is 55 decibels. In the case of residential areas, the limits are respectively 

55 and 45 decibels and for the silence zones, 50 and 40 decibels 

1.13 WORLD BANK POLICIES 

Following are the Operation Policy & Directorate of the World Bank. 

1.13.1 Environmental Assessment OP/BP 4.01 

This requires the borrower to screen projects upstream in the project 

cycle for potential impacts. Thereafter, an appropriate EA approach to assess, 

minimize / enhance and mitigate potentially adverse impacts is selected 

depending on nature and scale of project. The EA needs to be integrated in the 

project development process such that timely measures can be applied to 

address identified impacts. The policy requires consultation with affected 

groups and NGOs to recognize community concerns and the need to address 

the same as part of EA. 

1.13.2 Cultural Property - OP 11.03 

Requirements - World Bank’s Operational Policy Note 11.03 which aims 

at preserving and avoiding the elimination of structures having archaeological 

(prehistoric), paleontological, historical, religious and unique natural values. 

Projects that could significantly damage non-replicable cultural properties are 

declined for funding and the Bank will in turn assist protection and 

13


enhancement of cultural properties encountered in the project rather than 

leaving that protection to chance. 

1.13.3 Natural Habitats – OP/BP 4.04 

This policy sets out the World Bank’s policy on supporting and 

emphasizing the precautionary approach to natural resource management and 

ensuring opportunities for environmentally sustainable development. As per 

this policy, projects that involve significant conversion or degradation of critical 

natural habitats are not supported by the Bank. 

1.13.4 Forests – OP/BP 4.36 

This sets out specific policy on protection of forests through 

consideration of forest related impacts of all investment operations, ensuring 

restrictions for operations affecting critical forest conservation areas, and 

improving commercial forest practice through use of modern certification 

systems. The policy requires consultation with local people, the private sector 

and other stakeholders in forest area. 

Pest 

1.13.5 Pest Management - OP 4.09 

This policy supports environmentally sound pest management, including 

integrated pest management, but does not prohibit the use of highly hazardous 

pesticides. Pest Management is the borrower/s responsibility in the context of a 

project’s EA. 

1.13.6 Involuntary Resettlement - OP/BP 4.12 

This policy is implemented in projects which displace people. It requires 

public participation in resettlement planning as part of EA for projects. It is 

intended to restore or improve income earning capacity of displaced 

populations. 

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1.13.7 Indigenous Peoples –OP/BP 4.20 


The purpose of this policy is to ensure indigenous peoples benefit from 

Bank financed developed and to avoid or mitigate adverse affects on indigenous 

peoples. Applies to projects that might adversely affect indigenous peoples or 

when they are targeted beneficiaries. Requires participation of indigenous 

peoples in creation of “indigenous people development plans” 

1.14 LEGAL/REGULATORY CLEARANCES FOR THE PROJECT 

The following are the list of approvals required for the implementation of 

proposed project. 

Land approval 

Consent from Pollution Control Board 

Permission for laying of pipelines for disposal 

1.14.1 Land Approval 

The land belongs to the Thiruvarur Municipality. It was handed over to 

TWAD for the construction of STP in Kekkarai, Thiruvarur District. Hence, the 

land is ready for the construction of STP. 

1.14.2 Consent from Pollution Control Board 

The project has obtained the Consent to Establish from Tamil Nadu 

Pollution Control Board vide Proceedings No. AEE/TNPCB/NGT/F.MIS- 

438/O/L/W/2010/dt.12.08.2010, which is enclosed as Annexure II. The 

compliance status of the special conditions, additional conditions and general 

conditions issued by TNPCB are enclosed in Annexure III. 

1.14.3 Permission for laying of pipelines for disposal 

The treated effluent will be within the prescribed standards. The treated 

effluent from the STP will be discharged through 100m pipe line laid from site 

15


leading to Sukkanar drainage canal which is adjacent to the site. The 

Sukkanar drainage canal leads to Vettar river. 

1.15 AGENCIES RESPONSIBLE FOR PROJECT IMPLEMENTATION 

The agencies responsible for the successful execution of the Project are 

shown in Table 1.1. 

Table 1-1 Agencies responsible for Project Implementation 

S.No Agency Responsibility 

1 Thiruvarur Municipality Project proponent. 

2 Tamilnadu Water Supply and Drainage Project implementing 

Board 

agency. 

3 Hindustan Dorr-Oliver Limited Executing the Project 

Plan. 

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2.1 PROJECT PROPOSAL 

2. PROJECT DESCRIPTION 


Name of the Project : Designing, Providing, Constructing, Erection and 

Commissioning, startup of Sewage treatment 

plant with selected modern Technology at 

Thiruvarur Municipality of Thiruvarur District in 

Tamilnadu on DBOT Basis. 

Project Town : Kekkarai Village, Thiruvarur District, Tamil Nadu. 

STP Capacity : 6.92 MLD 

Technology used : Activated Sludge Process (ASP) 

Project cost : 5.9 crores . 

Land Available : 8.87 Acres 

2.2 LAND REQUIREMENT 

The total land available for the project is about 8.87 Acres. The proposed 

Sewage Treatment Plant will have an intermediate capacity of 6.92 MLD. Based 

on statistical analysis, in future, due to urbanization of the project area, the 

incoming sewage will be higher. Hence the ultimate capacity will be 8.55 MLD. 

The remaining land area will be occupied for storage and provision of 

chemicals, sludge, laboratory, employees shed houses and restrooms, 

remaining areas will be used for developing green belt in and around the site 

premises. The STP layout is given in Figure 2-1. 

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Figure 2-1 Layout of STP 


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2.3 PROCESS DESCRIPTION 


Sewage is collected from all the sources in the receiving chamber. The 

sewage is sent through a series of bar screens. Materials which are greater 

than 20 mm in size are removed from the sewage. Screening prevents the 

clogging of pumps and pipelines. 

First, the sewage is sent through the coarse screen chamber / mechanical 

coarse screen chambers. Here materials greater than 20 mm & 15 mm are 

removed respectively. Then the sewage is sent through operated / automatic 

fine screens to remove materials sized 15 mm & 10 mm. 

From here the sewage is sent to the grit chamber where fine particles like 

sand are removed through sedimentation. The sand being heavier than sewage 

settles down and can be removed. From the grit chamber the sewage is sent to 

the parshall flume chamber. Parshall flumes are used to check the flow in the 

plant. The Screened sewage is then led to the Primary Clarifier tank. The 

excess sludge is sent to the sludge digester tank. The sewage from the primary 

clarifier is then led to the aeration tank. Biological treatment takes place in the 

aeration tank. Air is diffused through air blowers to oxidize organic matters. 

The overflow from the aeration tank is sent to the secondary clarifier. The 

underflow clarifier sludge is returned to the aeration tank for mixing and the 

excess sludge from the secondary clarifier is sent to the Sludge digestor tank. 

The recirculation of the sludge will takes place effectively. In the Sludge 

digestor tank, air is diffused through the sludge for the proper digestion and 

the digested sludge is dosed by poly dosing system. The digested sludge is then 

pumped into the centrifuge through screw pump to separate the solids from 

the treated effluent. The drain out from the Centrifuge is collected in the 

filtrate sludge sump which is then sent back to the receiving chamber through 

filtrate pump. 

The overflow from the secondary clarifier is sent to Chlorine Contact tank 

where Chlorine is dozed through gas chlorinator. The treated effluent from the 

19


Chlorine contact tank is led to the Sukkanar drainage Channel. The schematic 

representation of the process flow is shown in Figure 2.2. 

2.3.1 Sewage Receiver 

Figure 2-2 Process Flow of STP 

Raw Sewage will be delivered through pipe lines at a hydraulic head of 

6.0 m into a receiving chamber from where it will be taken into downstream 

screens. The function of the receiving chamber is to reduce the incoming 

velocity. Receiving chamber shall be of adequate size to meet the requirements 

of workability inside it. The flow from the receiving chamber will lead to screen 

Chamber. 

2.3.2 Primary Treatment 

In primary treatment, a portion of the suspended solids and organic 

matter is removed from the wastewater. The liquid effluent from primary 

treatment, often contains a large amount of suspended organic materials, and 

has a high BOD (about 60% of original). Sometimes, the preliminary as well as 

primary treatments are classified together, under primary treatment. 

The organic solids, which are separated out in the sedimentation tanks 

in the primary treatment, are often stabilized by anaerobic decomposition in a 

digestion tank or incinerated. The residue is used for landfills or as a soil 

conditioner. The principal function of primary treatment is to act as a 

precursor to secondary treatment. 

20

2.3.2.1 Fine Screening 


Fine screens are to be provided for the removal of fine floating material 

coming with the sewage. One is mechanically operated and the other screen is 

provided as standby. The fine screens should be capable to screen out most of 

the medium & fine floating and material such as hair, debris, weeds, paper, 

rags etc. which could clog the downstream units. The Fine screen shall be 

inclined with bar screen. It should be of sturdy design and the bar screen shall 

be of stainless steel flats. The screenings shall be dropped on conveyor above 

the top of the screen channel. A conveyor system of suitable width shall be 

provided which shall be adjacent to the screens. The screening materials as 

collected will drop automatically into a wheelbarrows for its disposal. 

2.3.2.2 De-gritting 

Screened sewage will be gravitable to minimum two numbers of Grit 

separator tank for the removal of grit and small inorganic particulars matter of 

specific gravity above 2.65 and particle size above 150 microns. One is 

mechanically operated and the other is provided as standby. The Grit 

separator tank shall be of RCC construction complete with mechanical 

internals and square in size. The grit separated shall be properly collected and 

be transferred for disposal. The degritted sewage shall flow through open 

channels from the grit separators and confluence into a single channel of 

suitable width. 

2.3.2.3 Flow Measurement 

A Flow measurement unit in the form of ultrasonic flow transmitter 

shall be provided in the common header of the raw sewage Pumps. 

The mechanical screen chamber, mechanical fine screen chamber and 

grit chamber are mechanically operated and the other screens are provided as 

standby. 

21

2.3.3 Secondary Treatment Process 


Screened, de-gritted sewage shall be fed into the Activated Sludge 

Treatment system to meet the treated effluent quality prescribed in Table 2-1. 

The effluent from the secondary biological treatment will usually contain BOD 

of 5 to 10%. The organic solids/ sludge separated out in the primary as well as 

in the secondary settling tanks are disposed of by stabilizing under aerobic 

conditions in a Sludge digestion tank. Any problem in aeration tank will be due 

to diffusers provided in the tank. This can be rectified by lifting the diffusers 

and manually cleaning the blockages. If the blower has any problem, a 

standby blower is also provided in aeration tank. 

2.3.4 Tertiary Treatment 

Tertiary treatment is used to further purify the water contaminants, 

especially pathogens. The level of tertiary treatment performed depends on the 

quality of effluent desired. This is determined by the size of the receiving body 

of water, and the intended use of that water. 

2.3.4.1 Chlorination 

This is the most widely practiced means of disinfecting water. The strong 

oxidizing capacity of chlorine destroys or inhibits the growth of pathogens, 

reduces the BOD, reduces odour, water color and oxidizes metal ions. 

2.3.5 Sludge Handling System 

The sludge from the Treatment Plant shall be collected in a sludge sump 

where it is aerated continuously for mixing. Then the aerated sludge shall be 

passed through mechanical dewatering system. The sludge cake shall be 

transported to the compost yard of Thiruvarur municipality in a safe manner. 

22

2.4 STP PIPELINE AND BYPASS ARRANGEMENT 


The necessary bypass arrangement is provided in the above process as 

follows. Coarse screen chamber, Fine screen chamber & Grit chamber are 

provided with 2 units. Two numbers of shutter arrangements are provided in 

the outlet of the fine screen chamber to grit chamber. This arrangement is 

provided so that the sewage from fine screen chamber moves to either of the 

grit chamber. When one grit chamber is under fault, the other one will operate 

and vice versa. 

When the primary clarifier is under fault, the outlet from the grit chamber 

is taken to the inlet of the aeration tank. Aeration tank is provided with the 

enough cushion to take the load and the sludge settling will be taken care by 

the secondary clarifier. Generally the problem in aeration tank will be due to 

the blockage in diffusers. This will be rectified by cleaning the diffuser by 

washing. The bypass arrangement is made to use when any failure occur 

during the STP functioning. 

In aeration tank, the partition provided will split the aeration tank as two 

parts. If any problem occurs in any one part of the aeration tank, the other part 

will be in full operation. Two lines from the bottom of the aeration tank are 

taken to the sludge tank. The sludge formed in the partition portion under 

failure will be pumped to the sludge digester tank during the rectification 

period. 

When the secondary clarifier unit is under fault, aeration arrangement in 

one of the partition in the aeration tank will be stopped so that the settling of 

sludge will take place in that particular partition. Two lines from the bottom of 

the aeration tank is taken to the sludge tank. A portion of sludge settled 

(activated sludge) as indicated above, will be recycled through pumping to 

common inlet of aeration unit for maintain the plant efficiency. The balance 

sludge will be drawn to sludge digester tank with necessary pumping 

arrangements. The supernatant or treated effluent will be bypassed to the 

23

EIA EIA FOR FOR FOR 6.92 6.92 MLD MLD STP STP AT THIRUVARUR 

chlorination tank. After rectification of secondary clarifier, this aeration tank 

will be working as usual. This may be helpful to send supernatant from 

aeration tank to chlorine contact tank until the secondary clarifier is made in 

ready condition. In chlorine Contact tank where Chlorine is dozed through the 

water through gas chlorinator. The treated effluent from the Chlorine contact 

tank is led to the Sukkanaru. 

Thus, the bypass arrangement provided in STP will be operated without 

shutting down the STP during the failure situation. All the faults can be 

attended in few hours time. In such cases, the above points can be carried out 

for the treatment. The STP is designed to take a peak factor of 2.25 and the 

flow diagram of STP provide with all bypass arrangements is shown in Figure 

2.2. 

. 

24

Figure 2-3 Bypass Arrangement for STP 


25

Figure 2-4 Flow Representation for the Proposed STP 

EIA EIA EIA FOR FOR 6.92 6.92 MLD MLD STP STP AT THIRUVARUR 

26

2.5 RAW SEWAGE CHARACTERISTICS 


The sewage collected from the various chambers is almost of same type. 

The domestic wastewater from the local residential area constitutes the raw 

sewage. The wastewater characterization is presented in Table 2.1. 

Table 2-1 Raw Sewage Characteristics 

S.No. Parameter Values 

1 pH 6 to 6.95 - 

2 Total suspended solids 6.92 mg/l 

3 Bio-chemical Oxygen Demand 180 to 300 mg/l 

4 Chemical Oxygen demand 385 to 600 mg/l 

2.6 TREATED EFFLUENT QUALITY 

Unit of measurement 

The STP is designed in such a way that the treated effluent quality attains 

the limits or even better so as to attain the standards well below given by the 

Pollution control board. 

The parameters to be monitored and to maintain within limits are 

presented in Table 2.2. 

Table 2-2 Treated Effluent Quality 

S.No Parameter Values Unit of measurement 

1 pH 5.5-9.0 - 

2 Total suspended solids 30 mg/l 

3 Bio-chemical Oxygen Demand20 mg/l 

4 Chemical Oxygen demand 250 mg/l 

2.7 DISPOSAL OF TREATED EFFLUENT 

Finally the treated effluent shall be disposed through pipeline of about 

100m to link canal leading to Sukkanar drainage canal. The grit and waste 

from the screens and sludge will be stored in the project site and will be 

disposed to Thiruvarur Municipal Compost Yard at regular intervals. 

27

3.1 METHODOLOGY 


3. BASELINE ENVIRONMENTAL DATA 

The baseline environmental status with respect to various environmental 

components like air, noise, water, land, flora & fauna and socio-economic, 

being integral part of an EIA, forms the basis for predicting/assessing the 

environmental impacts of the proposed project. Field monitoring at site was 

performed for the month of April 2010, representing the post-monsoon season. 

Various environmental components were monitored and samples were 

analyzed. Apart from this, additional data were also collected from secondary 

sources like Government/Non-Governmental Agencies, Universities, Irrigation 

Department, India Meteorology Department, Ground Water Board, etc. 

3.2 BRIEF DESCRIPTION OF THE PROJECT SITE 

The Thiruvarur Sewerage scheme plan is shown in Figure 3.1. The 

satellite imagery of 10 Km radius is shown in Figure 3.2. The nearby 

residences are located with a distance of about 2 km from the site. The 

surrounding features in and around the project site is shown in Table 3.1. 

Table 3-1 Surrounding Features of the Project Site 

S.NO Surrounding Features Distance from 

Project Site 

Direction with 

respect to 

project site 

1 Government Boys School 2.8 Km SW 

2 Palani Andavar Temple 2 Km S 

3 Oxford Convent 3.5Km SW 

4 Thiyagaraja Temple 2.5 Km SW 

5 NH 83 5.9 Km S 

6 SH 202 20 Km SW 

7 State Highway 23 5.6 Km N 

8 Residences 2 Km SW 

28

PS III 

Kulundankula 

m 

Figure 3-1 Surrounding features around Project site 


29

Thiruvarur-kodavasal-kumbakonam road 

Thruvarur-Mannagudi road 

Oxford convent 

Thiruvarur Thiyagarajar 

State Highway 23 

Palani Andarar Temple 

Govt Boys School 

State Highway 148 

Nagappattinam-Trichy-Karur-Coimbatore-Mettupalayam-Ooty-Gundlupet road 

Figure 3-2 Satellite Imagery of the Project Site - 10 Km Radius 


C oa rse Scre en 

C ha m ber (T102A/B) 

G rit Ch am b er 

(T1 0 4A ) 

Mec ha nica l 

M anu al Man u al 

Me chan ical 

Fin e Scree n 

C ha mb er (T1 0 3A /B) Sc rew Pu mp 

Re ceiving 

Cha mbe r (T101) 

Grit C ha m ber ( T10 4 B) 

Primary 

Clarifier tank 

(T105) 

Administration Block 

3'0" x 7'0 " 

(0 .9 0 x 2.1 m) 

230 wall 

Primary Sludge 

Pump - 2 nos 

Aeration tank (T106) 

Size: 15.0m x 6.0 m x 4.5m ht 

D 

D 

W 

Admin Building 

W 

Cum 

Lab 

E lectrical R oom 

Air Blower - 3 nos 

1 0 # @ 150 c/c 

10 # @ 150 c/c 

Secondary Clarifier tank (T107) 

Air Blo wer - 2 nos 

INTERNAL 

ROAD 

Screw Pump - 3 nos 

Chlorine Contact 

tank (T109) 

Sludge 

digestor tank 

(T108) 

Secondary Sludge 

Pump - 2 nos 

Filtrate 

Slu d ge Su mp 

Cen trifug e 

H ou se 

INTERNAL 

ROAD 

ROAD 

W 

Filtrate Pump - 2 nos 

Size: 6m x 6m x 5m ht 

Chlorine T onner Room 

W W 

D 

INTERNAL 

ROAD 

30

3.3 CONNECTIVITY 

120 km. 

EIA EIA FOR FOR 6.92 6.92 MLD MLD MLD STP STP AT THIRUVARUR 

Airport - The nearest airport to the town is in Trichy at a distance of 

Railway – The town is well connected with railways. It serves as a 

railway junction for Thanjavur- Nagapattinam and Chidambaram- 

Pattukkottai railway sections. 

Roads 

National Highways State Highways 

NH 45 A - Villupuram-Tiruvarur SH 23 Mayiladuthurai - 

NH 67 - Tiruvarur-Coimbatore- 

Mysore Road 

NH 68 - Nagapattinam- 

Coimabtore- Gudalur-Mysore 

Road 

3.4 LAND USE 

Thiruthuraipoondi Road 

SH 63 Thanjavur - Mannargudy - 

Thiruthuraipoondi - Vedaranyam - 

Kodiakkarai Road 

SH 65 Thiruvarur - Kodavasal - 

Kumbakonam Road 

SH 66 Kumbakonam - Mannargudi 

- Athirampattinam Road 

SH 67 Nagoore-Nanilam-Nachiyar 

Koil Road 

SH 146 Mannargudi - Pattukkottai 

- Sethubhavachatram Road 

SH 147 Kumbakonam - Karaikal 

Road 

SH 151 Kilvelur - Katchanam Road 

Existing land use in Tiruvarur town, as per Master Plan 2001, is given 

in the table below 

Table 3-2 Existing land use of Thiruvarur Town 

Land use Developed % to Total 

Area (in Ha) Area 

Residential 436.75 38.5 

Commercial 55.90 5.0 

Industrial 14.43 1.5 

Educational 16.09 1.5 

Public & Semipublic 

5.60 0.5 

31

Transportation 80.51 7.0 

Total 

Developed Area 

609.29 54.0 

Agriculture 393.09 34.5 

Water Bodies 132.05 11.50 

Total area 1134.43 100 


Developed area constitutes around 54% of the total area of the town. Of 

total developed area of the town, about 72% of the land is under residential 

use and 14% under public and semi-public uses, which includes land under 

transportation also. Land under industrial use constitutes only 2.4% 

reflecting that there are no major industrial activities in the town. 34% of 

the total area of the municipality is under agriculture. 

Existing land use in Tiruvarur Local Planning Area (excluding Tiruvarur 

town), as per Master Plan 2001, is given in the table below 

Table 3-3 Land use distribution in Tiruvarur Local Planning Area 

Land use Developed % to Total LPA 

area (in Ha) area 

Residential 769.31 10.00 

Commercial 4.85 0.06 

Industrial 93.89 1.00 

Educational 4.70 0.04 

Public & Semi-public 102.58 1.20 

Transportation 119.59 1.50 

Developed Area 1094.74 13.80 

Agriculture 6292.80 79.60 

Water Bodies 510.87 6.60 

Total area 7898.41 100 

Developed area constitutes around 14% of the total planning area. 

Residential use constitutes 70% of the total developed area of LPA, excluding 

town. Land under industrial use forms 8.5% of the total developed area of 

LPA, excluding town. The proportion under industrial use is high due to 

presence of ONGC establishments in the Planning Area. Land under 

agriculture is about 80% and under water bodies is 6.6%. 

Tiruvarur town being district headquarters is expected to grow at a 

rapid pace in the future. There are possibilities for setting up of more public 

offices in this town. Trend of migration is expected to go up. Keeping all 

32


these considerations in mind, vacant lands within developed area and dry 

lands are drawn under residential use zone. 

Table 3-4 Proposed Land Use Plan 

Land use Tiruvarur Town Tiruvarur LPA 

(excluding Town) 

Requirement 

(in Ha) 

% to 

Total 

Area 

Requirement 

(in Ha) 

% to 

Total 

Area 

Tiruvarur LPA 

Requirement 

(in Ha) 

% to 

Total 

Area 

Residential 664.80 58.00 1385.00 17.50 2049.00 23.00 

Commercial 65.50 6.00 6.30 0.10 71.80 0.80 

Industrial 11.50 1.00 135.00 1.70 146.50 1.60 

Educational 17.00 1.50 4.70 0.05 21.70 0.20 

Public & 

Semi-public 

(including 

Transportati 

on) 

90.00 8.00 308.40 3.80 390.40 4.20 

Agriculture 285.63 25.50 6067.01 76.85 6353.34 70.20 

Total 1134.43 100.00 7898.41 100.00 9032.84 100.00 

3.5 RAINFALL & CLIMATE 

The district receives rainfall from both during southeast and northeast 

monsoons. The normal annual rainfall in the district ranges from 1100 to 

1260 mm. It gradually increases towards east and south and attains a 

maximum around Thiruvarur in the eastern part. It is observed that the 

chances of receiving normal annual rainfall vary from 40% at 

Needamangalam to 51 % at Thiruthuraipoondi. These changes are the 

highest (50-55 percentage) in a small area around Thiruthuraipoondi in the 

eastern part. In the rest of the district these chances are in the range 40-50 

percentages. 

The district has a hot tropical climate the summer season, which is very 

oppressive, is from March to about the end of May. The humidity is 

generally high in the coastal region throughout the year and exceeds 70 

percentages during period from August to May. It is much drier towards the 

interior of the district. 

3.6 GEOLOGY 

Thiruvarur district is made up of tertiary and alluvial deposits. The 

cuddalore sand stones of tertiary age are well developed as seen near 

33


mannargudi. These sand stones are covered by a thin layer of windblown 

sandy clays, unconsolidated sands, clay bound sands and mottled clays 

with liginite seams. This tertiary formation is invariably capped by laterite. 

The alluvial deposits of the river cauvery and its tributaries lie over the 

tertiary sand stone. They consist of medium to firm sands, clays and sandy 

clays. The thickness of these formations range from 30m to 400m. 

3.7 AIR ENVIRONMENT 

Figure 3-3 Geology Map of Thiruvarur District 

Pollutants / contaminants discharged into the atmosphere with 

consequent impact on air environment have to be taken into consideration 

for the review of the present and future impact study. It governs the 

concentration of pollutants and varies with time and location with respect to 

their sources. 

3.7.1 Sampling Location and Rationale 

The identification of the sampling stations is based on the sensitivity 

of the location, distance and direction with respect to the proposed project 

site. The location of sampling stations are given in Table 3-7. 

34


The fine samplers PM 10 were placed at height of 2.5 m above the 

ground level, free from obstructions. Samples were collected for various 

parameters at hourly intervals. The collected samples were shifted to HECS 

laboratory through standard chain of custody norms and practices and they 

are analyzed according to the Standards prescribed by Indian Standards 

(IS). 

S. 

No. 

Table 3-5 Mode of collection of Ambient Air Quality Parameters 

S.No Parameters Absorbing solutions/ 

Filter paper 

1 PM 10 Whattman glass fiber 

filter paper 

2 SO2 Sodium tetra chloromercurate 

3 NOx Sodium Hydroxide 

Instrument 

Fine sampler PM 10 

Respirable dust 

sampler/Enviro Tech 

Respirable dust 

sampler/Enviro Tech 

Table 3-6 Techniques used for Ambient Air Monitoring 

Parameters Technique Technical Protocol Minimal 

Detectable 

Limit (µg/ m3 ) 

IS: 5182 part 3 1970 >1 

method 

IS: 5182 part 2 2001 0.1 

1 PM 10 Gravimetric 

2 SO2 p-Rosaniline 

method 

3 NOx NEDA method IS: 5182 part VI 

1975 

3.7.2 Data Inference 

0.01 to 1.5 

All the Ambient Air quality monitoring is under the category of 

commercial and industrial zone. The locations were selected based on the 

wind direction, taking into the consideration of one location in the up wind 

direction and 5 locations in the down wind direction. In all the locations the 

observed values of PM 10, SO2, & NOX are within the prescribed limits of 

CPCB. The detailed air quality data are given in the Table 3-8. 

35

Table 3-7 Air Sampling Locations 


Location 

Code 

Location 

Distance w.r.to project 

site (km) 

L1 Project site --- 

L2 

Bore well near the proposed 

site 

0.05 E 

L3 

Near Keekarai Govt. 

Elementary School 

2.8 SW 

L4 Near Keekarai Post Office 1.5 SW 

L5 Near Keekarai Railway Gate 2.5 SW 

L6 

Near Keekarai Pumping 

Station 

3 SW 

Table 3-8 Ambient Air Quality Data 

Date Location Gaseous Pollutants, 

µg/m 3 

PM10 SO2 NOx 

12.04.10 Project Site 16 9.6 12 

12.04.10 Bore well near STP 42 11 

14 

12.04.10 Near Keekarai Govt. 

Elementary School 

35 10 13 

12.04.10 Near Keekarai Railway Gate 56 9.6 12 

6.2.2010 Near Keekarai Post Office 55 9 10 

6.2.2010 Near Keekarai Pumping 

Station 

60 11 12 

NAAQ Norms* 100 80 80 

Legend: PM10 –Particulate Matter 10; SO2- Sulphur dioxide; NOx- Oxides of Nitrogen 

* NAAQ Norms-National Ambient Air Quality Norms Stipulated by CPCB 

The PM10 concentration was found between 16 – 60 µg/m3. The SO2 

concentration was between 9 – 11 µg/m3 and the NOx concentration was 

observed between 10 – 14 µg/m3. The observed AAQ values in the study 

area are found to be within the limits of CPCB norms. 

3.8 Noise Environment 

The main objective of noise monitoring in the study area is to establish 

the baseline noise levels and assess the impact of the total noise generated 

by the operation of the proposed project activities around it. The noise level 

has been monitored from 12.00 hours to 18.00 hours and their results are 

shown in Table 3-9. 

36

Date: 15.12.09 

Table 3-9 Noise Level Data Sheet 

HOURS NOISE LEVEL (dB) 


10 20 30 40 50 60 Average 

min min min min min min 

12.00 45.3 43.6 45.2 48.2 45.6 48.2 46.2 

13.00 40.2 41.5 46.9 45.9 40.5 41.9 42.8 

14.00 40 55.4 51.2 46.3 54.2 54.2 50.8 

15.00 42.6 50.2 49.5 41.2 56.2 54.2 50.1 

16.00 41.2 42.5 43.2 50.2 42.5 46.2 44.5 

17.00 46.3 41 43.3 51.2 41 41.3 44.0 

18.00 42.6 42.2 54.9 57.5 45.2 54.9 50.1 

The project site is classified under residential zone. The noise level in 

the project site shows that the area is void of any noise. The noise level is 

well within the permissible standards prescribed by TNPCB. The maximum 

noise level is 50.8 dB (A). 

Table 3-10 CPCB standards for Noise 

Limits in dB (A) Leq 

Category of Area Day Time Night Time 

Industrial Zone 75 70 

Commercial Zone 65 55 

Residential Zone 55 45 

Silence Zone 50 40 

3.9 WATER QUALITY 

3.9.1 Selection of Sampling Locations 

The assessment of present status of water quality within the study 

area was conducted by collecting water samples from ground water sources 

(Hand Pumps) during the period of April 2010. The sampling locations have 

been identified on the basis of their importance. The identification of the 

sampling stations is based on the sensitivity of the location, distance and 

direction with respect to the proposed project site. 

Details of ground water locations, their distance and direction from 

the proposed plant site are presented in Table 3-11. The locations were 

37


selected based on the vicinity of the treatment plant, to establish the 

existing base line water quality. 

Table 3-11 Sampling Locations in the Study Area 

Location 

Code 

Location 

Distance w.r.to project 

site (km) 

W1 Proposed site for STP --- 

W2 Borewell Near STP 

Near STP (Kekkarai)Bridge 

0.05 E 

W3 (Downstream point of 

Sukkanar) 

0.5 NE 

W4 

Near Kekkarai Govt. Elementary 

School 

2.8 SW 

W5 Near Kekkarai Post Office 1.5 SW 

W6 Near Kekkarai Railway Gate 2.5 SW 

W7 Near Kekkarai Pumping Station 3 SW 

3.9.2 Methodology 

The samples were analyzed for selected physico-chemical parameters 

to establish the existing water quality of the study area. Samples were 

collected, preserved and analyzed as per the methods given in Standard 

Methods for the Examination of Water and Wastewater (APHA and WPCF 

2000). 

38

Table 3-12 Ground Water Quality in Project Site 


S.No Parameters Units W1 W2 W3 W4 W5 W6 W7 

1 Color Hazen


S.No Parameters Units W1 W2 W3 W4 W5 W6 W7 

19 Manganese mg/l as Mn

W4 

3.9.3 Observations 


The analysis of the results indicates that the average pH ranges 

between7.13 - 8.02. TDS ranges from 1030 to 1480 mg/L. Total hardness 

ranges from 57 to 67 mg/L. The chloride values ranges from 176 to 514 

mg/L. The ground water quality data is given in Table 3-12. The sampling 

locations of water are shown in Figure 3.3. 

3.9.4 Inference 

The water analysis shows that the quality of the water in the study 

area is fine and free from contaminants. 

W7 

3.10 SOIL QUALITY 

W5 

W6 

W3 

Project Site 

W1 W2 

Figure 3.3 Satellite Image showing sampling locations for water 

Figure 3-4 Water Sampling Locations 

The soil sampling locations were identified to assess the fertility and 

agricultural characteristics of the soil and also to assess the impact of the 

sludge leachate in the immediate surroundings. The sampling location has 

W8 

41


been located 50 m randomly around the project site and is given in Table 3- 

13. The identification of the sampling stations is based on the sensitivity of 

the location, distance and direction with respect to the proposed project site. 

Table 3-13 Soil Sampling Stations 

Location 

Location 

Distance w.r.to 

Code 

Project Site (m) 

S1 Project Site - 

S2 Towards East 

(disposal site of sludge) 

50 m 

S3 Towards West 50 m 

S4 Towards South 50 m 

S5 Towards North 50 m 

S6 Towards North East 

(disposal site of sludge) 

50m 

S7 Towards South West 50 m 

3.10.1 Methodology 

The soil samples were collected in the above mentioned stations 

during the study period for analysis. The samples collected from all 

locations are homogeneous representative of each location. At random, 7 

sub locations were identified at each location and soil was dug from 30 cm 

below the surface. It was uniformly mixed before homogenizing the soil 

samples. The samples were filled in polythene bags, labeled in the field with 

number and site name. The soil samples collected were transported to 

laboratory for further analysis. Soil sampling and analysis is done based on 

the method of sampling and analysis: 1978 Annual Book of ASTM 

Standards IS 2720 Part I 1983. 

3.10.2 Observations 

The analytical results of soil in and around the study area are given in 

Table 3-14. Since the district is represented by Cauvery Deltaic Zone, sandy 

coastal alluvium is the predominant soil type in this district accounting for 

56.78% and other types of soil cover 43.22% of the total area. 

42

Figure 3-5 Photographs during field survey 


43

3.10.3 Inference 


These soils are dark, low in organic matter, calcareous, neutral to 

moderately alkaline (pH 7.0 to 8.5) and high in clay content. Hence, they 

exhibit the characteristic cracking during dry periods. They are usually 

located in gently sloping to nearly level lands. The levels of potassium and 

calcium are moderate and those of nitrogen and phosphorus, low. 

S.N Paramete 

o rs 

1 Textural 

Class 

Table 3-14 Soil Quality data 

Units S1 S2 S3 S4 S5 S6 S7 

- Browni 

sh 

Dark 

Sand 

Browni 

sh 

Dark 

Sand 

Browni 

sh 

Dark 

Sand 

Browni 

sh 

Dark 

Sand 

Browni 

sh 

Dark 

Sand 

Browni 

sh 

Dark 

Sand 

Browni 

sh 

Dark 

Sand 

2 Silt & Clay % 31.5 32.3 31.7 32.8 32.0 31.7 32.3 

3 Sand % 61.8 61.8 62.5 61.4 61.5 62.7 62.1 

4 pH of 10% 

Solution 

- 7.77 7.5 8.0 7.9 8.2 8.1 8.3 

5 Bulk 

Density 

g/cc 0.94 0.96 0.99 0.98 0.95 0.94 0.96 

6 Conductivi Ohm 121 117 130 128 136 133 138 

ty 

/cm 

7 Moisture 

Content 

% 25.1 23.1 25.6 26.4 25.4 26.9 25.4 

8 Organic 

matter 

% 2.5 2.6 2.9 2.7 2.8 2.5 2.6 

9 Nitrogen % 0.33 0.36 0.32 0.39 0.36 0.35 0.33 

10 Phosphoru 

s 

% 0.23 0.27 0.23 0.28 0.25 0.27 0.24 

11 Potassium % 0.04 0.03 0.02 0.03 0.03 0.02 0.04 

12 Oil & 

Grease 

% BDL BDL BDL BDL BDL BDL BDL 

3.11 SOCIO-ECONOMIC DATA 

Information about demography and socio-economic profile was collected 

from the District Census Hand look (1991) (District - Thiruvarur, Tamil 

Nadu and census CD 2001, Tamil Nadu). The census data available for 

different blocks, taluks and towns have been analyzed with respect to 

demographic profile, community structure, educational facilities, occupation 

structure and infrastructure facilities. 

44

3.11.1 Demography 


The population details in the district with male & female classification 

as per 2001 and 2011 census are shown in Table 3-15 and Figure 3-6.. 

The decadal growth rate from 2001 to 2011 is 8.43 % 

Table 3-15 Population Statistics 

S.No Description 2001 Census 2011 Census 

Male Female Male Female 

1. Population 580784 588690 627616 640478 

2. Rural 

Population 

3. Urban 

population 

3.11.2 Literacy 

463502 468729 500543 508868 

117282 119961 127073 131610 

Figure 3-6 Population Distribution of Thiruvarur District 

The number of literates and the literacy rate are given in Tables 3-16 

& 3-17 respectively. 

45

Table 3-16 Literacy Statistics 




1. Population 435421 352881 510137 449899 

2. Rural 

Population 

3. Urban 

population 

340202 268095 401896 346672 

95219 84786 108241 103227 

Table 3-17 Literacy of Thiruvarur District 

Table 3-18 Literacy Rate of Thiruvarur District 



1. Population 85.43 67.90 89.65 77.02 

2. Rural 

Population 

3. Urban 

population 

83.81 64.92 88.53 74.69 

91.79 79.44 94.10 86.05 

46

3.11.3 Land use Pattern 

Figure 3-7 Literacy Rate of Thiruvarur District 


The total geographical area of the district was 2,811.36 sq. Km. in 

1995-96. Cropped area accounts for 81% of the total area. Forest cover is 

very minimum accounting for only about 1% of the total area. A significant 

portion of the land falls under the category of ‘non available for cultivation’ 

and ‘fallow lands’. Land use Pattern of the Thiruvarur is given in Table 3-19 

and Figure 3-3. 

Table 3-19 Land use Pattern 

Land Use Pattern Area in Ha 

Forest 2452.000 

Uncultivable waste 113.000 

Non - Agriculture use 37079.089 

Cultivable Waste land 1737.700 

Permanent Pasture and Grass land 785.665 

Misc tree crops & Groves 2189.078 

Current fallow 2139.161 

Other fallow 7973.985 

Net Cultivated Area 155239.522 

Total 209709.200 

47

3.11.4 Agriculture 


Figure 3-8 Land Utilization Pattern of the Thiruvarur 

This district is essentially a deltaic plain comprising of old and new 

delta. Hence the district abounds in green paddy fields, tall coconut groves, 

and vast gardens of mango and plantain tree and other verdant vegetations. 

Paddy is the main crop of this district and it is grown three times in a year. 

The first crop is known as 'Kuruvai' (the short-term crop) with duration of 

three and half to four months from June - July to October - November. The 

second crop called the 'Thaladi' has duration of five to six months from 

October - November to February-March. Third is the 'Samba' (the long term) 

crop and has duration of almost six months from August to January. Other 

cereal crops of the district are cumbu, ragi, maize, korra and varagu. The 

pulses grown in the district are redgram, greengram and blackgram. Other 

food crops are condiments and species, sugar cane, fruits and vegetables. 

48


Among nonfood crops, cotton/fibre, edible oil crops (groundnut, gingelly and 

coconuts) non-edible oils crops (castor, miger seeds, though in very small 

area) are the important ones. The agriculture in the district is given in Table 

3-20. 

Table 3-20 Agriculture in the District 

Total Cultivated Area (Hec) 237715 

Net Area Sown (Hec) 153227 

Area Sown more than once 84488 

Area and production of principal Area (Hec.) Production 

crops 

( Tonnes) 

Rice 156 243 

Pulses 65 22 

Sugarcane (Gur) 4 4 

Groundnut 1 7 

Gingelly 2 0.7 

Cotton (BL) 3 1 

Agricultural Land Holdings (1995-96) 

Holdings 167878 

Area (Hec) 151702 

Average Size of Holdings 0.903 

Important Food Crops Rice, Greengram, Blackgram 

Important Non Food Crops Cotton, Groundnut, Coconut, Gingelly, 

Palm, 

Flowers, Oil seeds 

The cropping calendar is given in Figure 3-9 

49

3.11.5 Irrigation 

Figure 3-9 Cropping Calendar 


The main sources of irrigation in Thiruvarur region are Canals, Tanks 

and Wells. Tanks and Wells are not used in some blocks for irrigation in the 

district. The total area irrigated by canals, tanks, wells and other sources is 

1, 46,245 Hectares. The gross area irrigated by canals, tanks and wells are 

50


97,867 Hectares, 7,250 Hectares and 1,374 Hectares respectively. Therefore 

canal irrigation constituting 66.99% of the total cropped area remains the 

predominant source of irrigation. On an average about 64.62% of the total 

cropped area is irrigated. 

3.11.6 Animal Husbandry and Fisheries 

Animal Husbandry could not keep pace with the development works 

undertaken in the field of latest agricultural techniques and so the district 

cannot boast of any special breed of cattle and the indigenous cattle still 

continue to be of poor quality. Of late, cattle development has taken place 

through setting up of an intensive cattle development project. Apart from 

the cattle and buffaloes, goats, sheep and pigs are other important livestock 

found in the district. The livestock census, 2004 is shown in Table 3-21. 

Table 3-21 Livestock Census 2004 

Livestock Numbers 

Cattle 332022 

Buffaloes 56666 

Sheep 16050 

Goat 375318 

Poultry 255845 

The coastline of this district is around 47 Km and there are around 14 

Coastal centers in this district. The details of fishery production are given in 

Table 3-22. 

Table 3-22 Fishery Production 

Marine fish production 

(tonne) 

2500 

Inland fish production (tonne) 8700 

No. of fisherman engaged 

(Marine/In land) 

3973 / 3802 

3.11.7 Mineral Resources 

There are no mineral reserves that have been proved to be available in 

the district. 

51

3.11.8 Industries 


The district has been a flourishing centre of cottage industries. Mats 

made of korai, screw pine, palm and coconut leaves are much in demand. 

The mat weaving is spread over in a number of places, but the superior 

varieties of mats are made in Mudukkur. The district is also famous for 

safety matches. The district is equally well known for its pith articles 

consisting of beautiful models of Hindu idols, temples, mosques, flower 

garlands, bouquets, parrots etc. Pith is grown on the beds of tanks in 

Mannargudi. Tiruvarur is known for the manufacture of musical 

instruments of Jack wood like the Veena, Tambura, Violin, Mridangam and 

Kanjara. The details of large scale industries in the district are given in 

Table 3-23. 

Table 3-23 Industries in the district 

S. 

No 

Name of the Industries Capacity Line of activity Employment 

1. Tamilnadu Civil Supplies 92 M.T. Modern Rice 52 Nos. 

Corporation, Modern Rice 

Mill, Tiruvarur 

Milling 

2. Tamilnadu Civil Supplies 100 M.T. Modern Rice 60 Nos. 

Corporation, Modern Rice 

Mill,Sundarakottai 

Milling 

3. South India Edible Oil, 125 TPD Palm Oil 20 Nos. 

Karuppur, Tiruvarur 

Refinery 

4. Pamani Fertilizers, 120 TPD Fertilizers 100 Nos. 

Mannargudi 

Manufacturing 

5. Southern Energy 39 M.W. Power 

10 Nos. 

Development Corporation, 

Nallur, Mannargudi Taluk 

Generation 

6. T.N.E.B. Power Plant, Koil 107 MW Power 

125 Nos. 

Kalapal, Kottur Block 

Generation 

3.11.9 Education 

The literacy level of Tiruvarur district according to figures available for 

the year 1996 is 54.99% with male literacy level being more than the female 

literacy level. It is also observed while the male literacy level has grown 

steadily from 63.44% in 1981 to 64.67% in 1996, there has been a 

significant increase of female literacy level from 38.51% in 1981to 45.01% in 

52


1996. The information on the list of educational institutions is given in 

Table 3-24. 

3.11.10 Work Force 

Table 3-24 List of Educational Institutions 

S.No. Institution Numbers 

1. Primary Schools 696 

2. Middle Schools 190 

3. High Schools 70 

4. Higher Secondary Schools 56 

5. Engineering Colleges 2 

6. Arts and Science Colleges 7 

7. Technical Institutions 3 

8. Music School 1 

9. Teacher Training Schools 2 

Table 3-25 presents details on workforce in the district. While the 

rural workers are employed in agriculture and allied activities, the urban 

workforce is employed in industries. 

Table 3-25 Workforce in the District 

Workers Number Percentage 

Total Workers 386956 100 % 

Male workers 282611 73.03 % 

Female workers 104345 26.97 % 

Rural workers 320502 83.83 % 

Urban Workers 66454 16.17 % 

3.11.11 Medical and Health Facilities 

district. 

Table 3-26 presents the medical & health care facilities in the 

Table 3-26 Health care facilities in the District 

Modern Medicine 

No. of Government Hospitals 8 

Primary Health Centres 39 

Health Sub Centres 195 

Panchayat Union Dispensaries 10 

Rural Dispensary 23 

53


Beds in Hospitals & Dispensaries 648 

Total No. of Doctors 76 

Total No. of Nurses 224 

Indian Medicine 


Primary Health Centres 7 


Homeopathy Medicine 



54


4. PREDICTED IMPACTS AND MITIGATION MEASURES 


When identifying the potential impacts of a new project on the existing 

environment, such as the proposed Sewage Treatment Plant at Thiruvarur, 

it is necessary that it should be measured against the existing baseline 

conditions. Construction of sewer line with sewage treatment plant and 

there after operation of this system, if undertaken without a proper 

understanding of the relationships inherent in environmental function, can 

be accompanied by disruptions to the environment, from which it may take 

a long time to regain equilibrium. In human terms, this may mean that 

generations must function in a debilitated environment and suffer many 

possible associated socio-economic hardships and financial losses. 

Some of the major environmental impacts of sewerage system include 

damage to local ecosystems, loss of productive agricultural lands, 

demographic change, accelerated urbanization, and introduction of disease. 

The need of development and growth in the area must be matched with the 

conservation of the existing natural resources. 

In general, construction of a new sewage treatment plant will have a 

positive environmental impact on the town. It is expected to produce a long 

term improvement in public health of the residents Thiruvarur as well as to 

significantly reduce a source of chronic water pollution of an ecologically 

valuable portion if the water body where the sewage drains. 

4.2 IMPACT EVALUATION 

4.2.1 Air Quality 

This section presents an assessment of air quality impacts associated 

with the construction and operation of the proposed STP activity at Kekarai, 

Thiruvarur, Tamil Nadu. Major sources of air pollution have been identified 

namely construction dust emission and road traffic emissions. The sources 

of air pollutants at the different phases of the development are categorized 

as follows: 

55


• Construction Phase: Construction works include site clearance, 

site formation, STP units & administration building works. The 

major temporary air pollution is dust generated as a result of these 

construction works. Cutting and welding operation, loading- 

unloading, operation is mainly responsible for the release of SPM, 

SO2, NOx, etc. However the overall impact may be rated as direct, 

short-term, adverse, and reversible. 

• Operational Phase: The primary emission sources during the 

operations phase would include compressor and pumping station 

operations, vehicular traffic, carbon dioxide and a small quantity 

of Hydrogen sulphide may be produced in Aerobic Tank. 

4.2.2 Noise Quality 

The noise quality around the proposed site area is under the 

permissible limit. 

• Construction Phase: The construction of the proposed sewage 

treatment plant may generate noise during the constructional 

phase due to activities of loading unloading, material handling and 

machine operation equipment & vehicular movement. Impact of 

noise level may be categorized as direct, short-term, adverse, 

reversible and of low to moderate magnitude. 

• Operational Phase: The main sources of noise during the 

operations phase would include compressor and pumping station, 

producing wells (including occasional flaring), and vehicle traffic. 

The noise levels from the pumping stations may between 64 - 86 

dBA or between 58 - 75 dBA at about 1 mile (1.6 kilometers ) from 

the station. Other noise pollution during operation would be 

generated by other mechanical equipment, and sludge dewatering 

units. 

56

4.2.3 Odour Problems 


• Operation Phase - Inlet chamber, grit channels, screening and grit 

handling, aeration tanks, and sludge holding and dewatering units 

are the main sources of odor at the Sewage treatment plant. 

4.2.4 Water Quality 

• Construction Phase - The construction of the proposed sewage 

treatment plant will facilitate improvement of water quality in and 

around the site by avoiding the unhygienic disposal of the raw 

sewage in the vicinity. 

• Operational Phase: There will not be any adverse impact on the 

4.2.5 Soil Quality 

ground water quality since the treated effluent will be within the 

standards prescribed by the CPCB / TNPCB. 

• Construction Phase - Topsoil shall be stripped to a depth of 200 

mm from areas proposed to be occupied by buildings, roads, 

paved areas and external services. 

4.2.6 Solid Waste Handling 

• Construction Phase - Solid waste generated during site 

preparation and construction work would include cut vegetation 

and typical construction waste (e.g. wasted concrete, steel, 

wooden scaffolding and forms, bags, waste earth materials, 

etc.). This waste would negatively impact the site and 

surrounding environment if not properly managed and disposed 

of at an approved dumpsite. 

• Operation Phase – Grit, screenings and the sludge generated 

from the treatment plant will be the major source of solid waste 

generation. 

57

4.2.7 Cultural and Socio-Economic Impacts 


• The construction of proposed sewage treatment plant is a mark 

beneficial socio-economic aspect since it leads to safe and 

hygienic disposal of the treated effluent. 

• It enhances the existing environment as the untreated raw 

sewage disposal will be ceased. 

• Also, the project will provide employment to the people during 

the constructional and operational phase hence creating a 

positive impact due to this project. 

4.2.8 Outfall location and design 

• The domestic waste collected from the residential area of 

Kekarrai is discharged into Sukkanar drainage canal after 

treatment which is located around 3 km from the STP site. The 

Sukkanar is declared as drainage canal which drains into Vettar 

River. 

• The dissolution of treated effluent in the Sukkanar as well as in 

Vettar River minimizes the impact. As the sewage is discharged 

after treatment, the treated effluent quality will be within the 

standards prescribed by TNPCB. 

• The water can be used for irrigation. 

4.3 PROPOSED MITIGATION MEASURES 

4.3.1 Air Quality 

• The fugitive emissions and dust from the proposed site during 

construction phase can be reduced by sprinkling of water. 

• The release of volatile organic compound, Carbon di oxide and H2S 

may take place during the operational phase which will be 

mitigated by implementing Environmental Management Plan. 

58


• The power requirement during the operation of STP will be 400 

KVA. DG sets are operated only during power failures and the D.G 

sets are proposed to provide 200 KVA as required suitable power 

back up to run the plant. The emissions from the D.G sets will 

have marginal impact on the existing air quality, however adequate 

Stack height of 10 m is provided as per the CPCB norms to combat 

the effect on the air quality and also to facilitate proper dispersion. 

• Steps will be taken to create environmental awareness for the 

commuters so that the vehicles will be maintained properly in turn 

will not have any impact due to the vehicular emissions. 

4.3.2 Noise Quality 

• It can be mitigated by restricting the vehicular movement only 

during the day time. 

• Noise problems shall be reduced to normally acceptable levels by 

incorporating low-noise equipment in the design and/or locating 

such mechanical equipment in properly acoustically lined 

buildings or enclosures. 

• The minimum distances between units are proposed to be 3m and 

adequate greenbelt is proposed in an area of about 2134 m 2. 

Adequate care will be taken to maintain the noise levels within the 

prescribed limits 

• The greenbelt is provided along the periphery of the STP. The 

nearest residential development is about 1.8 km from the periphery 

of the STP and the sensitive areas such as temple and school are 

located at a distance of more than 2 km. The attenuation by the 

proposed greenbelt will be more than the adequate to maintain the 

noise level well within the prescribed standards by CPCB. 

59

4.3.3 Odour Problems 


• Odour can be reduced or prevented through continuous process of 

the operation. The grit and screenings will be cleaned twice a day 

to facilitate normal flow of the water. The sludge developed in 

Clarifier and Aeration tank will be removed and part re-circulated 

to maintain the MLSS around 3000 mg/L as per field 

requirements. 

• Surplus sludge will be pumped to the Sludge digester and to the 

Centrifuge for making Sludge cakes and subsequent disposal to the 

Compost yard. 

• Thick shrubs and the trees along the periphery and in between the 

STP units will help in mitigating the odour from the site. 

• Fly and Mosquito breeding is not envisaged since there will not be 

any stagnation of water inside the plant area. 

• The odour impacts to the community are expected to be minimal. 

There is no significant habitation around 1 km from the proposed 

site and there will not be any impact. 

4.3.4 Water Quality 

• Adequate care will be taken to the leakages in the plant and leak 

proof joints are already proposed for the construction. 

• All yard piping inside the plant will be cast iron or ductile iron. All 

pipe work and fittings will be a class rating in excess of the 

maximum pressure attained in service including any surge 

pressure. 

• The sewage pipes inside the plant premises will be made up of DI 

internally lined with SFRC lining. 

• The treated and chlorinated sewage will disposed off to the disposal 

site by closed RCC pipe or DI pipe. 

60


• All underground-buried mild steel piping will be protected by the 

application of hot coal tar enamel and fiberglass wrapping. The 

coating will consist of one coal tar primer one coat, wrapping of 

fiber glass one more coat of enamel and the final wrap of enamel 

impregnated fiber glass. 

• All sanitary piping will be of UPVC class 4 suitably buried below 

the ground with a sand cushion of 20 cm all round. The pipes will 

painted with two coats of anticorrosive bit mastic paint. 

• The drained water will be sent back to the inlet for treatment 

through pipelines. 

• Administrative building, chlorine tonner and centrifuge house are 

provided with rain water harvesting facilities. Pipe culverts will be 

provided at road crossings for storm water drainage of the area at 

the required number of places. 

• There will not be any impact on the Sukkanar drainage canal 

4.3.5 Soil Quality 

downstream usage. However as mentioned above the quality of the 

treated effluent will meet the standards prescribed by the Central 

and State pollution control Boards. 

• Top soils shall be stockpiled to a height of 400 mm in pre – 

designated areas for preservation and shall be reapplied to site 

during plantation of the proposed vegetation. 

• Top soil shall be separated from sub-soil debris and stones larger 

than 50 mm diameter. So that, the soil erosion can be prevented 

and proper construction procedure will be done. 

4.3.6 Solid Waste Handling 

• Grit and screenings will be immediately removed and taken to 

municipal solid waste dump site in consultation with the 

municipality. 

61


• The sludge from the Treatment Plant shall be collected in a sludge 

sump where it is aerated continuously for mixing. The aerated 

sludge shall be treated through mechanical dewatering system by 

aeration, digestion and thickening. 

• Before dewatering, the sludge shall be aerated and polyelectrolyte 

is to be added for best settlement of sludge. 

• The sludge cake from the centrifuge pump will be moved to the 

composting yard through trucks. 

• During transportation sludge will be covered in tarpaulin sheets. 

• The sludge will be removed at frequent intervals in order to avoid 

accumulation inside the site. 

4.4 CONCLUDING REMARKS 

The Environment Impact Assessment gives the following facts. 

The proposed activity will not result in any significant 

negative impact to Environment. Instead, various beneficial 

impacts have been envisaged. 

Any adverse impacts of proposed unit will be fully mitigated 

by the Environment Management Plans (which is 

elaborated in chapter 6). 

62

5. PUBLIC PARTICIPATION 


The Govt. of Tamil Nadu has accorded administrative sanction for 

Thiruvarur Municipality Underground Sewerage Scheme for an amount of 

Rs.39.26 crores. 

Weekly meeting are being conducted by the District Collectors to review 

the works, from the very beginning of the project. To appraise and clarify 

the various doubts of the public, the District Collector instructed the 

Municipal Commissioner to convene a public meeting to explain the benefits 

of the scheme and also clear the doubts of the public. The announcement 

for public consultation was made in local newspaper and through local 

panchayat. Based on that, the public meeting was conducted at AKM 

Thirumanamandapam on 16.02.2008 by the Municipality. 

In the public meeting headed by District Collector, Thiruvarur, 

Chairman and Councilors participated and public near about 600 persons 

attended. The Hon’ble Minister for Diary Development visited the venue and 

offered valuable suggestions. The public mainly enquired about the sewer 

collection, about size of conveying pipe only. The Executive Engineer, TWAD 

Board, Sewerage Division, Thiruvarur explained the various aspects in 

detailed manner as follows: 

The detailed Project is prepared after conducting necessary survey and 

collection of all vital basic details from the Municipality. The pipe sizes were 

designed based on the collection of sewage generated from each street. The 

size of pipes will be finalized based on the quantity of flow. The sewer pipe 

will be laid from a minimum of 1m depth and maximum 6.0m depth. At 

every junction, or for every 30m to 45m intervals along the alignment, 

manholes will be constructed and these manholes will be utilized during 

maintenance to clean the blocks anticipated. Stoneware pipe materials will 

be made use of for sewer line up to 3.5m depth and above this depth. RCC 

pipes will be laid for sewer line. 

63


A display board was also placed in the stage of meeting, showing the 

details of location of Pumping Stations, alignment of Pumping Main and the 

location of STP site. The methodology proposed for the sewage treatment 

was also explained in detailed manner. Also the treatment methodology and 

the parameter standards of the treatment effluent was displayed. It was 

mentioned that the disposal point (ie. Sukkaranar drain canal) will be as per 

the norms and conditions of the TNPCB. Further it was specifically 

emphasized that, due to letting out of the treated effluent not only the 

hygiene of the area will be improved but also treated effluent can be utilized 

for agriculture purpose also. 

There was no objection from the public against the proposed STP. 

64



6. ENVIRONMENTAL MANAGEMENT PLAN 

Environmental Management Plan (EMP) is aimed at mitigating the possible 

adverse impact of a project and ensuring the existing environmental quality. 

The EMP converse all aspects of planning, construction and operation of the 

project relevant to environment. It is essential to implement the EMP right from 

the planning stage continuing throughout the construction and operation 

stage. Therefore the main purpose of the Environmental Management Plan 

(EMP) is to identify the project specific activities that would have to be 

considered for the significant adverse impacts and the mitigation measure 

required. 

6.2 EMP DURING CONSTRUCTION PHASE 

The environmental impact during the construction phase will be of short 

term and reversible nature and will gradually eliminate after the construction 

activity is over. Further the area of the unit is small in size. Still the following 

measures will be considered on priority basis to minimize the impacts. 

6.2.1 Mitigation for Modification of Drainage Pattern 

• Rainwater harvesting prevents the flooding of low-lying areas in the 

project premises. 

• A basic surface drainage system can be provided for the site to avoid 

water runoff on to the surrounding properties and roads, especially 

during the monsoon months. 

• If during excavation, water accumulates in the excavated areas, then 

it should be pumped out and disposed off either in the municipal 

storm water drain or into recharge soak pits of dry bore wells. 

65

6.2.2 Mitigation for Materials Transportation 


• All fine earth materials must be covered during transportation to the 

site to prevent spillage and dusting. 

• The cleanup of spilled earth and construction material on the main 

roads should be the responsibility of the contractor and should be 

done in a timely manner (say within 4 hours) so as not to 

inconvenience or endanger other road users. These requirements 

should be included as clauses within contracts made with relevant 

sub-contractors. 

• The transportation of lubricants and fuel to the site should only be 

done in the appropriate vehicles and containers, i.e. fuel tankers and 

sealed drums. 

• As far as possible, transport of construction materials should be 

scheduled for off-peak traffic hours. This will reduce the risk of traffic 

congestion and of road accidents on the access roads to the site 

6.2.3 Mitigation for Materials Storage 

• The stockpiling of construction materials should be properly managed 

and controlled. Fine grained materials (sand, marl, etc.) should be 

stockpiled away from surface drainage channels and features. 

• Low beams should be placed around the piles and/or tarpaulin used 

to cover open piles of stored materials to prevent them from being 

washed away during rainfall. 

• Safe storage areas should be identified and retaining structures 

constructed prior to the arrival of material. 

• Hazardous chemicals (e.g. fuels) should be properly stored in 

appropriate containers and these should be safely locked away. 

66


Conspicuous warning signs (e.g. ‘No Smoking’) should also be posted 

around hazardous waste storage and handling facilities. 

6.2.4 Air and Noise Environment 

a) Site clearance, excavation and earthmoving 

• The working area for the uprooting of shrubs or vegetation or for 

the removal of boulders or temporary or permanent structures 

shall be sprayed with water or a dust suppression chemical 

immediately before, during and immediately after the operation so 

as to maintain the entire surface wet. 

b) Access road 

• Every main haul road shall be paved with concrete, bituminous 

materials, hardcore or metal plates, and kept clear of dusty 

materials; or sprayed with water or a dust suppression chemical so 

as to maintain the entire road surface wet. 

c) Construction equipments 

• All machineries to be used for construction purpose will be of 

highest standard of reputed make and compliance of noise 

pollution control norms by these equipments will be emphasized by 

company. 

• Transport vehicles and construction equipments / machineries will 

be properly maintained to reduce air emissions. 

• Equipments will be periodically checked for pollutant emissions 

against stipulated norms. 

• Exhaust vent of DG set will be kept at proper height to ensure 

quick dispersal of gaseous emissions. 

67

d) Excavation and earth moving 


• The working area of any excavation or earth moving operation 

should be sprayed with water or a dusty suppression chemical 

immediately before, during and immediately after the operation so 

as to maintain the entire surface wet. 

e) Stock Piles 

f) DG Set 

• All loose material either stocked or transported shall be provided 

with suitable covering such as tarpaulin, etc. 

• Water sprinkling shall be done at the location where dust 

generation is anticipated. 

• Over Burden (OB) waste dumps shall be sprayed with water as 

they are major sources of air borne particulate matter/dust. 

• OB waste dumps shall be reclaimed / afforested to bind the loose 

soil and to prevent soil erosion. 

• D.G. set should be placed in an acoustic enclosure. 

• D.G. set should be placed on the wooden platform to minimize the 

vibration. 

• The green belt development will also help in reducing noise levels 

in the campus. 

• Any generator to be installed at the site shall meet the guidelines 

as laid down by Central Pollution Control Board. 

6.2.5 Mitigation Measures for Noise Environment 

• Construction activities that will generate disturbing sounds should be 

restricted to normal working hours. 

68


• Workers operating equipment that generates noise should be 

equipped with noise protection gear. Workers operating equipment 

generating noise levels greater than 80 dBA continuously for 8 hours 

or more should use earmuffs. Workers experiencing prolonged noise 

levels of 70 – 80 dBA should wear earplugs. 

• The construction activities will be restricted to the daytime and no 

construction will be practiced during night. 

• Barricades will be provided around the construction site to confine 

noise within the site. 

• To reduce the impact of air and noise pollution and to provide a clean, 

healthy environment, it has been proposed to create and maintain a 

green belt within the site and along the roadsides. 

6.2.6 Mitigation Measures for Water Environment 

• Excavation can be avoided during monsoon season 

• Check dams shall be provided to prevent construction runoff from the 

site to the surrounding water bodies. 

• Pit latrines and community toilets with temporary soak pits and septic 

tanks shall be constructed on the site during construction phase to 

prevent wastewater from entering the ground water or surrounding 

water bodies. 

• To prevent surface and ground water contamination by oil/grease, 

leak proof containers shall be used for storage and transportation of 

oil/grease. 

6.2.7 Mitigation Measures for Biological Environment 

• The dust emissions will be suppressed by spraying water and then the 

activities will be carried out. 

69


• Emissions from D.G sets and vehicles will be minimized by proper 

maintenance and by avoiding use of adulterant fuels and will be 

maintained below the standard limits prescribed by competent 

authority. 

• Important species of trees will be identified and marked and will be 

merged with landscape plan. 

6.2.8 Construction Waste Disposal 

• A site waste management plan should be prepared by the contractor 

prior to commencement of construction work. This should include the 

designation of appropriate waste storage areas, collection and removal 

schedule, identification of approved disposal site, and a system for 

supervision and monitoring. Preparation and implementation of the 

plan must be made the responsibility of the building contractor with 

the system being monitored independently. 

• Special attention should be given to minimizing and reducing the 

quantities of solid waste produced during site preparation and 

construction. To reduce organic waste, softer vegetation may be 

composted onsite and used for soil amendment during landscaping. 

• Most of the construction materials like soil, bricks, concrete will be 

reused in the backfilling, road construction, sub-grade reparation etc. 

works. Metals, word scraps & bitumen junks will be recycled either 

within site or outside with help of the local authority. The measures 

like reusing materials on-site and /or donating /selling salvaged 

items reduces waste, virgin material use and disposal cost. 

• Vegetation and combustible waste must not be burnt on the site. 

• Reusable inorganic waste (e.g. excavated sand) should be stockpiled 

away from drainage features and used for in filling where necessary. 

70


• Unusable construction waste, such as damaged pipes, formwork and 

other construction material, must be disposed of at an approved 

dumpsite. 

6.2.9 Mitigation Measures for Land Environment 

• The soil will be collected separately and preserved in stacks with side 

slopes not exceeding 1:5. The topsoil (soil on the top 15 cm patch) will 

be preserved separately in a stack covered by tarpaulin. Efforts will be 

made to reinstate the soil for backfilling purposes. Topsoil will be 

reused for horticultural areas. 

• The spillage of oil from the machinery or cement residue from 

concrete mixer plants might contaminate the soil if not properly 

collected and disposed off. Thus most stringent safety and 

construction management norm will be implemented at site. 

6.2.10 Health & Safety Measures During Construction Phase 

• Construction related activities will be confined only to project site 

area, hence no health related impact are envisaged within the project 

influenced area during the construction stage and will be limited to 

occupant levels. 

• At the project site much direct exposure to dust generation and high 

noise generation sources likely to cause occupant health related 

impact such as asthma, bronchitis and noise induced hearing loss 

etc. on the construction workers. 

• In order to offset such effects, proper drinking water, sanitation and 

first aid facility will be provided at the construction site, with trained 

shift supervisors, which will ensure minimum adverse occupational 

health impacts on the construction worker. 

71

6.3 EMP DURING OPERATION PHASE 


During the operation phase, the plant will contribute to environmental 

pollution in the following manner: 

• Atmospheric emission 

• Noise Pollution 

• Solid Waste Disposal 

6.3.1 Management of Atmospheric Emissions and Noise Pollution 

There is no source of air or noise pollution except the DG sets to be used 

as standby only. In addition there may be release of volatile compounds from 

the aeration tank. The emissions from the D.G sets will have marginal impact 

on the existing air quality, however adequate Stack height of 10 m is provided 

as per the CPCB / TNPCB norms to combat the effect on the air quality and 

also to facilitate proper dispersion. Proper acoustic enclosure will be provided 

so that there will not be any vibrations and incremental noise in significant 

level. The Process does not involve any activities to generate heavy noise levels. 

The essential features of the EMP are as follows: 

• A Stack of suitable Height shall be provided for generator. 

• Good housekeeping is the easiest and often the cheapest way to 

reduce waste by keeping work area as clean environment. 

• Improve inventory procedures by procuring suitable specification 

materials. 

• Designate protected raw material and hazardous waste storage areas 

without spill containment. Keep the areas clean. 

• Conduct periodic inspections of tanks, tank liners, and other 

equipment to avoid failures. Repair the malfunctioning units when 

they are identified immediately. Inspection logs are to be updated 

regularly. 

72


• In order to bring down the noise level to its permissible values a 

multiple strategy shall be used: 

Control of noise at the source. 

Use of personal protection devices. 

• An acoustic enclosure shall be provided to DG sets. The acoustic 

enclosure shall be designed for meeting the ambient noise standards. 

6.3.2 Solid Waste Disposal 

activity. 

The main source of solid waste is sludge generated during operational 

• The sludge from the Treatment Plant shall be collected in a sludge 

sump where it is aerated continuously for mixing. The aerated sludge 

shall be treated through mechanical dewatering system by aeration, 

digestion and thickening. 

• Before dewatering, the sludge shall be aerated and polyelectrolyte is to 

be added for best settlement of sludge. 

• The sludge cake from the centrifuge pump will be moved to the 

composting yard through trucks. 

• During transportation sludge will be covered in tarpaulin sheets. 

• The sludge will be removed at frequent intervals in order to avoid 

accumulation inside the site. 

6.4 ENVIRONMENTAL MONITORING PROGRAM 

Regular monitoring of all significant environmental parameters is essential 

to check the compliance status as per the environmental laws and regulation. 

The objectives of the monitoring will be as follows: 

• To verify the results of the impact assessment study with respect 

to the proposed project. 

73


• To study the trend of concentration values of the parameters, 

which have been, identified as critical. 

• To check and assess the efficacy of pollution control equipment. 

• To ensure that any additional parameters, other than those 

identified in the impact, do not become critical. 

To implement the EMP, a structured Environmental Management Cell 

(EMC) interwoven with the existing management system will be created. EMC 

will undertake regular monitoring of the proposed pollution control system and 

conduct yearly audit of the environmental performance of the system. It will 

also check that the stipulated measures are being satisfactorily implemented 

and operated. 

To monitor the extent of environmental impact of the proposed project, the 

contractor will periodically monitor the environmental quality along the 

proposed project area. As per the agreement document, Operation and 

maintenance will be carrying out by M/s. Hindustan Dorr-Oliver Limited, 

Chennai. The monitoring requirement for the different environmental 

components is presented below in Table 6.1. 

Apart from the mentioned monitoring requirements, any major accidents / 

spillage during bulk transport of hazardous materials, depending on the type of 

spillages / accidents the parameters will be monitored and is decided by the 

engineer and will be carried out by the contractor through approved monitoring 

agencies and supervised by the Implementing agency. 

6.4.1 Air Pollution Monitoring 

The Stack emissions from the DG Set shall be monitored on monthly 

basis for PM, NOx & SO2. The ambient air at the plant site shall be monitored 

at regular intervals for PM10, PM 2.5, NOx, SO2, CO & odour. 

74

6.4.2 Treated Wastewater Monitoring 


The quantity of waste generated from STP will be regularly measured 

using flow meters. Wastewater samples will be collected and analyzed for 

critical parameters like pH, BOD, COD, Solids, Oil and Grease. The frequency 

of monitoring will be at regular intervals. 

6.4.3 Water Monitoring 

The water quality of Sukkanar drainage channel and Groundwater 

quality of bore-well will be regularly monitored. 

6.4.4 Sludge Monitoring 

intervals. 

Solid waste generated from the plant will be monitored at regular 

S. No Particulars Monitoring 

Frequency 

Table 6-1 Environmental Monitoring Schedule 

1 Ambient Air Quality Monitoring 

a Project site Once in 3 

Months 

b Downwind 

direction between 

250m - 500m 

Once in 3 

Months 

2 Stack Monitoring 

a DG Set – Stack Once in 3 

Months 

3 Ambient Noise Level 

a Near DG set Once in 3 

Months 

b Site boundary Once in 3 

Months 

4 Water Quality Monitoring 

Duration of 

Sampling 

24 hr 

continuously 

24 hr 

continuously 

Important 

Monitoring 

Parameters 

PM10, PM2.5, SO 

2, NO x , 

CO 

PM10, PM2.5, SO 

2, NO x , 

CO 

30 min SO 2, NOx, SPM, CO, 

8 hr continuous 

with 1 hr 

interval 

8 hr continuous 

with 1 hr 

interval 

CO2, Temperature, 

Flow rate & Velocity of 

the gas 

Noise level in dB(A) 

Noise level in dB(A) 

75

a Ground Water – 

at project site 

b Ground water at 

500m-1000m in 

the flow direction 

b Sukkanar 

Drainage 

Channel u/s of 

point of disposal 

c Sukkanar 

Drainage 

Channel at 1km 

d/s of point of 

disposal 

Once in 3 

Months 

Once in 3 

Months 

Once in 3 

Months 

Once in 3 

Months 

5 Sewage Quality Monitoring 

a STP Inlet Once in a 

b STP Outlet 

Month 

6 Soil Quality 

a At the green 

belt area 

b Near Sludge 

Disposal area 

7 Sludge Quality 

a Composite 

Sludge 

Once in 3 

Months 

Once in 3 

Months 

Once in a 

month 


Grab Sampling Parameters specified 

under IS:10500, 1993 

& BOD 


under IS:10500, 1993 

& BOD 


under IS:10500, 1993 

& BOD 


under IS:10500, 1993 

& BOD 

Grab Sampling Physical, Chemical & 

Biological Parameters 

specified under 

IS:2490:1982 

Samples were 

collected from 

three different 

depths viz., 

30cm, 60cm, 

and 100cm 

below the 

surface 

Samples were 

collected from 

three different 

depths viz., 

30cm, 60cm, 

and 100cm 

below the 

surface 

pH, texture, electrical 

conductivity, organic 

matter, nitrogen, 

phosphate, sodium, 

calcium, potassium 

and Magnesium. 

pH, texture, electrical 

conductivity, organic 

matter, nitrogen, 

phosphate, sodium, 

calcium, potassium 

and Magnesium. 

Grab sample pH, Phosphorus, 

COD,BOD, Heavy 

metals, Phosphate, 

sodium, potassium, 

Total coliforms 

76

S.N 

o. 

1 

2 

3 

4 

1 

2 

3. 

4 

5 

Table 6-2 Cost for Environmental monitoring 

a. CONSTRUCTION PHASE 

No of 

Unit 

Components 

locations Cost/Sample 

Air quality Monitoring 


Total Cost/year 

Total Cost/5 

years 

Ambient Air 2 2500 20,000 1,00,000 

Water quality Monitoring 

Surface water 1 2000 8,000 40,000 

Ground water 1 2000 8,000 40,000 

Noise quality 

monitoring 

2 500 4,000 20,000 

Soil Quality 

Monitoring 

2 2500 20,000 1,00,000 

TOTAL COST 60000 3,00,000 

B.OPERATION PHASE 

Air quality Monitoring 

Ambient Air 3 2500 30,000 1,50,000 

Stack emission 1 2500 10,000 50,000 

Water quality Monitoring 

Surface water 2 2000 16,000 80,000 

Groundwater 2 2000 16,000 80,000 

Effluent 2 2000 48,000 2,40,000 

Noise 

monitoring 

2 500 4,000 20,000 

Soil Quality 

Monitoring 

2 2500 20,000 1,00,000 

Sludge 

Monitoring 

1 3000 12,000 60,000 

Total 1,56,000 Rs. 7,80,000 

6.5 GREEN BELT DEVELOPMENT PLAN 

The main objective of the green belt is to provide a barrier between the 

source of pollution and the surrounding areas. The green belt helps to capture 

the emission and to attenuate the noise generated apart from improving the 

aesthetics. Development of green belt and other forms of greenery shall also 

prevent soil erosion and washing away of topsoil besides helping in stabilizing 

the functional ecosystem, make the climate more conducive and restore water 

77


balance. The area along the plant boundaries shall be used to plant various 

trees and shrubs. While making choice of plant species for cultivation in green 

belts, importance has to be given to the natural factor of bio-climate. It is also 

presumed that the selected plants will be grown as per normal horticultural (or 

forestry) practice given above and authorities responsible for plantation will 

also make adequate provision for watering and protection of the saplings. 

An area of 8.87 acres (35895.63 sq.m) is available and handed over to 

TWAD Board for STP. The area to be utilized for STP for the present along with 

inside roads. An area of around 0.52 acres with 7 m wide along the boundary 

of STP area is approved for proposing the green belt area and an addition area 

of 1.5 acres will be proposed as a green belt in phase II at the time of 

maintenance period. 

It is planned that three rows of 40 trees per row (total no. of trees - 120) 

are proposed to be planted. Maintenance of the saplings will be taken care and 

the survival monitoring done on monthly basis till the completion of years. The 

cost of greenbelt maintenance will met from the operation and maintenance 

budget. 

H2S source may be from the pipelines and in aerobic tank. Being an 

aerobic treatment the production of H2S will be less. To rectify the odour due to 

H2S, the greenbelt areas to be formed near the STP plant. More plantation to be 

done in Eastern direction since the dominant wind direction is from western 

side. 

It is proposed to develop greenbelt with commercially and aesthetically 

important plants based on the nature of the soil and plant characteristics shall 

be planted. The most common tree species considered are Delonix regia 

(Gulmohar), Neem, Eucalyptus, Pungan, Bamboo, Ashoka, and plant species 

like Tulsi shall be planted along the premise. 

The greenbelt development plan is shown Figure 6-1. 

78

Figure 6-1 Green Belt Development Plan 

6.6 SAFETY TRAINING & HEALTH MONITORING 


Safety & training will be given to the O & M staff to rectify the problems 

araised during the operation of STP. 

The following are safety training will be provided for the workers: 

79


• Workers should wash their hands with anti-bacterial soap 

frequently. 

• Open cuts or wounds should be protected. 

• Always wear rubber gloves and protective clothing when working 

with wastewater. 

• Do not wear contaminated or soiled clothing, wash clothes regularly 

to remove contaminants. 

• Workers need to be able to identify and deal with hazards associated 

with confined spaces. 

• To train them how to use the personal flotation device (PFD) during 

drowning. 

• Regulatory requirements to be applied while traffic hazards occur. 

• Proper techniques to be given for trenching and shoring while 

digging. 

• Good housekeeping practices to be given for removing slipping or 

tripping hazards. 

• The staff will be given training on awareness & first aid to save 

during electrocution or mechanical hazards 

• All facilities available should be utilized properly during 

emergencies. Proper preplanning can save lives and property. 

• Periodical medical facilities to be arranged for health check up. 

Table 6-3 Safety Measures for the operation of the STP 

S.No Components DOs DONTs 

1. Bar Screen 1. Wear gloves, safety shoes. 

2. Use rakes for cleaning 

Avoid using bare hands 

2. Grit Chamber 1. Use safety shoes, gloves 1. Do not attempt any 

and tools 

maintenance during 

2. Replace with original 

operational modes. 

80

spares 

3. Clean regularly 

4. Inspect regularly. 

5. Perform routine 

maintenance 

3 Aeration tank 1. Use ear muffs/ safety 

shoes and required tools 

2. Frequent inspections and 

maintenance of the pump 

3. Use aerator pump of 

required capacity 

4 Clarifiers/ 

Settling tank 

5 Sludge 

holding tank 

specifications 

1. Use safety gloves and 

shoes. 

2. Use original spare parts. 

3. Have spare/alternative 

drive motor. 

4. Conduct frequent 

inspections/ maintenance 

1. Wear safety gloves and 

shoes. 

2. Clean the tank regularly. 

3. Frequent inspections and 

maintenance to be 

performed. 

6 Screw pump 1. Perform routine 

maintenance. 

2. Replace faulty parts 

3. Conduct inspections 

4. Inspect for leaks. Perform 

regularly maintenance of 

pump 

9 Centrifuge 1. Perform frequent cleaning 

of the centrifuge. 

2. Control the speed as per 

the operational conditions. 

3. Check for damage of the 

vessel regularly. 

4. Monitor the quality of the 

sludge as it should not 

corrode the centrifuge. 

5. Frequently lubricate their 

spares, bearing etc. 


2. Do not use bare feet or 

hands. 

1. Do not attempt repairs 

during operation. 

2. Do not operate beyond 

process specifications. 

1. Do not attempt 


operations 

2. Inlet sewage should not 

exceed beyond STP 

capacity. 

1. Do not allow excess 

dosing of polyelectrolyte 

2. Do not leave valves 

open 

1. Do not attempt 


operations 

2. Do not let objects flow 

into pump. 

1. Do not let the quantity 

of sludge beyond its 

capacity. 

2. Do not allow the speed 

beyond its capacity. 

3. Do not let the sludge 

after centrifuge in the 

container for a long 

time. 

81

10 Chlorination 

tank 

12 Electrical 

panel & 

piping 

1. Check the tanks for leaks 

2. Perform routine 

maintenance of pumps 

3. Inspect the pipes. 

4. Use good quality pipes and 

equipments 

5. Fire Department responds 

to all chlorine leak alarms 

immediately remedied by 

shutting the gas off and 

tightening the fitting. 

6. Safety equipment, like gas 

masks, rubber gloves, 

aprons shall be housed in 

easily accessible (unlocked) 

cupboard placed outside 

the chlorination room. 

7. First aid box and eye wash 

fountain shall be provided 

outside chlorinator room. 

1. Wear safety gloves and 

shoes. 

2. Do frequent inspections 

3. Use acoustic enclosures for 

DG sets 

4. Take anti rusting 

precautions for pipes 

13. D.G rooms 1. Check fuel level 

2. Check lube oil level and 

quality 

3. Check coolant level 

4. Check for any leakage 

5. Check for any loose 

connections 

6. Check electrolyte level in 

Battery 

7. Check the battery 

terminals 

8. Check fan belt tension 

9. Check battery charger 

working 

10. Drain the water from 

the fuel tank, weekly 


1. Do not use excess 

chlorine than necessary 

2. Only skilled personnel 

are permitted to enter. 

3. Never apply heat to 

pipes or container 

valves, containers 

unless they have been 

thoroughly purged of 

chlorine. 

4. Never assume a 

container is empty and 

therefore nonhazardous 

even though 

it may weigh empty 

1. Do not perform repairs 

during operations. 

2. Do not touch live wires. 

3. Do not use low quality 

electrical spares. 

1. If the DG set is with 

AMF panel please do 

not touch live wire as 

mains also flow from 

AMF panel even if DG 

SET IS OFF. 

2. Do not check coolant 

level, while DG is 

running. 

3. Do not change any 

wiring or modify wiring 

it may attract void of 

Warranty 

4. Please do not get the 

DG set repaired and 

serviced by any 

82

during winters 

11. Please check all the 

Nuts, Bolts, 

Engine/alternator 

foundation bolts and 

12. loose cable connections 

tightening at the time of 

commissioning and then 

monthly 

13. Always use K-oil to avail 

two year warranty 

14. Purchase all spare parts 

from dealer 

S.No Components Daily 

Activities 

1. Bar Screen 1. To clean the 

bar screen 

every one hour 

2. Screenings 

have to be 

disposed to the 

bed. 

2. Grit Chamber 1. To check the 

operation of 

grit chamber in 

every shift. 

2. To check for 

overload. 

3. Dispose grit 

regularly to 

municipal 

authority. 

3 Aeration tank 1. To check 

sludge index 

volume every 

day. 

2. To check 

pH, MLSS, 

MLVSS, BOD, 

COD 

Blower 

Table 6-4 Steps to be taken during Trouble shooting 

Issues or 

Problems 

1. Choking 

2. Built up of 

sewage 


1.Drive failure 

2. Clogging of grit 

material 

1. Excessive 

foaming. 

2. Aeration pump 

failure 

3. Noise due to 

malfunctioning in 

blower 

unauthorized person. It 

may attract void of 

warranty. It should be 

done by the 

manufacturer 

How to Attend 

1. Cleaning 

regularly 

1. Stop operations. 

Use the backup 

drive or standby. 

Repair or replace 

the faulty drive 

manually. 

2. Operate the 

standby grit unit 

until the 

rectification. 

1. Use defoaming 

agent to suppress 

the form. 

2. Stop aeration 

and use standby 

blower. 

3. Remove the 

diffuser, clean and 

refix manually. 

83

4 Clarifiers/ 

Settling tank 

5 Sludge 

holding tank 

3. To check the 

oil level in the 

blower. 


safety valve is 

released. 


excessive noise 

6. To change 

the silencer 

filter cloth 


pressure 

Diffuser 

To check for 

excessive 

bubbles. 

To check for 

worn out 

diffusers 


drive for 

overloading 

2. To clean the 

overflow 

launder 

3. To transfer 

excessive 

sludge into 

sludge holding 

tank 

1. Sludge has 

to be aerated 

2. Sludge has 

to be regularly 

removed for 

dewatering 

unit. 


poly electrolyte 

dosing. 


1. Choking in the 

launder due to dry 

leaves. 

2. Drive failure 

1. Clogging of 

drains 

2. Cracks and 

leaks in the tank 

3. Overflowing 

4. Less sludge 

retention time 

4. Shut down the 

blower, rectify and 

replace. 

1. Clean the 

launder 

2. Replace the 

faulty part. 

1. Clean the drains 

and pipes 

2. Seal the cracks. 

3. Check the 

valves and pipes. 

Control the inlet 

flow 

4. Control the 

outlet flow. Allow 

more retention 

time. Check for 

leaking valves. 

84

6 Screw pump 1. To check the 

oil level 


excessive 

heating in the 

motor end. 


leak in 

sectional 

cleaning 

operational 

valves. 


abnormal 

vibrations 

stroke 

excessive 

sounds. 

9 Centrifuge 1. Regular 

operation of 

centrifuge 

2. Empty the 

sludge after 

removing the 

cakes from the 

centrifuge. 

3. Dispose the 

sludge after 

10 Chlorination 

tank 

dewatering. 

1. Wear safety 

glasses. 


operation 

booster pump. 

3. To check 

chlorine 

solution level 

in tank 


chlorine level 

in cylinders 


arrangement of 

valves in 


1. Pump failure 

2. Inefficient 

pumping 

3. Leaks. 

4.Malfunctioning 

1. Clogging of 

centrifuge 

2. Leaks in 

centrifuge 

3. Overflow 

1. Pump failure. 

2. Excessive 

chlorine dosing 

3. Cracked pipes or 

tanks 

4. Chlorine leaks 

1. Stop operations 

Repair/ replace 

faulty pump. 

2. Seal the leaks. 

Replace faulty 

parts. Replace the 

pump. 

3. Stop operation. 

Use alternate 

pump and repair 

the malfunctioning 

pump. 

4. Stop operations. 

Reduce flow rate or 

use pump of apt 

capacity 

1. Reduce the load 

2. Check the leak 

part and replace 

3. Reduce inlet 

flow into 

centrifuge. 

1. Stop operations 

Repair or replace 

faulty pumps. 

2. Stop the flow of 

chlorine being 

dosed into tank. 

3. Seal cracks. 

Replace cracked 

pipes 

4. Alarm 

throughout the 

plant. Necessary 

arrangements to 

be made for 

stopping the 

leakage. 

85

12 Electrical 

panel & 

piping 

booster pump. 

1. Local on/off 

check. 

2. Check for 

leaks and 

cracks in 

valves 

13. D.G rooms 1. Check fuel 

level 

2. Drain water 

fuel tank 

(especially 

during winter 

season) 

3. Check 

coolant level 

4. Check water 

level in the 

radiator 


any leakage 


any loose 

connections 


Battery 

conditions 

8. Check lube 

oil level and 

quality 


1. Short circuiting 

2. Power outages 

3. Cracked pipes 

4. Malfunctioning 

electrical circuits 

5. Fires due to 

electrical short 

circuit. 

1. Engine does not 

start 

2. No power & 

misfiring of Engine 

3. Engine emits 

3 Engine grows 

excessively hot, 

high fuel 

consumption, 

low oil pressure 

1. Switch off mains 

and repair the 

source of 

circuiting 

2. Use DG sets. 

3. Seal the cracks 

or replace pipes 

4. Turn off mains. 


switch boards 

5. Turn off mains. 

Extinguish fire. 


electric 

components 

-Check fuel , vent 

fuel system 

- Charge batteries 

- Change lamp, 

heat up piping, 

change filter 

- open cock 

- Clean fuel tank, 

fill in clean fuel 

replace filter 

- Inspect & replace 

- Set correct, start 

fuel 

- let engine to heat 

up in open 

- Tighten or 

replace V belts 

- Perform electrical 

check up of 

temperature 

controller 

- Check fuel 

injection system or 

replace air filter or 

solenoid valve 

- Replace paper 

filter cartridge 

86

6.7 EMP BUDGETARY ALLOCATION 


4 Increase in 

lube oil 

5 Unbalance 

voltage 

6 Excessive 

vibration 

8 Smokes, spark or 

flames 

- check for leakage 

or brand of oil 

- Inspect & replace 

or tighten 

- Inspect piping, 

filters & ducts for 

tightness 

- Correct the load 

- Tighten the loose 

connection 

- Check winding 

resistance & 

rewind if wind 

- Replace the 

coupling & check 

the alignment 

Reset the speed to 

the nominal 

- Check and 

correct the load, 

rewind the stator 

- Stop the gen-set 

immediately. 

A capital cost provision of about Rs. 4 Lakhs has been kept in the project 

cost towards the environmental protection, control & mitigation measures and 

implementation of the EMP. The budgetary cost estimate for an annum is given 

in Table 6-5. 

During operation & maintenance, STP performance is to be monitored. For 

that, the working efficiency of STP and the waste water quality to be analyzed. 

This will be done in Environmental Management Plan. 

After the STP is constructed, the area around the Plant should be beatified 

by planting trees and gardens. This will mitigate the odor and particulate 

matter during operation. 

87


Once STP is functioning, the ambient air quality and waste water quality 

to be analyzed and suitable action to be taken to mitigate the pollution. For 

this regular environmental parameters are to be monitored. 

The operators and the workers involved in STP should be regularly 

checked the health by providing some safety and medicines. 

Table 6-5 Environmental Budget 

S.No. Description Capital 

Cost per 

annum 

(Rs. Lakhs) 

1. Environment Management 

Plan 

Operation 

Cost per 

annum 

(Rs. Lakhs) 

0.6 0.1 0.5 

2. Safety training & PPEs 0.4 0.12 0.6 

3. Landscaping & Gardening 

(Development and 

Maintenance) 

1.3 0.38 1.9 

4. Environmental monitoring 1.56 7.80 

5. Health monitoring 0.5 0.1 0.5 

Total Cost 2.8 2.26 11.3 

Operation 

cost for 5 

years 

(Rs. Lakhs) 

The project cost has been arrived at including the cost for implementing the 

environmental management measures. The Operation cost will be incurred 

from annual Operation and Maintenance cost. 

6.8 PERMISSIONS FROM VARIOUS DEPARTMENTS WITH PRESENT 

STATUS 

The present stage of Land, Implementation and Procurement related 

issues till date are tabulated as below in Table 6-6. 

88

Table 6-6 Authorities Clearances 


S.No. Description Present Stage Responsible agencies Time frame 

1 Land Issues for Pumping 

Stations and STP. 

2 Present stage of submitting 

general arrangements drawing 

and layout plan, structural 

designs for the STP site to the 

Chief Engineer and stage of 

approval. 

The land has been 

handed over to 

Thiruvarur TWAD 

Board by Thiruvarur 

Municipality. 

Approval from the Chief 

Engineer, TWAD is 

obtained on 24.08.10 

for the layout plan and 

structural designs. 

3 Permission laying of pipelines The sewer lines are 

proposed to be laid 

inside the premises, 

hence no permission is 

4 Consent to Establish from the 

Pollution Control Board 

5 Consent to Operate from the 

Pollution Control Board 

applicable. 

Consent to Establish 

under water Act has 

been obtained vide 

Proceeding No. 

AEE/TNPCB/NGT/F.MI 

S- 

0438/O/L/W/2010/dt. 

12.8.2010 

Consent to operate will 

be obtained upon 

ULB / TWAD (Monitoring)/ 

Concerned Departments & 

agency / Contractor 








Concerned agency / 

Before 

construction 


construction 


construction 


construction 

Contractor Before 

operation 

89


S.No. Description Present Stage Responsible agencies Time frame 

S.N 

o. 

5 Implementation issues i.e., 

Court Case, Public Objection, 

Change of Technology, Change 

of Site etc. 

Potential 

Negative 

Impacts 

1 Compensatory 

plantation of 

trees 

2 Protection of top 

soil & 

Environmental 

enhancing. 

3 Disposal of 

construction 

debris and 

excavated 

materials. 

completion of 

construction work. 

NA ULB / TWAD (Monitoring)/ 



Table 6-7 Construction Phase Impacts & Mitigation Measures 


construction 

Mitigation Measures Time frame Responsible 

agencies 

1) The proposed site is a barren land and there are 

no trees at present. 

2) There is no tree cutting hence there is no need of 

any compensatory plantation during the 

construction period. 

1. The top soil will be protected and compacted after 

completion of work. 

2. Top soil from the STP area should be stored in 

stock piles and that will be used for gardening 

purposes at the STP site as an environmental 

enhancing measure. 

The construction debris and excavated materials will 

be disposed of to the low lying area which is 

identified and approved by the Thiruvarur 

Municipality for the disposal. 

It will be taken care that the material does not affect 

natural drainage system. 

Preconstruction 

and 

Construction 

During 

construction 

During 

construction 

Contractor. 

Monitoring 

by TWAD 

Contractor. 

Monitoring 

by TWAD 

Contractor. 

Monitoring 

by TWAD. 

90

S.N 

o. 

Potential 

Negative 

Impacts 

4 Pollution from 

Fuel and 

Lubricants 

5 Contamination 

of ground water 

quality 

6 

Water Pollution 

from 

Construction 

Wastes 

7 Impact of 

surrounding 

areas 



agencies 

The contractor will ensure that all construction 

vehicle parking location, fuel/lubricants storage 

sites, vehicle, machinery and equipment 

maintenance and refueling sites will be located at 

least 500 m from rivers and irrigation canal/ponds. 

i. The treated effluent quality will ensure within 

the PCB standards for disposal onto land, water 

body or for irrigation use. 

ii. The sewage pipes inside the plant premises 

will be made up of DI internally lined with SFRC 

lining. The treated and chlorinated sewage will 

disposed off to the disposal site by closed RCC pipe 

or DI pipe. 

iii. The treated effluent quality and also the 

ground water quality in the nearby areas will be 

regularly monitored and ensures within PCB 

standards. 

The Contractor will take all precautionary measures 

to prevent the wastewater generated during 

construction from entering into streams, water 

bodies or the irrigation system. 

Odour: Odour can be reduced or prevented through 

continuous process of the operation which can be 

ensured by the provision of D.G sets, regular 

maintenance of the operation units and greenbelt 

around the STP helps in controlling odour. The odor 

Construction 

and operation. 

During 

construction 

and operation 

During 

Construction 

During 

Construction 

and Operation 

Contractor. 

Monitoring 

by TWAD. 

Contractor. 

Monitoring 

by TWAD 

Contractor. 

Monitoring 

by TWAD 

Contractor. 

Monitoring 

by TWAD 

91

S.N 

o. 

Potential 

Negative 

Impacts 

8 Informatory 

Signs and 

Hoardings 

9 Risk from 

Electrical 

Equipment(s) 

10 Disposal of 

treated effluent. 



agencies 

impacts to the community are expected to be 

minimal by providing the separation between the 

facility and the nearest adjacent property. Temporary 

odor impacts during construction are expected to be 

minimal and typical of construction odors. 

Noise: Installing the pumps underground and DG 

sets is provided by acoustic enclosures. 

Greenbelt around the STP helps in controlling noise. 

The contractor will provide, erect and maintain 

informatory/safety signs, hoardings written in 

English and local language, wherever required or 

suggested by the Engineer. 

The Contractor will take all required precautions to 

prevent danger from electrical equipment and ensure 

that - 

i) No material shall be stacked or placed as to cause 

danger or inconvenience to any person or the public. 

ii) All necessary fencing and lights will be provided to 

protect the public in construction zones. 

All machines to be used in the construction will 

conform to the relevant Indian Standards (IS) codes, 

will be free from patent defect, will be kept in good 

working order, will be regularly inspected and 

properly maintained as per IS provision and to the 

satisfaction of the Engineer. 

i) The treated effluent quality compile with the 

standards of TNPCB before let out into the stream 

During 

construction 

During 

construction 

Preconstruction 

/ 

Contractor 

Contractor 

Contractor. 

Monitoring 

92

S.N 

o. 

Potential 

Negative 

Impacts 

11 Disposal of 

sludge 

12 

Labour camp & 

facilities 



agencies 

/irrigation purposes and necessary permission will 

be obtained from the concerned department and 

will ensure efficient working condition of treatment 

plant. 

ii) Prevent the pollution of stream water and other 

water bodies receiving STP discharge. 

The sludge safely disposed to suitable site which is 

mentioned in Table 3.11. 

The contractor will guaranteed the following: 

i) The location, layout and basic facility provision of 

each labour camp will be submitted to Engineer 

prior to their construction. 

ii) The construction will commence only upon the 

written approval of the Engineer. 

iii) The Contractor will construct and maintain all 

labour accommodation in such a fashion that 

uncontaminated water is available for drinking, 

cooking and washing. 

iv) Supply of sufficient quantity of potable water (as 

per IS) in every workplace/labor camp site at 

suitable and easily accessible places and regular 

maintenance of such facilities. 

v) The sewage system for the camp are designed, 

built and operated in such a fashion that no health 

hazards occurs and no pollution to the air, ground 

construction 

and operation 

stage. 

Preconstruction, 

construction 

and operation. 

During Pre- 

construction 

and 

construction 

by TWAD. 

Contractor. 

Monitoring 

by TWAD 

Contractor. 

Monitoring 

by TWAD 

93

S.N 

o. 

Potential 

Negative 

Impacts 

13 Safety Aspects 



agencies 

water or adjacent water courses take place. Adequate 

water supply is provided in all toilets and urinals. 

i) Adequate precautions are taken to prevent the 

accidents and from the machineries. 

ii) Protective footwear and protective goggles to all 

workers employed on mixing of materials like 

cement, concrete etc. 

ii) Welder’s protective eye-shields will be provided to 

workers who are engaged in welding works. 

iv) Earplugs will be provided to workers exposed to 

loud noise, and workers working in crushing, 

compaction, or concrete mixing operation. 

v) Supply of safety appliances such as safety goggles, 

helmets, safety belts, ear plugs, mask etc. are 

provided to workers and staffs by the contractor. 

The contractor complies with all the precautions as 

required for ensuring the safety of the workmen as 

per the International Labor Organization (ILO) 

Convention No. 62 as far as those are applicable to 

this contract. 

The contractor will make sure that during the 

construction work all relevant provisions of the 

Factories Act, 1948 and the Building and other 

Construction Workers (regulation of Employment 

and Conditions of Services) Act, 1996 are adhered. 

The contractor will not employ any person below the 

age of 14 years for any work and no woman will be 

During 

construction & 

maintenance 

period. 

Contractor. 

Monitoring 

by TWAD 

94

S.N 

o. 

Potential 

Negative 

Impacts 



agencies 

employed on the work of painting with products 

containing lead in any form. 

14 First Aid The contractor will arrange for the following : 

i) A readily available first aid unit including an 

adequate supply of sterilized dressing materials and 

appliances as per the Factories Rules in every work 

zone 

ii) Availability of suitable transport at all times to 

take injured or sick person(s) to the nearest hospital 

Table 6-8 Environmental Enhancement measures 

S.No Environmental enhancement and special issues 

1 Flora and 

Chance found 

Fauna 

The contractor will take reasonable precaution to 

prevent the workmen or any other persons from 

removing and damaging any flora (plant/vegetation) 

and fauna (animal) including fishing in any water 

body and hunting of any animal. Clear instructions 

will be given to the workmen regarding the same. 

If any wild animal is found near the construction site 

at any point of time, the contractor will immediately 

upon discovery thereof acquaint the Engineer and 

carry out the Engineer's instructions for dealing with 

the same. 

During 

construction & 

maintenance 

period. 

Location 

Project area 

Contractor. 

Monitoring 

by TWAD 

Implementing 

Agency 

Contractor 

95


2 Chance Found 

Archaeological 

Property 

3 Monitoring of 

environment 

parameters 

The Engineer will report to the nearby forest office 

(range office or divisional office) and will take 

appropriate steps/ measures, if required in 

consultation with the forest officials. 

All fossils, coins, articles of value of antiquity, 

structures and other remains or things of geological 

or archaeological interest discovered on the site will 

be the property of the Government and be dealt with 

as per provisions of the relevant legislation. 

The contractor will take reasonable precautions to 

prevent his workmen or any other persons from 

removing and damaging any such article or thing. 

The contractor immediately upon discovery thereof 

and before removal acquaint the Engineer of such 

discovery and carry out the SC's instructions for 

dealing with the same, waiting which all work will be 

stopped. 

The Engineer will seek direction from the 

Archaeological Survey of India (ASI) before 

instructing the Contractor to recommence the work 

in the site. 

Monitoring of environment parameters are 

mentioned in Table 6.1 & 6.2 

4 Sensitive Areas The contractor shall undertake seasonal monitoring 

of air, water noise and soil quality through an 


Location 

Project area 

Implementing 

Agency 

Contractor 

Project area Contractor 

Project area Contractor 

96


5 Clearing of 

construction of 

camps and 

restoration 

6 Tree Protection, 

Tree Planting 

approved monitoring agency. The parameter to be 

monitored, frequency and duration of monitoring 

plan has been prepared and mentioned under 

section 6.4. 

Contractor will prepare site restoration plans for 

approval by the engineer. The plan will be 

implemented by the contractor prior to 

demobilization. 

On completion of the works, all temporary structures 

will be cleared away, all rubbish cleared, excreta or 

other disposal pits or trenches filled in and 

effectively sealed off and the site left clean and tidy, 

at the contractor’s expenses, to the entire 

satisfaction of the engineer. 

I. Masonry tree guards, Low level RCC tree 

guards, Circular Iron Tree Guard with Bars, 

use of plate compactors near trees may also be 

considered where necessary. 

II. The major portion of the project road may 

pass through open lands, planting of trees 

along the entire stretch of the road is 

recommended as an enhancement measure. 

III. Growth and survival of trees planted shall 

be ensured and monitoring done at least for a 

period of 3 years .Survival status shall be 

reported on monthly basis to Engineer in 

charge. 


Location 

Corridor of 

Impact 

Corridor of 

Impact 

Implementing 

Agency 

Contractor 

Contractor 

97

7. CONCLUSION 


• The impact on environment will be minimum and can be further reduced 

by implementing various mitigating measures and regular monitoring 

programs. 

• The proposed sewage treatment Plant have beneficial impacts in terms of 

hygienic and safe disposal of treated effluent in Thiruvarur with 

incidental benefits like employment opportunities both in the 

construction stage and operation stage. Also the modernized 

installation will facilitate greater level of operating safety. 

• Due to the proposed project the socio economic activities will be 

developed in and around the project area. 

• The monitoring program on various environmental parameters will be 

undertaken for the continual improvements towards protecting the 

environment to achieve the above requirements. 

• Proper methods have been planned to safe and secured disposal of 

treated effluent and handling of solid waste. Hence the project has been 

strongly recommended by the consultants. 

98

ANNEXURE 

ANNEXURE-1 

ANNEXURE

Annexure-I 

Basic Information on Proposed project in Thiruvarur 

--------------------------------------------------------------------------------------------------------------------- 

Particulars Statistics 

-------------------------------------------------------------------------------------------------------------------- 

Area 10.47 sq.m 

Population: 2001 Census 56,280 

Base year 2008 62,100 

Design year 2023 76,900 

Ultimate year 2038 95,000 

Civic status Selection Grade Municipality 

Number of wards 30 Wards (5 Nos) 

Households 10439 Nos 

Existing Sewerage System No sewerage system at present. A majority of 

Sewage contribution 90 lpcd 

Sewage Flow 

Design year(2023) 6.92mld 

Intermediate year (2023) 6.92 mld 

Ultimate year (2038) 8.55mld 

households have water borne sanitation facilities 

such as septic tanks. Existing liquid waste 

disposal in open storm water drains without any 

treatment. 

Sewage Flow Zonewise Intermediate Ultimate 

Zone I (Srinivasapuram) 0.33 mld 0.41mld 

Zone II (Chettikulam) 2.14 mld 2.64 mld 

Zone III (Kulunthankulam) 1.95 mld 2.4 mld 

Zone IV (Arasankulam) 1.59 mld 1.97mld 

Zone V (Ramagaye Municipal School) 0.91mld 1.13mld 

Total 6.92 mld 8.55mld

Length of Sewer SW Pipes RCC pipes Total 

Zone I (Srinivasapuram) 52926m 1472m 7398m 

Zone II (Chettikulam) 14577m 1491m 16068m 

Zone III (Kulunthankulam) 14313m 3409m 17722m 

Zone IV (Arasankulam) 16768m 2546m 19314m 

Zone V (Ramagaye Municipal School) 9327m 1850 11177m 

Total 60911 m 10768 m 71679m 

Manholes Shallow MH Deep MH Total 

Zone I (Srinivasapuram) 184 no. 97 no. 281no. 

Zone II (Chettikulam) 467no. 171no. 638no. 

Zone III (Kulunthankulam) 449no. 230no. 679no. 

Zone IV (Arasankulam) 634no. 174no. 808no. 

Zone V (Ramagaye Municipal School) 318no. 126no. 444no. 

Lift manholes (2m Dia. RCC) 

Zone I (Srinivasapuram) 1 no. 

Zone II (Chettikulam) 4no. 

Zone III (Kulunthankulam) 5no. 

Zone IV (Arasankulam) 2no. 

Zone V (Ramagaye Municipal School) 4no. 

Pumping Stations 

Total 2052no. 798no. 2850no. 

Total 16no. 

Screen well details 5no. 

Grit well details 5no. 

Suction well details 5no. 

Detention period for suction well 10 minutes

House Service Connection 10439no. 145390 m 

Zonewise 100mmSW 150mmSW Total 

Zone I 1000no. 9000m 1000m 10000m 

Zone II 3100no. 26000m 5000m 31000m 

Zone III 4600no. 36800m 9200m 46000m 

Zone IV 3760no. 30080m 7520m 37600m 

Zone V 2079no. 16630m 4160m 20790m 

Total 118510m 26880m 145390m 

STP at Kekarai 

Capacity (year 2023) 6.92mld 

Land required Ultimate 8.87 acres 

Technology used Activated Sludge Process (ASP) 

Project cost 5.9 crores 

Pumping Station Area 

Zone I (Srinivasapuram) 1200 m 2 

Zone II (Chettikulam) 2750 m 2 

Zone III (Kulunthankulam) 1950m 2 

Zone IV (Arasankulam) 1240m 2 

Zone V (Ramagaye Municipal School) 1144m 2 

---------------------------------------------------------------------------------------------------------------------

Figure 1.1–Sewage Entry Direction and Outlet of the treated water to Sukkanar

ANNEXURE 

ANNEXURE-2 

ANNEXURE 

ANNEXURE

:'ze'|: 

F 

-- 

- --Sff1ryT*:.fy,#J" 

:-'l::4ry41f *Rry., *.\.; fB:#F 

-- 

,?i; f -F,*, *., J|;;t* f t eHe tr€r F? tr L & {r ?T e} rd s # ru Fffi tr & ts ff A H n, 

(rr,i" ;:;;;;#i :,:l :;1 f:-,f,,,,: :: ft en ie j i {,, . 

t 

I\dulricipatrif.y, 

j: 

{Sepr,,age ?.r€af&r 

;::::, ;ffi :,", i,,i "lffi:il.' #,:,, * s a i i B, s a / 2, 

Distr"ict" *for r hiruvarur 

the estabrjshrnent 

or u** ,,o,ro*e 

uncier to estabiish 

'section 25 the 

of the 

indusrry 

water grr"u"nu.o'tos 

Acr., and 

1974, as 

controi 

anrended jn of pollution) 

lggs ec*t ul ,n Acf 53 of 1988)" 

ftef: 0i. \,our Application No 

02.i3r:i""it*"1 og,at ia tNil 

COF{SE}{T fi }?.f_}ER N o.49/20I * 

T:yi: .:T*Tr/F..'ff s - a 43 8 / o fr_ lw / 20 10/dr. I 2. 0 8 .2 a 1 t 

dared I 0' 08'2005 and addirionai parricuJars 

03 i ; ),l j :f#i :?#g_T" ryrrs. 043 8 / 20 r 0 / dt., e . 07 .20 1 0 

comrniitee rneeting heri 

of rhe s:::: 

"' ii oe'zor o 

(cenrrare"rsso*il-rffi ffi;;:xgf;;':ance 

nruor tL*ro ?;T$"?#f":"i$ili:L'tlTebv€ra'tedundersecri,,'25 

(hereinafter 

referrec! ," :frrl\,^_:?ro,.u ont.nd*d in tggg 

""o.ii"'vutl) 

", .ct') and the Rule: and Orders 

(hereinafter refer.r.ei 

l],heCommissionero 

lirtrls' Thiruvarur Municiparify (sewa ge Treafnrent prau f), 

"'uuurl, ti*^t;,;,::;i i? i: 'rhe Apptrica-nt') 

'y tn authorizini: 

the sire i.,, 

nreniioned bellow, o -'er to cstablish or tajce steps to 

S.F.l{c:9011A, g$/1.8, gglZ, gfrld, g?ll, gS/Z, gSlSu 

Keii:rrai gSlT 

Viilage ' 

ete 

,, 

Thiruvarur h{uni 

Th i i " irva ru " o* *r, lut"o 

a !idy' (s er"a ge Tl"ea f rn e* t Fxa' t) 

establish is vplid f 

seeti-:n 25 

";'il, {9I r*" }'e&r$, rllj rti,-' "r indusrry obrains 

i;: I e88 wti;;:;J;'?:r (P-revention ar 

r rs earlier of 

subjectY"*tl"l Polluticn) 

to spccial and gerteral 

! ,\, , t-l) 

._J . \e*^.- __.__.+ 

_ . l rril. S'fAtdT Er{,", I.tt 0 j.{ h,f E\ir^}l' " fX 

TAi''{lL NAIlir pol., T

To 

The Commissioner, 

M/s" Thiruvarur Municipality (Sewage Trestment P[ant), 

Thiruvarur" 

Thiruvarur District. 

Copy to 

The Commissioner 

Thirurarur Panchayat Union, 

Thiru.varur" 

Copy Submitted to: 

The Member Secretary, 

TNPC Board, 

Chenhai-32. 

Spare

t 

"r&NtttttAffu p#E turtsF$ ssH-rRok B$ARE! 

; 

a 

- )* 

, :tJ.:iffk fi1xiJffi"s*qrrshin g the fac'itv for the m anufacture 

ofproductslbyproducts(Cot'Z)attherate(Coi.3)mentionedbelow.Anychangeinthe 

product/by product and its quant* has to be brought to the notice of the Board and fresh 

consent has to be obtained" 

S1.No. 

I 

ent Plant 

ffiItiwAvlonth 

egz tw,n 

l.Thisconsenttoestablishisvalidforestablishingthefacilitywiththebelow 

mentionedoutretsforthedischarge"t:J:tJ:i:lt*-li;il-H:;:::;-* 

mentioned outlets for the dtscnargv " "" " 

1"-, G.och cnnsont has to be obtained if 

has to be brouglrt to the notice of the Board and fresh consel 

necessary. 

2. The unit shall provide Sewage Treatment Plant as indicated below: 

pesAtfr* of units 

n"*Tng--g charnber 

CoffiGeen Chamber 

Fdsrt".n 'hamber 

GfrThamber 

@tsR) 

ffi;atty;ilifter tank 

elG6eont"ctTank 

Filter Press 

Size 

ffiIx4.t5 

1-8 xdfi 1.55m 

T76Txzsm 

+filt x3.25m 

flrnfrrr.x 6'55rn 

ffi 

T3ili7srn 

x 5'8m 

ffix-ooutx3'on'r 

t" Additiontil ' 

conditions 

Additionat conditions "mpact to the existin;; 

' ^TP 

project shall not create any adverse r 

0i. The proposed D r r yrw;""" "--"' 

. .-- ^+^n^ae 

condition 

"nunot',*tntal 

under any circumstances' 

Veige Or any SOI1G $erterowu ^" "-- 

^ n I - ^- r--lnqoe can&l WhiOh iS 

r by channellwater souroe other than Sukkanar drainage ean 

,,;il::i:ffJ:'##;;;;**::*:,T:::::T:ff :J:-1#ffili;;,'**u 

j 

i 

1 

l I 

1 

l 

I 

j

.**:-*Ji-';-;';.;'*-,';,g;:{*3;-s"r:l'a---:-.--- I -:--:-:,5;';i-- - - -:J 

g*ffi f e#$ffiax poulruTs{rF.E 

C0!rrR0t B{}ftft ffi 

05' The unir shall develc;: fhi,;ir and adequei* gieen belt ag nround the prernises o . 

the r.rnit ta alleviate Air arad noise poiluticn" 

06" The unit siraii provide cornpound wa'of aaequate height around the sewaige 

treahnent plant. 

07' The unit shali provide rainwater harvesting facilities so as to increase the ground 

water level in the vicinity of the unit. 

08. The unit shall maintain good house keeping. 

09' The unit's activify shan not attract any pubiic compliant. 

F\.4.----

\] 

1i 

I 

! l. 

r 

i 

! I 

I I 

i 

,5- 

S 

COT{DITION 

GBI..{ERAL 

0 r rhe above consent to cstabrish "T::ffi:Xffi?:t""H:1"";*: 

T nit shall not cornroence th* "n""t:::":;;;;;;** operate atleastthirtv 

ar:equestfor 

02. The industrv ;;;;;"- grant of consentl 

uni'f 

;.-o-'*u*'r'lhe 

*^*, 

o+' Sampl-, ", from the SouIcoS 

have to be 

*,u,1, *v othor nearby-watef 

taken by the unrt and ger rhem *;;; by the tsoard Laboratory to deverop has 

: trj*:***'::xilffffi:* 

,,1T"H;***m'::m$::'h::":-wi'lhsepara'ie:":" 

moterfortheEffluentr,.u.*"*,i*.*ensure.o,,ti',ooo,operationofthe 

Plant' 

Effluent Treatment 

, u 

annr.Vo the construction of anY Ph-vsical 

:[:ff *:,1"ffi,:::il:ffi::ff"H' *'- in anv na'iur ar wa'{eroourse 

0? Any chango in the detairs *#;; ;:"T::*-#::J:rTt#-:j::ii" 

notice of iit" Board and got approved by the Boat 

operate under the said A"''. 

*"' *'rovisions of Publio Liability Act' 1991 to 

,; oomply 

08. The 

",,*il, with the provisions tlt_l 

r" humzmbcin*l_ll"t tiving 

":$$$$P:'ffi:rhTry::"- 

''. substanc* Gt "nt::-11?.rr- issued unless the unit oonoplles with ail the 

nt lo oPerate will no 

tt 

:::;ions of consent to establish 

't' the rrnit shall inform the change 

t0' ln case thcre is an'v change inthe rnanagenrsn 

irnrnediately " 

with relev ant doouments 

$r,W*{b 

,m;msuslrryffistualtb 

V-,-." 1:0 

t'j,' Y

ANNEXURE 

ANNEXURE-3 

ANNEXURE 

ANNEXURE

S.No. 

Compliance status of the Special condition given in the Consent issued by TNPCB 

Special conditions 

1 The consent to establish is valid for establishing 

the facility for manufacture of product (Col.1) at 

the rate (Col.2) mentioned below. Any change in 

the product/ by product & its quantity has to be 

brought to the notice of the Board and fresh 

consent has to be obtained. 

S.No. Description Quantity/Month 

1 Treatment of 

Sewage through STP 

6.92 MLD 

2 The consent to establish is valid for establishing 

the facility with the below mentioned outlets for 

the discharge of sewage/trade effluent. Any 

change in the outlets has to be brought to the 

notice of the Board and fresh consent has to be 

obtained if necessary. 

3 The unit shall provide STP as indicated below: 

S.No Description of 

the units 

No. Size 

1 Receiving 

Chamber 

1 1.7x2x4.15 

2 Coarse screen 1 1.8x0.6x1.55 

Chamber 

m 

3 Fine Screen 

Chamber 

1 2.7x0.7x2.6m 

4 Grit Chamber 1 4.1x4.1x3.25 

m 

5 Areation tank 1 17m x 17m x 

6.55 m 

6 Secondary 1 21m Dia x 

clarifier tank 

Depth 6.9m 

7 Chlorine Contact 1 7.5m x 7.5m x 

Tank 

5.8 m 

8 Filter press 1 5m x 3 m x 

3m 

Current status 

No change in the 

proposal. Any change in 

the product/ by product 

& its quantity will be 

intimated to the Board 

as per the condition. 

No change. Any change 

in the outlet will be 

intimated to the Board. 

The STP units will be 

provided as committed.

Table 1.2 Compliance status of the additional condition given in the Consent issued by 

TNPCB 

S.No. Additional conditions Current status 

1 

2 

3 

4 

5 

6 

7 

8 

9 

The proposed STP project shall not 

create any adverse impact to the existing 

environmental condition under any 

circumstances. 

No sewage or any solid generated in the 

treatment plant activity shall find access 

to nearby channel/water source other 

than Sukkanar drainage canal which is 

used by the farmers for irrigation. 

The components of STP shall be 

sufficiently above ground level, so as to 

ensure that the sewage shall not be 

mixed with storm water during 

monsoon are to avoid carryover of 

sediments from site. 

The unit shall adhere to Ambient Noise 

level standards prescribed by the Board. 

The unit shall develop thick adequate 

green belt all around the premises of the 

unit to alleviate Air and Noise pollution. 

The unit shall provide compound wall of 

adequate height around the STP. 

The unit shall provide rainwater 

harvesting facilities so as to increase the 

ground water level in the vicinity of the 

unit. 

The unit shall maintain good 

housekeeping. 

The unit’s activity shall not attract any 

public compliant. 

It is assured that there will not be 

any adverse impact to the 

existing environment condition 

under any circumstances during 

construction & operation phase. 

The treated water will be let only 

in the Sukkanar Drainage. The 

sludge cake as manure will be 

disposed through local farmers. 

All the structures of the STP are 

above ground. 

Adequate green belt and Noise 

control measures will be adhere 

to maintain the ANQ. 

About 2134 m2 will be green belt 

is proposed along the periphery 

and also in between the STP 

component. 

The Unit will provide compound 

wall of adequate height around 

the STP. 

Administrative building, chlorine 

tonner and centrifuge house are 

provided with rain water 

harvesting facilities. 

Good housekeeping is ensured. 

Accepted. The unit activity shall 

not attract any public compliant.

Table 1.3 Compliance status of the general conditions given in the Consent issued by TNPCB 

S.No General conditions Current status 

1 The above consent to establish cannot be 

construed as consent to operate and the unit 

shall not commence the operation without 

obtaining the consent to operate. 

2 The industry shall make a request for grant 

of consent to operate at least thirty days 

before the commissioning of trial 

production. 

3 The unit shall construct compound wall 

around the boundary of the unit. 

4 Samples of water from the wells or any other 

nearby water sources have to be taken by 

the unit and get them analyzed by the Board 

Laboratory to develop has line date to 

assess the existing water quality. 

5 The unit shall provide an alternate power 

source along with separate energy meter for 

the Effluent Treatment Plant to ensure 

continuous operation of the Effluent 

Treatment Plant. 

6 The consent does not authorize or approve 

the construction of any physical structures of 

facilities, or the undertaking of any work in 

any natural watercourse. 

7 Any change in the details furnished in the 

conditions have to be brought to the notice 

of the Board and got approved by the Board, 

before obtaining consent to operate under 

the said Act. 

8 The unit has to comply with the provisions of 

Public Liability Act, 1991 to provide 

immediate relief in the event of any hazard 

to human beings, other living 

creatures/plants & properties while 

handling and storage of hazardous 

Accepted. 

The industry will make a 

request for grant of consent to 

operate at least thirty days 

before the commissioning of 

trial production. 

The Unit will provide 

compound wall of adequate 

height around the STP. 

Samples of water from the 

wells will be analyzed by the 

Board Laboratory to develop 

line date to assess the existing 

water quality. 

The unit will provide an 

alternate power source along 

with separate energy meter 

for the Effluent Treatment 

Plant & it ensure continuous 

operation of the Effluent 

Treatment Plant. 

It is assured that the consent 

does not authorize or approve 

the construction of any 

physical structure of facilities, 

or the undertaking of work in 

any natural watercourse. 

Any change in the detail 

furnished in the condition will 

be intimated to the Board, 

before obtaining consent to 

operate. 

The unit will ensure the 

provisions of Public Liability 

Act, 1991 to provide 

immediate relief in the event 

of any hazard to human 

beings, other living

substances (if applicable). creatures/plants & properties 

while handling and storage of 

9 Consent to operate will not be issued unless 

the unit complies with all the conditions of 

consent to establish. 

10 In case there is any change in the 

management, the unit shall inform the 

change with relevant documents 

immediately. 

hazardous substances. 

The unit will comply with all 

the conditions of consent to 

establish. 

Any change in the 

management, the unit will 

inform the change with 

relevant documents 

immediately to the Board. 

All the TNPCB consent conditions will be adhered during the construction and the 

compliance will be submitted as per the statutory requirements.

ANNEXURE 

ANNEXURE-4 

ANNEXURE

Annexure IV – List of Activities 

S.No. Activities Responsibility / 

Responsibility for 5 

years 

Responsibility / 

Responsibility after 

5 Years 

1 Compound wall - TWAD/Local body 

2 Bared wire fencing Contractor - 

3 Civil Works Contractor Future expansion- 

TWAD/Local body 

4 Greenbelt – Phase I Contractor - 

5 Greenbelt – Phase II - TWAD/Local body 

6 Environmental Monitoring Contractor for O & M 

period 

TWAD/Local body 

7 Safety Training Contractor for O & M 

period 

TWAD/Localbody

ANNEXURE 

ANNEXURE-5 

ANNEXURE

Reply to the Query 

1. How is it proposed to withdraw sludge from aeration chamber which 

would be flat bottomed? 

The aeration chamber will function as clarifier till the secondary 

clarifier is rectified. 

This will be only for short duration. Hence there will not be 

withdrawal of sludge form Aeration Tank. – Page 23 of EIA report (STP 

Pipeline & Bypass Arrangement) 

2. Description of transfer of treated sewage from aeration 1 to aeration 

chamber 2 in case of use as secondary clarifier. (Please also verify 

possibility of implementation and O&M issues). 

The overflow from aeration chamber will be bypassed to chlorine 

contact tank, when the secondary clarifier is not working. The bypass 

arrangement is enclosed. There is no O & M issue involved in 

implementing the same as the bypass arrangement will be in 

operation only during failure of secondary clarifier until it is restored. 

–Page 23 of EIA report. 

3. The proposal to bypass excess flow eg. During rainy days. 

While designing, we have considered the peak flow of 2.25 and inlet 

chamber is designed based on the peak flow. This will take care of 

excess flow during rainy season. - Page 23 of EIA report. 

4. Where is it proposed to fix the flow measurement arrangement? 

A Flow measurement unit in the form of ultrasonic flow transmitter 

shall be provided in the common header of the raw sewage Pumps. – 

Page 21 of EIA report.

5. The layout may clearly depict the above and may please be provided in 

A3. 

Provided separately.

Enviornmental Assessement report for tiruvarur STP - Municipal ...

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