IWE_SSR_15.1.19

CEE 4733
Industrial Wastewater Engineering
Samia Syeoti Ramim
Lecturer, CEE, IUT
Samia Syeoti Ramim

Syllabus
• Characteristics and volume of industrial wastewater;
• Estimation of pollution load;
• Environmental chemistry and microbiology;
• Physical, chemical and biological treatment of industrial
wastewater;
• Problems associated with treatment of wastewaters from
different industries;
• Toxicity and biodegradability;
• Treatment and disposal of sludge;
• Advanced treatment process: Electrochemical processes,
membrane bio-reactors, sequential batch reactor etc.;
• Tertiary treatment;
• Resources recovery, reuse and recycling of industrial
wastewater;
• Zero-discharge technologies.
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What is an industry?
Industry is the economic activity that produces goods
and services through the utilization of available material
resources.
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Levels of Industry
Primary
Secondary
Tertiary
Quaternary
Quinary

Levels of Industry
Primary: Industries that extract or produce raw
materials from which useful items can be made
Example: mining activities, forestry, fishing, agriculture
Secondary: Industries that change raw materials into
usable products through processing and
manufacturing. The term “value added” is sometimes
applied to processed and manufactured items since
the change from a raw material into a usable product
has added value to the item
Example: bakeries that make flour into bread, factories
that change metals and plastics

Levels of Industry
Tertiary: Industries that provide essential services
and support to allow other levels of industry to
function. Often simply called service industries.
Since primary and secondary levels of industry
cannot function without these services, they are
sometimes referred to as “spin-off” industries.
Example: transportation, finance, utilities etc.
Quaternary: Industries for the creation and transfer
of information, including research and training. Often
called information industries.

Levels of Industry
Quinary: Industries that control the industrial and
government decision making process. Policies and
laws are made and implemented at this level. This
level includes industry executives and management
and bureaucrats and elected officials in government

Standard Industrial Classification (SIC) system
• The Standard Industrial Classification (SIC) system has
been developed with an objective to identify
groupings of businesses which carry out similar
economic activities
• In Bangladesh, the industries are categorized as red,
orange and green based on highest to the lowest
pollution creation accordingly
• The Department of Environment has produced a list
of industries consisting red, orange and green
industries and has separate policy, rules and
legislation according to the category to mitigate and
manage the environmental pollution.
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Bangladesh Standard Industrial Classification(SIC-2009)
DOE, GoB
For the purpose of issuance of Environmental Clearance
Certificate, the industrial units and projects shall, in
consideration of their site and impact on the
environment, be classified into the following four
categories:-
(a) Green;
(b) Orange – A;
(c) Orange – B; and
(d) Red
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Water Uses
Agricultural
o Worldwide water use for irrigation -70%, with 15-
35% of irrigation withdrawals being unsustainable
o Around 2,000 - 3,000 liters of water to produce
enough food to satisfy one person's daily dietary
need
o For drinking -2-5 liters
Industrial
o Worldwide water used in industry around 22%, with
high-income countries using 59%, and low-income
countries using a minuscule 8%
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Water Uses
Drinking water
o Worldwide water use for household purposes-8%.
Recreation
o Water use is usually a very small but growing the
percentage of total water use
Environmental
o Explicit environment water use is also a very small
but growing percentage of total water use.
Environmental water may include water stored in
impoundments and released for environmental
purposes
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High Water Consumption Industries
• Energy Production (boiler and cooling unit)
• Food and beverage
• Metal production and transformation
• Chemicals
• Paper and pulp
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What is industrial wastewater ?
• It consists of liquid discharges generated by raw
material extraction or transformation processes with
a view to manufacturing industrial products or
consumer goods
• This type of water is extremely heterogeneous. Its
quantity and quality vary depending on the process
implemented and industrial domain
• It often contains a broad range of chemical
pollutants: solid or dissolved compounds, organic and
mineral materials, metals, hydrocarbons, solvents,
polymers, oil, grease, salts etc., with various toxicity
levels
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Characteristics of Industrial Wastewater
The selection and design of treatment facilities is
based on a study of
- the physical, chemical and biological characteristics
of the wastewater
- the quality that must be maintained in the
environment to which the wastewater is to be
discharged or for the reuse of the wastewater
- the applicable environmental standards or discharge
requirements that must be met
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Characteristics of Industrial Wastewater
Physical
Biological
- Solids
- Odor
- Color
- Temperature
- Bacteria
- Virus
- Plants
- Animals
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Characteristics of Industrial Wastewater
Chemical
‣ Organic
- Carbohydrates
- Fats, Oils and Grease
- Particles
- Phenols
- Proteins
- Surfactants
- Pesticides
- Agricultural
Chemicals
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‣ Inorganic
- Alkalinity
- pH
- Heavy Metals
- Chlorides
- Nitrogen
- Phosphorus
- Sulfur
- Toxic Compound
‣ Gases
- H 2 S
- CH 4
- O 2

Characteristics of Industrial Wastewater
Solids Content:
o The total solids in a wastewater consist of the
insoluble or suspended solids and the soluble
compounds dissolved in water
o Between 40 and 65 % of the solids in an average
wastewater are suspended
o Usually about 60 % of the suspended solids in a
municipal wastewater are settle able
o Solids volatilized at a high temperature (600 °C) are
known as volatile solids, and those which do not
volatilized are known as fixed solids
o Usually, volatile solids are organic
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Characteristics of Industrial Wastewater
Solids Content:
o TS = TSS + TDS = TFS + TVS
o TSS = FSS + VSS
o TDS = FDS + VDS
o TFS = FSS + FDS
o TVS = VSS + VDS
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Characteristics of Industrial Wastewater
Odor:
o Usually caused by gases produced by decomposition of
organic salts
Color:
o Color is a qualitative characteristic that can be used to
assess the general condition of wastewater
o Wastewater that is light brown in color is less than 6 h
old
o a light-to- medium grey color is characteristic of
wastewaters that have undergone some degree of
decomposition or that have been in the collection
system for some time
o If the color is dark grey or black, the wastewater is
typically septic, having undergone extensive bacterial
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decomposition under anaerobic conditions

Characteristics of Industrial Wastewater
Temperature:
o Wastewater temperature is usually higher than the
receiving stream temperature
o Water temperature has effect on aquatic life,
chemical reaction, reaction rate and aquatic life
o Oxygen is less soluble in warmer water
o Increase in temperature increases biochemical
reactions and decreases the quantity of oxygen
present in water
o Affects chemical reactions during the wastewater
treatment process
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Characteristics of Industrial Wastewater
Fats, Oils and Grease:
o Fats are more stable and not easily decomposed by
bacteria
o Fats, oils and grease interfere with the biological
process, cause excessive foaming and results in
increased sludge volume
Surfactants:
o Large organic molecules that are slightly soluble in
water and cause foaming in treatment plant
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Difference between
Industrial & Domestic Wastewater
Parameters
Industrial
Wastewater
Domestic
Wastewater
Temperature
BOD, COD, TDS, TSS
Equalization during
treatment
May have
drastic swings
Comparatively
higher
Must
Usually
uniform
Comparatively
lower
May or may
not be needed
Fats, Oils and Grease Mostly present
Usually not
present

Difference between
Industrial & Domestic Wastewater
Parameters
Industrial Wastewater
Domestic
Wastewater
Pathogenic
Microorganisms
Dissolved metal
salt
Flow Patterns
Usually absent
Relatively high
Depends on shift and
nature of work at
factories; possibility
of zero flow on
days when a factory is
not operating
Largely present
Relatively low
Usually two
peaks— in the
morning and in
the evening

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Effects of Pollutants on Water
(a) Physical effects
(b) Oxidation and residual dissolved oxygen
(c) Inhibition or toxicity and persistence
(d) Eutrophication
(e) Pathogenic effects
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Parameters to be Addressed
Industrial wastewater treatment would typically be
required to address at least the following parameters:
(a) Suspended solids (SS);
(b) Temperature;
(c) Oil and grease (O&G);
(d) Organic content in terms of biochemical oxygen
demand (BOD) or chemical oxygen demand (COD);
(e) pH;
(f) Specific metals and/or specific organic compounds;
(g) Nitrogen and/or phosphorus;
(h) specific micro-organisms
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Pollution load
In most industries, wastewater effluents result from the
following water uses:
sanitary wastewater (from washing, drinking and
personal hygiene);
cooling (from disposing of excess heat to the
environment);
process wastewater (including both water used for
making and washing products and for removal and
transport of waste and by-products); and
cleaning (including wastewater from cleaning and
maintenance of industrial areas)
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Pollution load
The level of wastewater loading from industrial sources
varies markedly with the water quality objectives
enforced by the regulatory agencies
There are many possible in-plant changes, process
modifications and water-saving measures through
which industrial wastewater loads can be significantly
reduced
Up to 90 % of recent wastewater reductions have been
achieved by industries employing such methods as
recirculation, operation modifications, effluent reuse or
more efficient operation
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Pollution load
The level of wastewater loading from industrial sources
varies markedly with the water quality objectives
enforced by the regulatory agencies
There are many possible in-plant changes, process
modifications and water-saving measures through
which industrial wastewater loads can be significantly
reduced
Up to 90 % of recent wastewater reductions have been
achieved by industries employing such methods as
recirculation, operation modifications, effluent reuse or
more efficient operation
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Wastewater Microbiology
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Role of Microorganisms
• The stabilization of wastewater is accomplished
biologically using a variety of microorganisms
• The microorganisms convert colloidal and dissolved
carbonaceous organic matter into various gases and
into protoplasm (biosolids or sludge)
• Because protoplasm has a specific gravity slightly
greater than that of water, it can be removed from the
treated liquid by gravity settling
• Unless the protoplasm produced from the organic
matter is removed from the solution, complete
treatment will not be accomplished because the
protoplasm, which itself is organic, will be measured
as BOD in the effluent
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Bacterial Metabolism
• Metabolism sums up all the chemical activities that
occur within a cell
• Metabolism is divided into two parts:
Catabolism
Anabolism
• Metabolism can be viewed as an energy-balancing act
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Bacterial Metabolism
• Catabolism:
Includes all the biochemical processes by which a
substrate (waste) is degraded to end products with
the release of energy
Results in the breakdown of more complex organic
molecules into simpler substances
• Anabolism:
Includes all the biochemical processes by which
the bacterium synthesizes new chemical
compounds needed by the cells to live and
reproduce
Simpler substances are combined to form more
complex molecules
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General Scheme of Bacterial Metabolism
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Decomposition of Waste
• Aerobic decomposition is a biological process in which
organisms use available organic matter to support
biological activity. The process uses organic matter,
nutrients, and dissolved oxygen, and produces stable
solids, carbon dioxide, and more organisms.
• Anoxic decomposition is a biological process in which
a certain group of microorganisms use chemically
combined oxygen such as that found in nitrite and
nitrate. These organisms consume organic matter to
support life functions. They use organic matter,
combined oxygen from nitrate, and nutrients to
produce nitrogen gas, stable solids and more
organisms.
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Decomposition of Waste
• Anaerobic decomposition is a biological process for
the decomposition of organic matter without oxygen.
Two processes occur during anaerobic decomposition.
First, facultative acid forming bacteria use organic
matter as a food source and produce volatile (organic)
acids, gases such as carbon dioxide and hydrogen
sulfide, stable solids and more facultative organisms.
Second, anaerobic methane formers use the volatile
acids as a food source and produce methane gas,
stable solids and more anaerobic methane formers.
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Decomposition of Waste
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Cycle of Aerobic Decomposition of Waste
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Cycle of Anaerobic Decomposition of Waste
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Growth Pattern of Microorganisms
• When microbes are first added, they begin growing
and dividing slowly as their enzyme systems adjust to
the presence of new nutrients. This is referred to as
lag phase
• After a period of time the microbes begin to grow and
divide very rapidly to take advantage of the favorable
growth conditions – the exponential or log phase
• There may then come a point at which the microbes
have used up some vital nutrient in the growth
medium and they are no longer able to divide – the
stationary phase
• Eventually the microbes become old and start to die –
the death phase
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Growth Pattern of Microorganisms
• These growth stages are important for sewage
treatment processes
• Food becomes the limiting factor in further growth in
between log phase and stationary phase. This is called
declining growth phase and is generally used for
biological treatment systems
• To produce maximum amount of microbes and
microbial products, they must be consistently
provided with new nutrients to prevent them from
entering the stationary phase
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Mathematical Problem
For an industrial wastewater activated sludge process, the
amount of bsCOD in the influent wastewater is 300 gm/
m 3 and the influent nbVSS concentration is 50 gm/m 3 . The
influent flow rate is 1000 m 3 /d, the biomass
concentration is 2000 gm/m 3 , the reactor bsCOD
concentration is 15 gm/ m 3 and the reactor volume is 105
m 3 .
Determine the net biomass yield.
[bsCOD = bidegradable soluble
nbVSS = non biodegradable volatile suspended solid]
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Wastewater Treatment
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The steps in sewage treatment are:
–Separation of solids from liquids
–Treatment and disposal of liquids
–Treatment and disposal of solids
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Phases in Sewage
Treatment Processes
•Preparatory/Preliminary Treatment: To remove coarse
suspended, readily settleable and floating matters, oil or
grease
•Primary/Physical Treatment: To remove settleable and
suspended solids
•Secondary/Biological Treatment: To remove organic
solids through biological processes
•Tertiary/Advanced Treatment: To achieve additional
removal of suspended solids, colloidal particles, removal
of nutrients, refractory organics and further reduction in
fecal coliform
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Wastewater Treatment Options
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Phases in Sewage
Treatment Processes
Preparatory Treatment:
–Screens
–Cutting Screens or Comminutors
–Grit Chamber
–Skimming Tanks
Primary Treatment:
–Sedimentation Tanks
–Septic Tanks
–Imhoff Tanks
Secondary Treatment:
–Stabilization Ponds
–Trickling Filters
–Activated Sludge
–Rotating Biological Contactors
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Septic Tank
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Imhoff Tank
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Waste Stabilization Ponds
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Waste Stabilization Ponds
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In oxidation pond we do all the process naturally and it
requires longer time to regenerate the water. the area
needed is also much more as compared with other
process.
An aerated lagoon (or aerated pond) is a simple
wastewater treatment system consisting of a pond with
artificial (mechanical) aeration to promote the biological
oxidation of wastewater.
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SBR- Sequential Batch Reactor
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Planning an Effluent Treatment Plant:
Factors to Consider
What national or international standards should be
complied with?
↓
Choosing an Effluent Treatment Plant
↓
What volume of effluent is generated?
↓
What chemicals does it contain?
↓
At what concentrations?
e.g. 30m3/hour with COD of 500ppm, and pH of 11.5
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Planning an Effluent Treatment Plant:
Factors to Consider
↓
Is there any plan to increase production?
↓
Will this increase the amount of effluent to be treated?
↓
How much can be afforded to spend on constructing an
ETP?
↓
How much can be afforded to spend on running an ETP?
↓
How much land is available, or can be bought, on which
the ETP is to be built?
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Planning an Effluent Treatment Plant:
Factors to Consider
↓
Which ETP expert or designer should be used?
↓
What type of plant will best suit the requirements?
↓
What capacity does the factory have to manage the ETP?
Does it require to hire more staff or train existing staff?
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