Final Report on Mosquito Breeding Research - SNV

<strong>Final</strong> <strong>Report</strong> on
Mosquito Breeding Research
Prepared by:
Research & Development Unit.
Biogas Sector Partnership - Nepal,
Kathmandu, Nepal.
March 2005
1

Table of Contents
TABLE OF CONTENTS 2
ABBREVIATION 3
ABSTRACT 4
1. INTRODUCTION 5
2. OBJECTIVES 7
3. TECHNICAL DESCRIPTION 7
3.1. INSTALLATION PROCEDURES FOR SIPHON AND FLIP TYPE TRAP 8
4. GOALS 9
5. METHODOLOGY 9
6. LOCATION 10
7. FEEDING RATIO 10
8. FINDING 10
8.1 SIPHON TYPE 10
8.2 FLIP TYPE 10
8.3 INCREASE IN MOSQUITO 10
8.4 DEVICE PROBLEM 11
8.5 BLOGASPIANT OPERATION CONDITION 11
8.6 OPINIONS OF PLANT OWNER 12
9. CONCLUSIONS 13
10. RECOMMENDATIONS 13
11. PLANT RECORDS 15
REFERENCES 15
Annex I
Annex II
Drawings
Data Summary Sheets
3

Abbreviation
CDC
COD
IEIA
MCD
TOC
Centers for Disease Control and Prevention.
Chemical Oxygen Demand
Integrated Environmental Impact Assessment
Mosquito Control device
Total Organic Carbon
4

Abstract
Incident regarding increase of mosquito after installation of biogas have been mentioned in the study
carried out by IEIA in the year 2002. Since, major tropical disease arc spread by biting insects and
malaria being considered as the major international public health problem and is directly associated
with mosquitoes. BSP-Nepal's attention in this incident was fully drawn to preserve the image that it
had muscled to create in the past 13 years.
The First major cause of mosquito increase incident is directly related to the indoor air quality
because before biogas, the households used to use firewood as a source of daily energy that used to
produce smoke. The smoke so produce worked as the insects repellent that drove off insects and
mosquitoes from the house. After the installation of biogas the smoke free indoor environment
became safe and pleasant conditions for mosquito activities. Therefore, this improvement indoor
environment is the root cause of increased mosquito activities inside the house.
The second cause is due to deviation in the dung and water ratio that is fed into the plant As we
know that the most potential breeding place for Mosquito is water therefore, if the mixing
proportion of dung and water is not maintained as specified, the slurry texture becomes thin and
provides breeding ground for mosquitoes.
To overcome this problem, BSP-Nepal have designed two types (Siphon and Flip) of low cost
mosquito control devices. These devices were tested at Lalbandhi of Sarlahi and Birtamod of Jhapa
districts of Nepal. Total 40 (20 siphon and 20 flip type) devices were installed. During the
observation, most of siphon type device were clogged by slurry effecting the functioning of the plant
As for the flip type it functioned well, corrosion in the hinge were developed due to the hydrogen
sulphide content in the slurry. If the hinge can be replaced by the non-corrosive material the flip type
mosquito devices can be used to control mosquito breeding in the outlet tank.
During our interview with the owner 17.5% agreed upon breeding of mosquito in the biogas outlet
tank. 35 % did not agreed with the fact that the increase of mosquito is due to biogas plant and 47.5 %
percent of users said there was no changes even after the installation of mosquito control devices.
It is recommended that the most effective way is to get rid of mosquito before they appear by
maintaining the clean surrounding and feeding the biogas plant with recommended quantity of
dung and water. Not allowing standing water accumulated for more than two days.
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1. Introduction
A wide range of tropical diseases are spread by biting insects, the most dangerous being malaria.
Since, mosquitoes tap into the blood of birds, animals and humans; they can be ghoulishly efficient at
transmitting certain diseases. While some mosquito-borne diseases can be deadly to humans, many
cause only minor, passing symptoms in most people. Malaria is considered to be a major
international public health problem, causing 300-500 million infections worldwide and
approximately one million deaths annually, according to the Centers for Disease Control and
Prevention (CDC) 1 . Since, Mosquitoes carry many different kinds of diseases including malaria,
heartworm, dengue fever, encephalitis and yellow fever. Complains regarding, increase of
mosquito breeding in the outlet tank of biogas plants certainly will rupture the image of Biogas
technology.
In study carried out by IEIA during the first months of 2002, contained over 50 positive points; apart
from one striking negative points mentioning the increase of mosquitoes in the kitchen of the house
holds with biogas plant. Incident of mosquito increase in some 70% of plant, out of 600 plants that
they surveyed, have been reported. The most likely cause, that we perceive in regard to increase in
mosquito is because, the houses using biogas for cooking produced no smoke in comparison to that
of houses using traditional fuel wood. Though the Smoke free indoor environment has provided
numerous health benefits to households it has also provided a pleasant environment for mosquitoes as
well. As we recall the past, we come to know that smoke was used as insect repellent before man
made chemical repellent invaded our society. Thus the smoke free indoor environment is the main
cause of increase of mosquito inside the house of biogas users. Such cases therefore can be assumed
in about 1, 34,000 household having biogas throughout Nepal.
The second most likely cause is due to improper feeding practices such as difference in mixing
proportion, excessive amount of water entering biogas digester through attached toilet and so on.
The nitrogen content of the slurry also discourages mosquito breeding when they are at the
specific range. Excessive water content in the mixture will dilute nitrogen levels that otherwise
would be high enough to retard mosquito breeding. High nitrogen values alone will
1 Centers for Disease Control and Prevention report - 2003.
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dramatically reduce larval survival even when TOC and COD values are ideal for mosquito
production 2 .
Since biogas plants needs recommended quantity of feeding for its optimum operation regularly
however, in urban areas dung feeding is observed to be below the recommended quantity
compared to rural areas where water fetching is considered a hard task. It is due to this malpractice of
under feeding of dung and excess feeding of water, problem of mosquito breading is intense in the
urban areas in comparison with the rural areas.
Therefore, based on the survey report, there was an urgent need to work toward solving the
existing problem, for the sustainability and most importantly to preserve the popularity of this
indigenous technology. Hence, a research to prevent mosquito breeding inside the outlet tank of
biogas plants was initiated.
2
Mike Stringham, Extension Specialist, and Wes Watson, Veterinary
Entomologist, NCSU
7

2. Objectives
The main objective of this research is to identify the actual reason behind the increase in mosquito
breeding inside the outlet tank and to find the best solution to prevent or to minimize the existing
mosquito-breeding problem. This will help in minimizing the epidemic cases cause by mosquito.
Since this emerging concept of increase in mosquito due to installation biogas will have an adheres
negative effect in the technology, there is an urgent need to find the root cause and come up with the
remedies / conclusion in solving the problem to restore the good impression of biogas technology
in Nepal.
3. Technical description
The main cause of mosquitoes breading inside the outlet tank needs to be prevented. Since,
female mosquitoes lay their eggs in the watery surface inside the outlet tank. The eggs are glued
together to form small rafts that float on the slurry watery surface. The larvae, often called
"wrigglers", that hatch are filter feeders that eat small bits of organic matter, bacteria and other
microscopic organisms. The larvae feed and develop and eventually molt into pupae
commonly called "tumblers." This is a non-feeding stage of development. The adult mosquito
emerges from the pupa and completes the life cycle.
Therefore, a technical solution in preventing mosquito breeding inside the outlet tank needs to
be identified. At the other hand a major barrier; 'Cost' needs also to be overcome. Therefore,
the technology should both be cheap and effective at the same time. Keeping these parameters in
mind a cheap type of mosquito control device was designed using cheap HDPE pipe of 4" dia.
The device consists of two components a trap and air vent. The trap is to be installed at the
overflow of the outlet and the air vent for the circulation of air during slurry movement next to
the trap in the outlet. (See the attached drawing in annex 1).
The trap is of two types siphon type and flips type; these traps are made out of 0 4" low quality
HDPE pipe. The air-circulating vent is made out of 01.5" low quality HDPE.
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After installing the trap and air vent pipe at the overflow of the outlet, all the openings in the outlet
slabs needs to be sealed by cement and sand mortar. Then the outlet tank will be covered by earth
except for the air vent and the trap device.
3,1. Installation Procedures for Siphon and Flip type trap
> The HDPE traps are installed as shown in drawing (see annex-1)
> The outlet tank are fitted with two HDPE pipe connections, a trap and air circulating vent
at overflow hole and needs to be fixed with cement and sand mortar as illustrated in
drawing.
> Air vent, pipe is installed next to the trap device and covered by nylon mosquitoes mesh in
order to restrict the mosquitoes from entering the outlet through the air circulating vent.
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4. Goals
• To minimize the mosquito breeding inside the outlet tank of GGC 2047 model biogas plant.
• To find the conclusion of mosquito increase problem.
• Identify the most efficient trap.
5. Methodology
Install the developed mosquito control devices with the assistance of company masons and
conduct periodical observation regarding the functioning.
Fanners are interviewed regarding the increase or decrease of mosquito activities after the
installation of the device.
All the devices are installed in terai regions only because mosquito problem is intense in terai than in
hills.
Companies conduct close monitoring of all the plants installed with the Mosquito Control Device
for the proper operation through out the research time of a year.
BSP- Nepal's R&D Research staff provides training to the company mason during the installation.
R&D Research staffs conducts visit to the site from time to time for observation and interview with
the farmers.
A questionnaire will be used to record the development, which will be analyzed to confirm the
appropriate device and farmers' perception.
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6. Location
Two terai locations were identified for the installation of the mosquitoes control device namely
Birtamod of Jhapa and Lalbandhi of Sarlahi District were selected as the appropriate location for the
testing of these devices. 10 Siphon and 10 Flip type mosquito control devices in each district are
installed. Name and address of the farmers are attached in the Annex -II.
7. Feeding ratio
All the plants owners with the mosquito control device are requested for regular feeding of the
plants and with recommended feeding mixture of 1:1 ratio to maintain the correct slurry thickness.
8. Finding
8.1 Siphon Type
7 out of 10 siphon type devices installed at Lalbandi VDC of Sarlahi were found to be not
functioning in proper condition. Most of them were clogged with dried slurry. The company
removed 2 of the siphons since the functioning of the plant was disturbed. At Birtamod 6 out of 10-
siphon type device installed developed blockage.
8.2 Flip Type
Flip type device seemed to function properly in comparison to the siphon type; 3 out of 10
developed faults in the hinge due to rust which jammed the movement. Rest functioned properly
since the owner took initiative to oil the hinge from time to time. One of the owner removed MCD
from the plant after the flip did not function. In the case of Birtamod, out of 10 flip types device
installed only 2 developed problems due to rusting of the hinge.
8.3 Increase in mosquito
Out of 40 users interviewed regarding increase in mosquito, 7 users (17.5%) agreed, 14 users (35%)
denied and 19 users (47.5%) admitted to have no changes. Most of the farmers assumed that the
increase of mosquito is due to vegetation and ditches in their vicinity.
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Analysis Table:
Installation
Control device Increase in
mosquito
Good Bad Yes No Same
20 Siphon 40% 60% 20% 25% 55%
20 Flip 75% 25% 15% 45% 40%
8.4 Device problem
8.5 Biogas plant operation condition
Out of 40 Plants 10 plants were semi well operated and only was fed at the weekends. In
those plants the slurry thickness was very thin.
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During device installation period we did not see any indication of mosquitoes breeding sign in the
outlet of the well operational plant having proper slurry movement at the outlet. (<strong>Report</strong> on
10May,2004.)
Growth of mosquitoes was observed at heavily dense areas of Human settlement (In city areas)
especially were there were unmanaged waste disposals and uncovered drainages, providing safe
ground for mosquito breeding.
8.6 Opinions of plant owner
Some users (17.5%) agree upon breeding of mosquitoes in the biogas plant They admitted that
increase in mosquitoes was observed after installation of a biogas plant. Therefore, the owner
allowed us to install the device in their plant and showed their commitment to keep the
surrounding environment also clean. 35% did not agreed with the fact that the increase of
mosquito was due to biogas plant. Instead they said that it is due to vegetation and unmanaged
drainage and potholes in their area and 47.5% of user said there was no increase in mosquito
breeding. The summary of data sheets is attached in annex-II,
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9. Conclusions
• Mosquito problems are not created by the biogas plant but it's depends on surrounding
environments like dirt, garbage, water ponds, farm etc. which are suitable condition for the
mosquitoes to breed.
• The mosquito problem is already there in the area, due to unhygienic surrounding which
was not due to installation of biogas plant. This was a very wrong concept.
• Due to daily feeding biogas plant there is always movements of slurry in the outlet tank,
which do not allowed for the breed of mosquitoes.
• Mosquito larvas were found in the plants with excessive water content e.g. plants operated
only with toilet and water under fed plants. Plants with correct slurry thickness and
adequate feeding had no signs of larva in the outlet.
10. Recommendations
Most effective way to get rid of mosquito is to prevent their breeding. Therefore, by
implementing the following steps one can prevent mosquito breeding around biogas home:
1. Biogas owner should maintain clean surrounding and the biogas plants should be
adequately feed with the recommended slurry consistencies (1:1 of water to dung)
2. If recommended slurry thickness cannot me maintained, than they should installed the
mosquito control device designed by BSP-Nepal.
3. Do not allow standing water to accumulate for more than two days in such areas like: old
tires, buckets, unused plastic, the base of a flower pot pet dishes, plastic covers or any
container that may collect water.
4. Clean debris from rain gutters and remove standing water under or around
structures.
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5. In the flat roof, check for standing water several days after a rain.
6. Check rain barrels for mosquito larvae. A tight cover will prevent egg laying. A thin
layer of oil will kill existing mosquitos' larvae.
7. Fill or drain large puddles, ditches and swampy areas.
8. Remove, drain or fill tree holes and stumps with mortar.
9. Keep hedges and bushes trimmed to reduce shade.
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11, Plant Records
S.NO. Owner Name Address Company
1. Shiva Bdr.Karki Lalbandi-1, Sarlahi GGCLAL
2. Mishrimaya Karki Lalbandi-1, Sarlahi GGCLAL
3. Adish Khatiwada Lalbandi-1, Sarlahi GGCLAL
4. Sarswati Dahal Lalbandi-1, Sarlahi GGCLAL
5. Yashoda Pokharel Lalbandi-1, Sarlahi GGCLAL
6. Kamal Dhungel Lalbandi-1, Sarlahi GGCLAL
7. Dol Kumari Karki Lalbandi-1, Sarlahi GGCLAL
8. Kaman Sing Ghising Lalbandi-1, Sarlahi GGCLAL
9. Tulsi Ram Gautam Lalbandi-1, Sarlahi GGCLAL
10. Naw Raj Thapa Lalbandi-1, Sarlahi GGCLAL
11. Mohan Kumari Thapa Lalbandi-1, Sarlahi GGCLAL
12. Punya Psd.Neupane Lalbandi-1, Sarlahi GGCLAL
13. Ganesh Bdr.Ranamagar Jabdi-8, Sarlahi GGCLAL
14. Bal Bdr.Gole Lalbandi-1, Sarlahi GGCLAL
15. Bushnu Psd.Bakharel Lalbandi-1, Sarlahi GGCLAL
16. Gyanu Acharya Lalbandi-1, Sarlahi GGCLAL
17. Tara Devi Baral Lalbandi-1, Sarlahi GGCLAL
18. Ajit Adhikari Lalbandi-1, Sarlahi GGCLAL
19. Durga Kumari Wagle Lalbandi-1, Sarlahi GGCLAL
20. Kapil Paudel Lalbandi-1, Sarlahi GGCLAL
21. Januka Devi Prasain Arjundhara-8, Jhapa KMLJHA
22. Ramesh Prasain Arjundhara-8, Jhapa KMLJHA
23. Kedar Psd. Mainali Anarmani-3, Jhapa KMLJHA
24. Paras Mainali Anarmani-3, Jhapa KMLJHA
25. Harisankar Khadka Anarmani-6 ,Jhapa KMLJHA
26. Qiandra Bdr.Kliadka Anarmani-6, Jhapa KMLJHA.
27. Parbati odari Charpane-1, Jhapa KMLJHA
28. Buddharani Limbuni Charpane-1, Jhapa KMLJHA
29. Prakash Chandra Rai Sanischare-8, Jhapa KMLJHA
30. Pushpa Bhandari Arjundhara-8, Jhapa KMLJHA
31. Umesh Luitel Arjundhara-8, Jhapa KMLJHA
32. Devi Psd.Niraula Arjundhara-8, Jhapa KMLJHA
33. Bishwa Khadka Anarmani-6, Jhapa KMLJHA
34. Parsu Ram Mainali Anarmani-3, Jhapa KMLJHA
35. Paras Mainali Anarmani-3, Jhapa KMLJHA
36. Binita Klianal Anarmani-3, Jhapa KMLJHA
37. Yuba Raj Dahal Anarmani-2, Jhapa PGCJHA
38. Gauri Man Budhathoki Anarmani-8, Jhapa PGCJr-IA
39. NarBdivKhadka Anarmani-4, Jhapa PGCJHA
40. Ganga Raj Prasai Anarmani-4, Jhapa PGCJHA
18

References
• http://science.howstuffworks.com/mosquito.hbn
• Sjoerd Nienhuys, Senior Renewable Energy Advisor, SNV/Nepal report. <strong>Report</strong> date IEIA-
BSP-2003-SJN
• Rutz,, D. A. and R. C. Axtell. 1978. Factors affecting production of the mosquito Culex
quinquefasciatus (=fatigans) from anaerobic animal waste lagoons. North Carolina
Agricultural Experiment Station Technical Bulletin, no. 256; pp. 32.
• Zublena, J. P., J. V. Baird, and J. P. Lilly. 1991 (rev. 1997). Nutrient content of fertilizer
and organic materials. North Carolina Extension Service Publication, AG-439-18 .
• Florida Mosquito Control. An excellent overview of mosquito management control,
monitoring, etc.). Note that not all recommendations are approved for use in North
Carolina.
• 2002 North Carolina Agricultural Chemical Manual provides the latest chemical control
recommendations for mosquitoes and other pests, as well as useful information about
applicator safety, application equipment and calibration, and waste water analysis.
• Mosquitoes and Mosquito-Borne Diseases (NCCES web site)
19

Mosquito Control Device Observation Format
s.n Owner Address Device Type Good Bad Increase
of
Yes No Same
Remarks
1 Jaauka Devi Prasain Arjundhara-8, Jhapa Siphon Excessive water content in the slurry from the
toilet and the plant was not fed as per the
recommended quantity of dung
2 Ramesh Prasain Arjundhara-8, Jhapa Siphon As per owner the increase of mosquito is due to
shrubs and ditches in the vicinity
3 Kedar Psd. Mainali Anarmani-3, Jhapa Siphon Clogged siphon
4 Paras Mainali Anarmani-3, Jhapa Siphon No difference
5 Harisankar Khadka Anarmani-6 ,Jhapa Siphon Irregular feeding and excessive water from the
toilet
6 Chandra Bdr.Khadka Anarmani-6, Jhapa Siphon No idea
7 Parbati odari Charpane-1, Jhapa Siphon may be due to ditches
8 Buddharani Limbuni Charpane-1, Jhapa Siphon no idea
9 Prakash Chandra Rai Sanischare-8, Jhapa Siphon No difference
10 Pushpa Bhandari Arjundhara-8, Jhapa Siphon no idea
11 Umesh Luitel Arjundhara-8, Jhapa Flip The owner thinks that the increase of mosquito is due
to compost pit
12 Devi Psd.NirauIa Arjundhara-8, Jhapa Flip No idea
13 Bishwa Khadka Anarmani-6, Jhapa Flip my be due to pot holes
14 Parsu Ram Mainali Anarmani-3, Jhapa Flip No idea
15 Paras Mainali Anarmani-3, Jhapa Flip Very thin slurry
16 Binita Khanal Anarmani-3, Jhapa Flip They think it is usual
17 Yuba Raj Dahal Anarmani-2, Jhapa Flip Jammed flip
18 Gauri Man Budhathoki Anarmani-8, Jhapa Flip increase of mosquito is due to shrubs and ditches in
the vicinity and no idea regarding from plant
19 Nar Bdr.Khadka Anarmani-4, Jhapa Flip
20 Ganga Raj Prasai Anarmani-4, Jhapa Flip No difference felt
20

sr Owner Address Device
Type
Mosquito Control Device Observation Format
Good Bad Increase of
Mosquito
Yes No Same
1 Shiva Bdr.Karki Lalbandi-l, Sarlabi Siphon clogged sip hone
2 Mishrimaya Karki Lalbandi-1, Sarlahi Siphon No difference
3 Adish Khatiwada Lalbandi-l, Sarlahi Siphon removal of siphon due to blockage
4 Sarswati Dahal Lalbandi-1, Sarlahi Siphon No changes
5 Yashoda Pokharel Lalbandi-l, Sarlahi Siphon removal of siphon due to blockage
6 Kanial Dhungel Lalbandi-1, Sarlahi Siphon due to forest near by
Remarks
7 Dol Kumari Karki Lalbandi-1, Sarlahi Siphon No changes / Slab of outlet not sealed properly with cement
mortar
8 Kaman Sing Ghising Lalbandi-1, Sarlahi Siphon due to in consistency of slurry thickness
9 Tilsi Ram Gautam Lalbandi-1, Sarlahi Siphon Due to toilet
10 Naw Raj Thapa Lalbandi-1, Sarlahi Siphon unmanaged cattle pin
11 Mohan Kumari Thapa Lalbandi-1, Sarlahi Flip No idea
12 Punya Psd.Neupane Lalbandi-1, Sarlahi Flip may be due to ditches
13 Ganesh Bdr.Ranamagar Jabdi-8, Sarlahi Flip No difference
14 BalBdr.Gole Lalbandi-1, Sarlahi Flip feels no difference
15 Bushnu Psd.Bakharel Lalbandi-1, Sarlahi Flip flip not working
16 Gyanu Acharya Lalbandi-1, Sarlahi Flip No idea
17 Tara Devi Baral Lalbandi-1, Sarlahi Flip Flip out of order and not functioning properly
18 Ajit Adhikari Lalbandi-1, Sarlahi Flip same as before
19 Durga Kumari Wagle Lalbandi-1, Sarlahi Flip Device do not prevent mosquito breeding
20 Kapil Paudel Lalbandi-1, Sarlahi Flip As per owner the increase of mosquito is due to shurbs and
ditches in the vicinity
21