Final Report on Mosquito Breeding Research - SNV

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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