Biogas is a form of clean cooking mechanism, an eco-friendly sustainable source of renewable energy, economically and environmentally compatible to use.  It is produced out of organic waste and can be used for multiple purposes i.e. thermal, electric etc. The slurry that the biogas system produces is a convenient source of organic fertilizer which is a key factor on multiplying the agro-productions maintaining the environmental sustainability.

It is necessary to identify and understand the different components of biogas plant and their activities before installing it. The biogas plant installed in your house is used to produce biogas and this gas is mainly used for cooking and lighting purpose.

Inlet: The fresh cattle dung is properly mixed with water in the proportions of 1:1. The prepared fermentation slurry is allowed to flow into digester through inlet. A metal fan or electric rotor is installed at inlet bunker to mix cattle dung and water properly. The slurry prepared by this process is more effective than prepared by using man hand and produces more gas.

Digester (fermenter): It  is a thermally insulated reservoir tank where the main process of biogas production is completed, in the environment without the presence of oxygen. The slurry present inside the digester starts to produce gas within 55 days at Tarai region but at Hilly region it takes around 70 days because of cold climate. The gas produced inside the digester is collected and reserved at dome which is installed at upper side of digester.

Dome: The main feature of dome is to collect the gas produced at digester. Dome is made fully insulated to minimize the chances of gas leakage. Gas is collected depending upon the capacity of dome. If the produced gas is more beyond the dome capacity, it generates the pressure and slurry is forced to move towards outlet of digester.

Outlet Gas Pipe: The gas collected at dome is supplied to the kitchen and light through outlet gas pipe. During consumption of gas, the slurry starts moving backward towards digester. But when we stop consuming gas or at night time, the pressure created by gas at dome forced the slurry to move out from the digester. The slurry discharged from digester can be used as a good fertilizer for farmers.

Water drain: Sufficient temperature should be maintained at digester for fermentation to produce gas. Because of temperature, so particles present at slurry is converted into moisture. This moisture is finally then moved along with gas toward outlet pipe and is converted into water. The main purpose of water draining system is to drain out this water out of pipe line. Frequently we need to check and remove out the water present inside the pipe line otherwise it may block the flow of gas towards kitchen.

Overflow: Everyday excess amount of slurry after fermentation is drained out from digester through overflow pipe. The drainage overflow should be properly cleaned everyday to make easy flow of slurry. The design of over flow should be maintained so as to block the rainwater enter inside during rainy season.

Domestic Bio-Gas Systems Large Bio-Gas Systems