There is no wifi in the forest, but I promise you will find a better connection.


    • In small-scale Biogas plants, food and vegetable waste come under decay waste which is a deliberate environmental and economical responsibility all around the world.


  • The fast and highly decompose nature of this waste demands effective management for it to become tenable operation. Since these wastes are generated in huge quantities in highly populated and urban areas, the space available for it to be handled is very limited.


  • It has become a global warning to the environment and health due to its suitable clearance in the developing countries, while in developed countries a plurality of them is still ending up in landfills. In many places, vegetable waste is taken away by farmers as animal feed, however, mixed vegetable and food waste is still a problem to control.

Small Scale Biogas Plant
Fixed Dome Biogas plant

Design of Small-scale Biogas Plant

    • Biogas reactors can be brick-constructed domes or prefabricated tanks, installed above or below ground, rely upon space, soil characteristics, accessible resources and the volume of waste produced.


    • They can be built as a fixed dome or floating dome digesters. In the fixed dome, the volume of the reactor is constant. As gas is produced it expend a pressure and evict the slurry upward into a development chamber. When the gas is taken out, the slurry flows back into the reactor.


  • The burden can be used to move the biogas through pipes. In a floating dome reactor, the dome increase and decrease with the production and withdrawal of gas. Alternatively, it can expand (like a balloon). Rubber-balloon biogas plants are the most simple and cheapest ones to construct.

Types of Biogas Reactors

Rubber-balloon Biogas plants

    • Rubber-balloon biogas plants are the easiest and low-cost ones to build. The balloon plant subsists of a large common plastic bag (e.g. PVC) in which the mud settles on the lowest and the gas is composed in the upper part from where it is withdrawn.


    • The inlet and outlet hook up precisely to the plastic skin of the balloon and there is now development chamber.


  • To transfer the gas from the balloon to where it will be used, the needed burden is accomplished through the elasticity of the balloon and can be enlarged by weights placed on the balloon. 
Rubber Balloon

Fixed-dome Reactors

    • The hooked-dome (fixed-dome) plants subsist a digester with a fixed, non-movable gasholder, which sits on top of the digester. When gas creation starts, the slurry is displaced into the coverage tank.


    • Gas pressure boost with the volume of gas stored and the height difference between the slurry level in the digester and the slurry level in the coverage tank. Fixed-dome biogas plants have comparably low build costs and do not contain corrosion steel. Thus, if they are well build up, they have a wide lifespan.


  • The buried construction saves area and take care of the digester from temperature alterations. However, temperatures are mainly comparably low.

Floating-drum Reactors

    • Floating-drum plants consist of an underground digester and a moving gasholder. The gasholder floats either directly on the fermentation slurry or in a water jacket of its own.


    • The gas is collected in the gas drum, which rises or moves down, according to the amount of gas stored. The gas drum is prevented from tilting by a guiding frame.


  • If the drum floats in a water jacket, it cannot get stuck, even in a substrate with high solid content. Floating dome reactors have the benefit that the gas pressure remains fixed as it relies upon the weight of the gasholder.
Floating Dome


    • The liquid organic wastes like leftover milk, curd, rice wash water, dhal wash water, kanji waste water etc can be directly fed into the digester.


    • Biogas plant/ Bio-Digester should be placed in an open area of smooth & even surface to avoid any physical damage.


    • Biogas plant must be filled with cow dung as inoculum for initial start-up only.


    • Biogas plant should be fed daily without fail for the proper operation of the plant.


    • Solid organic wastes such as vegetable waste, food waste, fruit peels must be mixed with water in a ratio of 1:1 before feeding into the biogas plant.


  • The particle size of the solid waste should be below 25 mm.


    • Avoid feeding chemicals, acidic substances (like tamarind & citrus fruit wastes), plastics, papers, glass & rubber into the Biogas plant which will affect its functioning by killing methanogenic microbes.


    • Avoid feeding more waste into the biogas plant if the previously generated biogas is not used and is stored in the gas holder.


  • Do not overfeed the biogas plant as it creates acidity & reduction in microbial population.

FAQ’s About Small Scale Biogas Plant

Yes, if you have time and money you can surely make one. You will have to educate yourself on the intricacies of a biogas plant design, build a plan, research equipment, find suppliers, hire engineers and contractors, get permits, get financing, negotiate energy contracts, perform construction supervision, register your project for greenhouse gas credits, etc.
After feeding initial start-up, it takes minimum 15 days and maximum 30 days for using the biogas for the first time only. Then after, Biogas can be generated within a time duration of 12-15 hrs after feeding the digester.
Do not use Papers, Plastics, Glasses, Sand, Stones, Chemicals and Metal particles, Bones, Dry leaves, Stems & Sticks, Pseudo stem (Banana stem), Eggshells, Fibres (like Drumstick skin, climbers, etc.,), Acidic materials (like Tamarind, Lemon Peels, Orange Peels, etc.,), Soaps & Detergents.
There will be a rotten egg smell when the Biogas leaks.
Not at all. The Biogas is highly safer than LPG. The density of LPG is heavier than air. When LPG is leaked, it flows for long distances along the ground (downward direction) and can collect in drains, gullies, and cellars which causes an explosion. Unlike LPG, the density of biogas is lighter than air. When leaked, Biogas moves in the upward direction in the air and easily mixes in the atmosphere.