The Bio-Gas Plant produces gas from the raw materials of human excreta and cowdung. The residue obtained from the plant is used as the food of fish. It is a system to process livestock wastes into safe, high-quality, efficient organic fertilizer without exhausting greenhouse gases into the air.
These gas plants also contribute to safe-keeping and clean environment by preventing bad odor and contamination of the underground. Furthermore, they are capable of generating electric power and hot water by processing methane gas which is produced during the fermentation process.
Widespread use of the bio-gas plants could deliver a badly needed means of energy self-sufficiency, and the decentralized structure of the biogas plants means less need for expensive distribution of energy in rural areas
The Bio-Gas Plant Process
A Bio-Gas Plant consists of two components:
- Digester also known as fermentation tank.
- Gas holder.
Gas Holder : It is an airproof steel container, which cuts off air to the digester and collects the gas thus generated, by floating like a ball on the fermentation mix. An ever-increasing number of these tanks are covered with a roof to collect as much biogas as possible.
Bio-gas contains carbon dioxide and a slight amount of hydrosulfide as well as methane gas. Hydrosulfide is an obstacle for utilization of biogas, because it is corrosive. After desulfurising through biological method, biogas can be used for power generation. All large-scale biogas plants are controlled by an overall process control system and comes with various devices for measurement and safety purposes.
One of the key features that is commonly found in almost every kind of Bio Gas Plant is that, the gas holder is equipped with a gas outlet, while the digester is provided with an overflow pipe in order to lead the sludge out into a drainage pit effectively. For biogas plant construction, the most significant criteria should be, the amount of gas required, and the amount of waste material that is available for processing purpose.
Alternate Raw- Material
To improve economy of bio-gas plants scientists have discovered other organic substances that can be used alongwith the manure. The examples of such substances are, fats, spice residues, market wastes, residues from food industry and many similar substances. The usage of these as raw material also improves the production level of Bio Gas Plants.
The Bio-Gas Plant that is used to generate gas from this kind of feedstock involves the following steps :-
- Decomposition of organic matter contained in manure.
- Synthesis of acetic acid out of decomposed matter.
- Methane gas formation from acetic acid through the action of microorganism called methanogen.