August 2022

Biogas Plant Installation-Another Step Towards a Sustainable Campus


Increasingly, the IIIT Bangalore campus is embracing sustainability as it improves the quality of campus life. It is a forward-looking approach to the energy and well-being of the campus community. IIITB can benchmark green initiatives such as the installation of Biogas plant and use them to develop sustainability as an accomplishment parameter towards having a sustainable campus. It is also a step towards making the campus a laboratory for students to learn, innovate and be inspired to become change makers.

The Biogas plant has been installed to convert the organic waste into methane gas(biogas) and bio fertilizers to reduce the dependency on Fossil fuels. A decentralized 100kg capacity of a biogas plant has been installed to make IIIT Bangalore more sustainable. It will generate 10-11 m3 of methane gas per day. With the guidance and support of ELCITA, it was installed recently. Ms. Brunda M, Sustainability Engineer, ELCITA, explains in detail, “The main contain biogas is methane approximately 55 to 65% and carbon dioxide about 30 to 40%. Other than this a very small percentage of ammonia, hydrogen, sulphide and nitrogen is available in biogas. Biogas is having calorific value 5000 to 5500kcal/kg. It is suited for lighting, cooking, drying and fuel for internal combustion engines. Biogas can be produced by fermentation through anaerobic digestion of organic material. The container in which digestion takes place is called digester. A common material used as feedstock is a food waste generated from the IIIT Bangalore canteen.”

Biogas is produced from food waste with 90% water for the action of anaerobic bacteria. Part of the carbon is oxidized and another part is reduced to produce carbon dioxide and methane (CH4). These bacteria live and grow with very less amount of oxygen. The airtight container used for conversion is called a digester. The conversion process is called anaerobic fermentation or bio digestions. The soluble nitrogen compounds known as nutrients are available in solution and produce good quality fertilizer with methane gas.

For a generation of biogas, the chemical process occurs in three stages

  • Stage 1. – The food waste in a digester which is in the form of organic matter and contains a complex compound (carbohydrates, proteins, and fats). With the process of hydrolysis, large molecules of polymers are reduced to small molecules of monomers. This operation takes place in 24 to 48 hours at a temperature of 25˚C in a digester.
  • Stage 2. – The anaerobic bacteria that can grow without oxygen are to gather known as acid formers that produced acetic and propionic acids. In this stage, carbon dioxide is also released, which takes 24 hours at a temperature of 25˚C.
  • Stage 3. – In this stage due to anaerobic bacteria reaction, the methane, carbon dioxide and less quantity of hydrogen gas is produced. These processes take about two weeks to complete at 25˚C.

Scrubbers are used to remove the Hydrogen sulphide and water content. The generated methane gas is stored in the balloon and used in the kitchen for cooking. The quantity of gas generated and utilized is recorded by the Gas Flow meter.