Bio-Gas Plant at NIT Silchar

The Biogas plant at NIT Silchar was established on 27th July 2013. The plant is based on the Bhaba Atomic Research Center's 'Nisargruna' technology and was developed by AVI Plast, Mumbai. This biogas plant is located at the back side of Boys Hostel 8, opposite to their mess. The hostel, having a 500 student capacity, generates enough organic food wastes everyday which are used to power this Biogas plant.

The digestor has a 100Kg waste per day capacity. Initially, about 20kg waste per day was used for the Biogas generation but now, as the plant is fully functional, roughly 45 Kg food waste is used everyday which might reach 60 Kg in peak days.

A cow dung slurry is prepared as a base for this digestor. Water is mixed with the cow dung to give it a smooth liquid consistency .This is then added to the digestor. The food wastes, which are carefully separated from non biodegradable wastes, are mashed using a motor powered masher and sent to the digestor which then undergoes anaerobic digestion to create biogas. The waste is processed in a sequential manner first by aerobic and then by anaerobic process.The products of the process are biogas consisting of methane, carbon dioxide and water vapor & weed free good quality manure. About 70% of Water can be recycled at the end of the process.

A substantial portion of the biodegradable waste is food waste which is used to generate methane. This methane gas is then used by the Hostel 8 mess employees for cooking purposes. The food wastes yield manure which has high nitrogen contents. This manure acts as an excellent soil conditioner. The manure output is about 10% of the total waste processed. The carbon to nitrogen ratio of this manure is 12:1 (similar to fertile land). It has phosphorous, potassium, iron and magnesium in small quantities. It is weedfree and does not have any offensive smell.

The average total gas output of this plant is currently about 3Kg per day which is stored in a balloon near the plant . There is a pipeline based linkage from the balloon to the Hostel 8 mess where the gas is used for cooking purposes.
This Biogas, even though very small at this stage, serves a very important purpose at our institute-

1. Proper food waste management at Hostel 8.

2. Generation of weed free, odorless , nutrient rich manure.

3. Generation of biogas which is then used for cooking purposes, thus saving energy.

The success of this Biogas plant can certainly pave way for similar projects to be established in every hostel of NIT Silchar and possibly in a larger scale than the current one.