Bio-gas production for sustainable agriculture

 I took up farming in 1992, at my native village (after retirement) Ammachiyapuram, near Theni District, Tamil Nadu, after my retirement from Tamil Nadu electricity board. We started farming with one native cow and calf. Presently we own twenty cattle (cows and bulls). We bred and sold more than hundred native cows and bulls. We have a poultry farm with fifty birds. Our farm is surrounded by 300 hundred coconut trees.

    We use bio gas for our cooking. We started our first bio gas plant in 1990 with a rotating drum model (drum holder made of steel). We could not run the bio gas plant as we did not own the cows, then. We started our second plant in 1994 and it was a rotating drum model (holder drum made of plastic). We could not run the plant as the plastic drum got jammed inside the holder and the drum got damaged.

    After failures we decided to go for other type of models. We constructed dome (Dinapandhu) model bio gas digester. We constructed one digester and after seeing the performance decided to go for two more digesters. Presently we have three bio gas digesters of 2.5 meter cube each. All the inlets for feeding cow dung (into the digester) is interconnected by PVC pipe and valves are provided at each plant inlet. Inter connection of inlets minimizes labour and saves time for feeding cow dung. For mixing the cow dung with water, cements tubs are provided and tub is connected with water tap. Daily cow dung is loaded to the tub and mixed with water and fed through the PVC pipes at once. These three plants can provide bio gas 24 hours a day. The biogas digesters are running for more than ten years now.

The outlet of bio gas digester is taken through tubes (tubes are taken to 10 meter height before using in stoves to reduce the moisture droplets in the gas). Bio gas is one of the best methods for sustainable agriculture. It is said that 2-3 cows are enough for running one 2.5 meter cube bio gas digester. We have a portable digester in house which I am testing for its performance.  I being an electrical engineer my main aim is to produce electricity from biogas. We also purchased a diesel motor and diesel generator for doing experiments with biogas. We tried to purchase a generator running with biogas from an IIT Professor who is working on biogas. We could not purchase the bio gas generator as it was costing us around 1.25 lakhs.

The bio gas digesters supply good manure for fields. The outlet of the plant is connected to the canal. The digester outlet canal is provided with pump set water which carries the digester cow dung to the fields. This reduces the labour for transport of digested cow dung to the fields. The digesters are built at high level from ground so that water and cow dung from digester easily flows into the fields. The insects which are generated by cow dung are good feed for hens and ducks.

We own more than 300 coconut trees. We have our own oils extractor and rice huller. We also sell coconut oil, rice and other cereals to farmers in our village. We also produce our own cattle feed. Presently, we are using the rice husk and oil cake as a feed for cattle and poultry. Around 5-6 labourers work on the farm and my son Rajaseelan takes care of the farm. Being a well known organic farmer in Theni district, many farmers visit our farm daily for innovative approaches and advice.

I feel bio gas digester is one of best options for sustainable agriculture if a farmer has cattle and water availability and is prepared to invest in a small way.  With LPG getting expensive, bio gas digester is the best option for any organic farmer which also helps in promoting sustainable agriculture.

Er.K. Rajarathinam

Retired Chief Engineer, Tamilnadu Electricity Board

SRR Industries, Ammachiyapuram, Theni district,  Tamil Nadu-626531

CELL NO:  9786179262,  8098888242

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