Introduction: kitchen waste to energy
Add kitchen bio degradable Solid waste to a 5 HP mixer to process the waste before putting it into predigestor tank. The waste is converted in slurry by mixing with water (1:1) in this mixture.
Use of thermophilic microbes for faster degradation of the waste. The growth of thermophiles in the predigestor tank is assured by mixing the waste with hot water and maintaining the temperature in the range of 55-60oC. The hot water supply is from a solar heater. Even one-hour sunlight is sufficient per day to meet the needs of hot water.
After the predigestor tank the slurry enters the main tank where it undergoes mainly anaerobic degra-dation by a consortium of archae-bacteria belonging to Methanococcus group. These bacteria are naturally present in the alimentary canal of ruminant animals (cattle). They produce mainly methane from the cellulosic materials in the slurry.
The undigested lignocellulosic and hemicellulosic materials then are passed on in the settling tank. After about a month high quality manure can be dug out from the settling tanks. There is no odour to the manure at all. The organic contents are high and this can improve the quality of humus in soil, which in turn is responsible for the fertility.
As the gas is generated in the main tank, the dome is slowly lifted up. It reaches a maximum height of 8 feet . This gas is a mixture of methane (70-75%), carbondioxide (10-15%) and water vapours (5-10%). It is taken through GI pipeline to the lamp posts. Drains for condensed water vapour are provided on line. This gas burns with a blue flame and can be used for cooking as well.
The gas generated in this plant is used for gas lights fitted around the plant. The potential use of this gas would be for a canteen. The manure generated is high quality and can be used in fields.
Success of this biogas plant depends a great deal on proper segregation of the kitchen waste. The materials that can pose problems to the efficient running of plant are coconut shells and coir, egg shells, onion peels, bones and plastic pieces. Steel utensils like dishes, spoons etc. are likely to appear in the waste bags from canteens. While bones, shells and utensils can spoil the mixer physically, onion peels, coir and plastic can have detrimental effects on microbial consortium in the predigester and main digestion tanks which could be disastrous for the plant.
THE PROPOSAL:
- Mixer with stirrer to mix hot water (1:1) to form a slurry,
- Aerobic Digester,
- Anaerobic digeter
Gas Holding MS Steel Dome
Steel Fabricated Covers on Manure Pits,
Mixer Stirrer ,3 HP, 1 no
Air Compressor
Solar Water Heater
Water Pump and Slurry Pump
Water and Gas Pipelines on Plant area
Electric Fittings & Miscellaneous
Total Project cost Rs.5,50,000/-
Technology and Consultancy Rs. 1,00,000/-
Grand Total Cost of Project Rs.6,50,000/-
POWER GENERATION: Bio Gas production = 100 cu mtr /day for 0.5 ton of waste
Methane content (65.75%) = 65.75 cu mtr
Calorific value =28.9 MJ/N.cu mtr
Energy content 65.75x28.9x273/(273+30)=1712 MJ/Day
Generator efficiency--- 30%
Electricity generated =0.3x1712x1000000/3600x1000
= 142.66
Electric power generated = 142.66x0.04167=5.944 kw say 6 kw
= 1.25x 6= 7.5 kva.
We can go for a gas engine of capacity 5 KW . If any gas is left , it will be flared or supplied to staff quarters
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