Disposal of cow dung is one of the major problem being faced by dairy products producers across the world. Cow dung is not a problem but it is a big asset. There are two ways of processing these to produce Organic Fertilizer.
1. Bio Gas Plant: Here the Biomass is digested in a simple plant and Bio Gas produced is stored and used. The area required for plant is very small.
2. Composting: Here the Biomass is digested underground but Bio Gas is not produced and fuel potential is wasted. It needs large area of land.
A Dairy plant, produces 2.5 to 3 tons of cow dung. If we carefully analyze this waste, we will realize that majority of it is biodegradable. Cow Dung can be converted to valuable organic fertilizer. Generally a slurry of 8 to 10% solids is used in Bio Gas palnt, and one get 350 Kilo Calories per Kg of Cow Dung Cake.
When compared with other organic sources, (manures, oil seed cakes), Cow dung provide aessential elements and thereby promote more harvests from nature.
Disposal of Cow Dung, can be achieved by several other means like incineration, landfills, dumping in the or other water bodies etc. These methods have their own hazards. Incineration can lead to respiratory illnesses. Moreover it may lead to disruption of biochemical cycles of several elements and will have long term effects on biosphere. Landfill and dumping can pollute water bodies.
Dairy Farm Based Bio Gas plant would serve many purposes such as:
Environment friendly disposal of waste, Which is need of hour considering mass pollution everywhere.
Generation of fairly good amount of fuel gas, which will definitely support the dwindling energy resources.
Generation of High quality manure, Which is an excellent soil conditioner. This is very important for replenishing fast decreasing resources of productive soils. It must be noted that need for replenishing the soil with high quality organic manure has been identified in plan documents.
Biogas is colour less, odour less and flammable gas. The gas generated in this plant can also be used as a source of natural gas. The production of biogas, is about 0.25 to 0.35 cubic meters per Kg of cake fermented, with following composition of biogas.
• Methane (CH_4)
• Carbon Dioxide (CO_2)
• Water vapour : 5-10%
Amount of Bio Material required for production of 1 cubic meter of BioGas (equivalent to 400 gms of LPG, fuel for 3 to 4 people).
• State, leftover food: 5kgs
• Animal Dung: 25 kgs
• Chicken dung 2kgs + animal dung 10 kgs
• Spoiled flour of wheat / corn: 1.5kgs