Waste farm, there are many inadequacies

While biogas promotes good economic and environmental benefits for small scale pig producers, medium-sized farms (over 50 pigs) and large (over 500 pigs) There are still many inadequacies, mainly related to the demand for gas and the waste treatment of animal waste and biogas waste water.

On demand for gas: For small scale livestock, a biogas plant with a capacity of about 9 m3 is enough to provide gas for a household's daily cooking needs. However, the gas produced by medium and large scale biogas plants is currently almost unused. Only a small fraction of the gas produced by pig farms is used for on-farm cooking, and most of the gas is burned or discharged into the environment. Some farms have tried to use gas generator models but are ineffective due to some of the following reasons: (i) The electricity price of the State grid is much cheaper than the cost of gas production from gas. ; (Ii) the current gas filtration technology is not good, leading to high levels of H2S and steam that remains in the gas causing generator damage; (Iii) Most of the current generators are of low quality or refurbished from oil or gasoline generators, so low efficiency, or poor quality, generators must be imported at a cost. Huge investment.

In fact, some farms have invested generators but only used the first time and then abandoned. Meanwhile, technology transferring gas from farms to households for cooking has not been studied in our country. Treatment of pig manure and waste water after biogas of pig farms are also inadequate. In many places the project staff surveyed, the water and the environment around the farms were severely polluted.

The main problem causing pollution is pig manure brought to the biogas tunnel in excess of processing capacity of the tunnel, faeces that have not yet dissolved in the drainage system, causing pollution of the surface water of the residential areas. Some pig farms incorporate fruit and industrial crops that have deposited biogas effluent in ponds and used to irrigate the plants but do not know how to properly use the wastewater after the biogas. Growing dead or developing poorly. Mr. Hung, owner of livestock farm has about 3,500 pigs and tens of hectares of forest and fruit trees in Huong Son district, Ha Tinh province said waste water after biogas is too black and many bubbles, fruit watering can The tree is dead, must discharge into the stream.

While the farm owner still has to buy large amounts of chemical fertilizer, he can not use the nutrients from animal waste to replace the cost of chemical fertilizer. At present, research and guidance for farmers on the use of organic fertilizers produced from livestock waste, biogas waste water to fertilize different crops, different soil types are still very limited. Taming and tinkering. In short, pig waste is a great source of energy that can be used to generate energy for cooking, electricity generation, organic fertilizers, fish and worms, and reducing environmental pollution. Pig farming, a very serious problem in many rural areas.

However, this area has not received adequate attention from researchers to find a suitable technology solution to form a market for gas for cooking, power generation or fertilizer markets. Production from livestock waste. Mountain gas generated from large-scale biogas reactors is still waiting technology suitable for Vietnam conditions to be used up for the needs of the people. Microorganic organic fertilizers are still being produced on a large scale from peat resources while peat and renewable resources are wastes that are still being wasted and polluting the environment.

TS. NGUYEN THE HINH

(Director of Central Project Management Unit LCASP).