Studies On Waste Treatment And Utilization In Large Scale Animal Farm

The pollution of animal farm is very serious near the suburbia of metropolis in China. On the one hand, around the animal farm, the manure and wastewater of animal emit odor and polluted river, soil and underground water. On the other hand, the manure is the better organic fertilizer, after it was treated or composted; the wastewater of pig farms is hard to treated to reached the National Standard of wastewater drainage because high pollute and NH₃-N concentration; dead animal always treated by filling or setting on fire. Therefore, on the basic of references and cooperation with research projects, the writer researched on three programs: Solid waste treatment, wastewater treatment and discharge, and dead poultry composting. The results as following:Animal manure composting by the enclosed composting bin:Three treatments reached the harm-free require of USEPA. The temperature reached to 55 of three treatments sequence is stalk + manure, sawdust + manure and pure manure.For the first time, the pure manure composting experiment was carried out, the result shows the pure manure composting was successful in the condition of lower C/N ratio.This composting system is enclosed system, which can control and reduce the odor emission effectively.This composting system is suit for rainy, cold districts and winter.Wastewater treatment of pig farm:Preliminary investigating the wastewater quality and quantity in different manure removal mode.After 1 to 2 hours settling, the suspended solid removal percentage is 60-70%. It is not useful to extended the settling time.The 5kgCOD/m³Â·day load is the best design parameter of UASB.In the different hydraulic retention time (HRT), study on NH₃-N removal by the SBR treatment of UASB effluent. The NH₃-N removal increased along with the HRT increasing. When the HRT set to 2 days, the SBR is more economical.In practice, the effluent water treated by UASB + SBR reached the National Standard " Integrated Wastewater Discharge Standard " 2^nd scale.Dead poultry treatment:It is first time developed treating dead poultry by composting system. In the studies, three treatments were plan, and measure 3 indexes, the results as following:In the treatments, the sequence of temperature and maintain high temperature is: manure + sawdust > manure + stalk > pure manure. But the pure manure treatment can not reach the sanitation standard.The coliform mortality rate is same as temperature change.Dead poultry decompounded rate: the fastest is manure + sawdust, the second is manure + stalk, and then is pure manure.