Research Progress on Resource Utilization of Livestock and Poultry Manure

Although mass livestock and poultry breeding brought magnificent econom-ic benefits to the society, it made great harm to the environment. By reviewing the current status of environmental pol ution caused by livestock and poultry manure in China, harm-free treatment technology for livestock and poultry manure including fer-tilization technology, feed processing technology and energy technology were elabo-rated so as to address the existing issues in this regard and provide references for resource utilization and eliminating environmental pol ution through modified technical system and environment laws.

Black soldier fly:A new vista for livestock and poultry manure management

The number of intensive livestock and poultry farms is expected to increase substantially in future because of consumer demand.Unfortunately,such demand also results in a great deal of manure being generated,which threatens the environment if it is not properly managed.Concurrent developments in biotransformation of these wastes with the black soldier fly(BSF),Hermetia illucens(L.)(Diptera:Stratiomydiae),demonstrates such concerns can be abated,while also producing products(e.g.,protein,chitin,biodiesel,and fertilizer)of value.In this review,we analyzed the factors influencing black soldier fly larvae(BSFL)conversion processes,the role of microorganisms,and the mechanisms used by BSFL when converting livestock and poultry manure into these valuable products.The effects of BSFL conversion technology on reducing the hazards of such materials and their associated pathogens are reviewed,and the economics of livestock and poultry manure conversion by BSF larvae is discussed.

Bearing Capacity of Livestock and Poultry Breeding in Nanjing City Based on Planting-breeding Pattern

To assess the status of environmental beating capacity of livestock and poultry manure in Nanjing City, the environmental pollution warning value and environmental bearing potential of livestock and poultry manure in various districts of Nanjing were calculated according to livestock and poultry manure discharge coefticiem and manure content. The results showed that based on planting-breeding pattern, the livestock and poultry manure load in Nanjing City was 14.08 t/hm2 pig manure equivalent; the warning values of environmental bearing capacity of livestock and poultry breeding calculated by nitrogen and phosphor- us were 0.23 and 0.26, respectively, which were within the scope of environmental hearing capacity, with no threat to the environment. Under the premise of reasonable planing of livestock and poultry breeding and comprehensive utilization of manure, the environmental beating potential of livestock and poultry breed- ing in Nanjing City were 5. 667 3 million （nitrogen） and 11. 109 1 million （phosphorus） pigs equivalent, and there were nearly one third of bearing space more than the existing total breeding quantity.

NUMERICAL MODELING OF BIOMASS GASIFICATION USING COW DUNG AS FEEDSTOCK

In this study,a biomass gasification model was developed and simulated based on Gibbs free energy minimization by using software Aspen Plus.Two reactors,RYIELD and RGIBBS,were moslty used.The biomass feedstock used was cow dung.The model was validated.The composition,H_(2)/CO ratio and low heating value(LHV)of the resulting synthetic gas(also known as syngas)was estimated by changing the operating parameters of gasification temperatures,steam and biomass ratios and pressures.Simulation results showed that increased gasification temperature helped to elevate H_(2) and CO content and H_(2) peaked at 900℃.When steam increased as the gasification agent,H_(2) production increased.However,the steam/biomass(S/B)ratio negatively affected CO and CH4,resulting in lower LHV.The optimal S/B ratio was 1.5.An increase in pressure lead to a decrease in H_(2) and CO content,so the optimal pressure for gasification was 0.1 MPa.