Study On Ammonia Emission Characteristics Of Large-scale Poultry Farms In Jiangxi Province

Poultry has a large ammonia emission potential.The research on the ammonia emission characteristics of typical large-scale chicken farms is of great significance of improving the air quality of chicken houses,reducing pollution of poultry breeding,and controlling harmful gas emissions.This study takes the typical large-scale laying hen and broiler farms in Jiangxi Province as the research object,monitored the ammonia concentration level of the two main ammonia emission nodes in barns and manure treatment facilities,calculated the ammonia emission coefficients,analyzed the ammonia emission characteristics,and discussed the effects of Meteorological factors such as temperature and humidity on ammonia emission.The main results are as follows:(1)Ammonia emissions from layer house and manure treatment facilities have a daily change process of high in daytime and low at night,and also have a seasonal change feature of high in summer and low in winter.In spring,summer,autumn and winter,the average ammonia emission concentrations of layer house were 1.480mg/m~3,0.765 mg/m~3,1.425 mg/m~3 and 2.452 mg/m~3,the average ammonia emission rates were 11.668 mg/(h·bird),21.155 mg/(h·bird),19.093 mg/(h·bird)and 9.996mg/(h·bird).In spring,summer,autumn and winter,the average ammonia emission concentrations of layer manure treatment facilities were 18.899 mg/m~3,63.614 mg/m~3,22.808 mg/m~3 and 52.114 mg/m~3,the average ammonia emission rates were 0.180mg/(h·bird),0.608 mg/(h·bird),0.218 mg/(h·bird)and 0.497 mg/(h·bird).(2)Ammonia emissions from broiler house and manure treatment facilities have a daily change process of high in daytime and low at night,and also have a growth cycle change feature of low in 6 weeks and high in 18 weeks.The average ammonia concentrations at 6-week-old,12-week-old,and 18-week-old broiler house were 2.430mg/m~3,3.177 mg/m~3 and 3.187 mg/m~3,the average hourly ammonia emission rates were 10.279 mg/(h·bird),19.367 mg/(h·bird)and 27.291 mg/(h·bird).The average ammonia concentration at 6-week-old,12-week-old,and 18-week-old broiler manure treatment facilities were 15.418 mg/m~3,12.433 mg/m~3 and 13.297 mg/m~3,the average hourly ammonia emission rates were 0.153 mg/(h·bird),0.476 mg/(h·bird)and 0.644mg/(h·bird).(3)In four seasons,the average ammonia emission coefficient of laying hen house was 0.372 g/(d·bird);the average ammonia emission coefficient of manure treatment facility was 0.009 g/(d·bird).In three growing stages,the average ammonia emission coefficient of broiler house was 0.456 g/(d·bird);the average ammonia emission coefficient of manure treatment facility was 0.010 g/(d·bird).The ammonia emission coefficient of the house is significantly greater than the ammonia emission coefficient of the manure treatment facility,indicating that the house node is the most important source of ammonia emission contribution from large-scale poultry farms.It is recommended to add ventilation facilities and timely treat the manure in the house.(4)Temperature and humidity are important factors affecting ammonia emission.Ammonia emission rate has a significant positive correlation with temperature and a significant negative correlation with humidity.There is a great difference in the comprehensive effect of temperature and humidity on ammonia emission from poultry farms.The ammonia emission of laying hens in the spring was more affected by temperature and humidity than that in summer,autumn and winter.Ammonia emission of 12-week-old broilers was more affected by temperature and humidity than that of 6-week-old and 18-week-old broilers.