集约化奶牛养殖场不同粪尿处理阶段氮素分布及氨排放特征

为促进奶牛养殖场的大气氨排放控制,形成奶牛养殖场粪便中氨排放的阻控体系,该文在冬季和夏季对内蒙古呼和浩特地区奶牛养殖场A和奶牛养殖场B的大气、牛粪和牛尿进行了采样试验分析,研究了2种奶牛养殖场不同处理工艺的氨排放特征。静态试验结果表明,奶牛养殖场A和奶牛养殖场B氨气排放浓度最高的是氧化塘处理工艺、预处理工艺,分别为冬季0.862,3.169 mg/m3,夏季2.785,2.130 mg/m3。动态试验结果表明,牛粪的氨排放系数要高于牛尿1.85倍,奶牛养殖场A和奶牛养殖场B平均排放系数分别为29.23%、49.36%。奶牛养殖场A和奶牛养殖场B总大气氨排放量分别为冬季172.69,1 101.00 kg/d,夏季284.70、1 395.32 kg/d。2种处理工艺冬季和夏季大气氨含量均满足畜禽场环境质量标准,但超过人居空气质量标准。

Nitrogen distribution and ammonia emission characteristics in different livestock manure treatment processes in intensive dairy farms

Abstract: In order to strengthen atmospheric ammonia emission control in dairy farms and further establish a control system for ammonia emissions from the dairy farm manure, the research conducted sampling test analysis on the atmosphere, cow dung and bovine urine of Dairy Farm A and Dairy Farm B in Hohhot, Inner Mongolia in the winter and summer. The ammonia emission characteristics of 2 treatment processes were studied. Static sampling test results show that the highest concentration of ammonia in Dairy Farm A occurs under the oxidation pond treatment process. And the higher concentration of ammonia emissions occurs in the dairy cow cowshed and the pregnant dairy cow cowshed. The ammonia concentrations in the oxidation pond, dairy cow cowshed and pregnant dairy cow cowshed were 0.862, 0.823, and 0.585 mg/m3 in winter and 2.785, 2.155, and 2.146 mg/m3 in summer. The highest concentration of ammonia in Dairy Farm B occurs under the pretreatment process. The higher ammonia emission concentration occurs in the pregnant dairy cow cowshed and the biogas residue composting area. The ammonia concentrations in the pretreatment, pregnant dairy cow cowshed and biogas residue composting area were 3.514, 3.169, and 2.614 mg/m3 in winter and 2.130, 1.429, and 1.601 mg/m3 in summer. The ammonia concentration in winter for Dairy Farm A is 1.8 times of the habitat standard, and the highest is 4.3 times of the habitat standard. In summer, the ammonia concentration is on average 5.4 times of the habitat standard, and the highest is 10.7 times of the habitat standard. The ammonia concentration in winter for Dairy Farm B is 8.3 times of the habitat standard, and the highest is 17.5 times of the habitat standard. In summer, the ammonia concentration is on average 4.1 times of the habitat standard, and the highest is 10.6 times of the habitat standard. Dynamic sampling test results show that cow urine can release most of the ammonia gas quickly in a short time and cow dung can release ammonia gas for a long time. The cow urine of Dairy Farm A and Dairy Farm B quickly releases ammonia within 8 h. But cow dung from Dairy Farm A releases ammonia for up to 60 h and cow dung from Dairy Farm B releases ammonia for up to 32 h. The ammonia emission coefficient of cow dung in Dairy Farm A is higher than that of cow urine, which is 1.35 times of that of cow urine. The ammonia emission coefficient of cow dung in Dairy Farm B is higher than that of cow urine, which is 2.27 times of that of the cow urine. The average ammonia emission coefficient of Dairy Farm A is 29.23%. The average ammonia emission coefficient of Dairy Farm B is 49.36%. The ammonia emission of cow urine in Dairy Farm A is higher than that of cow dung, accounting for 70.51% of total emissions in winter and 86.22% of total emissions in summer. The contribution of cow dung and cow urine to atmospheric ammonia emissions in winter and summer from Dairy Farm B is similar. In winter, the ammonia emissions of cow urine account for 53.06% of the total emissions, and the ammonia emissions of cow urine in summer account for 49.36% of the total emissions. Ammonia emissions from Dairy Farm A are 172.69 kg/d in winter and 284.70 kg/d in summer. And ammonia emissions from Dairy Farm B are 1 101.00 kg/d in winter and 1 395.32 kg/d in summer. Correlation analysis shows a significant positive correlation between ammonia nitrogen and total nitrogen, with a correlation coefficient of 0.911 (P<0.01).