多级处理模式下粪污中氮、磷削减规律及其农田可消纳量——以苏南水网地区规模猪场为例

摘要

The actual removal rates of nitrogen and phosphorus in animal manure and waste water during multi-level treatment process remain vague for large-scale farms.This limits its land application in water network regions of China.The aims of this study were:(1)to verify the removal characteristics of total nitrogen(TN)and phosphorus(TP)during a multi-level treatment process for swine manure and waste water,and(2)to calculate its land carrying capacity.An intensive swine farm in Southern Jiangsu,which possessed a typical manure and waste water treatment plant with two anaerobic digesters,three natural sediment ponds,and one aquatic plant ponds,was chosen to monitor for the four seasons during a whole year. The results showed that total productions of manure and urine were 4 086.9 t and 10 995.8 t, respectively,in 2016.The collection rate of manure was around 90.5%.The available TN and TP were 183.12 t and 148.97 t,respectively,for land application. The removal rates of TN and TP were less than 25.3% and 57.2% respectively, after secondary anaerobic digestion. The residual TN and TP in the digestates could be removed more than 80% by oxygen ponds treatments. Then the effluent was processed by aquatic plants,and the removal rates for TN and TP were more than 95%,which guaranteed the effluent to be up to the discharge standard. The multi-level processing technology could improve the land carrying capacity and reduce the manure and waste water treatment costs for the intensive animal farms,which were suitable for very intensive,economically developed and land resource limited regions.%针对规模养殖场粪污多级处理模式下氮、磷削减规律及土地承载力不清等问题,以苏南水网地区一规模猪场为研究对象,系统分析了污水经二级厌氧消化、三级沉淀池和水生植物塘逐级处理后氮、磷的去除特征,进一步核算了此模式下粪污实际农田可消纳量.结果表明:猪场全年粪、尿总产生量分别约为4086.9 t和10995.8 t,粪便收集率约为90.5%.收集的粪污中可利用的总氮(TN)和总磷(TP)量分别为183.12 t和148.97 t.粪污经过厌氧消化后TN和TP去除率小于25.3%和57.2%,进一步通过三级沉淀池处理后二者可去除80%以上,最终通过水生植物生态处理后二者去除率均达95%以上.养殖废水经过多级处理工艺,可大幅提高其农田消纳量,降低粪污处理成本,特别适用于集约化程度高、经济发达、土地资源有限地区的畜禽养殖场.