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为了解沼液组分的变化特征,指导科学施肥,从长三角地区主要市县城郊区的养猪场、养牛场和一般农户的沼气池中共收集了39个沼液原样,测定了p H、有机碳、COD、全氮、NH_4-N、NO_3-N、有机氮、全磷、全钾和重金属元素铜、锌、铬、铅、砷、镉、汞等的含量,并用多元统计分析评估了组分之间的关系,分析了沼液灌溉农用的重金属污染风险。结果表明:除p H外,不同来源沼液的化学组成有较大的变化,变化幅度多属于中等变异和高强度变异。磷与多数重金属(包括Cu、Zn、As、Cr)含量由高至低依次为:养猪场沼液>养牛场沼液>一般农户沼液。主成分分析表明:沼液中磷、铜、锌、砷及铬含量变化相似,可能与饲料添加剂的使用有关;有机碳、COD和全氮、NH_4-N及有机氮显著相关,它们的含量可能与沼气发酵中有机物料的投量及成分有关;重金属镉和铅有相似的来源,可能受沼气池当地环境的影响。采用Nemerrow综合指数对沼液农用的重金属潜在污染进行评估,结果显示沼液的灌溉污染潜力均属于无风险的范围。但对于养猪场产生的沼液,在农用时应控制用量。
In order to understand the changing characteristics of biogas slurry components and guide scientific fertilization, a total of 39 biogas samples were collected from the digesters of pig farms, cattle farms and ordinary farmers in the suburbs of major cities in the Yangtze River Delta, Organic carbon, COD, total nitrogen, NH_4-N, NO_3-N, organic nitrogen, total phosphorus, total potassium and heavy metal elements such as copper, zinc, chromium, lead, arsenic, cadmium and mercury were calculated and analyzed by multivariate statistical analysis The relationship between components, analysis of biogas slurry irrigation of agricultural heavy metal pollution risk. The results show that the chemical composition of biogas slurry from different sources has a great change except for p H, and the variation ranges mostly belong to medium variation and high intensity variation. Phosphorus and most heavy metals (including Cu, Zn, As, Cr) from high to low were as follows: biogas slurry from pig farm> biogas slurry from cattle farm> biogas slurry from general farmers. The principal component analysis showed that the contents of phosphorus, copper, zinc, arsenic and chromium in biogas slurry were similar, which may be related to the use of feed additives. The contents of organic carbon, COD, total nitrogen and NH_4-N and organic nitrogen were significantly correlated And biogas fermentation organic material dosage and composition; cadmium and lead cadmium have similar sources, may be affected by the digester local environment. The Nemerrow composite index was used to evaluate the potential pollution of heavy metal in agricultural biogas slurry. The results showed that the irrigation potential of biogas slurry belongs to the risk-free range. However, for the production of biogas slurry farm, agricultural use should control the amount.