养殖粪便厌氧发酵沼液中金属含量分析

Analysis of Metal Content in Anaerobic Fermentation Biogas Slurry of Livestock Wastes

利用养殖废弃物进行沼气发酵可回收能源,同时沼液可用作肥料。但是,沼液中含有一定量的金属元素,如超过一定限值会限制后续的利用。本文分析了文献报道的46个猪粪沼液、8个牛粪沼液、9个鸡粪沼液中的金属浓度数据,将其与相关标准进行比较,为沼液进行农田利用的过程中降低了金属污染风险。分析发现,猪粪、牛粪和鸡粪发酵沼液均符合《水溶肥料汞、砷、镉、铅、铬的限量要求》和《农用沼液》Ⅲ类金属含量标准。猪粪沼液相比《农用沼液》I类标准,有31.3%的样品As浓度超标,8.3%的样品Cd浓度超标,3.7%的样品Cr浓度超标,2.6%的样品Pb浓度超标。牛粪和鸡粪沼液较为安全。相对于《农用沼液》I类和Ⅱ类标准,牛粪沼液的Cd浓度存在少量超标;鸡粪沼液存在Cr、Cd浓度超标。Pb、Hg在所调查的各类沼液样品中超标的数量极少。猪粪、牛粪、鸡粪发酵沼液均可直接用于非食用类作物的肥料,在用于草本和木本食用类作物肥料时要进行监测分析,以避免金属超标。

Biogas fermentation can be used to recover energy from livestock wastes,and the biogas slurry can be used as a fertilizer.However,the biogas slurry contains a certain amount of metal elements,if exceeding a certain limit,the subsequent utilization will be limited.In this paper,the metal concentration data of 46 pig manure biogas slurry,8 cow manure biogas slurry and 9 chicken manure biogas slurry reported in the literature were analyzed and compared with relevant standards,so as to reduce the risk of metal pollution in the process of farmland utilization of biogas slurry.The results showed that metals in the pig,cow and chicken manure biogas slurry all met the Water-souble fertilizers-Content-limits of mercury,arsenic,cadmium,lead and chromium and the class Ⅲ standard of Biogas Slurry for agricultural use.The problem of pig manure and biogas slurry is more prominent.Compared with the the class I standard of Biogas Slurry for agricultural use,the As concentration in 31.3% samples of the pig manure exceeded the standard,the Cd concentration in 8.3% of the pig manure samples exceeded the standard,the Cr concentration in 3.7% samples of the pig manure exceeded the standard,and the Pb concentration in 2.6% of the pig manure samples exceeded the standard.Cow manure and chicken manure slurry are relatively safe.Compared with the standards of class I and Ⅱ of Biogas Slurry for agricultural use,the Cd concentration in cow manure biogas slurry exceeded slightly the standard,and the Cr and Cd concentration in chicken manure biogas slurry also exceeded standard.The amount of Pb and Hg exceeding the standard in all kinds of biogas samples investigated was extremely small.Pig,cow,and chicken manure fermented biogas slurry can be directly used for fertilizers of unedible crops,and should be monitored and analyzed when using fertilizers for herbaceous and woody edible crops to avoid excessive metal.