养猪粪污厌氧消化重金属变化特征及影响

对太湖流域某典型养猪区域粪污收集后集中厌氧消化处理,分析猪饲料、猪粪和沼肥中重金属总量和形态变化特征,探讨厌氧消化过程重金属形态变化及其影响因素。结果表明,不同养殖阶段中猪饲料重金属含量差异较大,仔猪饲料和猪粪中Cu、Zn和Cd含量较高,而Cr和Ni在生长肥育猪后期饲料和猪粪中含量最高。猪粪中Cu主要以有机结合态、Zn主要以Fe-Mn氧化物结合态、Pb和Cr主要以残渣态、Ni主要以Fe-Mn氧化物态和碳酸盐结合态赋存,沼液中Cu和Zn平均值为猪粪液中含量的1. 59和1. 40倍,沼渣中Cu和Zn平均值为调节池猪粪的1. 58和1. 37倍,厌氧消化后重金属存在"相对浓缩效应",pH值、DOC和OM为厌氧消化过程影响重金属变化的主要因素。     

Contribution of additives Cu to its accumulation in pig feces： study in Beijing and Fuxin of China

Massive amounts of pig manure are produced by intensive pig farm in China, and the composition of pig manure has changed much due to the use of feed additives. However, little is known about the exact Cu （copper） feed as additives or present as contaminants in pig feed and the residues in feces. One hundred and thirty-seven feeds and one hundred and forty-two fecal samples from 48 pig farms were collected in Beijing and Fuxin cities in 1999 and 2005, respectively. The concentrations of Cu were in the range of 6.86-395.19 mg/kg in the feed samples, and the mean values were in the order of weaner〉 grower-finisher〉 sow＇s feeds. The high concentrations over EU recommendations implied that excessive levels of Cu are fed on many pig farms in Beijing and Fuxin. Cu was also present in high concentrations in feces, and concentrations were highly variable. Cu concentrations in the feces from grower-finisher and weaner pigs were significantly greater than feces of sows. The super-intensive and small-scale farms had higher levels of Cu in feces than the middle farms. Cu concentrations in pig feces were approximately 5-times greater than in pig feeds. Feed management in grower-finisher pigs on super-intensive and small-scale pig farms is needed to reduce high Cu concentrations in feces and risks to soil contamination while feces are land-applied.