pH值和原料配比对猪粪和玉米秸秆混合厌氧发酵后沼渣沼液中重金属含量的影响

Effects of pH Value and Mixing Ratio of Pig Manure and Corn Straw on Heavy Metal Content in Biogas Residues and Biogas Slurry

随着配合饲料养殖法的应用,畜禽粪便中重金属含量增加。畜禽粪便经沼气发酵重金属含量如何变化,国内外少有研究。因此,该试验研究不同pH值和原料配比条件下,猪粪和玉米秸秆混合厌氧发酵后沼渣沼液中重金属的含量变化,旨在评估其作为肥料的安全性。试验结果表明,在不同pH值及原料配比的条件下,沼渣中除各Zn外,其它重金属Cr,Cu,As,Cd,Pb含量均高于其在沼液中的含量;发酵后沼肥(沼渣+沼液)中重金属除Pb外,Cr,Cu,Zn,As,Cd含量均低于发酵前发酵原料中各重金属含量;通过与NY/T798-2004复合微生物肥料产品无害化指标的比较,沼肥中重金属Cr,Cu,Zn,As,Cd,Pb含量均低于有机肥料中重金属的限量值,因此将发酵后的沼肥作为有机肥施用是安全的。

With the application of formula feed breeding method, the heavy metal content in feces of livestock and poultry was increased. This research studied the heavy metals content changes in biogas residues after anaerobic fermentation of pig manttre and corn straw with different mixing ratio and different pH value, aiming at assessing its safeties as fertilizer. The test results showed that, with exception of Zn, the other heavy metals content, i.e. Cr, Cu, As, Cd, Pb in biogas resi- due, were higher than the content in the biogas slurry; and the content of heavy metals Cr, Cu, Zn, As, Cd in digestate （ both biogas residue and slurry）, were lower than that in raw material before fermentation with exception of Pb. Comparing with harmless standard of NY/T798-2004 for microbial fertilizer, the heavy metal levels of Cr, Cu, Zn, As, Cd, Pb in bio- gas fertilizer were all lower than the limit values, so it was safe to use biogas manure as fertilizer.