混合物料厌氧发酵对沼渣、沼液中重金属Cu、Zn的钝化作用

Passivation of heavy metals Cu and Zn in biogas residue and biogas slurry by anaerobic fermentation of mixed materials

为提高猪粪厌氧发酵过程中重金属钝化效率,选择猪粪、小麦秸秆、蓝藻为原料,组成猪粪+小麦秸秆(ZJ)、猪粪+蓝藻(ZL)的厌氧发酵物料组合,以猪粪单一发酵(CK)为对照,筛选钝化效果最优的物料组合。结果表明:和猪粪原料相比,厌氧发酵后CK、ZJ沼渣中重金属残渣态增加,ZJ增加最多,Cu、Zn残渣态分别增加8.17百分点和4.06百分点;CK、ZJ重金属生物有效性下降,ZJ下降最多,Cu、Zn分别下降44.46%和43.43%;沼液中Cu、Zn含量明显升高;厌氧发酵后特征荧光峰总强度和类蛋白物质特征荧光峰强度降低,且厌氧发酵前后特征荧光峰总强度差值、类蛋白质物质特征荧光峰强度差值与沼液Cu质量浓度增加率,沼渣Cu、Zn生物有效性下降率皆存在显著相关关系(p<0.05)。3组试验中ZJ对Cu、Zn钝化效果最优,可有效降低猪粪中重金属生物有效性。

To solve the problem of low passivation efficiency of heavy metals in the anaerobic fermentation of single pig manure,pig manure,wheat straw and cyanobacterial were used as raw materials to form an anaerobic fermentation material combination of pig manure+wheat straw(ZJ),pig manure+cyanobacteria(ZL),and single pig manure fermentation(CK)was set as a control to screen the material combination with the best passivation effect.The results showed that compared with pig manure raw materials,the residual state proportion of anaerobic fermentation of CK and ZJ increased after anaerobic fermentation,and ZJ increased the most.The residual state proportion of Cu and Zn increased by 8.17,4.06 percentage points,respectively.The bioavailability of heavy metals in CK and ZJ decreased,and the decrease rate of ZJ was the highest.Cu and Zn decreased by 44.46%and 43.43%,respectively.In addition,the content of Cu and Zn in biogas slurry increased significantly.The total intensity of the characteristic fluorescence peak and the characteristic fluorescence peak intensity of the protein-like substance decreased.There was a significant correlation between the total difference of characteristic fluorescence peak intensity befor and after anaerobic fermentation and the increased proportion of Cu concentration of biogas slurry,the decreased proportion of heavy metals Cu and Zn in biogas residues(p<0.05).And the difference of characteristic fluorescence peak intensity of protein-like substances had the same rule.ZJ had the best passivation effect on Cu and Zn in the three groups of experiments,and could reduce the bioavailability of heavy metals in pig manure effectively.