郇辉辉, 储昭霞, 王兴明, 范廷玉, 董众兵, 甄泉, 张佳妹, 代碧波. 蚯蚓粘液-秸秆炭共同作用对生活污泥堆肥中重金属的影响[J]. 中国生态农业学报 (中英文), 2023, 31(4): 577−586. DOI: 10.12357/cjea.20220253
引用本文: 郇辉辉, 储昭霞, 王兴明, 范廷玉, 董众兵, 甄泉, 张佳妹, 代碧波. 蚯蚓粘液-秸秆炭共同作用对生活污泥堆肥中重金属的影响[J]. 中国生态农业学报 (中英文), 2023, 31(4): 577−586. DOI: 10.12357/cjea.20220253
HUAN H H, CHU Z X, WANG X M, FAN T Y, DONG Z B, ZHEN Q, ZHANG J M, DAI B B. Effects of earthworm mucus and straw charcoal on heavy metals during domestic sludge co-composting[J]. Chinese Journal of Eco-Agriculture, 2023, 31(4): 577−586. DOI: 10.12357/cjea.20220253
Citation: HUAN H H, CHU Z X, WANG X M, FAN T Y, DONG Z B, ZHEN Q, ZHANG J M, DAI B B. Effects of earthworm mucus and straw charcoal on heavy metals during domestic sludge co-composting[J]. Chinese Journal of Eco-Agriculture, 2023, 31(4): 577−586. DOI: 10.12357/cjea.20220253

蚯蚓粘液-秸秆炭共同作用对生活污泥堆肥中重金属的影响

Effects of earthworm mucus and straw charcoal on heavy metals during domestic sludge co-composting

  • 摘要: 生活污泥中富含的重金属限制其资源化利用, 为钝化重金属活性, 降低污泥毒害效果和提高其利用价值, 以40 mL蚯蚓粘液和2%、4%、6%、8%秸秆炭为添加剂对2 kg污泥进行堆肥, 研究粘液、粘液协同秸秆炭添加对污泥堆肥后重金属变化的影响。结果显示, 与对照组污泥堆肥相比, 粘液堆肥污泥后pH升高1.42%, 总氮、总磷含量降低7.87%、14.18% (P<0.05); 而粘液协同秸秆炭堆肥污泥后, 污泥逐渐呈碱性, 电导率提升5.71%~9.58% (P<0.05), 有机质含量升高7.71%~24.60% (P<0.05), 丰富了堆体中可溶性离子和有机物含量, 但总氮、总钾含量分别降低19.10%~30.95%、7.87%~14.31%。在添加粘液对污泥堆肥后, 重金属总量均表现出下降趋势, Ni、Zn、Pb的较活泼形态向难以降解的残渣态转化, 使残渣态所占比例较CK处理分别升高61.81%、120.19%、72.51%; 当添加粘液和秸秆炭对污泥堆肥后, 重金属总量继续表现出下降趋势, 碳酸盐结合态Ni和Pb、铁锰结合态Pb、可交换态Zn逐步向稳定的残渣态转化, 而有机结合态Cu却向可交换态和残渣态转化, 钝化了堆肥污泥中Ni、Zn、Pb, 活化了Cu。最后根据分析得出结论, 粘液协同秸秆炭改变污泥中pH来影响重金属Ni、Zn、Pb、Cu有效态, 粘液+8%秸秆炭处理对污泥重金属的影响较为理想。

     

    Abstract: Heavy metals restrict the reuse of municipal sludge. To passivate the activity of heavy metals, reduce sludge toxicity, and create new value, 2 kg of sludge was composted with 40 mL earthworm mucus and 2%, 4%, 6%, and 8% straw charcoal, to investigate changes in the heavy metal mobility in sewage sludge. The results showed that, compared with the control sludge compost (CK), the pH increased by 1.42% (P<0.05) and the total nitrogen and total phosphorus decreased by 7.87% and 14.18%, respectively (P<0.05), after the addition of the mucus to the sludge. After adding both the mucus and straw charcoal to the sludge compost, the sludge gradually became alkaline; furthermore, its electrical conductivity value increased by 5.71%−9.58% (P<0.05), and organic matter content increased by 7.71%−24.60% (P<0.05). Although this enriched the content of soluble ions and available organic matter in the compost, the total nitrogen and potassium contents decreased by 19.10%–30.95% and 7.87%–14.31%, respectively, resulting in the loss of plant nutrients. By adding mucus to the sludge compost, different total heavy metal contents showed different declining trends; these included Cd, Cu, Ni, Zn, and Pb, which decreased by 3.59%, 7.03%, 10.93%, 8.39%, and 5.11% (P<0.05, except Ni), compared to the CK treatment group. The more active forms of Ni, Zn, and Pb were transformed into an unavailable residue form that was difficult to degrade; therefore, the proportion of residual forms increased by 61.81%, 120.19%, and 72.51%, respectively, compared with the CK treatment. When the mucus and different proportions of straw charcoal were added to the sludge, the total heavy metal contents decreased further. The total amount of Cd, Pb, Cu, Ni, and Zn decreased by 37.18%, 67.36%, 6.07%, 59.59%, and 31.82%, respectively, in the mucus plus 8% straw charcoal treatment group (P<0.05). The Ni and Pb associated with the carbonate, Pb associated with iron-manganese, and exchangeable Zn were gradually shifted to the residue form, so that the available contents of Ni, Pb, and Zn were significantly decreased by 28.08%, 42.00%, and 28.31%, respectively, in the mucus plus 8% straw charcoal treatment group, which passivated Ni, Zn, and Pb in the composted sludge. In contrast, organic form of Cu was converted into exchangeable and residual forms. Its available content was increased by 89.82 % (P<0.05) in the mucus plus 8% straw charcoal treatment group, and Cu was activated in the sludge during composting. In the analysis of the effect of mucus and different ratios of straw charcoal on the availability of heavy metals after composting, it was found that the correlation coefficients of straw charcoal addition with the available forms of heavy metals Cu, Zn, Pb, and Ni reached significant levels of 0.906, −0.909, −0.847, and −0.639 (P<0.05), respectively, while the correlation coefficients with Cd were lower. Finally, based on the principal component analysis and stepwise regression equations, mucus in combination with straw charcoal influenced the pH of the sludge compost, affecting the mobility of Ni, Zn, Pb, and Cu. Therefore, mucus plus 8% straw charcoal is an effective approach for treating the heavy metals in the sludge.

     

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