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以武汉某污水处理厂的污泥为研究对象(S1和S2),通过皂角苷和柠檬酸联合振荡淋洗试验,研究不同体积比(20∶1~1∶20)、固液比(1∶20~1∶80)、淋洗时间(0~2 880 min)、淋洗次数(1~4)对污泥中重金属Cu、Pb和Zn去除的影响.分析淋洗前后各形态重金属的去除特点,并通过计算稳定性指数(I_R值)和移动性指数(MF值)探究重金属稳定性和移动性的变化.结果表明,在体积比(皂角苷∶柠檬酸)为5∶1,固液比为1∶60,淋洗时间1 440 min时,污泥中Cu、Pb和Zn的最高去除率分别可达43.16%(S1)、32.45%(S2)和38.69%(S1).增加淋洗次数对Cu和Pb的去除率有较大幅度提高,而对Zn的影响较小,尤其在2~3次淋洗后差异显著.4次淋洗后Cu、Pb和Zn的最高去除率分别为78.89%(S1)、77.08%(S2)和49.39%(S1).单次淋洗后,除酸溶态和可还原态外,污泥中其余形态的去除率均较低.增加淋洗次数,重金属的各形态去除率逐渐升高,尤其是Pb中的残渣态去除率增长明显.淋洗改变了重金属的稳定性和移动性,4次淋洗后Cu、Pb和Zn的IR值最大增长率分别为43.63%(S1)、39.44%(S2)和32.00%(S1),MF值减少30.19%~79.45%.
Taking the sludge from a sewage treatment plant in Wuhan as the research object (S1 and S2), the effects of different volume ratio (20:1 ~ 1:20), solid-liquid ratio (1 (20 ~ 1:80), leaching time (0 ~ 2880 min) and leaching times (1 ~ 4) on the removal of heavy metals Cu, Pb and Zn in the sludge.The removal of heavy metals The stability and mobility of heavy metals were investigated by calculating the stability index (I_R value) and mobility index (MF value) .The results showed that when the volume ratio (saponin: citric acid) The maximum removal rates of Cu, Pb and Zn in sludge were 43.16% (S1), 32.45% (S2) and 38.69% (S1), respectively, when the liquid ratio was 1:60 and the leaching time was 1 440 min. The removal rates of Cu and Pb increased a lot, but had little effect on Zn, especially after 2 ~ 3 times of leaching.The maximum removal rates of Cu, Pb and Zn after 4 times of leaching were respectively Were 78.89% (S1), 77.08% (S2) and 49.39% (S1), respectively.After single leaching, the removal rate of all the remaining forms of sludge was lower than that of the acid-soluble and reducible forms. The number of heavy metal removal rate gradually increased, especially Pb The leaching removal changed the stability and mobility of heavy metals, and the maximum IR values of Cu, Pb and Zn were 43.63% (S1) and 39.44% (S2) respectively after 4 times of leaching 32.00% (S1), MF value decreased by 30.19% ~ 79.45%.