杨素娜

摘要：為了评价污水处理厂污泥及其浸出液的潜在生态环境风险，以上海嘉定区某污水处理厂为例，采用硫酸/硝酸法和醋酸缓冲溶液法对污泥进行重金属总量和浸出毒性检测分析。同时，也研究了浸出液pH值、浸出时间及消解条件对浸出的影响。试验结果表明：1）污泥中Cu，Zn，Ni和Cr的含量分别是城市污泥中相应物质的平均含量的20，7.5，15和13倍，而Pb和Cd的含量与城市污泥的平均含量差不多;2）污泥中Cu与Cr主要以稳定形态存在，不同浸提方法下的浸出量相当，对于Zn和Ni，醋酸缓冲溶液的浸出量分别约为硫酸/硝酸溶液的22倍和18倍;3）浸出时间为20 h时浸出达到平衡，浸出液pH值对污泥重金属浸出能力的影响，因重金属元素种类的不同而存在较大差异，电热板消解和微波消解对浸出几乎没有影响;4）醋酸缓冲溶液制备的浸出液中，Ni的浸出质量浓度为16.3 mg/L，高于鉴别标准限值5 mg/L，而硫酸/硝酸浸提方法中重金属浸出浓度均未超过规定值。因此，该污水处理厂的污泥不适合卫生填埋，应积极寻求新技术对污泥进行合理处置并减少其潜在生态环境风险。

关键词：水污染防治工程;污水污泥;重金属;浸出试验;评价

中图分类号：X750文献标识码：ADOI： 10.7535/hbgykj.2021yx06008

Analysis of content and leaching toxicity of heavy metals in sludge from

sewage treatment plants：Taking a sewage treatment plant

in Shanghai as an example

YANG Suna

（Shanghai Jiading District Environmental Monitoring Station，Shanghai 201822，China）

Abstract：In order to evaluate the potential ecological and environmental risks of sludge and its leachate from the sewage treatment plant，taking a sewage treatment plant in Jiading District，Shanghai as an example，the total amount of heavy metals and leaching toxicity of the sludge were detected and analyzed by sulfuric acid/nitric acid method and acetic acid buffer solution method.At the same time，the effects of leachate pH，leaching time and digestion conditions on leaching were also investigated.The results show that： 1） the contents of Cu，Zn，Ni and Cr in the sludge of the sewage plant are 20，7.5，15 and 13 times of the average content of municipal sludge，respectively，and the contents of Pb and Cd are similar to the average content of municipal sewage sludge;2） Cu and Cr in the sludge mainly exist in stable form，and the leaching amounts are equivalent under different leaching methods.For Zn and Ni，the acetate buffer solution leaches about 22 and 18 times more than the sulfuric/nitric acid solution，respectively;3） the leaching experiment reaches equilibrium in 20 hours.The effect of pH value on the leaching capacity of heavy metals in sludge varies considerably due to the types of heavy metal elements.Electroplate digestion and microwave digestion have little effect on leaching;4） in the leaching solution with acetic acid buffer solution，the leaching concentration of Ni is 16.3 mg/L，which is 5 mg/L higher than the limit of identification standard，while the leaching concentrations of heavy metals in sulfuric acid/nitric acid leaching method do not exceed the specified values.The study shows that the sludge of the sewage plant is not suitable for sanitary landfill，and the new technologies should be actively sought for rational disposal of sludge and reduction of its potential ecological and environmental risks.

Keywords：water pollution control engineering;sewage sludge;heavy metals;leaching experiment;evaluation

根据中国城乡建设统计年鉴数据，截至2020年底，全国城市共有污水处理厂2 471座，污水日处理能力达1 786万m3，污水处理率为96.81%，污泥的产量也随之大幅增加。在污水处理过程中，污水中50%～80%的重金属通过细菌吸收、细菌和矿物颗粒表面吸附、以及与无机盐（如磷酸盐和硫酸盐等）共沉淀等多种途径转移至污泥中[1]。……