杭州市政污泥中重金属污染及形态特征

Pollution and Morphological Characteristics of Heavy Metals in Municipal Sludge from Hangzhou

文章采集了杭州6座市政污水处理厂的污泥,分析了其基本理化性质,并重点研究了污泥中8种重金属含量和赋存形态,为研究杭州市政污泥资源化处置途径提供参考。结果表明,杭州市政污泥营养物质含量丰富,主要重金属含量低于污泥土地利用限值。各元素含量(均值)为Zn(380.3 mg/kg)>Ni(91.9 mg/kg)>Cu(89.1 mg/kg)>Pb(48.0 mg/kg)>Cr(46.6 mg/kg)>As(14.7 mg/kg)>Hg(2.7 mg/kg)>Cd(1.4 mg/kg)。形态特征分析表明不同污水厂间污泥重金属形态分布基本相似,As和Cd的生物可利用比例>80%。Zn、Ni、Cu的生物可利用态也较高,应重视其潜在生态危害。根据Cd、Hg和Ni等关键重金属的主要赋存形态,污泥资源化利用前可考虑使用生物淋滤法脱毒。

Sludge from 6 municipal sewage treatment plants in Hangzhou was collected and its basic physicochemical properties were analyzed.The contents and morphological characteristics of 8 heavy metals was studied,which would provide reference for the recycling and disposal of municipal sludge in Hangzhou.The results showed high land use potential of municipal sludge in Hangzhou due to the high nutrient content and the main heavy metal content lower than the standard limit.The mean content of each element ranked as Zn(380.3 mg/kg)>Ni(91.9 mg/kg)>Cu(89.1 mg/kg)>Pb(48.0 mg/kg)>Cr(46.6 mg/kg)>As(14.7 mg/kg)>Hg(2.7 mg/kg)>Cd(1.4 mg/kg).The morphological characteristic results showed that the distribution proportions of heavy metals in different sewage plant sludge were basically similar.As and Cd showed the highest bioavailable proportion of more than 80%.High bioavailable fraction was also found in Zn,Ni,and Cu,thus more attention should be paid to their potential ecological hazards when reuse.Considering the morphological characteristics of key metals in sludge,biofiltration can be used for detoxification before sludge resource utilization.