污水处理厂脱水污泥中重金属的形态分布特征研究

Speciation Distribution Characteristics of Heavy Metals in Dewatered Sludge from WWTP

研究了污水处理厂脱水污泥中重金属的形态及总量分布特征,对所采集的活性污泥和消化污泥样品的分析结果表明,镉、铜、铁和锌的主要分布形态为可还原态,在活性污泥中分别占各自总量的48.67%、83.74%、87.21%和64.90%,在消化污泥中则分别占各自总量的37.62%、83.44%、65.99%和61.64%;铬主要以残渣态存在,在活性污泥和消化污泥中分别占其总量的85.83%和67.64%;活性污泥中锰主要以弱酸提取态和可还原态存在,分别占47.16%和44.69%,在消化污泥中则主要以弱酸提取态存在,占61.69%;铅的5种形态分布比较均衡。活性污泥中7种重金属的总量呈现铁>铜>锌>锰>铬>铅>镉的趋势;消化污泥中7种重金属的含量排序则为铁>锰>锌>铜>铬>铅>镉。活性污泥中7种重金属的总量均高于消化污泥。

The speciation and distribution characteristics of heavy metals in dewatered sludge from WWTP were studied. The analysis results of activated and digested sludge samples showed that cadmium, copper, iron and zinc mainly existed as reducible fraction and the amounts were 48.67% , 83.74%, 87.21% and 64.90% respectively in activated sludge, and 37.62% , 83.44% , 65.99% and 61.64% respectively in digested sludge. Chromium mainly existed as residual fraction, the amount was 85.83 % in activated sludge, and 67.64% in digested sludge. Manganese mainly existed as weak acid extraction fraction and reducible fraction in activated sludge, the amounts of two fractions were 47. 16% and 44.69%, and it mainly existed as weak acid extraction fraction in digested sludge, the amount was 61.69%. Lead was balanced in the distribution of the five fractions. The total amounts of seven kinds of heavy metals showed Fe 〉 Cu 〉 Zn 〉 Mn 〉 Cr 〉 Pb 〉 Cd in activated sludge, while those showed Fe 〉 Mn 〉 Zn 〉 Cu 〉 Cr 〉 Pb 〉 Cd in digested sludge. The amounts of heavy metals in activated sludge were higher than those in digested sludge.