论文部分内容阅读
采用技术成熟的条垛式堆肥技术对来自广州市南沙区(以下称N区)和东莞市市区(以下称D区)铜、锌污染超标的城镇污泥进行堆肥处理,对堆肥过程中的重金属浓度随时间的变化规律进行研究。结果表明:N区污泥中,Cu、Zn、Cd、Cr、As含量分别下降了93.5%、60.2%、49.7%、93.0%、77.0%;D区污泥中,Cu、Zn、Cd、Cr、As含量分别下降了33.6%、40.8%、26.3%、24.2%、29.8%,Hg含量在两区污泥中均有上升,分别为49.1%和2.8%。采用单一试剂(DTPA)浸提法测定了重金属的生物有效性,N区污泥的Cu、Zn、Cd、As、Hg的金属活性系数平均值分别为15.8%、16.5%、25.5%、5.8%、11.7%,金属活性顺序为:Cd>Zn>Cu>Hg>As;Cu、Zn、Cd、As、Hg的金属活性系数平均值分别为19.3%、19.6%、24.3%、8.3%、6.2%,金属活性顺序为:Cd>Zn>Cu>As>Hg,Cr的有效性在两区中均未检测出。经过约20d的二次腐熟后,使堆肥产品中的重金属含量低于原污泥,符合了土地利用污泥污染物控制标准,而且也远低于美国USEPA503标准;同时堆肥也改变了重金属的生物活性,使污染超标的Cu、Zn的生物有效性大大降低。因此经过条垛式堆肥处理可将这两区污泥农林利用。
Composting of municipal sludge from cities like Nansha in Guangzhou (hereinafter referred to as Zone N) and urban areas in Dongguan (hereinafter referred to as Zone D) with excessive copper and zinc pollution is carried out by using the technology of the stacker composting technology. Heavy metal concentration changes with time study. The results showed that the content of Cu, Zn, Cd, Cr and As decreased by 93.5%, 60.2%, 49.7%, 93.0% and 77.0% respectively in the sludge in zone N; , As content decreased by 33.6%, 40.8%, 26.3%, 24.2%, 29.8%, respectively. Hg content increased by 49.1% and 2.8% respectively in the sludge in both areas. The bioavailability of heavy metals was determined by a single reagent (DTPA) extraction method. The average activity coefficients of Cu, Zn, Cd, As and Hg in N zone sludge were 15.8%, 16.5%, 25.5% and 5.8% , 11.7%, respectively. The order of metal activity was: Cd> Zn> Cu> Hg> As; the average activity coefficients of Cu, Zn, Cd, As and Hg were 19.3%, 19.6%, 24.3%, 8.3% and 6.2% , The order of metal activity is Cd> Zn> Cu> As> Hg, the validity of Cr is not detected in both areas. After about 20 days of secondary maturation, the content of heavy metals in compost products is lower than the original sludge, which is in line with the control standard of land-use sludge pollutants, but also much lower than the USEPA503 standard; at the same time, composting also changed the heavy metals Activity, so that excessive pollution of Cu, Zn bioavailability greatly reduced. Therefore, after the stacker composting can be used in these two areas of agroforestry.