城市污泥重金属含量分析及稳定化研究

文章以乌鲁木齐市水务(集团)有限公司污水处理公司产生的城市污泥为研究对象,对该污泥中的重金属含量和赋存形态进行了分析,并以新疆地产膨润土对污泥中的重金属进行了稳定化研究。结果表明:该污泥中铜、锌、铅、铬、镉、镍的含量(以干基计)分别为700 mg/kg、900 mg/kg、400 mg/kg、198 mg/kg、2.4 mg/kg、22 mg/kg。铜、铬主要分布在可交换态、碳酸盐结合态、铁锰氧化物结合态中,且在3种形态中均匀分布;锌主要分布在碳酸盐结合态、硫化物及有机结合态、残渣态中,其中碳酸盐态及残渣态分布较多;镉在可交换态、碳酸盐结合态、残渣态中均匀地分布,少量存在于硫化物及有机结合态中;铅在残渣态中分布最多,少量分布在可交换态中。重金属稳定化结果为膨润土投加量与干污泥质量比为1:12.5时,污泥中重金属(Cu、Zn、Pb、Cr)可达到很好的稳定效果。

Heavy Metals in Municipal Sludge:Analysis and Stabilization

Sludge sample taken from a wastewater treatment plant of Urumqi Water Group Co.was studied and the emphasis was laid on heavy metals contained in the sludge and the relevant chemical speciation.Cu,Zn,Pb,Cr,Cd,and Ni were detected and their concentrations analyzed.An investigation regarding the speciation of these heavy metals was conducted,e.g.Cu and Cr mainly existed in exchangeable and carbonate bounded forms,while Cd was evenly distributed in exchangeable,carbonate and residual forms with only small amount present in sulfides and organic-bound forms.Work on heavy metal stabilization in sludge was conducted as well,which indicated that heavy metals such as Cu,Zn,Pb,Cr tended to a stabilized state within the sludge when bentonite was added into the sludge with the weight(g) ratio — 1(bentonite):12.5(dry sludge).