粉煤灰对城市污泥中重金属钝化作用的研究

Study on Passivation of Heavy Metals in Municipal Sludge by Coal Fly Ash

以济南市西区污水处理厂的脱水污泥为研究对象,在分析其基本理化性质的基础上,研究了粉煤灰对污泥中的Cu、Ni、Pb和Zn四种重金属的钝化作用。结果表明:污泥中含有丰富的有机质和N、P等营养成分,Pb、Zn、Ni和Cu的含量符合《城镇污水处理厂污泥处置园林绿化用泥质》(GB/T23486-2009)标准。添加粉煤灰可有效钝化四种重金属,且不同重金属的钝化效果不同,添加量为10%~20%时钝化效果最好。粉煤灰添加量超过40%,对Zn的钝化不利。钝化处理的污泥与粉煤灰颗粒粘结在一起,有利于污泥中的重金属与粉煤灰进行离子交换;通过XRD发现,污泥中含有AlPO4,有利于与粉煤灰的粘结,加入粉煤灰可使污泥中的SiS2减少,减少污泥的臭味,而生成的新物质NaAlSi_3O_8有一定缓冲作用。

The properties of dewatering sludge from the Wastewater Treatment Plant in the West of Jinan were analyzed to investigate the passivation effect of fly ash on four kinds of heavy metals（Cu,Ni,Pb and Zn）in sludge.The results showed that the contents of organic matter,N and P were rich in the sludge and contents of the four heavy metals were accord with China Disposal of sludge from municipal wastewater treatment plant-Quality of sludge used in gardens or parks standard（GB/T23486-2009）.Four kinds of heavy metals could be passivated effectively by adding fly ash,and their passivation effect is different for the different heavy metals.The optimum effect could be obtained by adding 10-20%coal fly.It＇s unfavorable to the passivation of Zn when the applied amount of sludge exceeded 40%.It was found by SEM analysis that sludge was bonded with the fly ash particles together after passivation treatment,which was beneficial to the ion exchange between heavy metals and fly ash.The analysis of XRD was shown that the sudge contained AlPO4,which was favorable to cohesive action with fly ash.The addition of fly ash could reduce the SiS2 in sludge and reduce the stink of sludge.The new substance NaAlSi3O8 in the treated sludge had a certain buffer effect for the pH of soil.