强化化学淋滤对污泥重金属溶出及磷释放的影响

针对采用传统化学淋滤方法处理污水污泥时重金属溶出率低的问题,设计了两种强化化学淋滤方法的对比试验,通过检测重金属形态分布、污泥有机质及磷释放、污泥含固率,研究了强化化学淋滤对污泥各方面综合性能的影响。结果表明:稀硫酸与氯化铁联合处理(处理方法1)对Cu和Cr的溶出效果不明显,但在加入NaNO₂(处理方法2)后使Cu溶出率由7%提升至82%,Zn溶出率由79%提升至88%;同时,两种强化化学淋滤方法均增加了污泥中有机质和磷的释放,污泥中磷含量由23.2 mg/g分别降至12.3 mg/g和10.7 mg/g;与原污泥相比,强化淋滤后的污泥脱水性也均得到了明显改善,其污泥含固率分别提高了52%和61%。

Effect of Enhanced Chemical Leaching on Heavy Metal Dissolution and Phosphorus Release from Sludge

In order to solve the problem of low dissolution rate of heavy metals when using traditional chemical leaching method to treat sewage sludge,contrastive tests of two enhanced chemical leaching methods were designed,and effects of enhanced chemical leaching on comprehensive properties of the treated sludge were explored through determination of heavy metal speciation distribution,sludge organic matters and phosphorus release and sludge solids content.The combined treatment of dilute sulfuric acid and ferric chloride(method 1)had no obvious effect on Cu and Cr dissolution,however,the addition of NaNO₂(method 2)could enhance the Cu dissolution rate from 7%to 82%and the Zn dissolution rate from 79%to 88%.Meanwhile,both methods increased the release of organic matters and phosphorus in sludge,and the phosphorus contents decreased from 23.2 mg/g to 12.3 mg/g and 10.7 mg/g,respectively.Compared with the raw sludge,dewaterability of the enhanced leaching sludge was also improved obviously,and solid contents of the sludge increased by 52%and 61%,respectively.