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污染控制技术及原理

摘要：利用嗜酸性硫杆菌复合菌群,通过摇瓶试验对制革污泥进行生物沥浸,研究了在以硫粉作为底物的基础上,添加不同量的Fe²⁺对污泥生物沥浸效果的影响.结果表明,在制革污泥生物沥浸处理中,外源添加Fe²⁺虽有助于加快生物酸化进程,特别是在pH>2的阶段该作用较为明显,但由于也促进了羟基硫酸高铁沉淀的生成,导致已溶出的Cr³⁺部分被重新固持,因此,在制革污泥生物沥浸中外源加Fe²⁺促进Cr溶出的效果并不明显.此外,外源添加Fe²⁺在较小程度上可降低污泥的比阻值,从而使污泥更易脱水,但Fe²⁺不同添加量之间差异较小.综合考虑药剂成本和处理效率,在制革污泥生物沥浸中添加Fe²⁺对大幅度加快Cr溶出速率和显著提高污泥脱水性并没有理想效果.

Abstract：The aim of the present study was to investigate effect of different concentrations of Fe²⁺ on tannery sludge bioleaching efficiency with a focus on Cr solubilization and sludge dehydration. Tannery sludge bioleaching using combined indigenous iron-and sulfur-oxidizing bacteria was conducted in a batch flask experiment in which 4 g·L^-1 of Spowder combined with different amounts of Fe²⁺ (0～6 g·L^-1) as FeSO₄·7H₂Owere added and acted as the energy substrate. Results showed that the addition of Fe²⁺ to the sludge bioleaching system accelerated acid production in the regime of pH>2, in comparison to the control without added Fe²⁺. However, the increase of Fe²⁺ resulted in more ferric precipitates in the bioleached sludge by which, in turn, soluble Cr³⁺ might be re-attenuated through co-precipitation. Thus, the solubilization efficiency of sludge-born Cr facilitated by the addition of Fe²⁺ hardly differed from that in the control. Also, the addition of Fe²⁺ improved, to a lesser extent, sludge dehydration The Fe²⁺ added sludge exhibited a lower specific resistance compared to the control. In the light of the cost of the chemical agent (FeSO₄·7H₂O) and the bioleaching efficiency after the addition of Fe²⁺, it was concluded that addition of Fe²⁺ is perhaps unnecessary for tannery sludge bioleaching, as it does not significantly improve Cr solubilization or sludge dehydration.