Bioleaching role in improving sludge in-deep dewatering and removal of sludge-borne metals and its engineering application | 污泥生物沥浸处理技术及其工程应用

Chinese. 污泥高水分含量和存在重金属已成为影响我国污泥处置与资源化的重要＂瓶颈＂。生物沥浸技术被证实是一种即可以有效去除污泥重金属,同时显著提高污泥脱水性能的生物方法。本文较系统介绍了目前我国污泥深度脱水的几种方法及生物沥浸处理技术在污泥处理上的优势,生物沥浸法促进污泥深度脱水和重金属去除的基本原理、工艺流程及影响因素。以无锡芦村污水处理厂日处理200 t污泥的生物沥浸处理―――高温发酵堆肥的实际工程为例,阐述该工艺的技术参数、污泥处理及其后续堆肥和土地利用的效果。连续2年多的生产性试验和工程实践表明,经生物沥浸处理的污泥可不加任何絮凝剂能一步机械脱水到含水率60%以下,呈土黄色无臭的半干化饼状。且污泥干基有机质、热值和氮磷养分含量几乎不变,利于后续资源化（如土地利用、焚烧等）,处理成本低廉,同时压滤水水质较好,可就近排入污水处理厂处理。因此,污泥生物沥浸技术是一项有广泛应用前景和市场需求的新技术。

English. High moisture content of and the presence of toxic metals in sewage sludge restrict, to a great extend, the disposal or recycling of sludge including landfill,incineration, and land application. Bioleachiog with Acidithiobacilli species has been proved to be a technologically feasible process in removing sludge-borne toxic metal and improving sludge in-deep dewatering. This paper compared several methods for sludge in-deep dewatering and described the advantages of bioleaching technology against other physical or chemical approaches. Furthermore, the principle, technological process, and the influence factors of sludge bioleaching technology were demonstrated in details. Taking bioleaching practical engineering application project with treating sludge 200 t＂ d-1 located in Wuxi Lucun Sewage Treatment Plant, Wuxi City, Jiangsu Province as an example, bioleaching technique parameters and sludge treatment effect were reported. The results obtained from the two-year operation of the engineering project that bioleached sludge could be dewatered mechanically into semi-drying odorless khaki-colored sludge cake with the moisture of 60% or below. Mo- reover, dewatered bioleached sludge cake contained similar levels of organic matter, calorific value, N, and P to fresh sludge on dry basis, indicating that it had good physic-chemical properties for its consequent reutilization such as incineration or land application. Besides, the fihrate of bioleached sludge could be discharged into sewage treatment plant without adverse effect. It is concluded that bioleaching approach is a novel technology with an extensive application prospect.