工业石膏在自来水厂污泥调解和脱水中的作用

On the role of gypsum (CaSO4·2H2O) in conditioning and dewatering of a waterworks sludge

自来水厂污泥的处理和利用是一个至今没有得到完全解决的问题,通常的做法是将其直接排放或脱水后填埋.在实验研究的基础上,论述了采用工业石膏(CaSO4·2H2O)和有机聚合物对自来水厂污泥进行双重调解进而脱水的方法.实验结果表明,用1:1(工业石膏和有机聚合物的重量比)的投量对自来水厂污泥进行双重调解可明显改善污泥的过滤性能.脱水实验证明双重调解后的污泥经机械脱水,其泥饼含水率可比单纯有机聚合物调解后脱水的泥饼含水率低大约7个百分点.此项研究的意义在于探索自来水厂污泥脱水后农用及作为人工湿地填料的可能性,同时也为自来水厂污泥脱水后的最终处置探索新思路.

Problems concerning the management and utilization of sludge derived from water treatment processes are still not fully solved. A common approach is direct discharge to a landfill site. This study provides experimental data to demonstrate the effectiveness of a combination of gypsum (CaSO_4·2H_2O) and an organic polymer in alum sludge conditioning and dewatering. Experimental results demonstrated that the filterability of dually conditioned alum sludge was significantly improved by the addition of gypsum at a 1∶1 ratio (WT/WT) to original sludge solids. Dewatering tests showed that a further decrease of almost seven percentage of sludge cake equilibrium moisture content was achieved by the involvement of gypsum compared to the situation of single polymer conditioning. The importance of this study lies in the possible application of dewatered alum sludge to land use or as a filter medium in constructed wetland for wastewater treatment, providing a positive solution to the problem of alum sludge disposal.