Dried alum sludge for sewage sludge dewatering performance improvement

摘要

Aluminum sulphate is commonly used as coagulant in current water treatment plants, correspondingly resulting in a large number of alum sludge production. Since dewatered alum sludge is composed of amorphous aluminium ions, it can be used as a valuable material, that is sewage sludge dewatering conditioner, in sewage sludge treatment. The study investigated the role of alum sludge in improving sewage sludge dewatering and settling performance and supernatant quality. The alum sludge was dried, grinded, and screened by 100 meshes filter. Taking this alum sludge 0.00g, 0.25g, 0.50g, 1.00g, 1.50g, 2.00g, 2.5g into seven 100 ml cylinders which were filled with sewage sludge, stirring 20s, 40s, 60s, 80s, 100s, and testing sewage sludge specific resistance (r), settling velocity (SV) and supernatant TP concentration. The optimum conditions of improving sewage sludge dewatering and settling performance and supernatant quality were 20g/L aluM sludge and 80s stirring time.