Assessment of the correlation between odors release and dewaterability of sludge in sludge dewatering process under different conditioning methods

In this paper, we assessed the correlation between odors release and dewaterability of sludge in sludge dewatering process under different sludge conditioning methods. In experiments, four sludge conditioning methods were adopted, such as polyaluminum chloride, FeCl3 cooperates with CaO (FeCl3 + CaO), acidizing conditioning and Fenton conditioning. The purpose of the study was to investigate the influence factors of odors release, and what conditioning method was the best to be used for sludge dewatering of Xiaohongmen WWTP in Beijing. According to the conditioning experiments, qualitative and quantitative analysis of odors and the correlation analysis between odors concentration and characteristics of sludge, we found that Fenton conditioning showed the best dewaterability of sludge. Moreover, soluble EPS (SEPS) content in the supernatant was the most with Fenton conditioning and consists of tryptophan protein-like substances, aromatic protein-like substances, humic acid and fulvic acid. The amount of H2S release and the amount of NH3 release were the most under Fenton conditioning. And the amount of volatile organic compounds (VOCs) release was the most with FeCl3 + CaO conditioning. There was the positive correlation between odors release and SEPS. And hydrocarbon was the main factor causing the total amount of VOCs change. Fenton conditioning as the best conditioning method for sludge dewatering, promoted a large number of odors gas to release. Odors gas was gathered to the subsequent resource utilization. Meanwhile, the weight of raw sludge was reduced, and raw sludge as a kind resource was used to produce odorous gases. Finally, a new resource concept, chemical raw materials derived from odors, was submitted.