Stepwise hydrolysis to improve carbon releasing efficiency from sludge
Hongbo Liu, Yuanyuan Wang, Ling Wang, Tiantian Yu, Bo Fu, He Liu*. 全文下载
Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environmental and Civil Engineering, Jiangnan University, 214122 Wuxi, PR China
Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment, Suzhou 215011, PR China
Based on thermal alkaline hydrolysis (TAH), a novel strategy of stepwise hydrolysis was developed to improve carbon releasing efficiency from waste activated sludge (WAS). By stepwise increasing hydrolysis intensity, conventional sludge hydrolysis (the control) was divided into four stages for separately recovering sludge carbon sources with different bonding strengths, namely stage 1 (60 °C, pH 6.0–8.0), stage 2 (80 °C, pH 6.0–8.0), stage 3 (80 °C, pH 10.0) and stage 4 (90 °C, pH 12.0). Results indicate stepwise hydrolysis could enhance the amount of released soluble chemical oxygen demand (SCOD) for almost 2 times, from 7200 to 14,693 mg/L, and the released carbon presented better biodegradability, with BOD/COD of 0.47 and volatile fatty acids (VFAs) yield of 0.37 g VFAs/g SCOD via anaerobic fermentation. Moreover, stepwise hydrolysis also improved the dewaterability of hydrolyzed sludge, capillary suction time (CST) reducing from 2500 to 1600 s. Economic assessment indicates stepwise hydrolysis shows less alkali demand and lower thermal energy consumption than those of the control. Furthermore, results of this study help support the concepts of improving carbon recovery in wastewater by manipulating WAS composition and the idea of classifiably recovering the nutrients in WAS.
Waste activated sludge; Stepwise hydrolysis; Sludge carbon; Biodegradability; Anaerobic fermentation for VFAs production;
Water Research
Elsevierjournal
10.1016/j.watres.2017.04.055
2017
225-233
Elsevier Ltd
