Effect of S0 on fractions of EPS in sludge and dewaterability by bioleaching

To investigate the dewaterability of sludge and its relationship with protein (PN), polysaccharide (PS) of extracellular polymers (EPS) in sludge bioleaching, S0was added as substrate with different dosage of S0 (0g/L, 2g/L, 4g/L, 6g/L, 8g/L) +10% inoculum for 10 days. Results showed that dissolved PS, PN and sludge specific resistance (SRF) reduced at 0~2days, but increased later, while the bound PN and PS decreased during 0~8d of bioleaching, and slightly increased later. Moreover, the above trend increased with the increasing loadings of S0. Statistical results showed that the SRF and dissolved PN, PS had a significantly positive correlation (R=0.861, 0.875, P0, thus affecting the dewatering performance of sludge, in which, the dissolved PS had more effect on the dewatering of sludge. The best bioleaching process for sludge dewatering performance was 8g/L of S0 for 2days, followed by 2g/L of S0 for 6days. with the SRF 58% and 54% lower than that of the original sludge, respectively. The heavy metal removal rate in the latter case was higher, thus the latter with 30℃, pH dropped to 2.66 was recommended as the optimization conditions. © 2019, Editorial Board of China Environmental Science. All right reserved.