Sewage Sludge Conditioning by Bioleaching-Dual PAC and PAM Addition
生物淋滤-PAC与PAM联合调理城市污泥

Bioleaching-dual polyaluminum chloride (PAC) and polyacrylamide (PAM) addition was used to condition sewage sludge. The results showed that FeSO4·7H2O addition improved the bioleaching rate obviously with a fixed sulfur power dosage of 3g·L-1; when the FeSO4·7H2O dosage was 8g·L-1, the bioleaching lasted 1.5 d to decrease the sludge pH below 2. Bioleaching improved the sludge dewaterability significantly with a specific resistance to filtration (SRF) reduction of 77.52% from 6.45×1010 s2·g-1 to 1.45×1010 s2·g-1, but the bioleached sludge was still difficult to be dewatered. After adjusting the bioleached sludge pH to 6, PAC and PAM were used to enhance conditioning of the bioleached sludge. The results indicated that the optimal dosage was 200 mg·L-1 for PAC or 50 mg·L-1 for PAM when single chemical was used. When PAC and PAM were dually used, the optimal dosages of PAC and PAM were 100 mg·L-1 and 25mg·L-1, respectively; SRF and moisture of sludge cake reduced to 2.02×108 s2·g-1 and 74.81%, respectively, showing good dewaterability of the treated sludge. Compared with the single use of PAC and PAM, the dual use of PAC and PAM showed the advantages of lower cost and better conditioning effect.