Enhancement of cationic polyacrylamide conditioning of sewage sludge with modified coal fly ash.

To improve the efficiency of sewage sludge conditioning, modified coal fly ash (MCFA) was introduced into the sludge conditioning with cationic polyacrylamide (CPAM). Specific resistance to filtration (SRF), net sludge solid yield (YN), modified filter cake moisture (FCMm), and time to filter (TTF) were analyzed to evaluate the sludge filterability and dewaterability. Results showed that the MCFA addition significantly promoted the sludge filterability and dewaterability, compared with the single CPAM conditioning. There was a synergistic effect between the MCFA and CPAM conditioning. The suitable dosages of the CPAM and MCFA were 1.3 g kg⁻¹ and 60% DS for the experimented sewage sludge, respectively. Under the suitable conditions of dual conditioning, the Y_N of sludge conditioned increased by 383%, and the TTF reduced by 427 s, compared with that of raw sludge; the FCM_m of sludge conditioned was 82.9%. The change in zeta potential and floc size of sludge particles after conditioning suggested that the dual conditioning improved the sludge filterability and dewaterability mainly because of the interactions between sludge and MCFA, CPAM. [ABSTRACT FROM AUTHOR]