The combined effects of hydrothermal treatment and Na2S2O8/ CuFe2O4 magnetic oxidation on sludge dewaterability improvement

Na2 S2 O8 /CuFe2 O4 addition and hydrothermal pretreatment were combined in this paper to ameliorate the dewatering performance (DP) of sludge with specific-resistance of filtration (SRF), time of capillary suction (CST), and water content (Wc) as well as water types investigated. The results shown the synergistic effect between Na2 S2 O8 /CuFe2 O4 addition and hydrothermal pretreatment and the DP of sludge reached to the best when the hydrothermal temperature was 150o C, the addition amount of Na2 S2 O8 was 0.08 mmol/g-VSS and the mass ratio of Na2 S2 O8 /CuFe2 O4 was 2.0. Through the analysis of water distribution, it was also demonstrated that the sludge structure was destroyed with the surface moisture released. All the results obtained shown the significant impact of the combined methods on ameliorating DP of sludge and promoting sludge recovery and utilization.