Study on effect of chemical conditioning using different coagulants on sludge dewatering performance
不同混凝剂对污泥脱水性能的影响研究

This study investigated sludge dewatering characteristics by using inorganic and organic coagulants.The effect of different coagulants on sludge dewatering was evaluated by means of specific resistance to filtration(SRF).Zeta potentials,the concentrations of protein,polysaccharide and DNA in the supernatant of the sewage sludge was also measured.In addition,three-dimensional excitation emission matrix fluorescence(3DEEM) was adopted to characterize the organic matters in supernatant.The results showed that the lowest intensity for SRF and 3DEEM analyses was observed when the ratio of spiked ferric chloride(FeCl3),polymeric aluminium(PAC) and polyaluminium chloude(HPAC) to dewatered sludge was 10%,while zeta potentials,protein concentrations,polysaccharide and DNA kept constant.It was noticeable that combination of inorganic and organic coagulants significantly improved the sludge dewaterability in comparison to that using single coagulant.Our results also demonstrated that the addition of inorganic prior to organic coagulant could provide notably higher efficiency for sludge dewatering than that spiking in reverse order.By combining coagulants in various ratios of coagulant to sludge,the order of optimal dewatering was:10%PAC+0.5%PAM>10%FeCl3+0.5%PAM>10%HPAC+0.5%PAM.