Study On Improving The Dewatering Performance Of Anaerobic Granular Sludge By Ferrous/Persulfate System

In recent years,with the development of urbanization in China,the treatment volume of sewage has increased sharply.The problem that comes with it is the increase of sludge,a by-product of sewage treatment.The existing sludge treatment technology cannot be achieved the current factory standard,so sludge conditioning must be carried out before sludge dewatering.This thesis uses Fe²⁺ to activate S₂O₈^2-to produce persulfate free radical,acting on three anaerobic granular sludges,observing the effect of conditioning and analyzing the causes of dehydration performance improvement.At the same time,the anaerobic granular sludge is cultured in the laboratory.The results of the cause analysis were verified to illustrate the feasibility of this conditioning method for anaerobic granular sludge conditioning.According to the conditional optimization experiment,the optimum dosage of the anaerobic granular sludge for papermaking was S₂O₈^2-dosing amount 0.40 mmo L/g VSS,Fe²⁺ dosage 1.50 mmo L/g VSS,the best agent for alcohol anaerobic granular sludge was S₂O₈^2-dosing amount 0.50 mmo L/g VSS,Fe²⁺ dosage 0.50 mmo L/g VSS,the optimal dosage of food anaerobic granular sludge was S₂O₈^2-0.25 mmo L/g VSS,Fe²⁺ 0.25 mmo L/g VSS.Compared with the domestic and international research methods used in the treatment of common municipal sludge,it was found that this conditioning method is very promising for the conditioning of anaerobic granular sludge,and the treatment effect is already at the forefront level.The mechanism analysis showed that after the addition of the drug,the surface of the sludge was changed from a compact and smooth structure to a looser and coarser porous structure,and the sludge disintegrated,which reduced the median particle size of the sludge.At the same time,with the disintegration of the sludge,the combined water originally contained in the sludge was released;at the same time,the absolute value of the Zeta potential was gradually reduced to 0 after the treatment,which promotes the agglomeration and flocculation of the sludge particles.The moisture content in the mud was converted,and a part of the combined water?50%?was converted into free water,which makes the water easier to escape,thereby improving the dewatering performance of the sludge.By comparing the EPS of the sludge,it can be known that after the dosing treatment,the transformation of the polysaccharide and protein components of the sludge promotes the dewatering performance of the sludge.By analyzing the relationship between the basic properties of sludge and the dewatering properties during the cultivation of anaerobic granular sludge in the laboratory,it was found that the dehydration of anaerobic granular sludge was significantly correlated with the basic properties of sludge,and the correlation from high to low was Zeta potential > particle size > LB-EPS protein > EPS polysaccharide > S-EPS protein > VSS > TB-EPS protein.The dehydration performance was positively correlated with the protein content of S-EPS,the polysaccharide content of total EPS,and the zeta potential,and negatively correlated with the protein content,particle size and VSS of LB/TB-EPS.