Transform Of EPS In The Stabilization Of Excess Sludge In SSF-CW

The physical and chemical indexes,sludge stabilization indexes,the total quantity,morphology,substance composition of EPS in sludge,and the temporal and spatial distribution in the wetland system were studied in the constructed wetland with plant and without plant in the process of stabilizing residual sludge.In this research we found:In space,the contents of various forms of extracellular polymers in the sludge decreased gradually along the flow direction;The ratio of PN /PS increased as the sludge flowed through the constructed wetland system.In terms of time,the content of extracellular polymers in the sludge was lower in spring and summer,but more in autumn and winter.Protein and polysaccharide were the main components of extracellular polymers in different seasons and different forms,and only a small amount of DNA appeared in TB-EPS.There was no difference in temperature between the two constructed wetlands,and there was little difference in the contents of S-EPS,VS and SVI.There was a strong correlation between extracellular polymers and plant height,and a negative correlation between plant weight and the contents of S-EPS,LB-EPS and Total-EPS in the sludge stabilized by plant constructed wetland.There was a strong positive correlation between root exudates and S-EPS content(0.369**),and a weak positive correlation between root exudates and LB-EPS content(0.567*),but not with TB-EPS content.In each season,the amount of total extracellular polymer in the mud produced by the plant constructed wetland was less than that of the non-plant constructed wetland.Compared with the non-plant wetland,except S-EPS,the reduction rate of all forms of extracellular polymers was faster and the reduction effect was stronger in the plant wetland.Each form of extracellular polymer has a strong positive correlation with the sludge stabilization index,and is positively correlated with the content of total nitrogen and total phosphorus in sludge.Microbial activity was strongly correlated with EPS(0.452**),LB-EPS(-0.588**),TB-EPS(-0.489**),and DHA was weakly negatively correlated with total EPS(-0.446*).There was a strong positive correlation between PN /PS and DHA(0.274**).Based on the above put forward a kind of plant roots and sludge microorganisms extracellular polymer interaction model,by extracellular polymer contains tryptophan as substrate indole acetic acid generated to accelerate the sludge enrichment region elongation plant roots,promote root absorption of nutrient generated sludge stabilization process,accelerate plant growth,promote the secretion of root secretion,which affect the sludge flocs dephosphorization and denitrification ability,cut extracellular polymer plants,thus forming the acceleration of complete sludge stabilization,promote the growth of wetland plant,cut the positive cycle of EPS.