Study on the thickening of wasted sludge from municipal wastewater treatment plant by air flotation

SESN was used as surfactant in the flotation thickening of waste activated sludge from municipal wastewater treatment plant. Experimental results indicate that pH value and the concentration of added surfactant and flocculation were important factors which affect the water recovery and the water content of thickened sludge. The water content of sludge was decreased from 99.44% to 96.8% in 10 minutes flotation thickening with the concentration of added SESN was 37.5mg/L. The water recovery of 79.6% was also achieved under that condition. In this study, the Spectroscopic Analysis and SEM were used to investigate the effects of surfactant on sludge surface and their function mechanism. The results show that the adsorption mechanism between SESN and sludge is chemisorption.