Foam Ingredients Transformation and Control Method of Leachate Treatment by MBR System

In the present work, the formation of foam from leachate in a bench-scale Membrane Bio-reactor(MBR) was analyzed, and three kinds of defoamers (A (triethyl phosphate), B (fungicide), C(silicone) )was studied to control biologic foam by parallely pilot. The conclusions were that (1) During the analysis of foam components, the ash, moisture and bacteria composition ratio was different in the various stages of foam formation, moisture is 189 ml/L, 164ml/L, 87 ml/L, 10 ml/L, ash is 334 ml/L, 445 ml/L, 128ml/L, 31 ml/L, Filamentous bacteria is 315 mg/L, 336mg/L, 2315 mg/L, 4521 mg/L respectively during start early phase, denitrification phase, bio-foam prophase to bio-foam serious phase. (2) From the variation analysis of filamentous bacteria, the effluent COD and VSS/SS, the flux and pressure difference of membrane corresponding to the three defoamers in the system confirmed that the C type of defoamer has the best control effect on biologic foam in all, but suit to short-term application, the A kind of defoamer was suit to long-term application. (3) There was a little effect on water quality when it is dosed with these three kinds of defoamers in the system, the effluent quality satisfied the integrated wastewater discharge standard and kill the filamentous bacteria effectively when the dosage of the C-type defoamer is 40mg/L.