EFFECT OF BIOFILM ON FORMATION AND REDUCTION OF DISINFECTION BY-PRODUCTS

Abstract

The main objective of this study is to investigate the DBPs reduction and abiotic control by active and inactive biofilm as well as DBPs formation potential of biofilm in water distribution system in order to understand fate and transportation of DBPs that might be occurred by biofilm in water distribution system. The biofilm used in study was collected from water reservoir in Bangkok metropolitan area. The reduction and abiotic control of four representatives of main DBPs groups (chloroform (CF), dichloroacetic acid (DCAA), dichloroacetonitrile (DCAN) and 1,1 Dichloro-1-propanone (1,1 DCP)) were conducted by batch experiment under controlling pH at 7. The obtained results shown that DCAN is the most biological consumable followed by 1,1 DCP, therefore it might cause the reduction of DCAN and 1,1 DCP concentration in water distribution system. However, CF and DCAA were slightly consumed by physical attachment on biofilm surface. DBPs formation potential of biofilm and extracted extracellular polymeric substance (EPS) were conducted by chlorination for 7 days to obtain the maximum formation potential of each DBPs species. Cellular carbon might have higher potential to form CF than the carbon source from EPS. HAAs formation potential has closer relation to the carbon source from EPS than carbon from cellular source. And cellular carbon source of biofilm might be the main carbon source for HKs formation potential. Carbonaceous DBPs had higher formation potential and had a trend to produce higher halogenic DBPs.