Abstract
The Stage 2 Disinfectant and Disinfection By-Product (D/DBP) regulations of the United States force water utilities to be more concerned with their distributed water quality. Improved compliance requires understanding of reaction kinetics and wall effects of different distribution materials used on DBP formation. To validate results in a full-scale system, effect of different materials, wall effects, bulk reactions, and water movement is analyzed using simulated distribution system (SDS) tests, material specific simulated distribution system (MS-SDS) tests, pipe loop, and pipe section reactor (PSR); all built using materials from the city of Columbia, Missouri's distribution system. On average, the choice of polyvinyl chloride (PVC) and ductile iron can account for as much as 36% difference in trihalomethane (TTHM) formation and 60% difference in chlorine residual decay over time irrespective of the prediction model and operational strategy used. In the case of ductile iron, pipe effect (PE) is <1, which shows that in the ductile iron pipe systems there is a net loss of TTHM yield due to non-TTHM forming chlorine demand imposed by the pipe environment, whereas in PVC pipe, PE is >1. In PVC systems there is an overall increase in TTHM formation as a result of pipe wall surface reactions.
Biofilm forming ability of Sphingomonas paucimobilis isolated from community drinking water systems on plumbing materials used in water distribution
