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A polyvinyl chloride (PVC) pipe loop system was constructed inline at the Water Authority-Cayman treatment and distribution location at Red Gate. The pipe loop consisted of two parallel wall-mountedsystems fed by reverse osmosis (RO) water and exposed to chlorinated or non-chlorinated conditions. Couponsof PVC, polyethylene (PE), mild steel, brass, copper and cement lined ductile iron were inserted into thepipe loop system for a period of 32 days and 90 days respectively to determine the quantityand type of bacteria present in the bulk water and biofilm. Bacterial ID was successful usinga combination of fatty acid methyl ester (FAME) analysis and heterotrophic plate count (HPC) culture analysis on R2A.Results show that in general chlorination reduced bacterial quantities in the bulk water butfor surfaces such as mild steel the bacterial numbers increased due to enhanced corrosion of themetal under chlorinated conditions. Bacterial types in the bulk fluid were similar to thoseisolated from other parts of the treated distribution system, however a few morphologicallydifferent types of colonies were observed on the steel, copper and cement-lined ductile ironsurfaces. In some cases the bacteria isolated from the chlorinated section of the loop werecharacteristically different from those isolated from the non-chlorinated section.As the industry moves to understand more about the quality of water within the distributionsystem, this paper gives unique and valuable information on the characterization ofbacteria found in reverse osmosis systems served predominantly by a PVC piping systemand an in-line distribution system temperature of 24C or above. Includes 5 references, tables, figures.

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Edition: Vol. - No. Published: 11/01/2006 Number of Pages: 8File Size: 1 file , 400 KB