AWWA JAW68769

The city of Carlsbad, California, has planned construction of an ocean desalination plant capable of producing up to 50 mgd of potable drinking water. A six-month pilot study was conducted to determine the potential corrosion effect on distribution system materials when the city replaces a portion of its current imported, treated surface water with reverse osmosis (RO) permeate. Testing evaluated the effect of both water sources on distribution system and residential plumbing materials such as copper pipe, brass meters, cement-mortar-lined pipe, and cast-iron distribution system gate valves. Results indicated that after a brief period of conditioning, the water quality of the desalinated seawater supply was comparable to that of the current supply. Findings from this study provide both a blueprint for evaluating the effect of changes in water quality on corrosion outcomes and evidence of how a desalinated water supply can be treated to avoid corrosion problems when the water is introduced into an existing distribution system. Includes 51 references, tables, figures.