Full Description

Meeting the Stage 1/2 Disinfectant/Disinfection Byproduct Rules is a balancing act for most utilities. The CastaicLake Water Agency (Agency) treats imported water from the California Aqueduct (West Branch of State WaterProject) at its two water treatment plants. Although the water settles in two major reservoirs prior to treatment, high Trihalomethane(THM) concentrations have been experienced in the past upon addition of free chlorine for distribution systemresidual. To complicate matters, the presence of bromide ion in the range of 100 to 300 g/L is problematic for tworeasons that include: ozone is applied at both water treatment plants for preoxidation, which reacts with the bromide ion toform bromate byproduct; and, upon addition of free chlorine, brominated disinfection byproducts (e.g. THMsand HAAs) are formed. These brominated byproducts have been linked to greater health risks.To address this issue, several prototypes of an electrolytic process were tested at the Agency. Promising results wereobtained in terms of bromide, DBP minimization, and microbial inactivation. A Tailored Collaboration projectsponsored by AwwaRF was developed with the Agency to further advance the testing. The main purpose of theproject was to further characterize and develop technology to fully understand its potential for full-scale drinkingwater treatment. Optimal ranges of power amperage and of contact time for bromide removal and DBP formationpotential reduction were identified. The feasibility and synergy of an electrolytic reactor in a conventional watertreatment plant were tested and discussed. Scalability issues were addressed. Includes 23 references, tables, figures.

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Edition: Vol. - No. Published: 06/01/2007 Number of Pages: 45File Size: 1 file , 1.8 MB