Meeting the Stage 1/2 Disinfectant/Disinfection Byproduct Rules is a balancing act for most utilities. The Castaic
Lake Water Agency (Agency) treats imported water from the California Aqueduct (West Branch of State Water
Project) 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 system
residual. To complicate matters, the presence of bromide ion in the range of 100 to 300 µg/L is problematic for two
reasons that include: ozone is applied at both water treatment plants for preoxidation, which reacts with the bromide ion to
form bromate byproduct; and, upon addition of free chlorine, brominated disinfection byproducts (e.g. THMs
and 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 were
obtained in terms of bromide, DBP minimization, and microbial inactivation. A Tailored Collaboration project
sponsored by AwwaRF was developed with the Agency to further advance the testing. The main purpose of the
project was to further characterize and develop technology to fully understand its potential for full-scale drinking
water treatment. Optimal ranges of power amperage and of contact time for bromide removal and DBP formation
potential reduction were identified. The feasibility and synergy of an electrolytic reactor in a conventional water
treatment plant were tested and discussed. Scalability issues were addressed. Includes 23 references, tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 1.8 MB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 45 |
| Published : | 06/01/2007 |
