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Santa Clarita, CA, United States

Leserman J.R.,Castaic Lake Water Agency
Water Quality Technology Conference and Exposition 2011 | Year: 2011

This paper presents the Castaic Lake Water Agency's experience with starting up and operating its new Saugus Perchlorate Treatment Facility (SPTF) located in Santa Clarita, California. The 2,400 gpm capacity plant includes a lead-lag anion exchange process for removing perchlorate from an extremely impaired groundwater (about 20 to 60 μg/L perchlorate in the blended groundwater). The resin is single use and replacement of the lead bed resin is based on its effluent perchlorate concentration reaching the perchlorate MCL of 6 μg/L. In addition to perchlorate and other compliance monitoring, CLWA must also conduct nitrosamine monitoring after virgin resin is installed to characterize the duration and extent of nitrosamine formation and implement resin installation and flushing procedures to minimize the risk of producing water with nitrosamines. The paper describes the performance of the anion exchange process before and after modifications were made to address shorter than anticipated resin bed life. The paper also describes experience with addressing nitrosamine formation and chloride peaking issues. 2011 © American Water Works Association AWWA WQTC Conference Proceedings All Rights Reserved.


An inter-laboratory study was conducted to assess the Kaiser-Currie Model (KCM) for the determination of detection limits. Six laboratories participated in the analysis of samples prepared from distilled water, some containing organo-chlorine pesticides at a concentration of zero and other with a greater than zero concentration. The study consisted of three phases, the first of which was a study to assess the longer term variability of distilled water samples containing no organo-chlorine pesticides prepared by the participating laboratory analysed over a six month period. A second phase consisted of replicates of distilled water samples containing organo-chlorine pesticides prepared at a single concentration greater than zero by the laboratory and were analysed over several days. Finally, a third phase consisted of twelve distilled water samples, eleven containing organo-chlorine pesticides at a concentration of greater than zero and one with a concentration of zero prepared by a third party. Estimated detection limits were determined and then compared to the observed detection limits. Only in a minority of cases, where the distribution of results from samples containing a concentration of zero was normally distributed, did Currie's L C accurately predict a concentration which corresponded to a 1% false positive rate in distilled water samples with a zero concentration of the study analyte. The USEPA's MDL performed more poorly. In the majority of cases, when any non-zero results were obtained from distilled water samples containing a concentration of zero, they were not normally distributed. Contrary to expectation, false negatives and false positives rarely occurred simultaneously on any given day. The variability between days of analysis and the use of noise reducing techniques proved to be a significant source of the observed non-normal distribution of distilled water samples. Conventional procedures based on the KCM and their underlying analytical and statistical assumptions did not provide useful predictions of laboratory sensitivity in most cases in this study. © 2011 Taylor & Francis.


Kimbrough D.E.,Castaic Lake Water Agency
International Journal of Environmental Analytical Chemistry | Year: 2011

An interlaboratory study was conducted to assess two widely used procedures for estimating quantitation levels. Six laboratories participated in the analysis of artificially prepared water samples for organo-chlorine compounds by liquid-liquid extraction followed by gas chromatography-electron capture detector using USEPA Method 608. The study consisted of three phases, including six months of results from analyte free samples, the replicate analysis of fortified samples at a single concentration by the laboratory, and finally the analysis of blind fortified samples prepared by a third party. Estimated detection and quantitation limits (Currie's L C and L Q and USEPA's MDL and ML) were determined for each laboratory-method-analyte combination and then compared to the observed detection and quantitation limits. The overwhelming majority of analyte free samples had a reported value of zero. As a result, observed quantitation and detection limits were frequently zero. When they were not zero, the observed quantitation limits were sometimes less than the observed detection limits and when they were not, there was no observed fixed ratio between the quantitation and detection limits. The variability between days of analysis and the use of noise reducing techniques proved to be a significant source of the observed non-normal distribution of results from distilled water samples with a concentration of zero. Conventional procedures and their underlying analytical and statistical assumptions did not provide useful predictions of laboratory quantitation based upon the results of this study. Rather than one time statistical determinations, ongoing verification of quantitation limits may be a better approach. © 2011 Taylor & Francis.


Kimbrough D.E.,Castaic Lake Water Agency | Boulos L.,L. Boulos Consulting Inc. | Surawanvijit S.,University of California at Los Angeles | Zacheis A.,Carollo Engineers
Water Quality Technology Conference and Exposition 2010 | Year: 2010

A new technology for the removal of bromide from drinking has been described in several recent publications (Kimbrough & Suffet 2002, Kimbrough & Suffet 2005, Kimbrough 2007, Boulos et al. 2008). Bromide is known to react with Natural Organic Matter and oxidative disinfectants to product brominated Disinfection By-Products (DBPs) which are thought to be carcinogens. This paper presents recent advances in this technology as applied the California State Water Project (SWP) which has historically had high concentrations of bromide and, when treated, has produced brominated DBPs. The process consists of oxidizing bromide at the anode to bromine and volatilizing the bromine at the anode surface. SWP water was passed through this unit under various conditions and the bromide was oxidized and volatilized. Variables included the depth of the anodes (0.1, 1.2, 2, 5, 10 cm), the distance between the anode (1, 2, 5, 10 mm), water flow (50-200 mL/min), and applied current (0.02-8.0 amps), producing 272 experimental conditions. Bromide reaction rates and removal efficiency were observed for each of these conditions. The highest reaction rate (1,430 μg/L/min) was observed in the shallowest reactors (0.1 cm) and under the highest flow rates (150 mL/min), but the greatest removal efficiency (69%) was achieved in a slightly deeper reactor (1.2 cm) at lower flows (50 mL/min). When these two reactor configurations were combined, even greater removal efficiencies were obtained (>99%) but not greater reaction rates. There appears to be a general relation that the shallower the reactor is, the greater the reaction rates. However, since this also means less surface area, the shallower reactors are easily saturated. The development of this technology will require the balancing of anode depth to maximize the volatilization rates with the need for greater anodic surface area to maximize oxidation and gas formation rates. 2010 © American Water Works Association WQTC Conference Proceedings. All Rights Reserved.


Kimbrough D.E.,Castaic Lake Water Agency | Boulos L.,L. Boulos Consulting Inc. | Surawanvijit S.,University of California at Los Angeles
Journal of Water Supply: Research and Technology - AQUA | Year: 2011

To reduce the concentrations of brominated disinfection by-products, a process is presented here which removes bromide from a widely used surface water source, the California State Water Project (SWP). The process consists of oxidizing bromide to bromine and volatilizing the bromine. SWP water was passed through this unit under various conditions and the bromide was oxidized and volatilized under a variety of conditions. Five different reactor bodies with seventeen different configurations were tested. The reactors differed in the depth of the anode, in the distance between the anodes and, in the surface area of the anodes. Each reactor had SWP water pumped through the reactor at three or more different flows and at four or more different currents, producing 267 experimental conditions. Both reaction rates and removal efficiency increased with increasing current and were generally higher in the shallower reactors. The highest reaction rates were observed in the shallowest reactors and highest flow rates but the greatest efficiency was achieved is in a slightly deeper reactor at lower flows. This appears to have been the effect of the shallowest reactor having the smallest surface area that was easily saturated and but being closest to atmosphere, allowing the most rapid volatilization of bromine. © IWA Publishing 2011.

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