Determination of Mechanism(s) of Microfiltration Fouling by Reclaimed Wastewater; Development of Potential Mitigation Strategies – Improving the efficiency of microfiltration can represent a significant water production cost saving for the GWR System. This project continues past work aimed at characterizing nanoparticulate foulants, understanding mechanisms of foulant accumulation, and control of accumulation in the polypropylene HF-MF membrane material used in the GWR System advanced water purification facility by a variety of means, including application of coagulants.  This research includes both bench and pilot testing (at the GWRS Pilot Research Center), and includes the potential for collaborative research with other membrane research centers.

Characterization of RO Fouling in the Water Purification Plant – Accumulation of fouling materials on reverse osmosis membranes that impair performance in the GWRS advanced water purification facility are currently poorly characterized. R&D is planning an investigation in cooperation with OCWD's Water Production Department (and potentially in collaboration with the UCLA WaTeR Center) to study RO membrane fouling as it occurs in the GWR System, and to determine how biological activity early in the first RO pass influences fouling farther along the train (pilot and full scale studies).  Data from this study may result in a significant O&M cost improvement for the GWR System reverse osmosis plant.

Implementation of a Rapid Assay for Assimilable Organic Carbon (AOC) – Assimilable organic carbon (AOC) in feed waters supports growth of organisms that foul RO membranes.  Monitoring the levels of AOC would help provide a prediction of the time between chemical cleaning of the RO membrane systems used in the GWR System water purification plant, and also would provide a check on the effectiveness of operations designed to reduce feedwater AOC.  However, traditional AOC measurement methods are difficult and time-consuming to perform, and as such do not lend themselves to rapid monitoring.  R&D staff are researching application of a rapid method for determining AOC developed by CheckLight Ltd. (Qiryat-Tiv’on, Israel) based on microbial bioluminescence that promises to provide AOC data in hours as opposed to days.  Moreover, assay modifications performed by R&D also allow simultaneous determination of the presence of biotoxins in the water tested.

Modeling RO Removal of Organic Contaminants – R&D staff has considerable research experience determining and modeling removal of many types of micropollutants by RO membranes.  Staff is currently participating in the PAC overseeing WateReuse grant WRF 06-009 “Predictive Models to Aid in Design of Membrane Systems for Organic Micropollutant Removal” awarded to Dr. Jorge Drewes for developing a new hybrid (containing theoretical and empirical components) mathematical model capable of predicting removal of diverse organic micropollutants by RO membranes.

Advanced Oxidation Plant (AOP) Studies – This research is aimed at evaluating the capability of OCWD’s Trojan UV-Phox UV-peroxide plant to oxidation of specific organic compounds of public health concern under full scale operating conditions.  Research consists of a combination of full-scale AWPF data analysis and experiments at the pilot scale at the GWRS Pilot Research Center with a modified Trojan pilot UV reactor aimed at optimization of direct photolysis, advanced oxidation process (AOP) and potential for residual disinfection.  The activity includes collaborative research with Dr. Bill Cooper’s laboratory at the UCI Urban Water Research Center and with Dr. Joel Ducoste at North Carolina State University.  R&D staff also is participating in the WateReuse Foundation PACs for WRF 04-017 “Reaction Rates and Mechanisms for Advanced Oxidation Processes for Water Reuse” and WRF 06-012 “Optimization of Advanced Oxidation Processes for Water Reuse.”

GWR System Research Center Bacteriophage Testing Facility – Measurement of viral attenuation by water purification membranes provides a quantifiable assessment of the membrane to act as a biological barrier.  .R&D staff has expertise required to perform this type of testing, and will offer oversight support for a potential MS-2 bacteriophage testing facility at OCWD, including co-validation of results with established phage testing laboratories and providing training for the technicians performing the routine analytical work in support of GWR System operations. 

Potential Mobilization of Metals during AWPF Recharge/Injection – R&D staff will continue to review data provided by Water Quality for the GWR System, and if possible collaborate with Dr. Robert Bowman of New Mexico Tech to characterize mobility of metals observed in the field.  R&D staff is participating in the Water Reuse PAC for WRF 06-005 “Leaching of Metals from Aquifer Soils During Infiltration of Reclaimed Water of Low Ionic Strength” granted to Dr. Quilin Li of Rice University.

Injection Well Fouling Issues – R&D maintains a model injection well (MIW) system capable of simulating injection well conditions.  This can be used for ad-hoc investigations in case fouling issues arise with the injection well system requiring R&D experimental solutions.

Other Groundwater Replenishment System Support – R&D is equipped to engage in short-term research activities on an ad-hoc basis to assist the Water Production Department in solving acute physicochemical and biological problems arising during operation of the GWR System advanced water purification facility.

Collaborative Membrane Characterization Project – The R&D Department is collaborating with Dr. Amy Childress of the University of Nevada, Reno on an AwwaRF/USEPA grant “Evaluation of Membrane Characterization Methods.” This project will evaluate best methods for characterization of water processing membranes. OCWD participation will consist of providing operating data from the GWRS advanced water purification facility, consulting expertise, access to a test RO platform, modeling and analytical support.  Anticipated project completion is FY 09-10, with up to $40,000 in funding for OCWD.

Groundwater Recharge Support

Percolation Studies – Percolation of Santa Ana River (SAR) water in OCWD recharge basins decays over time, limiting the amount of water per year that OCWD can recharge. It is hypothesized that accumulation of inorganic and organic (biological) matter suspended in recharge water is responsible for this decay. R&D Department staff scientists at the Field Research Laboratory (FRL) in Anaheim, CA are conducting a combination of laboratory and field studies to determine the nature of the foulants in recharge water and their interaction with recharge basin sediments that leads to percolation reduction, including the influence of soil particle size distribution and sediment particle size distribution on the kinetics of basin fouling. Understanding of these interactions will be important in designing the most efficient means of desilting and cleaning basins for maximal water production.

Recharge Enhancement Working Group (REWG) Support – R&D staff members provide OCWD staff from Hydrogeology, Water Quality, Forebay Operations and Engineering with scientific assistance and analytical support for implementation and performance analysis of existing and proposed recharge enhancement scenarios. These scenarios currently include:
--Desilting Improvement Program
--Subsurface Recharge
--Alternative Basin Cleaning Methods Testing
--Basin Sediment Optimization
--Fletcher Basin Vadose Recharge Well Project
--Santa Ana River Armoring Study
 

BCV Support - Ongoing OCWD Field Research Laboratory research supports REWG strategies to improve basin cleaning vehicles (BCV) operations including analyses of sediment mass loading, mass removal analysis and correlation of BCV activities with recharge facility performance. Supported REWG projects include:
--Shallow Water BCV Optimization
--Deep Water BCV Development

Microbial Pathogen/TMDL Projects

Middle Santa Ana River Pathogen Total Maximum Daily Load Study - This is a joint study with SAWPA with the with the support of San Bernardino County Flood and Riverside County Flood to evaluate pathogenic sources in the Santa Ana Watershed and develop a list of tentative BMPs to address those sources. R&D staff will analyze surface water samples for Bacteroides thetaiotaomicron (a human waste-specific indicator organism) to identify the sources of contamination. Project duration: March 2007 to August 2008. Funding: $40,000 - $60,000 (depending on rainfall).

Middle Santa Ana River Pathogen and Bacterial Indicator Scoping Study – This is a potential study at the request of The Regional Water Quality Control Board (RWQCB) for OCWD to evaluate the occurrence and concentration of selected pathogenic organisms in the Middle Santa Ana River (MSAR). Funding for the study will be provided by the RWQCB; the Santa Ana Watershed Project Authority (SAWPA) will serve as project administrator. If executed, the anticipated completion is in FY 08-09. Funding: up to $50,000 (depending on rainfall). 

Potential Future R&D Research Projects

Evaluation of new generation water treatment membranes (MF, RO) for the GWR System advanced water purification facility.

Evaluation of new, improved AOP methodologies (e.g., catalytic AOPs).

Development of a rapid, low cost assimilable organic carbon (AOC) assay using local resources (current assays are costly and/or rely on imported materials).

Investigation of brine treatment technologies to mitigate discharge of organic compounds of concern, including endocrine disruptors.

Implementation of new molecular biological methodologies for virus detection.

Investigation of long-term effects of GWR System product water recharge on the groundwater basin.

Evaluation of new solid-state, real-time detection methodologies for biological and chemical species of public health concern.

Investigation of surface water treatment technologies for improvement of Santa Ana River water quality prior to infiltration.

Development of “self-cleaning” groundwater recharge systems (e.g., cross-flow systems) to improve recharge capacity in terminal basins.

R&D Department Contact:
Donald W. Phipps, Jr.
Research Director
The Orange County Water District
18700 Ward Street
Fountain Valley, CA 92708

Phone: (714) 378-3270
FAX: (714) 378-3375
E-mail: dphipps@ocwd.com