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The Desalination and Water Purification Research & Development Program Newsletter - No. 23 - Summer 2002

THE PROGRAM

Through the Desalination & Water Purification Research & Development (DWPR) Program, Reclamation has formed partnerships with private industry, universities, local communities, and others to address a broad range of desalting and water purification needs. The overall program objective is to reduce the cost of desalting and water purification technologies in order to augment U.S. water supplies. For more information, contact program manager, Tom Jennings, (303) 445-2130, or visit our website at http://www.usbr.gov/pmts/water/research/DWPR/.

NEW CONTRACTS

During fiscal years 2001 and at the beginning of 2002, the DWPR program awarded 8 new financial assistance agreements - 6 research and studies and 2 pilot-scale systems. Abstracts of these agreements are provided below.

RESEARCH AND STUDIES (1 year agreements)

Kamalesh Sirkar (973-596-8447 or sirkar@adm.njit.edu) and New Jersey Institute of Technology will study Novel Membrane and Device for Direct Contact Membrane Distillation-Based (DCMD) Desalination Process - Phase II (total both phases $163,000; Reclamation's contribution $140,173). This on-going research continues the study of a new innovative desalination process - DCMD. In phase I, exploratory studies of DCMD and vacuum membrane distillation were completed using a number of different hollow fiber membranes and a few different module designs. Potential routes for development of an economic membrane distillation technology were identified. In phase II, the plasmapolymerized coatings, porous hollow fiber substrates, cross-flow module configuration, and flow regime needed to achieve the desired pure water flux from a hot brine feed will be identified.

Ralph Hensler (609-683-0215) and Novaflux Technologies, Inc. will study Removal of Biofilm and Other Foulants from Spiral-Wound Reverse Osmosis Membranes (total project $174,142; Reclamation's contribution $73,871). This study refines the use of a new and innovative technology developed and validated by Novaflux for cleaning spiral wound RO membranes. Currently, the technology has been validated only for membranes up to 4-inches in diameter. The ability to clean larger membranes, particularly in series, will be addressed in this study. Fouled 8-inch membranes from the Yuma Desalting Plant and Orange County Water District will be cleaned in this study. The technical data will be compared to current cleaning methods and an economic evaluation will be made to determine the economic impact of the new technology for the above two facilities.

James Ranville (303-273-3004 or jranville@mines.edu) and Colorado School of Mines will study Predicting Membrane Flux Decline Using Parameters Derived from Field-Flow Fractionation Measurements (total project $93,613, Reclamation's contribution $93,613). This project will develop a new engineering model to predict UF and NF membrane fouling on a given source water based on the complexity of solute-solute and solute-membrane interactions - especially solute-membrane interactions. The ultimate goal of the investigation is to improve the costs and ease of use of membranes by developing methods that can predict membrane fouling. The concept of relating complex solute mixture characteristics to membrane fouling using flow field flow fractionation will be tested. Flow field flow fractionation has traditionally been used in separation science as a tool for characterizing the size and/or molecular weight distributions of mixtures of macromolecular and colloidal materials.

Robert Carnahan (813-974-3786 or carnahan@eng.usf.edu) and the University of South Florida will study Impact on Revese Osmosis Separation - A Laboratory Study (total project $111,366; Reclamation's contribution $90,996). This research will use magnetic fields to better understand the influences of the physical chemical functions such as ionic mobility, hydrated radii, and ionic charge in the separation processes. Since the permeate water produced in membrane systems is pressure dependent, this work will focus on determining those physical chemical characteristics of the electrolytes that control their separation from the water. Magnetic fields alter the quantum numbers, velocity, and the waters of hydration associated with the ionic species; therefore, this study will determine if there is a technique that will permit the prediction of the degree of separation of ionic species from the water.

Mike Mickley (303-499-3133 or mike@mickleyassoc.com) and Mickley and Associates will study Treatment of Concentrate and Backwash (total project $203,496; Reclamation's contribution $99,913). Under previous agreements with Reclamation, Mickley and Associates prepared the Membrane Concentrate Disposal: Practices and Regulations database and user's manual (available at www.usbr.gov/water/publications/reports.html). This study will identify and evaluate technologies to treat membrane concentrate and backwash, or to pretreat membrane system feedwater, to increase the options available for concentrate or backwash disposal. The proposed work will serve as a: (1) tool for defining industry issues and needs; (2) means for utilities to understand available treatment options; (3) guide to drinking water utilities considering membrane plants for addressing concentrate disposal issues; and (4) technology transfer tool - an important consideration in times of rapid development.

Robert Doneker (503-748-4053 or donekar@ese.ogi.edu) and Oregon Health and Science University will study Systems Development for Environmental Impact Assessment of Concentrate Disposal (total project $74,646; Reclamation's contribution $74,646). The study will develop a desktop computer software system to address the hydrodynamic, ecological, and regulatory issues associated with the fate and transport of desalination facility concentrate discharged into surface waters. The systems produced will improve the ecological impact assessment, regulatory management, and scientific prediction of concentrate behavior within the mixing zone - a limited region where the initial mixing of a discharge occurs. The computer visualization systems developed will enhance communication of environmental impacts associated with hydrodynamic mixing zone processes to scientists, engineers, regulators, industry, and the public. The techniques created will be state-of-the-art systems for hydrodynamic process simulation, environmental impact visualization, regulatory risk assessment, and infrastructure design.

PILOT STUDIES (2 year agreements)

Lisa Henthorne (303-670-1414 or lisahenthorne@cs.com) and Aqua Resources International, LLC, will investigate Evaluation of Membrane Pretreatment for Seawater RO Desalination (total project $503,435; Reclamation's contribution $250,258). This investigation will: (1) evaluate the performance of MF and UF membrane pretreatment compared to conventional pretreatment of seawater RO desalination, in terms of improved pretreated water quality and impact on RO performance; and (2) determine the subsequent cost benefits of membrane pretreatment compared to a range of conventional pretreatment options, through establishment of a objective life-cycle cost comparison. The project will be accomplished through 2 phases of piloting at the San Patricio Water District facility near Corpus Christi, TX.

Paul Gagliardo (619-533-4222 or PZG@sdcity.sannet.gov) and the City of San Diego Water Department will investigate Optimization of Various MBR Systems for Water Reclamation (total project $1,090,280; Reclamation's contribution $270,000). This investigation is based on several years of evaluation by the City with the use of membrane bioreactors (MBR) for water reclamation. The City is planning construction of a reclaimed water plant at their Point Loma Wastewater Treatment Plant. The proposed reclaimed water plant will treat advanced primary effluent to supply the plant's industrial water needs and would include the following processes: (1) submerged MBR; (2) RO; (3) and (3) in-line UV disinfection. Several research needs will also be studied to further develop the MBR process for water reclamation and to ensure successful design and operation of the reclaimed water plant. These include: (1) evaluating new MBR technologies; (2) determining the impact of chemical addition to MBR influent; (3) optimizing the MBR process operation; (4) evaluating various RO membranes on MBR effluents; (5) obtaining regulatory approval for the reclaimed water plant; and (6) updating the cost estimates for the MBR technology.


CONTACT US

Water from Water is published by Reclamation's Water Treatment Engineering and Research Group - Susan Martella, Editor. For more information about the DWPR program, contact Kevin Price at: Bureau of Reclamation, 86-69000, PO Box 25007, Denver CO 80225; phone (303) 445-2260; or e-mail a message to MPrice@usbr.gov.