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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

At the end of fiscal year 2002 (September 30), the DWPR program awarded 10 new financial assistance agreements - 7 research and studies and 3 pilot-scale systems. Abstracts of these agreements are provided below.

The fiscal year 2003 pre-proposals solicitations are now available at our website www.usbr.gov/mso/aamd/.

RESEARCH AND STUDIES (1 year agreements)

C. Robert Reiss (407-679-5358 or crreiss@reissenv.com) and Reiss Environmental will study Evaluation of Desalination on Waters Under the Influence of Surface Water Runoff forPretreatment, Water Quality, and Pathogen Removal Performance (total project $294,000; Reclamation's contribution $100,000). This research supports the advancement and application of desalination technologies by addressing the following research needs: (1) pretreatment of seawater sources under the influence of fresh water runoff; (2) pathogen removal; and (3) removal of low molecular weight constituents. The goals, with respect to each research need, are: (1) quantify reduction in fouling on RO system and associated costs when using conventional vs. MF/UF pretreatment and a surface water under the influence source; (2) quantify rejection capabilities of conventional, UF, and RO systems to reject pathogen-sized constituents and compare these log removal capabilities to other fresh water NF/low pressure RO research; and (3) compare what options are available to meet goals, quantify design criteria for options depending upon source water qualities and finished water quality goals, and quantify costs and optimal treatment options for a given range of conditions.

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 III (total all phases $273,936; Reclamation's contribution $240,172). 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 were identified. Phase III will: (1) develop larger-scale rectangular cross flow modules containing composite hydrophobic porous polypropylene hollow fiber membranes; (2) demonstrate the achievement of a steady water vapor flux; (3) explore the DCMD performance of a multi-module stack; (4) develop correlations to facilitate further scale-up of modules; and (5) if the performance of the larger-scale modules and module-stack are satisfactory, explore possible sites for a DCMD pilot-plant.

Sing-Foong Cheah (303-285-5156 or scheah@itnes.com) and ITN Energy Systems, Inc. will study Photovoltaic (PV) Reverse Osmosis Desalination System (total project $190,148; Reclamation's contribution $95,074). This project proposes to develop an energy efficient, modular, small scale PV-powered RO system that operates autonomously for extended periods with little maintenance. This system will address the needs of many communities world-wide that have access to saline water but no access to electricity. By using an energy efficient DC pump and energy recovery device, the system uses much less electricity compared to a conventional off-the-shelf RO desalination unit coupled with PV.

Gregory Characklis (919-843-5545 or charack@email.unc.edu) and the University of North Carolina will study An Expert System for Decision-Making in the Use of Desalination for Augmenting Water Supplies (total project $59,985; Reclamation's contribution $59,985). The primary objective is to develop an expert system that will allow communities to more comprehensively compare the costs of augmenting water supply through desalination with those of alternative supplies. The study will evaluate the true costs of various water supply options based on the costs of both acquisition and treatment, within the context of maintaining regulatory compliance and a high level of supply reliability. The expert system will include a cost model (which will compliment Reclamation's existing water treatment estimation routine - WaTER) and supporting guidance manual.

Tom Wolfe (530-273-0748 or tomwolfe@perlorica.com) and PerLorica, Inc. will study Development of a Membrane Process Optimization Methodology (total project $100,000; Reclamation's contribution $25,000). PerLorica has already developed and patented (6332110) a method for monitoring advanced separation processes using world wide web technology. This project will extend the capability of and demonstrate the usefulness of the technology in optimizing the performance of and evaluating operational trends in desalination membrane systems on a real time basis. With this funding, additional algorithms and procedures will be developed to make the predictive side of the software more useful.

Thomas Davis (803-777-7540 or tom.davis@sc.edu) and the University of South Carolina will study Zero-Discharge Seawater Desalination: Integrating the Production of Fresh Water, Salt, Magnesium, and Bromine (total project $100,000; Reclamation's contribution $100,000). This research is based on the premise that seawater has many valuable constituents, but their value can only be realized if they can be separated economically. The approach will be to separate and remove a variety of salts from RO concentrate. NaCl and KBr will be separated by ED. NaCl in the ED brine is recovered by crystallization after concentration by evaporation, and the Br ions are converted to Br2. Mg ions are recovered by precipitation with a base. For purposes of the study, all remaining solutions will be evaporated to dryness, but ultimately other minor constituents might be recovered from that residue.

Anthony Tarquin (915-747-6915 or atarquin@utep.edu) and the University of Texas at El Paso will study Development of a Brine Concentration Process Using Membrane Technology for High-Silica Brackish Water (total project $135,682; Reclamation's contribution $100,000). This project is a laboratory and pilot-plant investigation of processes directed toward further concentrating high-silica brine concentrate from a RO system. The pilot-plant investigation will be carried out in 2 phases: (1) hardness removal by NF followed by a single-pass RO system which will be operated on a batch basis with external recirculation to obtain rough estimates of operating conditions that will be required for concentrating the brine without fouling the membranes; and (2) the RO system (an NF, if necessary) will be operated in a single-pass mode to obtain design information for the full-scale system. Laboratory studies will also be conducted, during phase 1, regarding lime softening of the silica-saturated brine. If the NF pretreatment does not prevent fouling of the RO membranes, then a pilot lime-softening process will be substituted for the NF system. The project will result in design information for full-scale implementation of a brine concentration process.

PILOT STUDIES (2 year agreements)

Paul Shoenberger (310-660-6218 or pauls@wcbwater.org) and West Basin Municipal Water District will investigate Seawater Desalination Pilot-Plant to Advance the State-of-the-Art by Optimization of Microfiltration/Ultrafiltration and Reverse Osmosis (total project $365,725; Reclamation's contribution $176,385). This investigation will focus on the innovative use of MF and UF as pretreatment (instead of conventional filtration) for RO seawater desalination. As part of the pilot-plant design, the following issues will be addressed: (1) quantifying the effect of temperature on MF/UF and RO processes; and (2) determining optimum membrane flux and in-situ membrane cleaning cycles for seawater quality identical to that of proposed full-scale facilities. The pilot-plant will be capable of testing 2 MF and/or UF membranes simultaneously. Pilot-plant testing will determine the most effective membrane cleaning formulations, and contaminant removal techniques will also be optimized.

Bill Pearce (619-533-5274 or WPearce@sandiego.gov) and the City of San Diego will investigate Evaluation of Various Pre-Treatment Methods for Seawater Membrane Desalination (total project $600,000; Reclamation's contribution $250,000). This investigation will use an integrated approach to pilot-testing that will definitively quantify the relative advantages/disadvantages of membrane pretreatment to seawater desalination. The investigation will occur at the Aqua 2000 Research Center located in San Diego. The project team consists of the City's water department, Montgomery Watson Harza, Zenon, US Filter, Hydranautics, and Saehan. This investigation will: (1) evaluate the current state of knowledge through an exhaustive literature survey; (2) identify potential foulants in seawater through extensive analysis of seawater as feedwater; (3) optimize conventional treatment and membrane selection during comparative evaluation of the two pretreatment techniques; (4) collect data on simultaneous operation of treatment trains with different pretreatment methods; (5) evaluate the processes in terms of regulatory compliance; and (6) analyze the economics of the treatment scenarios based on actual operating data.

Graham Juby (714-540-4300 or gjuby@carollo.com) and Carollo Engineers will investigate Las Vegas Valley Membrane Pilot Study (total project $457,535; Reclamation's contribution $228,767.50). In this investigation, Corollo's novel IMANSTM (patent pending) treatment concept will be tested at pilot-scale to demonstrate to the public and regulators that high quality product water, acceptable for irrigation or groundwater injection, can be readily and economically produced from primary treated effluent. The IMANS system also provides a solution to the increasing salinity in source waters in the Las Vegas Valley. IMANS uses membrane processes, in combination with anaerobic biological treatment, to provide a more direct route to obtaining high quality water for reuse. IMANS uses MF for physical treatment of a primary treated effluent, followed by a second membrane treatment (e.g. RO) to polish the water to a desired quality. Soluble organic material concentrated by the membrane process is treated in a high-rate anaerobic digester.


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.