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The Water Treatment Technology Program Newsletter - No. 3 - Winter 1995

INTRODUCTION

The Water Treatment Technology Program (WTTP) continues to develop and apply new technologies related to water treatment for water supply augmentation, water quality improvement, and water quality protection. This newsletter is provided to keep you informed of the latest activities and developments in the WTTP. Funding for the WTTP is provided through Reclamation's Office of Research, Director, Dr. Stanley Ponce. For more information about the WTTP, contact Kevin Price at 303-445-2260.

TASK 2 - SMALL COMMUNITY WATER SUPPLY SYSTEMS

Task 2 focuses on research resulting in new technologies and appropriate water treatment processes which could benefit Native American communities, other small communities, or developing countries. Emphasis is placed on discovery of simple, economic technologies and processes which address the specific problems associated with small water supply systems. Following are a few of the sub-tasks currently being developed under Task 2:

PHOTOVOLTAIC ELECTRODIALYSIS REVERSAL (PV/EDR)

Reclamation has been actively involved in the research and testing of several alternate energy technologies, including photovoltaics for the purpose of water treatment, since the early 1980's. More recently, a solar powered PV/EDR desalting system was developed. EDR is a membrane separation process that uses d-c electricity to move and separate dissolved minerals in water. This system could be used at remote sites in the southwestern US where the need exists for obtaining potable water from brackish water sources with no access to electrical grid power. EDR was chosen because it can use the d-c power provided by photovoltaic arrays.

Building a cost effective, d-c powered PV/EDR system required finding solutions to the following problems: (1) finding an energy-efficient, variable speed, d-c powered feed pump; (2) minimizing the power consumption used for logic; and (3) minimizing control power for the reversing process.

Sixteen different windmill sites on the Navajo Nation in Arizona and New Mexico were considered for pilot testing of the initial unit, of which eleven were pump tested to determine well characteristics and obtain samples for water quality analysis. The Spencer Valley site, located on the Navajo Nation about 10 miles southwest of Gallup, NM, was chosen based on test results and site data. Spencer Valley is representative of many small, remote communities scattered across the southwestern US that need better quality water. The Spencer Valley photovoltaic equipment consists of two separate PV electrical systems: two tracking flat-plate arrays which form a 1000-W/120-V d-c system for the well pump; and three fixed arrays which provide 2300 W at 50 V d-c for the PV/EDR unit, and any other solar desalting technologies that may eventually be tested at the site.

Test results at Spencer Valley are encouraging. The pumping system has been operating continuously since September 1992, and has pumped over 750,000 gal with only minor interruptions for well maintenance. The EDR desalting unit has also performed well, producing over 90,000 gal of potable water and accumulating over 3000 hours of run time. During this test period, the unit successfully demineralized about 720 gal of water per day from 885 mg/L TDS to 333 mg/L product while consuming only 100 W of PV power.

Future plans include the installation of a prototype at another site to further develop the technology.

WATER TREATMENT ESTIMATION ROUTINE (WaTER)

WaTER is a FoxPro application developed for use with Reclamation's Mobile Water Treatment Pilot Plant (MTP) which: (1) provides cost estimates for all treatment processes used in the MTP; (2) contains default values which can be customized if more accurate values are available; (3) is expandable to include new processes as they are developed; and (4) is user friendly.

The program is a result of a cooperative effort between Reclamation, the National Institute of Standards and Technology (NIST), and the Chemical Engineering Department of the Colorado School of Mines. Unlike other cost estimation programs that require the user to have information about the size of equipment and chemical dosage rates, the only inputs required for the WaTER program are the production capacity and water quality composition.

The following processes are included in the program at this time: acidification, chlorination, KMnO4, chloramination, ozonation, alum, ferric sulfate and polymer addition, screens, lime feed, upflow solids contactor, carbon filtration, gravity filtration, ion exchange, electrodialysis, RO/NF, and pumps.

The program continues to be augmented and tested, and will be available for distribution to interested parties by late 1996. Those interested in providing verification testing of the program can contact Michelle Chapman Wilbert at 303-445-2264.

RECLAMATION'S MOBILE WATER TREATMENT PILOT PLANT (MTP) VIDEO

In edition 1 of our newsletter, we focused on Task 4 - Wellhead Treatment, and discussed the cost-shared groundwater treatment study in Maricopa County, AZ, using the MTP. The study is complete and the final report will be complete in February 1996.

In conjunction with the study, a video was prepared by Reclamation's Phoenix Area Office. The video illustrates operations at the Maricopa site, and will be used to portray our water treatment piloting capabilities related to small community water treatment systems. The video is currently being edited, and it will be available by early 1996.

CONSORTIUM

The Interagency Consortium for Desalination and Membrane Separation Research, established in 1992, is another WTTP technology transfer effort, initiated by representatives from Reclamation and the US Army Belvoir Research, Development, and Engineering Center. The Consortium consists of representatives from ten Federal Government laboratories who are involved in desalination or membrane separation research. Members work together to establish a communication network in order to gain the following benefits: (1) prevent duplication of efforts; (2) pool limited research resources to obtain common goals; (3) identify future research needs; and (4) allow for discussion of new technologies with experts.

The Consortium meets on an annual basis. In April 1995, the Consortium met and worked towards developing a formal Strategic Plan. Numerous additional areas of cooperation were also identified for partnerships and continuation of technology transfer between Federal Government research laboratories. The 1996 annual meeting will be held April 23-25, in Santa Fe, NM. For more information about the Consortium, contact Michelle Chapman Wilbert at 303-445-2264.


CONTACT US

Water from Water is published by Reclamation's Water Treatment Engineering and Research Group - Susan Martella, Editor. For more information about the DesalR&D 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.