The Water Treatment Technology Program Newsletter - No. 1 - Spring 1995
...the first issue of our newsletter which chronicles the activities and developments in the Water Treatment Technology Program (WTTP).
In review, the primary objectives of the WTTP are to:
- perform research to reduce desalting and water treatment costs to a point they become feasible alternatives for increasing usable water supplies;
- encourage cost-shared research in partnership with private industry, universities, and local communities;
- enable treatment of water of impaired quality in urban and rural communities;
- develop technologies for desalting and treatment of waters contaminated by industrial sources and irrigation drainage;
- promote more energy efficient and environmentally attractive technologies; and encourage technologies that minimize chemicals and reduce sludge volume; and
- provide technology transfer by sharing knowledge with private industry, other government agencies, and cooperators.
Following are the nine tasks within the WTTP:
- Task 1: Compile National Treatment Needs Survey
- Task 2: Small Community Water Treatment Systems
- Task 3: Desalting Membrane Process Development
- Task 4: Wellhead Treatment Processes
- Task 5: Encourage New Ideas from Small Operators
- Task 6: Western Water Projects
- Task 7: Technology Transfer
- Task 8: Support Emerging Water Treatment Technology
- Task 9: Wastewater Reclamation
Task 1 is complete, and Task 9 is inactive due to budget cuts.
The WTTP continues to develop and apply new technology related to water treatment for water supply augmentation, water quality improvement, and water quality protection.
Current active projects are promoting studies of advanced water treatment in cooperative projects with small communities, Native American communities, water districts, and commercial entities.
Tasks 4 and 6 are the focus of this issue.
TASK 4 - WELLHEAD TREATMENT
Cooperative studies with State and local water entities are being accomplished to develop water treatment systems that treat well waters of impaired quality, while producing lower concentration reject flows that can be used for other beneficial purposes.
A cost-shared Eastern Municipal Water District reverse osmosis (RO)/saline vegetated wetlands pilot study is concluding its second year of successful operation in Hemet, CA.
The purpose of the study is twofold:
first, to demonstrate the performance of low-pressure RO for desalting brackish groundwater for municipal and industrial applications;
and second, to investigate the use of RO reject brine for the support of constructed saline wetlands.
Several salt-tolerant plant species, which are attractive to wildlife, are being evaluated.
The successful demonstration of these goals could lead to the use of RO for the production of high quality water at a reasonable cost and, at the same time, provide saline water for the irrigation of green belts, open spaces, and habitat areas.
A draft interim report is presently being prepared (jointly by Reclamation and the National Biological Service) which will document the first two years of testing.
A cost-shared Lake Havasu City, AZ study to evaluate selected groundwater treatment options is complete, and a final report has been issued.
The study included pilot testing of a city-owned well, using Reclamation's mobile water treatment pilot plant.
In general, the city's water supply is in full compliance with all primary drinking water standards.
However, the concentrations of other constituents, including manganese, sulfates, hardness, and total dissolved solids (TDS) are in excess of the secondary maximum contaminant levels (MCLs).
High manganese levels are a particular concern to the community because of clogged water lines, and discolored water and clothing.
Blending of poor quality groundwater with better quality wells has been used, but with the declining quality of established wells this approach is becoming impractical or unavailable.
Pilot testing successfully demonstrated the removal of manganese using potassium permanganate oxidation, and compliance with all secondary MCLs using nanofiltration.
Construction, operation and maintenance costs, and life cycle costs are provided in the report for each tested process, as well as for lime softening (not tested).
Reclamation's mobile pilot plant was most recently used in a cost-shared groundwater treatment study in Maricopa County, AZ in cooperation with the cities of Avondale, Chandler, and the Gila River Indian Reservation.
The cooperating communities agreed to study a well owned by the City of Avondale because it shares many of the characteristic problem contaminates that exceed primary and secondary drinking water standards, including nitrates, hardness, sulfate, and TDS.
Both RO and nitrate specific electrodialysis (ED) were selected for evaluation; RO because of its ability to meet all MCLs and because of blending opportunities, and ED for its less stringent pretreatment requirements and lower associated costs.
The final report from this study will address treatment recommendations and costs.
TASK 6 - WESTERN WATER
Cost-shared preliminary research studies and laboratory tests are being accomplished in partnership with private industry, universities, and local communities to study water treatment at specific sites which can result in significantly more usable water in the West.
Results will be used for preliminary design and cost estimates of cost-shared pilot plants at a scale suitable to support full-scale water treatment plant designs.
Progress continues in each of the five cost-shared contracts originally awarded under Task 6.
Final reports were prepared by each of the contractors, and review comments are being provided by Reclamation.
The contracts include:
- In cooperation with Northern Arizona University, conducted a study of a nanofiltration system to remove salinity and hardness from well water at a school on the Hopi Indian Reservation in northern Arizona.
- In cooperation with University of Texas at El Paso, conducted studies of desalting, pretreatment, and post treatment systems for brackish wells to provide additional water for the rapidly growing El Paso area.
- In cooperation with Science Applications International, Corp., conducted a study of a positive displacement pumping and energy recovery system to reduce the cost of a proposed RO seawater project in the San Diego region.
- In cooperation with Super Systems, Inc., conducted a study of seawater desalination cogeneration systems for sites on the California coast.
- In cooperation with Thermal Energy Storage, Inc., conducted a study to evaluate a freeze desalination system to provide fresh water for the Navy on an island off the coast of San Diego.
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.