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Water Reuse Study E-Update - June 2005

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The Water Reuse Study team has created this "E-Update" to bring you up-to-date on Study activities and provide news about the recycled water industry. Each issue will be posted on this website. We are sending e-mail announcements of new issues to persons who have expressed an interest in the Study. If you did not receive an e-mail announcement and would like to, please join our news group. If you did receive an announcement about this issue, you are automatically in the news group.

If you are new to the Water Reuse Study, the Study Overview will provide helpful background information. The Frequently Asked Questions section contains additional material that also may be of interest.

Independent Advisory Panel Meeting

The Independent Advisory Panel (IAP), tasked with reviewing the technical aspects of the Water Reuse Study, met in San Diego on May 16 to discuss the Study's Interim Report. Panel members were selected by the National Water Research Institute's Research Advisory Board and panelists included a San Diego community representative. In preparation for the meeting, Panel members had been reviewing a number of technical memoranda (specific to their area of expertise) on various aspects of the Study. The IAP held an in-depth discussion at the meeting and provided valuable feedback to the Study team on the content of technical memos and Interim Report, which will be the basis for Study's final report to the City Council later this year.

Advanced Treatment Process Research Studies

Studies are currently underway at the North City Water Reclamation Plant to analyze the effectiveness of an advanced treatment process on tertiary level recycled water produced at the plant. The studies focused on testing four different brands of reverse osmosis filters. Reverse osmosis filtration is commonly used for desalinating seawater for drinking purposes. It is also the key step in treating tertiary level recycled water (the highest level of treatment) if the water is to be used to supplement drinking water supplies in a groundwater basin or storage reservoir. Tests were conducted to determine the integrity of the filters and their success in removing compounds from the recycled water that could be potentially harmful for human consumption; such as pharmaceuticals, personal care products and insect repellant.

As part of the research, the filters were purposely damaged to see how they performed "under stress." The best performing filter was then used in combination with an advanced oxidation process to test for effectiveness in removing specific unwanted compounds. Advanced oxidation involves adding hydrogen peroxide to the recycled water and then exposing it to ultraviolet light for additional disinfection.

Research study tests showed that the best performing filter, combined with advanced oxidation, produced "advanced treated" recycled water with undetectable levels of specific compounds (less than one part per trillion). Tests are continuing on the best performing filter to determine how effective it works after six to nine months of continual use.

Otay Water District to Expand Recycled Water Facilities

The Otay Water District recently approved an expenditure of $30 million to build recycled water facilities. These facilities include six miles of 30-inch pipeline and a 12 million gallon storage tank and pump station in Chula Vista.

Once the facilities are on line, the District will purchase recycled water from the City of San Diego's South Bay Water Reclamation Plant. The recycled water will be used for irrigating parks, sports fields and landscaped areas in the rapidly growing areas of eastern Chula Vista.

City Receives $1.75 Million in State Grants for Groundwater Studies

The City of San Diego has recently received approval of $1.75 million in Proposition 50 grants from the State of California. The grants are for feasibility studies for desalinating groundwater in the San Diego Formation and San Pasqual Aquifers. If the desalination projects are implemented, they are expected to produce 11,000 acre-feet per year of potable water.

One of the Water Reuse Study options for increasing the use of recycled water is adding recycled water to San Diego's groundwater basins (aquifers) to supplement the volume and/or improve the water quality. Exploring all reuse options will help San Diego in its efforts to develop a more reliable local water supply.

Impact of Pharmaceutical Disposal on Water Quality

Two of the options being researched for increased recycled water use involve blending it with untreated water that ultimately will be used for drinking (after being processed through a drinking water plant). Public health experts are now analyzing what compounds may remain in tertiary treated recycled water that might be harmful to humans if ingested. These compounds include pharmaceutical medications such as acetaminophen (Tylenol), antibiotics, hormonal supplements, etc. When recycled water is used for irrigation and industrial uses, these compounds are not a concern.

Traditionally, community residents have been told to flush any unused medications down the toilet to prevent them from getting in the hands of children or others who should not have access to the medications. However, due to their potential impact on recycled water, this may not be the best approach to dealing with unwanted or outdated medications - even over-the-counter medications.

Some communities are establishing programs where residents can safely dispose of medications so that they don't get into the wastewater stream, or even the landfill. Ask your pharmacist if there is a disposal plan through the pharmacy to prevent having to dispose of medications in the toilet, where they will become part of the wastewater and possibly recycled water.

Video Tour of South Bay Water Reclamation Plant Available Online

A video tour of the South Bay Water Reclamation Plant (SBWRP) is available for viewing on the City of San Diego's Metropolitan Wastewater Department's Website. Located in the Tijuana River Valley, the SBWRP provides wastewater treatment services in the South Bay area and has the capacity to treat 15 million gallons per day of wastewater to produce tertiary level recycled water. The plant opened in May 2002.

In the News

News Articles of Interest - a chronological compilation with links to articles, materials and information about recycled water and related topics. Recent additions include:

  • Recycled Water Facility Tops Fiscal Plans for Otay District
  • Vegas' Growth is Gamble for Lake

Be sure to visit these and other areas of our website

  • Speakers Bureau information - how to contact the Study team for a presentation, a list of completed presentations, and a downloadable flyer on the Speakers Bureau.

Previous E-Updates

May 2005 E-Update
April 2005 E-Update
March 2005 E-Update
February 2005 E-Update
January 2005 E-Update
December 2004 E-Update