CEM Chief Engineer Pete Hall inspects one of the disinfecting tanks that treats water now at non-detect levels for perchlorate.
Ground water clean up of inorganic pollutants is a major necessity. Some perchlorate apparently occurs naturally, but most often it is present because it is a byproduct of rocket fuel and munitions manufacture and is often found around current and past military bases and manufacturing facilities. High concentrations of percholorate are known to interfere with normal thyroid function, which is especially important for normal human growth and development. Thus, women who are pregnant and young children are especially susceptible to its effects.
Bioreactors have been in use to clean up perchlorate and nitrates in water intended for potable uses in Europe, where the problems have been especially acute. In the U.S. this type of application has been slow to win acceptance for fear of bacterial contamination. Nonetheless, Oklahoma and Kansas now allow bioreactors for such uses, so long as mandated disinfection of treated water is accomplished using any of the various approved surface water treatment methods. California's Dept. of Health Services has approved two bioreactor installations to date, but does so only on a case-by-case basis.
CCAT San Bernardino provided grants that allowed the Center for Environmental Microbiology to operate a test unit at a known high-concentration well site in the city of Rialto, on land operated by the West Valley Municipal Water District in western San Bernardino County. Data obtained during the extended test period showed that initial perchlorate concentrations in the source water as high as 600ppb were being reduced to non-detect levels (below 4ppb). The treated water was then subjected to multiple disinfection processes, including ozone and UV treatment and then discharged back into the ground water supply using an adjacent spreading ground. Interestingly enough, by the time the test period had ended ambient concentrations were in the 400ppb range, an apparent one-third reduction in the in situ contaminant level.
As a direct result of the successful proof of the technology's effectiveness, the West Valley Municipal Water District has requested a proposal for a full-scale bioreactor at the test site, to be used to supply industrial water users, who will benefit from reduced water rates. This will also free up potable water supplies for residential users, decreasing the need for costly potable water imports. The adjacent Three Valleys Municipal Water District has asked for a proposal to install a demonstration project unit in their area for treatment of nitrates, which are the major problem in their ground water aquifer. The biological process used by the bioreactor is highly effective in reducing both perchlorate and nitrates.
For more information, please contact:
Juli Gandasatria, Sr. Technology Program Manager
Office of Technology Transfer and Commercialization
E-mail: jgandasa@csusb.edu
Phone: 909-537-7758 / Fax: 909-537-7450