Impact Evaluation of Stream Flow Augmentation With Tertiary Treated Recycled Water : Final Report
Creator
Plumlee, Megan H. (Stanford University. Department of Civil and Environmental Engineering.) and Reinhard, Martin (Stanford University. Department of Civil and Environmental Engineering.) Stanford University. Department of Civil and Environmental Engineering Santa Clara Valley Water District Metropolitan Water District of Southern California California. Department of Water Resources WateReuse Foundation
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Description
Abstract: Water recycling for environmental applications requires consideration of a complex set of benefits and risks. The goals of the present study were to augment Coyote Creek in San Jose, CA with local recycled water as a research demonstration and to assess any potential impacts to water quality. Field site assessment included the selection of water quality constituents and sampling campaigns of recycled water and site water. Laboratory investigations of contaminant fate included biodegradation, sorption, and photolysis of particular organic contaminants. Results showed that water quality of the recycled water was better than the site water with respect to metals and microbes. However, the recycled water also contained some constituents which were not present in the creek, such as N-nitrosodimethylamine (NDMA) and alkylphenol polyethoxylate metabolites (APEMs). Some constituents were present in both water sources, such as perfluorochemicals (PFCs), organophosphates, and N-butylbenzene sulfonamide (NBBS). The recycled water and two of six urban creek sites exceeded a threshold concentration of 50 ng/L PFOS that is protective of upper trophic level avian species that consume organisms in equilibrium with the water. Laboratory investigations showed that NDMA is poorly degradable biologically but aquatic photolysis may be a significant attenuation mechanism. The quantum yield for NDMA was determined to be [phi] = 0.41 and [phi] = 0.43 to 0.61 for other nitrosamines. In contrast to the N-nitrosamines, PFCs (selected perfluorooctanesulfonamides) were found to undergo indirect photolysis when irradiated in a solar simulator in aqueous hydrogen peroxide solutions. However, rates of indirect photolysis for PFCs were quite slow, and thus significant rates of transformation would not be expected over the creek study reach. Biotransformation of the metabolites of alkylphenol ethoxylates (APEMs) was also assessed and could be expected at the Coyote Creek site upon infiltration of water the hyporheic and subsurface zones. In a laboratory study of the removal of PFCs by nanofiltration, rejections greater than 95% were measured for most PFCs tested. Reverse osmosis (RO) results in NDMA rejection of approximately 50 to 65% or less. For the overall treatment train, this rejection is an important contribution to NDMA removal. -- Authors' abstract. Authors' keywords: water reuse, wastewater reclamation, emerging contaminants, NDMA, perfluorochemicals Table of contents: 1.0. Introduction -- 2.0. Project approach -- 3.0. Project outcomes -- 4.0. Conclusions and recommendations -- 5.0. References -- Glossary.
Type
text
Format
Copy Book
Identifier
csjvwd_000551 ark:/13960/t5v77j40d
Provenance
Santa Clara Valley Water District Library California Revealed is supported by the U.S. Institute of Museum and Library Services under the provisions of the Library Services and Technology Act, administered in California by the State Librarian.
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