SCCWRP and its partners have successfully tested more than 20 underground sewer pipes in the San Diego area for leaks using a newly developed method that can detect volumetric losses of as little as a one liter out of 4,000 liters – a key milestone in ongoing efforts to estimate what portion of human fecal contamination in the region’s waterways can be attributed to raw wastewater exfiltrating from public sewer systems.
Data from the field testing, which is nearing completion and will wrap up by December, will enable researchers to extrapolate how much sewage is exfiltrating from sewer pipes across the lower San Diego River watershed. A final report is expected to be published next summer.
The exfiltration method utilizes prototype equipment and methods developed by SCCWRP and its partners. It involves pumping a known volume of water at a controlled rate through an isolated, 150- to 400-foot-long section of sewer pipe, then looking for a difference in the volume pumped in vs. recovered.
The sites where the method has been deployed represent a range of different pipe materials and ages.
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