Pilot study launched to evaluate biofiltration BMP effectiveness at removing fecal contamination

SCCWRP and the County of San Diego have launched a six-month pilot study to begin probing how design and operating characteristics of biofiltration systems can influence their effectiveness at removing fecal contamination in runoff.

The study, which began laboratory-scale experiments in July, represents an early effort within Southern California to identify alternatives to the design and operation of biofilter BMPs (best management practices) to improve their efficacy at removing pathogens that can sicken humans.

Compared to other types of common runoff pollutants, little work has been done to understand how BMP design and operating characteristics influence pathogen removal – even as fecal contamination remains one of the leading threats to runoff water quality across Southern California. Moreover, fecal contamination removal by biofiltration BMPs is often lower than expected, with effluent concentrations sometimes exceeding those measured in influent.

Researchers will use flow-through columns in a laboratory to mimic how runoff flows through a biofiltration BMP, working to evaluate specific properties of biofiltration media and treatment processes that influence the system’s ability to remove fecal indicator bacteria (FIB) and DNA-based FIB markers, including HF183 and crAssphage. After the laboratory testing phase, researchers plan to scale up the study to a field testing phase.