title: Effects of temperature on bacterial transport and destruction in bioretention media: field and laboratory evaluations.
abstract: Microbial activities are significantly influenced by temperature. This study investigated the effects of temperature on the capture and destruction of bacteria from urban stormwater runoff in bioretention media using 2-year field evaluations coupled with controlled laboratory column studies. Field data from two bioretention cells show that the concentration of indicator bacteria (fecal coliforms and Escherichia coli) was reduced during most storm events, and that the probability of meeting specific water quality criteria in the discharge was increased. Indicator bacteria concentration in the input flow typically increased with higher daily temperature. Although bacterial removal efficiency was independent of temperature in the field and laboratory, column tests showed that bacterial decay coefficients in conventional bioretention media (CBM) increase exponentially with elevated temperature. Increases in levels of protozoa and heterotrophic bacteria associated with increasing temperature appear to contribute to faster die-off of trapped E. coli in CBM via predation and competition.
authors.affiliation: Department of Civil and Environmental Engineering, University of Maryland, College Park, MD, USA.
authors.forename: Lan
authors.initials: L
authors.lastname: Zhang
authors.forename: Eric A
authors.initials: EA
authors.lastname: Seagren
authors.forename: Allen P
authors.initials: AP
authors.lastname: Davis
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Karns
mesh_terms: D001692:Biological Transport; D019149:Bioreactors; D004755:Enterobacteriaceae / Q000378:metabolism*; D013696:Temperature; D013997:Time Factors; D014865:Waste Disposal, Fluid / Q000379:methods; D014887:Weather