Pathogen inactivation during passage of stormwater through a constructed reedbed and aquifer transfer, storage and recovery

摘要

A study was undertaken to determine the potential inactivation rates of selected entericnmicroorganisms in captured urban stormwater within a constructed reedbed and in tertiaryncarbonated aquifer during an Aquifer Storage, Transfer and Recovery (ASTR) scheme. The studynwas undertaken in-situ in the constructed reedbed and aquifer using diffusion chambers. Thenresults showed that all tested bacteria had one log10 reduction time of less than 6 and 2.5 daysnrespectively in constructed reedbeds and aquifer, which suggests that presence of entericnbacteria in the recovered water is unlikely. However, adenovirus and Cryptosporidium oocystsnshowed lower inactivation rates with one log10 reduction times of more than 33 days in thenconstructed reedbeds. This means that the constructed reedbed with a mean residence timen10 days cannot be relied upon as an efficient treatment barrier for virus and protozoa. Storagenof stormwater in aquifer with brackish water resulted in slow inactivation of enteric viruses overnthe 35 day incubation period with adenovirus and rotavirus showing slowest inactivation timesn(extrapolated T90 of .100 days). Cryptosporidium oocysts showed similar inactivation rate innthe constructed reedbed and aquifer.