Virus removal from wastewater in a multispecies subsurface? flow constructed wetland.

Virus removal was studied in a multispecies subsurface?flow constructed wetland. Tracer studies and a virus survival test were conducted using bromide and bacteriophage PRD1 that were simultaneously added into a 6?year?old gravel?filled wetland. The estimated dimensionless variance and the observed bromide breakthrough curve suggest a plug?flow reactor with some dispersion. Most of the PRD1 was removed during the first 4 days; however, the PRD1 background concentration was not reached by the end of the study. Average bacteriophage removal was 98.8 percent, whereas bromide mass recovery was 75 percent. The removal rate of PRD1 was estimated to be ?1.17 d?1; in contrast, its inactivation rate in situ for a 12.4?day period was ?0.16 d?1. Apparently, virus removal is governed by an initial irreversible attachment followed by a comparatively long inactivation period. This study suggests that a subsurface?flow wetland can decrease the virus load by approximately 99 percent with a 5.5?day detention time.