Optimization of artificial wetland design for removal of indicator microorganisms and pathogenic protozoa

摘要

The enhancement of water quality by artificial wetland systems is increasingly being employed throughout the world. Three wetlands were studied in Tucson, AZ to evaluate their individual performance in the removal of indicator bacteria (coliforms), coliphage, and enteric pathogens (Giardia and Cryptospordium). A duckweed-covered pond, a multi-species subsurface flow (SSF) adn a multi-species surface flow (SF) wetland were studied. Removal of the larger microorganisms, Giardia and Cryptosporidium, was the greatest in the duckweed pond at 98 and 89 percent, respectively. The lowest removal occurred in the SF wetland, 73 percent for Giardia and 58 percent removal for Cryptosporidium. In contrast, the greatest removal of coliphage, total and feal coliforms occurred in the SSF wetland, 95, 99, and 98 percent respectively, whereas the pond had the lowest removals (40, 62, and 61 percent, respectively).