ABSTRACT
An assessment of human health risks posed by municipal wastewater treatment using constructed wetlands involves delineating pathogen content of inflowing water, degree of removal/inactivation of pathogens in wetland environments, and level of exposure of receptor (human) population to treated wastewaters. Four groups of pathogens (viruses, bacteria, protozoa, and worms) may cause human waterborne diseases. Since most excreta-related diseases in North America are caused by bacteria and viruses, this chapter focuses on use of constructed wetlands to reduce human health risks associated with these two groups. Important environmental stresses on viruses in a wetlands wastewater treatment process include temperature, pH, suspended solids, sunlight, redox potential, and microbial degradation. Constructed wetlands can make important contributions as wastewater treatment systems not only through their ability to reduce bacteria and virus levels but also due to their ability to remove suspended solids and ammonia, both of which interfere with efficient disinfection.
