Contaminant Management in Water Reuse Systems

Wastewater generated by domestic, municipal, and industrial sectors has been increasingly used, particularly in dry areas, to provide water and nutrients to agriculture, aquaculture, and agroforestry systems. While such use helps in income generation and livelihood resilience amid water scarcity, use of wastewater in untreated or inadequately treated forms may result in negative impacts on human and environmental health through chemical and pathogenic risks [16,24,29]. Although farmers using untreated or partially treated wastewater provide a service by avoiding or decreasing effluent entering into polluted streams and applying it to soils, thus reducing the pollutant load in downstream locations, such irrigation also generates risk for farm communities and consumers of farm products. Polluted canals and ditches, and wastewater-irrigated fields create hazards in which children and other residents are exposed to harmful pathogens and chemicals [10]. Consumers of farm produce also are at risk when they handle and ingest contaminated vegetables, particularly when the food is eaten raw or prepared with inadequate care toward reducing contamination risk. Although wastewater treatment is the best choice in managing wastewater in agriculture, wastewater treatment in developing countries is limited, as investments in treatment facilities have not kept pace with persistent increases in population and the consequent increases in wastewater volume in many countries. A key challenge in almost all cases relates to the fact that the price of treated water does not justify its treatment cost. Thus, most of the treatment plants are either abandoned in the short-run or are highly subsidized to ensure their sustenance. Even where wastewater treatment plants are externally funded, Manzoor Qadir United Nation University Institute for Water, Environment and Health (UNU-INWEH)