Irrigation with treated wastewater in Israel - Assessment of environmental aspects

Population growth increases the output of sewage, which must be treated and discarded. Agricultural reuse can function as wastewater disposal, and simultaneously convert an environmental threat to a benefit, i.e., the supply of irrigation water to agriculture. Both quantity and quality aspects should be considered when irrigating with treated effluents, since its constituents may affect crops and groundwater. In this paper we refer to nutrients, represented by nitrogen or nitrates (NO3) and salinity, represented by EC (electrical conductivity) or chlorides (Cl). The levels of these constituents in wastewater are usually elevated; therefore, they may affect crops, soil structure, or groundwater quality. Combining wastewater treatment and desalination processes to maintain groundwater quality can diminish these impacts and prevent environmental deterioration. We have assessed the environmental impacts of wastewater irrigation by focusing on nitrate and chloride constituents. To that end, we developed an economic-hydrological model that incorporates various water sources and treatment processes in order to analyze the accelerated contamination of groundwater.