Wastewater reuse—regional and economic considerations

Wastewater treatment and disposal has become a major component of policy-making subject, because of growing awareness of environmental quality issues. Agricultural use of treated effluents helps to maintain environmental quality, and simultaneously furthers other national goals such as providing sustainable agriculture while preserving scarce water sources. Another advantage of irrigation with wastewater is the possibility of decreasing the purification level and the derived treatment costs, thanks to the role of soil and crops in acting as a bio-filter. Also, using the nutrients available in wastewater may diminish fertilization costs. The considerations for policy decision making include many factors such as the level of purlfication, the location of agriculture and the types of crops. The regional dimension is reflected in the way the decision on where to convey the wastewater influences the choice of agricultural crops, the fate of aquifers and the related costs. For example, in Israel, wastewater treated in the center of the country may pollute the coastal aquifer, whereas conveying this wastewater to the south, where there is no active aquifer gives rise to increased conveyance costs and loss of agriculture in the center. In this paper a general methodology for environmental policy decision making in relation to wastewater is developed and applied in an Israeli case study.