Soheil Hosseiny Shirvany - Department of Chemical Engineering, Babol Noshirvani University of Technology, Babol, Iran
Zohreh Saedi - Department of Chemical Engineering, Babol Noshirvani University of Technology, Babol, Iran
Hassan Mehdipour - Department of Chemical Engineering, Babol Noshirvani University of Technology, Babol, Iran

With increasing global population, the gap between the supply and demand for water is widening and is reaching such alarming levels that in some parts of the world it is posing a threat to human existence. Scientists around the globe are working on new ways of conserving water. It is inopportune time, to refocus on one of the ways to recycle water through the reuse of urban wastewater, for irrigation and other purposes. In general, wastewater comprises liquid wastes generated by households, industry, commercial sources, as a result of daily usage, production, and consumption activities. Municipal treatment facilities are designed to treat raw wastewater to produce a liquid effluent of suitable quality that can be disposed to the natural surface waters with minimum impact on human health or the environment. The disposal of wastewater is a major problem faced by municipalities, particularly in the case of large metropolitan areas, with limited space for landbased treatment and disposal. On the other hand, wastewater is also a resource that can be applied for productive uses since wastewater contains nutrients that have the potential for use in agriculture, aquaculture, and other activities. The important uses of wastewater include recharge of groundwater, landscaping (golf courses, freeways, playgrounds, schoolyards, and parks), industry, construction, dust control, wildlife habitat improvement, and aquaculture. The objective of this paper is to provide a review of the characteristics of wastewater used for irrigation and the reasoning behind the international guidelines presently used in regulating wastewater reuse for agriculture. This paper presents various systems of wastewater treatment available and discusses their benefits and shortcomings. A selective review of recent empirical studies identifies major impacts both positive and negative impacts of wastewater irrigation. Finally, the paper provides the review of environmental valuation techniques for analyzing impacts of wastewater uses in agriculture, and suggest a framework for the application of some of these techniques.

Wastewater, Irrigation, Agriculture, Treatment