Essentiality of model design for using of wastewater in agriculture for major cities

Because of shortage of fresh water resources and poor quality soils for agriculture, the reuse of marginal quality water is necessary. These sources include domestic, municipal and industrial wastewater, leachate from urban and industrial waste, surface runoff from precipitation in urban and industrial areas, and drain water from parks and agricultural land. Because of urban expansion, population density and expansion of agricultural and industrial area in developing countries, the volume of marginal quality water is increasing. Uncontrolled reuses of these resources cause environmental problems. The best way of disposal wastewater and drain water, reuse in agricultural and landscapes when it´s doing with consideration to environmental and healthy impact, crops quality and plants sensitivity in long term. At the present time, there are many different standards for wastewater reuse. But these are inflexible for varying natural and artificial environment condition. Therefore designing models with flexibility for various conditions is necessary. In this research, the main input and output factors which can be used for designing a regional model of low quality water reuse in irrigation was presented.