Techniques And Methods For Reuse Of Wastewater For Irrigation: A Review

Abstract

Ground water resources in most areas of world are shrinking at an alarming rate and may not meet the ever increasing demands from agriculture and industry in future. Wastewater reuse is an option for the alleviation of the ever increasing irrigation water scarcity in many countries and for recycling plant nutrients. Countries suffering from water shortages are forced to use treated wastewater. Estimates revealed an annual production of ~30 million tons of wastewater in the World, of which ~70% is consumed as an agricultural fertilizer and irrigation source. In India, estimates revealed that ~73,000 hectares land were irrigated with wastewater during early nineties and presently the area under wastewater irrigation is on the rise. Studies have documented that direct disposal of effluents to land and water bodies has potential to contaminate air, surface, ground water as well as soils and crops grown on these soils. If the metals are ingested beyond the permitted concentration, they can cause serious health disorders. Therefore, it is necessary to treat metal contaminated wastewater prior to irrigation. Removal of heavy metals from wastewater effluent can be achieved by conventional treatment processes. Recently, numerous approaches have been studied for the development of cheaper and more effective technologies, both to decrease the amount of wastewater produced and to improve the quality of the treated effluent. This article presents an overview on beneficial and harmful effects of wastewater application in soil-plant-water system and various physico-chemical treatments for removal of heavy metals from wastewater.