Soil salinization of effluent irrigation and its control in Israel

Israel is a country situated in a semi-arid zone with insufficient natural water resources.Hence,effluent irrigation has been widely practiced for the past several decades.However,long-term effluent irrigation has posed a serious risk of salinization for the country's soils and aquifers,leading to degradation of soil physical properties such as soil structure,stability and hydraulic conductivity and soil fertility.Over the last two decades,average soil SAR(sodium adsorption ratio) value increased by 50%,from 6 increased to 9.In order to solve the problem caused by effluent irrigation,Israel has developed waste water desalination and relevant utilization mode.Nano filtration membrane and reverse osmosis membrane technologies have been used in waste water desalination.The cost for waste water desalination is generally lower than sea water desalination,with a better application future.Effluent treatment in Israel has experienced three stages:general secondary treatment,tertiary treatment,and desalination treatment.The treated effluents infiltrate into aquifers via recharge basins are stored in the aquifers.The effluents are further purified in the process of infiltrating into the aquifers.The recharged effluents are pump out for irrigation at growing season.Therefore,Israel experience would be an alternative approach for possible experimentation of waste water in insufficient natural water resources areas in China to control soil salination.