Groundwater contamination caused by wastewater irrigation and its controlling countermeasures

Wastewater irrigation can save water resources to a certain extent,but irrational utilization of wastewater can also cause pollution of groundwater.This paper reviews such an issue caused by wastewater irrigation in different cases,which is normally identified as increasing nitrate,hardness,heavy metals,pathogenic microbes,and organic compounds in groundwater.The mechanisms of migration and natural attenuation of pollutants are discussed,and the factors influencing the transport and transformation of contaminants in vadose zone are also examined.Subsequently,the measures to prevent the side effects of wastewater irrigation and the further studies on these topics were proposed.