Review and perspectives of research status on reclaimed wastewater irrigation technologies

Reclaimed wastewater irrigation（RWI） is one of the most important measures to deal with water shortage in the world. The present research status and problems of RWI in the domestic and foreign countries are analyzed and the future major research goal is offered in this paper. The effect of RWI on the soil-plant continuum concentrates on the crop quality, crop quantity, soil properties, heavy metals, salt, nutrients composition and utilization coefficient, ecological toxicity, etc. The research of RWI on groundwater focuses on salts, heavy metals, phosphorus, nitrogen composition and pollutants transport, and so on. There are many reports about the optimum distribution of water resources in the irrigation districts, safe irrigation technologies, pollutants transform and migration under different irrigation systems. Many guidelines on RWI have been drawn out in developed countries. Based on the situation of China, further researches, such as the feasible crop classification, feasible irrigation area allocation, the safe irrigation system, environmental and healthy risk evaluation, should be done in the future. Guideline and criterions about RWI should be established.