Theoretical Exploration of Risk Analysis of Sewage Irrigation in Farmland

Sewage irrigation can provide water and fertilizer resource. However, sewage irrigation may lead to the accumulation of toxic and harmful substances in the soil and water source in some areas, which will be a serious threat to the human health in these areas. Risk of soil-crops, risk of surface water or underground water and risk of population health, which are greatly influenced by sewage irrigation, are selected to be research objects via analytic hierarchy process; evaluation indicators of degree of contamination of sewage irrigation to soil-crops, surface water or underground water and population health, and the computing method of the total risk degree are proposed, and the probability distribution of the risk of sewage irrigation is analysed. On the basis of theoretical study, combined with practical data, risk analysis of sewage irrigation in a given area is researched in this paper.