| Filtration and irrigated cropping for land treatment and effluent reuse is mainly referred to irrigation with sewage water from non-industrial departments.Sewage water is rich in not only plant nutrients,including N,P,K,but also microelement such as Fe,Mn,Zn.So Sewage irrigation can increase soil content of the materials that are needed for plant growing.Other benefits are saving cost for chemical fertilizer.In recent years,area irrigated with Sewage water increased quickly in china.From now on,sewage has been important water source for irrigated district near outskirts of cities,especially droughty territory of north china,where the scarcity of water has been the main factor influencing human lives and economic development. We have to deal with sewage.On the basis of summing up the natural conditions and Sewage discharge conditions in the north of China,as well as the existing sewage treatment technologies and sewage irrigation technology,we explored a new suitable way to sewage resources of small cities and towns in the north of China with the assistance of the australian scientists,the advanced land treatment of sewage.This method overcomes the traditional shortcomings of sewage land treatment system,effectively improves the system's processing power,and thus applicable to a wider range of soil conditions and wastewater situation.It can achieve sustainable development results by means of maximizing the use of water in the fertilizer efficiency and reducing environmental impact.The method is a way to achieve wastewater treatment and effluent reuse through Combing wastewater land treatment methods with crops of sewage irrigation.Using this method, We chose a representative test area of Yang Gao in Datong. In this paper, Using the method of combination of laboratory and field experiments,we focus on nitrogen and phosphorus movement rules in the soil of the system.The indoor experiment was conducted in 2007, the main content were soil grading analysis which aimed at verifying whether the soil meet the operating conditions of wastewater treatment system, and 1-D vertical leaching test of soil column with the target of preliminary estimating the system operation and analyzing the migration law of nitrogen and phosphorus. The result shows that the test soil meet the system operating conditions and the system have better effect on removing the pollutants of N,P in wastewater.Field tests contain two aspects of Soil penetration test and Sewage irrigation. Soil penetration test mainly analyse infiltration rate of soil and the experimental results show that Soil penetration in the field accord with the requirement of sewage treatment systems. Sewage irrigation operation in the field begin in the summer of 2008,this article mainly describe the outdoor field in the detail . The Purpose is to verify pollutants removal efficiency of the system and migration and transformation rules of the pollutants nitrogen and phosphorus. The main contents as follows: water quality analysis before and after irrigation, groundwater quality analysis, soil analysis of field soil, uptake by plants of different crops under irrigation analysis, water balance analysis.The main conclusions are:(1)according to the analysis of water quality before and after irrigation, the ammonium concentration is small in drainage because of volatilization,soil adsorption and crop absorption. However, the concentration of nitrate in drainage is far greater than that in irrigation water because of its eluviation and nitrification process. Moreover, with reason of soil adsorption and crop absorption, phosphorus content is also low in drainage. So it is better consistent in the conclusions between laboratory and field test. (2) The analysis on chemical composition of groundwater quality showed that irrigation water has little effect on groundwater quality. (3) Field soil analysis shows that due to the strong soil adsorption ,post-harvest soil nitrate levels tend to be higher than it before planting. (4) Analysis of crop absorption and the yield of crops in different irrigation conditions shows that corn has high absorption efficiency on N, P in wastewater irrigation, and corn yield is little effected by high load of sewage irrigation. (5)According to the analysis of water balance, the volume of system operation water is basically balance.Experimental results show that the system has obvious effect on the pollutant removing and verify the technical feasibility.Having a lot of study,however, we can only analyse on water quality, soil quality, and crop absorbing condition during the trial from a macro point of view,due to incomplete experimental data.More detailed analysis of the work has yet to be able to carried out,for example,soil profile water content during water movement,changes of inorganic nitrogen of the profile,etc. We need to do further improvements。...
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