| Point source pollution and agricultural non-point source (ANPS) pollution are the main forms of water pollution. With point source pollution has been controlled, agricultural non-point source pollution has become the primary pollution source of water environment. Rural areas development depends on the quality and quantity of water resources, but agricultural non-point source pollution restricted the development of rural society and economy, therefore it has become an important environmental issues. In this paper, based on the estimation of ANPS pollutants, the status of ANPS pollution in our country was analyzed to provide a scientific basis for macroeconomic management of agricultural non-point source pollution. In addition, a reference was provided to select non-point source pollution control measures based on a comprehensive evaluation of the existing main agricultural non-point source pollution control technology. On this basis, the governance model and control technology were studied for the key ANPS pollution problems in typical regions. The results showed that:(1) In this paper, the spatial distribution of ANPS pollutants, main source types, and extent of contamination were studied. The results showed that:the annual release of ANPS pollutants was 10.81×106t/a and the average release of ANPS pollutants in 31 provinces was 3.18×105 t/a. The average release of TN and TP were 1590.47 kg N·km-2·yr-1 and 340.78 kg P·km-2·yr-1.The major ANPS pollutant source types included:fertilizer-livestock pollution, fertilizer pollution, rural livestock pollution, and fertilizer-domestic pollution. According to the calculation of the Nemerow index, the degree of contamination in 21 provinces were very severe contaminated or serious contaminated.(2) In this paper,15 kinds of common water resources conservancy measures were classified into three (source, process and terminal) control systems. The results indicated that pollutants removal rate, effluent water quality, cost of construction, operation, and maintenance should be given priority in real world applications they had the higher weight value than other indices. Conservation tillage and’One biogas pond with improvements of washroom, kitchen and sty’could be used as the preferred methods in source control. Moreover, land treatment technology was more suitable than other process control methods. Oxygen-liking biomembrane method could be used as the preferred methods when selecting terminal control methods.(3) Based on erosion control the soil erosion intensity was evaluated in Dongling Mountain Watershed in Mentougou District. The results showed that the average soil erosion modulus in the study area was 2685t·hm·2·a-1, the whole basin was moderate erosion, and the basin topography and vegetation coverage were the key factors in the regional erosion control.(4) The N and P produced by fertilizer using is ANPS pollution sources in Lanyi River and No.3-6 river section were the key ANPS pollutants control sections. The TN removal rate of the typical herbaceous vegetation buffer zones in the basin was 85% when the width of the buffer reached 18m and TP removal efficiency of Herbaceous and Grass-Shrub buffers were same when the width of the buffers were under 12m.The best widths of vegetation buffer in different river sections were 18.97m,28.01m, and 12.85m.(5) The results of the study showed:Ammonia nitrogen and phosphorus adsorption capacity of kaolin was better than bentonite and zeolite powder. Ammonia nitrogen and phosphorus removal rates in the simulation sewage reached 67% and 38%, respectively, at low temperatures, by using the abatement bags with sand and kaolin best ratio of 1:1. |
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