Study On Watershed Waste Load Allocation

Pollutant load control is the important measure to implement watershed water pollution control. With the improving of scientific and precise of environmental management, Pollutant load control based on water environmental capacity is the option for water pollution prevention and control in China. Waste load allocation is regared as the important step in pollutant load control which was the important area experts in home and abroad paid attention to. In this paper, the principles and methods on waste load allocation at home and abroad were studied. Daliao River control unit was chosen as a study area, COD and NH3-N were chosen as pollutant control factors, responseship between pollutant load and water quality was studied, the control unit-outlets into river-pollutant source was proposed, linear programming was used to allocate COD and NH3-N load for the sewage outlet level and pollutant sourse level. The allowable load was allocated to enterprises. The main study fields and achievements were:(1) Daliao River control unit was chosen as the study area, simulation-optimazation method was used, water quality model for Daliao River was established, considering the scientific soundness, fairness, and efficiency, calculation method of water environmental capacity and allocation system of control unit-outlets into river-pollutant source was proposed.(2) The constraint condition of water quality at each controlling section was determined by water function in Daliao River. Besides, the water pollution was diagnosed. The classification comprehensive pollution index was used to analyze the water quality of Daliao River in1995-2008. The results showed that water quality of Daliao River violated the Class V standard, representing the aerobic organic pollution. nutrients, heavy metals and toxic organic pollution was not severe. The main pollutants were COD and NH3-N, so COD and NH3-N were chosen as pollutant control factors.(3) Based on the pollutant data for the year of2007and land utilization data, GIS software was used to calculate the pollutant load from each pollutant source in Daliao River Control Unit. Besides, the structure of pollutant source was analyzed. The results showed that the main pollution source of COD and NH3-N was point source. In terms of point source, the industrial source contributed the most to the load into the river of COD and NH3-N. In terms of non-point source, agriculture source contributed the most to the load into the river of COD and NH3-N. While, the urban source contributed the least to the pollutant load into the river. In terms of the equivalent standard of pollutant source, the main contributor was industrial source. The second and third contributors were urban life source and agriculture source..(4) In2007, the background load of COD and NH3-N from upstream Taizi River and Hun River to Daliao River Control Unit were96896t/a and14815t/a, respectively. The pollutant load of Daliao River control unit into river of COD and NH3-N were54012t/a,3173t/a, The background load was greatly larger than pollutant load in Daliao river control unit. Daliao River was largely influenced by background load.(5) The papar established the coupled model of WESC2D and WASP. The responseship between pollutant load and water quality on design hydrodynamic conditions was studied. The results showed that the simulated results matched the observed data well. The couple model of WESC2D and WASP is efficient and stable, It could be used as a tool in pollutant load allocation and calculated the responseship between pollutant load and water quality on design hydrodynamic conditions.(6) The allocation schemes of COD and NH3-N were studied. On the allocation of sewage outlet into river, aiming at maximum of TCRI, water quality as constraint condition, optimization method was used to plan8schemes, the optimization one was determined by comparison method. On the allocation of pollutant source, based on the enterprised allocation load of the each sewage outlet, aiming at the maximum of GDP of each sewage outlet, loads of enterprises were allocated. The results showed that the pressure of pollutant control in Daliao River control unit was background load. It is necessary to control the pollutant load in upstream control unit and cut the pollutant load. On the condition of water quality of Sanchahe section meeting the standard of requirements domain in Daliao Control Unit, COD need not be reduced, the load of NH3-N should be reduced in Ganjian Greek. The NH3-N load of Dazuguanghua Printing Limited Company should be reduced by28.73%. The NH3-N load of Yingkou Benniu Textile and Apparel Limited Company should be reduced by...