Multi-level waste load allocation system for Xi'an-Xianyang Section, Weihe River

Since pollutant total amount control was introduced in China in the 1980s, many researches have focused on water environmental capacity, the allocation of pollutant load, and the pollution discharge right trading. The allocation of water pollution load is the core as well as difficult point in total amount control system of water pollutants discharge. There are a series of objects for water pollutions load allocation, including water basin, the water function zoning, administrative units, sewage outlets and pollutant discharging points. For different objects of allocation, a distribution planning must be able to meet both the regional requirements and the benefits of pollutant discharging enterprises. However, it is difficult to meet the interests of various levels by one kind method of load allocation. This paper intends to establish a new multi-level load allocation system for Xi'an-Xianyang Section, Weihe River. With large population, concentrated industrial discharging, and poor water quality, the approach needs to consider both regional development requirements and pollutant discharging point's economic interests. At the same time, for different objects at various levels, there is proper different distribution method according to the principles of efficiency and fairness in allocation. For regional water function zoning to administrative units, the environmental Gini coefficient analysis for regional allocation is applied in economic sphere to set up an appropriate allocation model for the optimal allocation. For administrative units to sewage outlets, optimal generation performance standard (GPS) method for enterprises allocation is used to improve the emission performance. The model's objective will be changed from minimum cost to greatest value. The results showed that Xi'an and Xianyang City has four counties needed to reduce the pollution load largely, respectively, because they have some prominent contradiction with the social and economic developments and the natural environment. In addition, in the key reduction region the discharge units should be cut the distribution in accordance with the ratio of distribution model. While in the maintaining present conditions regions, discharge units will have some "surplus capacity" for future emission control. This new approach for water total amount load is effective and may provide the foundation for the pollutant total amount control of Weihe River. (C) 2011 Published by Elsevier B. V. Selection and/or peer-review under responsibility of School of Environment, Beijing Normal University.