Approach To Municipal Wastewater Reclamation And Reuse Planning Based On NLO And SD Model

As unconventional water resources, the advantage of municipal wastewater is increasing to relieve the pressure on municipal water supply. Municipal wastewater reuse is able to not only help to keep the balance of water demand and supply, but also reduce the polluted drainage to improve water environment. In order to coordinate with conventional water resources system, the wastewater reuse system should be technologically designed to maximize the profit of its operation. This thesis, focusing on wastewater reuse system, aims at puting forwards the methodology of municipal wastewater reclamation and reuse planning and providing a guidline for wastewater reuse planning.The municipal wastewater reclamation and reuse system is comprehensively analyzed and a database for planning is developed. Based on identification of the internal and external constraints of wastewater reuse in urban, the key factors affecting the reuse system turn up to be the shortage of municipal water supply, the substitution of ground water, pollution reduced and ecological water drained downstream, which provide scenarios for different wastewater reuse purposes. A nonlinear optimization (NLO) model for municipal wastewater reclamation and reuse planning is developed to maximize the benefits of water resources and water environment in the process of wastewater reuse. It is able to make solutions for optimizing the reclaimed wastewater distribution in different scenarios between multi resources and users, which reveal the path of optimal development in every scenario. A system dynamic (SD) model for municipal wastewater reclamation and reuse planning is established to simulate the dynamic development of solutions and their influence on macroeconomic. Finally, an index system considering factors of water resources, economy, environment, engineering, and society is designed, and with an application of analysishierarchy process (AHP) and the output data of NLO model and SD model, the values of different solutions are synthetically assessed according to the indices to achieve the optimal solution.The method has been applied to make solutions in main municipal district of Handan city, China. As an implement of wastewater reuse, the entire reclaimed wastewater volume in 2010 is predicted to be 99.80 million m3, with 58.63 million m3 in main municipal district and 41.17 million m3 drained to downstream. The substitution volume of ground water is to be 42.65 million m3, and the discharged pollution in the form of COD is to be 1 647 t which is a little larger than downstream environmental capacity. As a result, the municipal water demand is able to be efficiently satisfied with little exploiture of fresh water resources, which facilitates sustainable development of Handan city. The over exploiture of ground water and the water environment are both gradually improved. The investment expected is about 96.07 million yuan which is 0.049 3 percent of GDP each year, and it is able to be accepted by city economy development.