The Model Of Urban Sewage Treatment Under Uncertainty Theory

With the increase of urbanization rate in China,the problem of urban sewage treatment has become more and more serious.Urban sewage treatment research has become very important in environmental governance.However,urban sewage treatment is affected by uncertainties such as equipment and environment,which makes the government have complicated agency relationship when entrusting sewage outsourcing to professional sewage treatment enterprises.Because the processing capacity of the enterprises is uncertain,the actual processing capacity cannot be guaranteed.In this kind of relationship,in order to increase revenue,the enterprise maliciously increases the amount of signings,and ultimately fails,and there is a “moral hazard”behavior.The government only has to join the punishment mechanism to constrain;based on the risk of the penalty mechanism,the enterprise will appear another kind of speculative behavior,Intentionally reduce contract volume and avoid risks.In order to tap the enterprise's potential sewage treatment capacity,the government can only join incentives at the same time to encourage companies to continue processing more sewage.Considering the complex relationship of government and enterprises,this thesis uses the urban sewage treatment problem as a background.Based on the uncertainty theory,we established a sewage treatment model in the coexistence with punishment mechanism,reward and punishment mechanism,and discussed the various of the real change relationship between the contract volume and the actual processing volume under the mechanism.The study is as follows,1.This thesis uses the set of axiomatic mathematical theory?the uncertainty theory which first proposed by Liu Baoding in 2007?to characterize the processing capacity of a company as a spatially uncertain variable.2.In the third chapter,a penalty mechanism was introduced to establish a model of urban sewage treatment expected benefit with penalty mechanism.Using uncertain opportunity constraints,the The model is transformed into a non-linear constrained optimization model,and the existence of feasible solutions to the model is proved.Using the control variable method,the risk index,penalty rate,riskfree processing volume and optimal solution in the model are discussed.The relationship was finally verified by a numerical example.Research shows that the punishment mechanism has a significant constraint effect on reducing the ”Ethical risk” behavior of enterprises.3.On the basis of Chapter 3,we has added incentives to encourage companies,And established a sewage treatment model with reward and punishment mechanism(reward and punishment mechanism).Similar to the third chapter,the Uncertainty Theory and Method are used to solve the model,and the existence of the feasible solution of the model under different reward ranges is proved.Discussed the relationship between the company's sewage contract volume,actual processing capacity,expected revenue and incentive mechanism.A numerical example is given to verify the validity and practicability of the model.The research shows that the reward mechanism has a significant incentive effect on the potential sewage treatment capacity of the enterprise,and the reward range implemented in the reward mechanism should not be too large.The results of this study can help the government to provide a reference value for both the government and the company in the signing of a contract with the sewage treatment enterprise.It has certain practical significance.