The Scale Benefit Study On BOT Sewage Treatment Plant

In this paper, the relationship between cost and treatment capacity of urban BOT waste-water handling project is studied. And the government controlling theory is applied to obtain the maximum social and economic benefit.In this study, the different data of cost and treatment capacity for the Dalian BOT waste - water handling projects are gathered and the relative theory of microeconomics, such as cost theory etc., will be used to process to the data. The average-cost curve is obtained with "Excel" software and the average cost function model is established. Then the function of total cost and the margin cost function are derived. After that the average cost curve and the margin cost curve are drawn in the same coordinate. The intersection of the margin cost curve and the margin Proceeds curve refers to the productivity of the waste-water treatment enterprises for the maximum economic profit, and the minimum point in the average cost curve is the intersection of the margin cost curve and the average cost curve, which refers to the breakeven productivity of the waste-water treatment enterprises for the maximum social profit.Government should regulation the price range for BOT waste-water handling project to ensure the best social benefit, and then to realize the balance between the enterprise's profit and the social benefit. In this paper, according to the calculation of the data gathered from different enterprises, the conclusion can be drawn that: in the present producing condition, the daily treatment capacity should be 95,000 tons for the BOT waste water handling project to obtain the best social benefit.By the government's regulation, the maximum social benefit of BOT waste-water handling project is realized, which will finally lead to the balance between the enterprise's profit and the social benefit. Besides, in the process of programming a new BOT waste-water handling project, the government should try to control the production scale of the new project, which will obtain the best profit.