Zastosowanie metod oceny ekonomicznej efektywności obiektów wodociągowych i kanalizacyjnych

The objective of the article is to evaluate two methods used for assessing the economic efficiency of investments in water supply and sewerage systems investment projects. The assessment methods discussed are cost-benefits analysis and cost-effectiveness analysis. Simple and developed indices are used in the cost-benefits analysis. The examples of cost-effectiveness analysis using simple indices are discussed. They include the payback period of capital outlays incurred on the construction of a sanitary sewerage system and the annual revenue to annual cost of investment ratio specified for a biological reactor of a wastewater treatment plant with anaerobic sludge stabilization. In order to assess the economic effectiveness of a sample municipal wastewater treatment plant, an absolute investment effectiveness index was used. The paper also presents an example of using such developed indices as NPV and BCR to assess the effectiveness of selected rural sanitary sewerage systems. The index of annual average cost was used in the cost effectiveness analysis. It allowed for the selection of the most effective variant of an on-site wastewater treatment plant. These examples confirmed the possibility of using of the cost-benefits analysis to assess the financial feasibility of constructing water supply and sewerage systems. In order to evaluate the efficiency of investment of wastewater treatment plants, it is recommended to use the absolute investment effectiveness index, which takes into account the level of avoided losses of the carried out investment, as well as the end results of the investment. In turn, the cost-effectiveness analysis, which uses the rate of the average annual unit cost, allows for the selection of an investment variant with the lowest total cost, taking into account both investment and operating costs.