Expenditure on the operation of municipal wastewater treatment plants for nutrient removal

Operating costs of Austrian municipal treatment plants are evaluated for 19 89/90 and for 1997, respectively The results indicate that presently the ex penses which can be directly connected to wastewater purification, i.e. ene rgy and chemicals for P removal, comprise only about 20% of the total opera ting costs. Today, in Austria like in other EU countries, the predominating factor is "labour costs", even at nutrient removal plants. A general schem e for estimating operating costs is presented that can be applied to WWTPs in other parts of the world. In this scheme the important factors relevant to the operating costs are integrated.