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

Operating costs of Austrian municipal treatment plants are evaluated for 1989/90 and for 1997, respectively. The results indicate that presently the expenses which can be directly connected to wastewater purification, i.e. energy and chemicals for P removal, comprise only about 20% of the total operating costs. Today, in Austria like in other EU countries, the predominating factor is “labour costs”, even at nutrient removal plants. A general scheme 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.