Municipal Wastewater Treatment in Poland – Efficiency, Costs and Returns to Scale

The paper reports the costs of municipal wastewater collection and treatment in Poland based on an empirical sample of 1400 operators. Treatment cost functions are investigated econometrically using the Box-Cox regression model, indicating high non-linearity and significant scale effects. Wastewater treatment costs are increasing with technology efficiency (moving from the primary, through the secondary, to the tertiary treatment), and decreasing with higher wastewater treatment plant capacity. Combining treatment and collection costs with treatment efficiency allows estimation of costs and potentials for reducing the nitrogen and phosphorus loadings to rivers by improving the efficiency of wastewater treatments plants, or building new ones, on an aggregated country-wide scale. Therefore, our results provide valuable input into any cost-benefit analyses of nutrient loadings reduction through extending or upgrading municipal wastewater treatment systems.