Conditional Efficiency of Wastewater Treatment Plants in Valencia, Spain

摘要

Given the growing importance of water resources at a global level, this paper analyses the efficiency of 158 wastewater treatment plants in the Region of Valencia (Spain) using an input-oriented order-m model of conditional efficiency, which allows information pertaining to context variables, both discrete and continuous, to be incorporated directly into the analysis, and enables significance to be verified. Findings point to the quality of the influent water, the amount of treated water and the age of the treatment plants being significantly relevant contextual factors. In addition, the average inefficiency levels are not so high as reported by previous studies.