Performance assessment of 23 wastewater treatment plants - a case study

Abstract

Water systems and particularly wastewater treatment may only improve or keep high-quality service if their performance is continuously measured and benchmarked against peers. This paper presents a casestudy developed under the Portuguese Initiative on Water Quality, Treatment and Energy (iEQTAWWTP), involving 7 water utilities, and focused on the performance assessment of 23 urban wastewater treatment plants (WWTPs) covering a wide range of treatment sequences and capacities (700-54000 m3/ d). An earlier developed system of key performance indicators (KPIs) with reference values was used to assess the plants’ overall performance for effectiveness and reliability, sludge production and energy efficiency taking into consideration, whenever adequate, treatment technology, treated wastewater volume and influent characteristics. This application proved the soundness of the KPI system and its reference values for a blind comparison among WWTPs but also for treatment type- and capacity-specific clustering, ultimately supporting water utilities in a continuous practice of WWTP performance improvement.