Results of ‘PASt21’ – the Portuguese initiative for performance assessment of water and wastewater treatment plants

Abstract

Performance assessment of water supply and wastewater services is today a major issue. Over the past six years, the National Civil Engineering Laboratory (Portugal) has been developing performance assessment systems for drinking water treatment plants (WTPs) and wastewater treatment plants (WWTPs). In 2009, a national field-test was launched in Portugal, ‘PASt21’, involving 27 plants (10 WTPs and 17 WWTPs). This paper presents an overview of the second generation of the performance indicator (PI) systems for the overall performance assessment of WTPs and WWTPs, the extent to which the systems were applied in the 5-year study period (2006–2010), and the aggregated results (average, median, percentiles 25 and 75, maximum and minimum) of representative PIs in each assessment group. It was concluded that all indicators are relevant, and the results show the ability of the proposed PI systems to assess the overall performance of a given treatment plant. The aggregated results are very important for the continuous improvement of the plant performance through benchmarking and periodic reassessment of targets.

Proposição de sistema de indicadores de desempenho operacional de estações de tratamento de água à luz do prestador de serviço: aplicação a cinco estações de ciclo completo

“…Para cada indicador e cada ano amostrado, foram determinados o primeiro e o terceiro quartis, a mediana, a média aritmética e os valores máximo e mínimo. Concluiu-se que a relevância de cada indicador se vincula ao objetivo delineado, e os resultados preliminares confirmaram adequação da aplicabilidade do grupo de indicadores como ferramenta para contínuo aumento do desempenho das estações de tratamento (SILVA et al, 2011). Nesse cenário, o objetivo principal da pesquisa consistiu na proposição de sistema de indicadores de desempenho operacional de estações convencionais de tratamento de água sob a ótica do prestador de serviço.…”

Sewage Treatment Plants

“…The 1st generation of PASs were tested in four WTPs (Vieira et al 2008;Silva, 2008;Vieira, 2009) and two WWTPs (Quadros 2010;Quadros et al 2010). The 2nd generation was an output of «PASt21»the Portuguese initiative for performance assessment of water and wastewater treatment plants (2009)(2010)(2011), a project involving 18 institutions, 17 WWTPs and 10 WTPs distributed nationwide Silva et al 2012).…”

“…Following the PDCA approach, the developed PAS is objective-driven and assumes two general objectives for any undertaking with regard to WWTP performance: (1) its effectiveness and reliability, that is, the compliance over time with the quality requirements of the treated water and (2) its efficiency (in terms of resources utilization) and sustainability (economic and environmental) Silva et al 2012).…”

“…The system comprises (i) a PI system for the overall assessment of the plant, on an annual-basis, in terms of treated water quality, plant efficiency and reliability (ER), use of natural resources and raw materials (RU), by-products management (BP), safety, personnel, financial resources (Fi), and planning and design (Silva et al 2012) and (ii) a system of performance indices (PXs) for assessing the daily performance in terms of treated water quality (Silva et al 2014a), operating conditions and removal efficiencies (Silva et al 2014b). The integrated analysis of PIs and PXs allows identifying improvement actions.…”

“…In order to ensure unit coherence and allow for comparisons, for these PIs (e.g., wtER35.1, Table 3.3), values calculated for other reference assessment periods are converted into annual values, multiplying by '(365 days/year)/Assessment period (day)' (Silva et al 2012). In order to ensure unit coherence and allow for comparisons, for these PIs (e.g., wtER35.1, Table 3.3), values calculated for other reference assessment periods are converted into annual values, multiplying by '(365 days/year)/Assessment period (day)' (Silva et al 2012).…”