title: Comparing the dynamic performance of wastewater treatment systems: A metafrontier Malmquist productivity index approach.
abstract: The assessment of productivity change of wastewater treatment plants (WWTPs) is essential to improve the performance over time of the facilities evaluated. This study assessed and compared the productivity growth of WWTPs operating with non-homogeneous technologies. The metafrontier Malmquist productivity index (MMPI) was computed for a sample of 99 WWTPs encompassing 4 alternative technologies: activated sludge (AS), aerated lagoon (AL), trickling filter (TF) and rotating biological contactor (BD). The results indicated that, on average, WWTPs with AS and BD exhibited better performance over time than WWTPs with AL and TF. The MMPI indicates that, over the period 2007-2009, the productivity rose by 0.9% and 0.3% for AS and BD technologies, respectively, whilst for the AL and TF processes, the productivity decreased by 0.5% and 2.2%, respectively. The decomposition of the MMPI into efficiency change (EC) and technical change (TC) illustrated that EC was a positive driver of productivity change for WWTPs that use AS, whilst TC contributed positively to the productivity growth of WWTPs using AL and BD. Several policy implications to help managers make informed decisions were drawn from our empirical analysis.
authors.affiliation: Departamento de Ingeniería Hidráulica y Ambiental, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, Santiago, Chile; Instituto de Estudios Urbanos y Territoriales, Pontificia Universidad Católica de Chile, El Comendador 1916, Santiago, Chile; Centro de Desarrollo Urbano Sustentable CONICYT/FONDAP/15110020, Av. Vicuña Mackenna 4860, Santiago, Chile. Electronic address: mmolinos@uc.cl.
authors.forename: María
authors.initials: M
authors.lastname: Molinos-Senante
authors.affiliation: Department of Applied Economics II, University of Valencia, Avda. Tarongers S/N, 46022 Valencia, Spain. Electronic address: francesc.hernandez@uv.es.
authors.forename: Francesc
authors.initials: F
authors.lastname: Hernández-Sancho
authors.affiliation: Department of Mathematics for Economics, University of Valencia, Avda. Tarongers S/N, 46022 Valencia, Spain. Electronic address: ramon.sala@uv.es.
authors.forename: Ramón
authors.initials: R
authors.lastname: Sala-Garrido
mesh_terms: D019149:Bioreactors; D004526:Efficiency; D012722:Sewage; D014865:Waste Disposal, Fluid / Q000295:instrumentation / Q000379:methods*; D062065:Wastewater
chemical_list: D012722:Sewage; D062065:Wastewater
keywords: Data envelopment analysis (DEA); Efficiency; Performance; Productivity change; Technological gap; Wastewater treatment plants