Wastewater reuse after treatment by MBR. Microfiltration or ultrafiltration? Arévalo, Juan Ruiz, Luz Marina Parada, Julián González, Daniel Pérez Pérez, Jorge Ignacio Moreno Escobar, María Begoña Gómez Nieto, Miguel Ángel This research (NET 324936/1) was funded by the Andalusian Government (Andalusian Water Agency) with European Union funds (FEDER), and was conducted at the Department of Civil Engineering and the Institute of Water Research, University of Granada, with the collaboration of EMASAGRA. J. Arévalo was supported by a Ph.D. scholarship from the Ministry of Education of Spain (PFPU). Efficiency of two MBR systems (microfiltration and ultrafiltration) at producing reusable effluent was evaluated. The ultrafiltration MBR (0.034 μm pore size) maintained recirculation sludge flow at six times the influent flow, and membranes were backwashed every 5 minutes. The microfiltration MBR (0.4 μm pore size) maintained recirculation sludge flow at four times the influent flow, and membrane-relax was applied after the production phase. Permeates of both systems were shown to be suitable for unrestricted reuse (based on Spanish reuse guidelines); however their colour and aerobic bacteria concentration may lead to their rejection for certain purposes. The capacity of the MBR systems to eliminate organic matter depends on the biological activity in the active sludge, and it is not affected by the type of membrane. The concentration of coliphages is one of the differentiating characteristics between the two systems in terms of the quality of the permeate. This concentration was higher in the microfiltration system, due to the larger pore size, a fact which also explained the higher concentration of aerobic bacteria and the different particle size distribution. Reuse of effluent from ultrafiltration MBR systems is more safety in view of its microbiological and physico-chemical quality. 2025-02-03T09:06:59Z 2025-02-03T09:06:59Z 2012-08-01 journal article J. Arévalo et al. / Desalination 299 (2012) 22–27. https://doi.org/10.1016/j.desal.2012.05.008 https://hdl.handle.net/10481/101852 10.1016/j.desal.2012.05.008 eng open access Elsevier