2026-06-21T20:34:53Zhttps://riubu.ubu.es/oai/request

oai:riubu.ubu.es:10259/62052021-11-24T01:00:21Zcom_10259_4402com_10259_5086com_10259_2604com_10259_4244col_10259_6209col_10259_4245

00925njm 22002777a 4500 dc Martínez Díaz, Raquel author Ruiz Pérez, María Olga author Ramos Rodríguez, Cipriano author Cámara Nebreda, José María author Diez Blanco, Victorino author 2021-12 The response surface methodology has been applied to study reversible and irreversible fouling rates caused by anaerobic sludge in membrane bioreactors, with the aim of controlling membrane fouling by adjusting filtration conditions. The challenge of obtaining statistically significant results of long-term fouling by means of mid-term assays has been addressed. The individual and combined effects of the filtration flux, backwashing intensity, gas sparging and crossflow velocity on membrane fouling, were analyzed in two types of membranes: an external tubular membrane and a submerged hollow fiber membrane. In the external membrane, the reversible fouling rate was as low as 0.27 ± 0.10 mbar/min, depending mainly on the filtration flux and gas sparging. However, the principal control parameter of the irreversible fouling rate was the crossflow velocity, reaching 2.12 ± 1.75 1012 m−2 in terms of increase of resistance per cubic meter filtered by square meter of membrane. In the submerged membrane, the irreversible fouling rate was quite lower, 0.78 ± 0.40 mbar/d, despite the reversible fouling rate was higher, 1.26 ± 0.42 mbar/min. In this case, the irreversible fouling depended mainly on the backwashing frequency despite the reversible fouling was more affected by the filtration flux and gas sparging. Hence, the approach used to control the reversible fouling rate does not involve mitigating irreversible fouling on both submerged and external membranes. This study provides a methodological basis for the selection of site-specific operating conditions, under which sustainable operation of membrane bioreactors could be achieved. 0959-6526 http://hdl.handle.net/10259/6205 10.1016/j.jclepro.2021.129336 Membrane bioreactors External membrane Submerged membrane Reversible and irreversible fouling rates Box-behnken experimental design Fouling control of submerged and side-stream membrane bioreactors based on the statistical analysis of mid-term assays