Critical flux determination by the flux-step method in a submerged membrane bioreactor
2003; Elsevier BV; Volume: 227; Issue: 1-2 Linguagem: Inglês
10.1016/j.memsci.2003.07.021
ISSN1873-3123
AutoresPierre Le‐Clech, Bruce Jefferson, In Chang, Simon Judd,
Tópico(s)Solar-Powered Water Purification Methods
ResumoA standard flux-step method has been developed for assessing fouling in a membrane bioreactor operating at constant flux. Three keys parameters based on transmembrane pressure (TMP) were derived to depict fouling behaviour and identify the onset of fouling at the so-called critical flux. A zero rate of TMP increase (dP/dt) was never attained during the trial, such that no critical flux, in its strictest definition, could be defined in this study for a submerged MBR challenged with real and synthetic sewage. The three TMP-based parameters all indicated roughly the same flux value at which fouling started to become significant (the weak form of critical flux), this being 10 and 18 l m−2 h−1 when the MBR was fed with synthetic and real sewage, respectively. Long-term filtration trials featured much lower dP/dt values compared to those obtained during short-term fouling test, but sub-critical flux operation led to a catastrophic increase in fouling rate after some critical time period apparently dependent on feedwater matrix and flux. It was concluded that flux-step determination of the critical flux cannot be used to predict long-term TMP behaviour in real MBR systems, but nonetheless provides useful data on comparative fouling propensity.
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