Influence of operating conditions on cleaning efficiency in sequencing batch reactor (SBR) activated sludge process - water rinsing introduced membrane filtration process

In this paper, the influences of water rinsing conditions on the cumulative membrane permeate filtrate volume (CMPFV) were systematically investigated by a combination of orthogonal table and multivariate linear regression methods. The experiments were performed with a feed suspension from an SBR and deionized water in a laboratory-scale dead-end microfiltration test unit with a 0.1 mu m polyethersulfone (PES) microfiltration membrane respectively. The results showed that the resistance due to cake filtration dominated the flux decline under the conditions studied. Water rinsing process can restore the declined flux nearly to its initial value, but its ability is gradually reducing with the increase of the cleaning cycle, which is associated with the increasing accumulation of irreversible pollutants onto and into the membrane pores. The average contribution of water rinsing conditions on CMPFV were relative flux (38.3%)> detergent temperature (21.6%)> washing times (19.3%)> agitation speed (11.2%)>detergent volume (9.6%). Here, except for the relative flux, the others factors, such as detergent temperature, washing times, agitation speed and detergent volume had a positive contribution to CMPFV. In addition, the relationship between water rinsing conditions and CMPFV was analyzed and defined quantitatively for 4 cycles respectively and it can give good predictive results. (C) 2010 Elsevier B.V. All rights reserved.