Sur+: A Short and Accurate Test to Monitor the Total Fouling Rate of WWTP Effluent During Dead end Ultrafiltration

Due to increasing requirements the quality of wastewater treatment plant effluent is improving. Therefore, further treatment and reuse of effluent became effective and beneficial. One of the techniques to improve effluent is dead-end membrane ultrafiltration (UF). During UF, foulant remain on the membrane and causes decline in flux. The decline in flux related to the time is called filterability. The fouling is regularly removed by a flush in the opposite direction i.e. backflush (BF) to recover the flux. The recovery of the flux is called reversibility. To get more insight into the filterability Roorda (2004) designed the Specific Ultrafiltration Resistance (SUR) test. This test determines the filterability of effluent in 30 minutes. The objective of this research is to extend the SUR with a BF to determine the reversibility in a fast way as well. Therefore the SUR+ is developed. This paper focuses on the investigation of different process conditions of the SUR+ test, to make it representative to full scale UF. The experiments revealed that the BF pressure must be similar to the filtration pressure (used during filterability determination) which is 0.5 bar. The backflush duration must be at least 30 seconds to remove all reversible fouling. A final adjustment to the SUR+ setup, enables to backflush with permeate collected during the filterability determination.