Combining submerged membrane technology with anaerobic and ...

Tertiary membrane filtration of industrial wastewater using granular or flocculent biomass SBRs3.3.1.2. Cleaning strategyFigure 3.2. Membrane module.Physical cleaning of the membrane module was performed by rinsing with tap water.Chemically enhanced backwashing was not used during the experiments. Chemicalrecovery cleaning was conducted when TMP in the membranes was higher than 30 kPa orpermeability value was below 50 L·m -2·h -1·bar -1 . The cleaning procedure was:- Soak in chlored water (2000 ppm Cl 2:l) for 2 h.- Backwashing with chlored water (2000 ppm Cl 2:1) for 1 h.3.3.1.3. Influent and operating strategyIndustrial wastewater from a fish freezing industry was treated during the study. Theraw wastewater contained 50-300 mg·L -1 ammonia and 1000-6300 mg·L -1 total COD. Totalphosphorous ranged between 70 and 190 mg·L -1 of which 60-70% was orthophosphate.Soluble COD represented around 85% total COD. Lots of the industrial wastewater weretaken and diluted with tap water to obtain the desired OLR and COD values in the influent.The soluble COD values varied from 100 to 1100 mg·L -1 . The dissolved total nitrogen(DTN) concentration ranged from 20 to 180 mg·L -1 , and the total phosphorus concentrationranged from 20 to 110 mg·L -1 .An exchange volume ratio of 50 % and a cycle length of 3 hours were fixed asoperating parameters. The two SBR were operated with constant and similar HRTs andSRTs during all the operation. The lengths of the feeding, reaction, settling and withdrawal89