Cake filtration model is described to establish/quantify transient flux decline mechanism for membrane separation of tanning effluent collected from tannery. Two membrane operations, Nanofiltration (NF) followed by Reverse Osmosis (RO), are adopted to treat tanning effluent. The experiments are conducted in a continuous cross-flow mode of operation. Three-flow regimes, namely, laminar, laminar with promoter and turbulent are investigated. Both for NF and RO, maximum cake resistance is observed in laminar flow regime followed by laminar with promoter and is the least in case of turbulent regime. For the nanofiltration process, the contributions of cake resistance towards total resistance are 85-88% for turbulent flow regime, 90-91% for laminar with turbulent promoter and maximum for purely laminar flow regime, which is 92-93%. In RO, cake resistance varies between 70-75% for turbulent flow regime, whereas it is 81% for laminar flow regime and 77% for laminar with turbulent promoter regime.
Keywords: tanning effluent, cake filtration modelling, transient flux decline, cake resistance, turbulent regime, membrane separation, nanofiltration, reverse osmosis, turbulent flow, laminar flow, turbulent promoter, wastewater treatment, leather industry, environmental pollution