One-step cleaning method for flux recovery of an ultrafiltration membrane fouled by banknote printing works wastewater Original Research Article

A method was developed to clean ultrafiltration (UF) membranes fouled by banknote printing works wastewater.The cleaning agent was comprised of 0.7 wt.% NaOH, 0.8 wt.% Na2EDTA, 0.3 wt.% Turkey red oil and 98.2 wt.% de-ionized water. Membrane flux recovered adequately when the cleaning agent was circulated for 20–30 min at 1.5 m/s and 50–60°C. The membrane surfaces before and after cleaning were characterized by SEM/EDX. The spent cleaning agent was analyzed by TOC and ICP. The results showed foulants were removed from the fouled membrane by the cleaning. Pilot-scale experiments were also conducted to validate the efficiency of the cleaning method. This one-step cleaning method replaced an existing four-step cleaning method and was employed to clean OF units in banknote printing works wastewater plants.