Acrylic wastewater treatment and long-term operation using a membrane separation system

The separation characteristics of acrylic wastewater were investigated with the variations of pressure and temperature using commercially available ultrafiltration (UF) and reverse osmosis (RO) membrane module sets composed of different membrane types and materials. The problem of fouling was also studied during long-term operation. It was found that TDS, T-N and COD removal efficiencies were low and not affected by the change of temperature and pressure in for UF modules contained in module sets 1, 2 and 3. However, TDS, T-N and COD removal efficiencies were very high in RO modules. The final water quality of acrylic wastewater was within the discharge limit value of plant wastewater. It was found that all the membrane module sets studied could be used for the reuse of wastewater. From long-term operation, the optimum cleaning time of UF and RO membranes was investigated. Membrane fouling with operating time was discussed. UF membrane flux of module set 4 decreased greatly after 8 h of operation with a similar result for the RO membrane. The removal efficiency of COD was not affected by Rf and was constant within 21% using the ceramic UF membrane. The removal efficiency of COD was above 92% for the RO membrane. The removal efficiency of T-N decreased with operating time with the ceramic UF membrane while that of T-N was excellent using the RO membrane. The flux of the UF and RO membranes declined rapidly after 14 h in operation.