Ion exchange as an efficient pretreatment system for reduction of membrane fouling in the purification of model OMW

摘要

Membrane technology is becoming increasingly accepted in the field of wastewater reclamation, but pretreat-ments are needed to prevent membrane fouling that limits system performance and recovery. In this research work, ion exchange (IE) is presented as an efficient pretreatment for reducing membrane fouling in the purification of olive mill wastewater (OMW). No previous studies are available in scientific literature regarding the treatment of OMW by means of IE technology. OMW was previously conducted to a secondary treatment comprising chemical oxidation with Fenton's reagent, coagulation-flocculation and filtration through olive stones. Chloride, sodium, iron and phenols are the major pollutants in OMW after secondary treatment (OMWST). A bench-scale study was undertaken to evaluate the performance of two IE columns working in serial connection. Simultaneous removal of those pollutants from synthetic water simulating OMWST using Dowex Marathon-C and Amberlite IRA-67 resins was examined by studying the disposition order of both resins in semi-batch system, as well as operating temperature in batch and continuous mode. Results of continuous IE operation verify the patterns observed for the studied species in batch-run experiments. The IE system proposed, with average removal efficiencies (50-80%), will be contributed to reduce concentration polarization and membrane fouling.