Investigation of mini pilot scale MBR-NF and MBR-RO integrated systems performance—Preliminary field tests

Abstract

Recovery of wastewater has become compulsory due to the reasons like lowered discharge limits, pollution of water resources, and increasing water cost depending on the population growth and increasing water use. Even though membrane bioreactor (MBR) processes seem to be an alternative solution providing high quality output water, still, another treatment process after MBR might be essential to be able to use obtained water as irrigation water or process water. In this study, applicability of nanofiltration (NF) and reverse osmosis (RO) methods for reuse of industrial wastewater treated with advanced treatment method at Organized Industrial Zone (OIZ) is investigated. Studies have been implemented with the mini pilot-scale spiral wound NF/RO system installed at OIZ, under applied pressure of 10bar. For this purpose, NF membrane (NF90-2540 DOW Filmtec) and RO membrane (BW30-2540 DOW Filmtec) were used. According to results obtained, NF90 permeate flux is higher than that of BW30 membrane from December to August. The maximum water recovery obtained with NF90 was about 52.5% while BW30 achieved a maximum water recovery of 44.5%. From September to November, NF90 and BW30 membranes showed similar performances in water recovery as a result of membrane fouling/scaling. NF90 membrane performed rejection percentages of analyzed parameters in the range of 80–100% while the rejection efficiencies of BW30 membrane were in the range 83–100%. Moreover, in comparison of permeate water of NF90 and BW30 membranes with the irrigation water standards; product water qualities of these membranes were found to be suitable for irrigation. According to Turkish water quality classification, first class water quality was produced with BW30 and NF90 membranes except chloride concentration for NF90 membrane.