Keywords: bio–treated wastewater, membrane bioreactors, MBR, nanofiltration, wastewater reuse, wastewater treatment, irrigation water, water quality, Turkey
Application of nanofiltration for reuse of wastewater
The present research is a part of efforts to reuse wastewater by applying nanofiltration (NF) method for the secondary treatment of bio–treated wastewater and to check the quality of product water as irrigation water by using various analytical methods. For this, the performances of three different NF membranes (CK, GE–Osmonics; NF–270 and NF–90, Dow–FilmTech) were investigated using a cross–flow flat–sheet membrane test unit (SEPA CF–II, GE). The bio–treated wastewater obtained from ITOB–OSB Wastewater Treatment Plant, Izmir where membrane bioreactor (MBR) technology is employed as a treatment process has a high salinity and a high conductivity which make the treated water unsuitable for irrigation purposes. After applying NF separation for the three membranes at 10 bar as operating pressure, it was concluded that NF–90 gave the best quality of product water for almost all analysed parameters such as salinity, calcium, magnesium, sodium, potassium, bicarbonate, chloride, sulphate, phosphate–phosphorous, nitrate–nitrogen, and conductivity.