Car wash industry in Malaysia: treatment of car wash effluent using ultrafiltration and nanofiltration membranes

Abstract

Three different types of commercial membranes, i.e. UF PVDF100 (MWCO 100 kDa), UF PES30 (MWCO 30 kDa) and NF270 were used to treat car wash effluent and were evaluated with respect to permeate flux, rejection of conductivity, total dissolved solid (TDS), chemical oxygen demand (COD) and turbidity. Results revealed that NF270 exhibited greater flux stability and higher flux recovery during treatment process compared to PVDF100 and PES30 membranes, indicating its higher resistance against fouling. With respect to turbidity removal, it is found that minimum rejection of 92% could be achieved irrespective of membrane properties and effluent characteristics. The performance of membrane in COD reduction was however dependent on its properties in which NF270 showed the highest retention rate (70.9–91.5%) followed by PES30 (54.9–83.9%) and PVDF100 (56.1–82.4%). Compared to NF270, both UF membranes were found ineffective in reducing conductivity and TDS of effluent. NF270 displayed at least 60% separation rate in conductivity and TDS removal compared to 13.6–35.4% reported in PVDF100 and PES30 membranes. The features demonstrated by NF270 in separating the pollutants from the car wash effluent coupled with stable water production make the membrane a good candidate to be employed and offer an environmentally sustainable option to car wash industry.