Wastewater recycling at an electronics company using a combined system of membrane bioreactor and reverse osmosis membrane processes

Interest in water reuse is increasing due to the water shortage. Especially, water supply will not catch up to the water consumption of the electronics industry in Korea. Two water reclamation processes, conventional activated sludge (CAS) and membrane bioreactor (MBR), were compared to evaluate the feasibility of thin-film transistor - liquid crystal display (TFT-LCD) manufacturing wastewater reclamation as a source of ultra pure water (UPW). Both CAS and MBR processes showed similar organic removal. However the effluent quality was slightly different due to the dynamic filtration in MBR. Activated carbon (A/C) process of CAS additionally removed 35% of the nonbiodegradable organics, whereas dynamic filtration removed 70%. Also, the MBR could remove the suspended solid (SS) perfectly, which made it possible to operate the reverse osmosis (RO) unit economically using MBR effluent; however, effluent from the SS in the CAS effluent made it uneconomical to use RO directly. Considering the increasing water consumption and supply restriction in the future, water reclamation system (WRS) using MBR and RO will be an economical process.