Trial runs on various fluxes of the RO membranes were conducted from 12th May to 20th August. The RO membrane showed a low operating pressure of 52-62 psi at the flux rate of 10 GFD and at water recovery of 51%, indicating the membrane had a high flux. When the RO unit was operated at flux rate of 15 GFD and 10 GFD, the normalized flux declined by 18.3% over 3 weeks and by 20% over 5 weeks, respectively. The flux after CIP compared to the initial flux could be recovered at 97%. It was found that rejections of the RO membrane in terms of conductivity at different fluxes were over 96% throughout the study. Also, the results showed that TOC (on-line) of the RO permeate reached 36-66 ppb at operating pressure of 60 psi. RO permeate quality in terms of conductivity, turbidity, TOC, ammonium-N, nitrate, hardness (as CaCO3), total bacteria and total coliform were 37 µS/cm, 0.08 NTU, 0.20 mg/L, 0.46 mg/L, 4.8 mg/L, 0.22 mg/L, 67 counts/100 mL and <1 count/100 mL, respectively, which met the target quality at NEWater.
CSM FRM RO pilot study at Bedok, Singapore
This report summarizes the results of a pilot study for the evaluation of Woongjin Chemical CSM FRM RO elements at Bedok Water Reclamation Plant, Singapore using a MF/RO system with the capacity of 20 m3/day. RE-4040-FL RO membranes from Woongjin Chemical were tested with pretreatment of 0.1 µm PVDF MF membranes. The pilot plant consists of 6 RO elements (7.9 m2 each). The RO train was configured in a single stage. The pilot plant was designed with an automatic control system and it was operated continuously for 24 hours during the study. The objective of this study was to evaluate the RO membranes under different operating conditions.