Reduction of biofouling potential in cartridge filter by using chlorine dioxide for enhancing anti-biofouling of seawater reverse osmosis membrane.

In general, cartridge filters (CFs) are installed before reverse osmosis systems as a safeguard to minimize fouling of the reverse osmosis membrane in seawater desalination plants. Depending on the retention time of microorganisms and various fouling matter in the storage tank, pipe, and filter housing, serious fouling of the CF may occur, decreasing its lifetime. More importantly, biofouling of CFs in a continuous process can have a significant impact on reverse osmosis membrane fouling. Few studies related to CF fouling and control have been undertaken due to the low cost of CFs. Herein, comparative evaluation of optical density (O.D) for Cl and ClO was performed to investigate the efficiency of biofouling control and for developing alternative disinfection processes because the chemistry and reactivity of ClO differ from those of Cl. The results showed that the concentrations of Cl and ClO required to achieve a log reduction value of 2 for the live bacterial cells with 180 min of contact time were 1.5 and 0.6 mg L, respectively. Both Cl and ClO were effective for the control of organic matter and particles. However, the required Cl concentration (1.5 mg L) was 2.5 times higher than that of ClO (0.6 mg L). Surface analysis and economic evaluation of the CF showed that ClO has higher biofouling control ability than Cl and is more economical, at a current cost of $ 23,667 during seawater desalination plant duration.