Evaluation of manganese removal by adsorption for prevention of membrane fouling

Abstract

In the membrane-applied water treatment process, residual manganese often generates a significant problem because scaling of oxidized manganese can lead to irreversible membrane fouling. For the membrane process to operate effectively, advanced treatment process should be considered for manganese removal. In this study, an adsorption process utilizing a newly developed magnetite-coated adsorbent was adopted to overcome manganese fouling in ultrafiltration (UF) applications, particularly during chemically enhanced backwashing. Typical manganese-coated sand (i.e., Ferox) was also evaluated simultaneously for comparison. These adsorbents were assessed for basic performance in a fixed bed adsorption column test under various operating conditions. With the addition of chlorine dosing, the efficiency of manganese removal was improved dramatically. Specifically, magnetite column was effective to prevent flux decline in typical UF applications even with an empty bed contact times of 1 min, while severe fouling was observed with no such pretreatment, suggesting it as a promising technology for the control of fouling caused by manganese.