Magnetic ion exchange (MIEX®) resin as a pre-treatment to a submerged membrane system in the treatment of biologically treated wastewater

Magnetic ion exchange (MIEX®) resin can remove a majority of hydrophilic compounds and a significant amount of hydrophobic compounds from biologically treated secondary effluent within a short contact time of 20 min. It removed a majority of small molecular weight organic compounds from the wastewater. MIEX® resin can easily be regenerated and even after several regenerations, it gives almost the same organic removal efficiency. MIEX® process, when used as pre-treatment to a submerged membrane reactor, resulted in a very high organic removal while significantly reducing the membrane fouling. The membrane fouling was further reduced by an addition of a small dose of powdered activated carbon (PAC) in the submerged membrane reactor. Combining MIEX® process with other pre-treatment methods such as adsorption, very high removal of organic matter can be achieved.

It was found that MIEX® resin could effectively remove organic matter from biologically treated sewage effluent. MIEX® process as a pre-treatment removed a majority of small molecular weight organic matter (500–1000 Da). MIEX® process was specifically useful in removing the hydrophilic portion of DOC in the secondary effluent, which is the major component in water. At optimal concentration, MIEX® process could remove as high as 60% of DOC in the wastewater, and enable the membrane process to operate longer time with less TMP increase. Combining MIEX ® p retreatment with PAC adsorption, one could achieve more than 80% TOC removal.