| Pilot plant simulating the activated sludge processes was operated to study relationship between conditions of dissolved oxygen (DO) concentration and estrogens removal efficiencies. Results from DO controlled batch experiments, showed that decrease of estrone (E1) under aerobic condition depended on the DO level. And it was found that 17b-estradiol (E2) and E1 increased under anoxic or anaerobic conditions where easily degradable organic matters had been already removed. From the results, it is advisable that DO concentrations in the latter part of the aeration tank and secondary sedimentation tank should be kept high for effective estrogen removal in the activated sludge process. |
