Membrane performance enhancer evaluations on pilot- and full-scale membrane bioreactors

Recently developed polymeric membrane performance enhancer product, MPE50, was tested in various pilot- and full-scale membrane bioreactors (MBRs). The Initial MPE50 dosage was determined by visual jar tests and by using various bench-top filtration tests. Different amounts of MPE50 were dosed, and the particle size and supernatant clarity of the mixed liquor were monitored visually. Bench-top filtration tests were also conducted. A 50% higher MPE50 dosage is recommended to be added to the pilot/full-scale bioreactors because, based on experience, some of the soluble microbial products in the mixed liquor do not completely react with polymer during the relatively short bench-test mixing time interval. With the addition of 400 mg/L MPE50 to a pilot MBR, the design flow was increased twofold without any significant transmembrane pressure (TMP) increase for 1 day. The control TMP surged within a few hours without MPE50. Long-term field trials in a full-scale plant also showed a substantial flux increase. In addition to flux enhancement, MPE50 helped to remove foam from the bioreactors and improved plant aesthetics, safety and general operating performance.