Although membrane bio-reactor (MBR) has been widely applied for wastewater treatment plants, the membrane fouling problems are still considered as an obstacle to overcome. Thus, many studies and commercial developments on mitigating membrane fouling in MBR have been carried out. Recently, high voltage impulse (HVI) has gained attention for a possible alternative technique for desalting, non-thermal sterilization, bromate-free disinfection and mitigation of membrane fouling. In this study, it was verified if the HVI could be used for mitigation of membrane fouling, particularly the internal pore fouling in MBR. The HVI was applied to the fouled membrane under different conditions of electric fields (E) and contact time (t) of HVI in order to investigate how much of internal pore fouling was reduced. The internal pore fouling resistance (Rf) after HVI induction was reduced as both E and t increased. For example, Rf decreased by 19% when the applied E was 5 kV/cm and t was 80 min. However, the Rf decreased by 71% as the E increased to 15 kV/cm under the same contact time. The correlation between E and t that needed for 20% of Rf reduction was modeled based on kinetics. The model equation, E1.54t = 1.2 × 103 was obtained by the membrane filtration data that were obtained with and without HVI induction. The equation states the products of En and t is always constant, which means that the required contact time can be reduced in accordance with the increase of E.
회분식 고전압 펄스 전기장 처리에 의한 막걸리의 비가열 살균 공정 적용의 가능성을 알아보았다. 막걸리의 초기 균수는 약 2×108 CFU/mL로 전기장의 세기와 처리시간이 증가할수록 사멸율은 증가하여, 30 kV/cm, 256 pulse 처리하였을 경우 약 2 log 정도의 사멸율을 나타내었다. 고전압 펄스 전기장과 열을 병합처리하였을 경우 50oC에서 20 kV/cm, 256 pulse 처리를 한 후 8 log의 높은 사멸율을 나타내었으며, 알코올 농도를 달리하였을 경우 알코올 농도가 높아질수록 높은 사멸율을 나타내어 12%의 알코올 농도에서 4.8 log의 사멸율을 보였다. 고전압 펄스 전기장 처리한 막걸리를 4oC와 30oC에서 4주간 저장하였을 경우 무처리막걸리에 비하여 4oC에서는 pH, 산도, 미생물의 수에 변화가 거의 없었으며, 30oC에서도 적정산도나 미생물의 증가가 일정 수준이하로 억제되어 막걸리의 비가열 살균 공정으로서의 가능성을 보였다.