Membrane bioreactors (MBRs) employ a process of biological treatment that is based on a membrane that has the advantages of producing high-quality treated water and possessing a compact footprint. However, despite these advantages, the occurrence of “fouling” during the operation of these reactors causes the difficulty of maintenance.Hence, in this study, three physical cleaning methods, namely, backwashing, air scrubbing, and mechanical cleaning ball was performed to identify optimum operating conditions through laboratory scale experiments, and apply them in a pilot plant. Further, the existing MBR process was compared with these methods, and the field applicability of a combination of these physical cleaning methods was investigated.Consequently, MCB, direct control of cake fouling on the membrane surface was found to be the most effective. Moreover, as a result of operating with combination of the physical cleaning process in a pilot plant, the TMP increasing rate was found to be – 0.00007 MPa/day, which was 185% higher than that obtained using the existing MBR process. Therefore, assuming fouling only by cake filtration, about one year of operation without chemical cleaning is considered to be feasible through the optimization of the physical cleaning methods.

This study compares characteristic of membrane fouling in MBR-RO systems. In lab. scale MBRs test, MBRs were operated at different Flux(10, 20, 30 & 40 LMH) and temperature(10, 15, 20, 25 & 30°C). The results show that MBR permeate was measured lower amounts of organic substances in Higher flux and lower temperature and led to lower RO fouling rates. The main cause was that due to cake fouling formed on membrane surfaces in MBRs. Under both cases, Cake layer of membrane surfaces formed in MBRs removed RO fouling factors, polysaccharide and protein, because of cake layer attached on membrane surfaces greater amounts of organic substances. This study implies that optimization of MBR with operating conditions is a crucial strategy to RO membrane fouling control.

The development of alternative water resources has emerged as an effective method for solving drought of water resources due to extreme weather and increase in water consumption. Recently, in Korea, there has been active research on reverse osmosis desalination technology, wastewater reuse using forward osmosis membranes, and the forward osmosis(FO)-reverse osmosis(RO) hybrid process combining these two technologies. In this study, the basic performance of FO membranes manufactured by three domestic and international manufactures such as Microfilter Co., Ltd., Toray Chemical Korea Inc., and Hydration Technologies Inc., were investigated for wastewater reuse. In addition, as an experiment to select feed solution, the selected membranes were operated 48 consecutive hours using three secondary effluents pretreated by the UF membrane with a pore size of 0.1 μm and auto strainer with pore sizes of 1 μm and 100 μm as feed solution. Although there was not much difference in the operating performance. Thus, the treated water using the 100 μm auto strainer was selected as feed solution applied to the assessment.

Laparoscopic appendectomy using three trocars has been widely performed. Recently, a single incision laparoscopic surgical procedure has become popular because it is less invasive. We report on our early experience in performance of single incision laparoscopic appendectomy (SIL-A). Data on the operating time, the duration to make the pneumoperitoneum, body mass index (BMI), rate of conversion to another operation, complication, hospital stay, dosage of analgesics, and pain score were collected prospectively at two centers. Twenty seven patients underwent SIL-A. The mean BMI was 23.3±3.1 kg/m2 (17.6-30.5). The mean time required to make a pneumoperitoneum was 9.9±5.0 minutes (5.0-28.0). The mean operating time was 37.6±26.7 minutes (10.0-100.0). The rate of intra-operative complication was 3.7% (1/27), and the rate of post-operative complication was 22.2% (6/27). The mean hospital stay was 4.1±1.2 days (2-6). The immediately postoperative pain score was 5.4±1.5 (3-8), however, the pain score at discharge was 0.4±0.7 (0-2). The mean dosage of analgesics was 1.5±1.3(0-4), however, none of the patients took analgesics after postoperative three days. SIL-A is feasible but requires improved instrumentation and experience.