【正文】 t cause membrane fouling. 4. Conclusions Stable operation of MBR process was possible without significant accumulation of biomass when a part of the biological solids were disintegrated with alkali at pH 11 and temperature 75℃ Thermo chemical sludge digestion favors the recovery of phosphorous in the supernatant using calcium salts. The system can run for a long period of time with any further detoriation in TP removal efficiency. Further studies focusing on fate of disintegrated sludge are in progress. Acknowledgements This work was partly supported by the GS group of panies and Brain Korea 21 program from the Korean Ministry of Education References 1. Akin, ., Ugurlu, A., 2021. The effect of an anoxic zone on biological phosphorus removal by a sequential batch reactor. Bioresour. Technol. 94, 17 2. APHA, 2021. Standard Methods for the Examination of Water and Wastewater, 21 st ed. American Public Health Association, American Water Works Association,Water Pollution and Control Federation, Washington, DC 3. Banu, ., Uan, I., Yeom, LT., 2021. Effect of ferrous sulphate on nitrification during simultaneous phosphorous removal from domestic wastewater using laboratory scale anoxic/oxic reactor. World J. Microbiol. Biotechnol. 24, 29812986 4. Choi, H., Jeong, Sw， Chung, Y 一 2021. Enhanced anaerobic gas production of waste activated sludge pretreated by pulse power technique. Bioresour Technol. 97, 198203 5. Choi, C., Lee, J., Lee, I., Iim, M., 2021. The effects on operation conditions of sludge retention time and carbon/nitrogen ratio in an intermittently aerated membrane bio reactor (IAMBR). Bioresour. Technol. 99, 53975401. 6. Guo, L., Li, ., Bo, X., Yang, Q., Zeng, ., Liao, ., Liu, J 一 2021. Impacts of sterilization, microwave and ultrasonification pretreatment on hydrogen producing using waste sludge. Bioresour. Technol. 99, 36513658 7. Iim, J., Park, C., Iim, ., Lee, M., Iim, S., Iim, ., Lee, J., 2021. Effects of various pretreatments for enhanced anaerobic digestion with waste activated sludge. J Biosci. Bioeng. 95 (3), 271275 8. Li, H., Jin, Y., Mahar, R., Wang, Z., Nie, Y., 2021. Effects and model of alkaline waste activated sludge treatment. Bioresour. Technol. 99, 51405144 9. Lopez, ., Hooijmansa, ., Brdjanovicb, D., Gijzena, ., Mark, ., van Loosdrecht, 2021. Factors affecting the microbial populations at fullscale enhanced biological phosphorus removal (EBPR) wastewater treatment plants in The Netherlands.、八 eater Res. 42, 23492360 10. Mervat, E., Logan, ., 199G. Removal of phosphorus from secondary effluent by a matrix filter. Desalination 10G, 247253 11. Tchobanoglous, G., Burton, F 土， David Stensel, H., 2021. Wastewater Engineering Treatment and Reuse, fourth ed. Mc Graw Hill publication, New York, USA Morita, M., Uemoto, H., Watanable, A., 2021. Nitrogen removal bioreactor capable of simultaneous nitrification and denitrification applicable to industrial wastewater treatment. J. Biotechnol. 131 (2), 24G252 12. Nishimura, F., 2021. Alternation and reduction characteristics of activated sludge by ozonation. Adv. Asian Environ. Eng. 1 (1), 1823 13. Peng, Y., Want, X., Wu,w， Li, J., Fan, J., 2021. O。 Yoon et al., 2021). During the study period, sCOD concentration in the aerobic basin of MBR was in the range of 1838 mg/L and corresponding anic concentration in the effluent was varied from 4 to 12 mg/L. From this data it can be concluded that the membrane separation played an important role in providing the excellent and stable effluent quality. Phosphorus is the primary nutrient responsible for algal bloom and it is necessary to reduce the concentration of phosphorus in treated wastewater to prevent the algal bloom. Fortunately its growth can be inhibited at the levels of TP well below 1 mg/L (Mervat and Logan, 1996). Fig. 2 depicts TP removal efficiency of the A2OMBR system during the period of study. It is clearly evident from the figure that the TP removal efficiency of A/O system was remains unaffected after the introduction of sludge reduction. In the present study, the solubilised phosphorous was recovered in the form of calcium phosphate before it enters into main stream. So, the possibility of phosphorus increase in the effluent due to sludge reduction practices has been eliminated. The influent TP concentration was in the range of mg/L. During the first four weeks of operation the TP removal efficiency of the system was not efficient as the TP concentration in the effluent exceeds over mg/L. The lower TP removal efficiency during the initial period was due to the slow growing nature of PAO anisms and other operational factors such as anaerobic condition and internal recycling. After the initial period, the TP removal efficiency in the effluent starts to increase with increase in period of operation. TP removal in A2O process is mainly through PAO anisms. These anisms are slow growing in nature and susceptible to various physicochemical factors (Carlos et al., 2021). During the study period TP removal efficiency of the system remains unaffected and was in the range of 7482%.。 1 mg/L total nitrogen (TN) and mg/L total phosphorus (TP). . A2OMBR The working volume of the A2OMBR was L. A baffle was placed inside the reactor to divide it into anaerobic ( L) anoxic (25 L) and aerobic basin (50 L). The synthetic wastewater was feed into the reactor at a flow rate of L/h (Q) using a feed pump. A liquid level sensor, planted in aerobic basin of A2OMBR controlled the flow of influent. The HRT of anaerobic, anoxic and aerobic basins were 1, 3 and 6 h, respectively. In order to facilitate nutrient removal, the reactor was provided with two internal recycle (1R). IRl (Q= 1)connects anoxic and anaerobic and IR 2 (Q=3) was between aerobic and anoxic. Anaerobic and a