Impact of intermittent aeration mode on enhancement of biological nutrient removal by the novel prototype IT/OD-MBR(Inclined Tube/Oxidation-Ditch Membrane Bioreactor) for high-rise building's wastewater recycling

- A novel prototype IT/OD-MBR (Inclined Tube/Oxidation Ditch Membrane Bioreactor) was developed for biological nutrient removal from high-rise building wastewater.
- Biological nitrogen and phosphorus removal could be enhanced by intermittent aeration practice in long-term system operation.
- The intermittent aeration with the on/off control of aeration can reduce aeration intensity and promote energy efficiency for low strength sewage treatment.
- The most efficient energy-saving system with high performance of nutrient removal could be achieved with the aeration on/off mode of 30/90 min.
- The biofoulant that was extracted from the biofilm on membrane surface indicated that protein and carbohydrate were predominant composition.

A novel prototype IT/OD-MBR (Inclined Tube/Oxidation Ditch-Membrane Bioreactor) system has been developed for biological nutrient removal purpose. The intermittent aeration modes (aeration/non-aeration period) were varied to 60/60, 40/80, 30/90,80/40, 90/30 min. The prototype system was operated with horizontal flow velocity of 0.3 m/s, hydraulic retention time (HRT) of 24 h and fed with the raw wastewater from Julajakrapong building, which is a high-rise building inside Chulalongkorn University at a constant flowrate of 2 m3/day. From the long-term system operation, the most efficient energy-saving system with high performance of nutrient removal could be achieved with the aeration on/off mode of 30/90 min. Moreover, investigation of biofoulant characteristics on membrane surface was performed by SEM-EDX and FT-IR analyses. It was found that protein and carbohydrate were predominant compositions of the biofoulant substances. Main protein composition in the biofoulant was carbonyl group. The reclaimed water can be used for gardening and landscape purposes. Therefore, the novel IT/OD-MBR system can be considered as an alternative for high-rise building's wastewater recycling.