การนำกลับน้ำเสียจากอาคารสูงมาใช้ใหม่โดยใช้ระบบถังปฏิกรณ์ชีวภาพ ที่มีไมโครฟิลเทรชันเมมเบรนแบบจมตัว / อริยะ เตกษณานนท์ = High-rise building wastewater reclamation using the submerged type MF.-membrane bioreactor system / Ariya Tekasananont
This study is on the microfiltration membrane installed in the AS. system reactor for the use in high-rise building wastewater reclamation system. Treated water is intended for nonpotable uses, such as toilet flushing , cooling tower, fire fighting water reservoir , washing purposes, etc. The experiment investigates the stability of the membrane process, the treatment efficiency, the quality of treated water and the approximate cost of treatment. Keeping the flux constant, the pressure loss in the filtration system will indicate the stability of membrane process. When the flux 5 the organic load or MLVSS increases, pressure loss will be affected. The agitation creating shear force at the membrane’s surface are made by aerator, jet aeration and internal circulation pump will help prevent or reduce the sludge deposit on the surface of the membrane. The system can remove the organic and nitrogen only by single reactor. The intermittent aeration is applied to make possible the switching between the aerobic and anoxic condition. Findings are that the nitrification efficiency is 94-98%; 120 min. intermittent aeration period gives better result of nitrogen removal than of 90 min. ; the denitrification efficiency is 41-93% varied with COD/TKN ratio of 2.1-6.2 The accumulated differential of TKN and N03 in anoxic and aerobic period resulted from nitrification and denitrification reaction-limited respectively, would slightly affect the efficiency of the system, depending on the aeration period, the retention time and TKN loading. The system can remove higher than 99% of the turbudity and ss , 90% COD and 40-90% of nitrogen. Treated water has the average color intensity of 0.9 SU. and fecal coliform bacteria is not detectable. This makes it safe and aesthetic that have reached the standard quality of reclaimed water for nonpotable uses of the organizations having reliable study results in the environmental field in the US. and Japan. The treatment cost per unit volume is very high because of high membrane cost per treatment capacity through its life time and the high initial cost of equipment that is not in a good match with the treatment volume. The intermittent aeration operating also makes the cost of the energy consumption higher, but makes the cost of chemical many times lower comparing to the continuous aeration operating.
