| Membrane Aeration Biofilm Reactor is a new kind of biological treatment processesin which membrane technology is combined with biofilm process for the treatment ofwastewater. The process exploit a membrane's ability to separate two distinct phases,while allowing transport of components from one phase to the other, in order tooptimise conditions within the bioreactor for enhanced microbial degradation ofwastewater pollutants. The main feature of the process is the use of hydrophobicmicroporous membrane for oxygen transfer without bubble formation and assubstratum of biofilm.The whole work was divided into two aspects: study on bubble free aeration usinghollow fiber membrane;study on degradation of synthetic wastewater using a MABR.When hollow fiber membranes are immersed in water, and air or oxygen is suppliedto the inside of the fibers, gas can transfer across the membrane and dissolve directlyinto the water without bubble formation. Bubble free aeration using membraneprovides a number of advantages in biological treatment. These include operationalflexibility, high oxygen transfer efficiency, reduced energy requirements, lessstripping of volatile compounds, and low noise pollution. In this paper, the influencesof hydrologic condition and air pressure on the oxygen transfer ability were studied.Also, a contrast experimental study on aeration using traditional air-blast-head wasconducted to investigate the high oxygen transfer efficiency of bubble-free aerationusing hollow fiber membrane.Simultaneous organic carbon removal and nitrification have been reported boththeoretically and practically. In a MABR, O2 is supplied from the bottom of thebiofilm, NH3-N and organic carbon are supplied from the biofilm surface.Consequently, at the bottom of the biofilm, where O2 concentration is high and theorganic carbon concentration is low due to diffusion limitation, nitrifying bacteriagrow fast due to no competition for O2 by heterotrophic bacteria. For heterotrophicbacteria located in the middle of biofilm, pollutant concentration and O2 concentrationare both proper, the excessive growth does not tend to occur. Thus no or very lowbiofilm detachment exists, and no clarification would be required after treatment. Inthis study, with initial COD of synthetic wastewater 410±10mg/L, NH3-N 50±2 mg/L,HRT 12.5h, volumetric COD loading 0.61kg/m3, COD loading based on the surfacearea of membrane 7.68g/m2, 80% COD removal efficiency and over 90% ammoniacalnitrogen removal efficiency was obtained. Meanwhile, low effluent SS is observedand there is a slight decrease in TN concentration.The factors affecting function of MABR, such as air pressure, DO, HRT, etc werestudied in this work. It was found that air pressure and HRT played important roles.Also, the average oxygen utilization efficiency (rate of oxygen expected to beconsumed and oxygen supplied into reactor) was calucated to be over 90% during thewhole operation.
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