Membrane-aerated Biofilm Reactor System Research Articles

Mixed pharmaceutical wastewater treatment by integrated membrane-aerated biofilm reactor (MABR) system – A pilot-scale study

A pilot-scale integrated membrane-aerated biofilm reactor (MABR) system, consisted of hydrolysis/acidification pretreatment, MABR process and activated carbon adsorption post-processing, was designed to treat the high-loading mixed pharmaceutical wastewater. A study of MABR process was conducted to investigate the effect of aeration condition, circulation flow rate and water quality on performance over 260days. The performances of these processes were evaluated by the removal efficiency of COD, BOD5, turbidity, NH4+–N and TN. MABR process could effectively remove above 90% of COD and 98% of ammonia. The capacities per unit volume of MABR could reach up to 1311gCOD/m3d and 48.2gNH4+–N/m3d with single membrane aeration, and the oxygen utilization rate could be as high as 45%. After post-processing, the effluent of integrated treatment MABR system kept stable with COD below 200mg/L and NH4+–N below 3mg/L.

Nitrogen Removal Characteristics and Biofilm Analysis of a Membrane-Aerated Biofilm Reactor Applicable to High-Strength Nitrogenous Wastewater Treatment.

A membrane-aerated biofilm reactor (MABR) capable of simultaneous nitrification and denitrification in a single reactor vessel was developed to investigate the characteristics of nitrogen removal from high-strength nitrogenous wastewater, and biofilm analysis using microelectrodes and the fluorescence in situ hybridization (FISH) technique was performed. Mean removal percentages of total organic carbon (TOC) and nitrogen were 96% and 83% at removal rates of 5.76 g-C m −2 d −1 and 4.48 g-N m −2 d −1 , respectively. For stable removal efficiency, constant washing of the biofilm was needed. Dissolved oxygen microelectrode measurement revealed that the biofilm thickness was about 1600 μm, and that oxygen penetrated about 300 to 700 μm, from the outer surface of the membrane. Furthermore, FISH analysis revealed that ammonia-oxidizing bacteria (AOB) were located near the outer surface of the membrane, whereas other bacteria were located from the inner to the outer part of the biofilm. Combining these results demonstrated that simultaneous nitrification and denitrification occurred in the biofilm of the MABR system. In addition, stoichiometric analysis revealed that after 130 d −1 , the free ammonia (FA) concentration ranged within the concentration causing inhibition of the growth of nitrite oxidizing bacteria (NOB) and that AOB consumed 86% of the oxygen supplied through the intra-membrane. These results indicate that nitrogen removal not via nitrate but via nitrite was mainly achieved in the MABR system.

Nitrogen removal characteristics and biofilm analysis of a membrane-aerated biofilm reactor applicable to high-strength nitrogenous wastewater treatment

A membrane-aerated biofilm reactor (MABR) capable of simultaneous nitrification and denitrification in a single reactor vessel was developed to investigate the characteristics of nitrogen removal from high-strength nitrogenous wastewater, and biofilm analysis using microelectrodes and the fluorescence in situ hybridization (FISH) technique was performed. Mean removal percentages of total organic carbon (TOC) and nitrogen were 96% and 83% at removal rates of 5.76 g-C m −2 d −1 and 4.48 g-N m −2 d −1, respectively. For stable removal efficiency, constant washing of the biofilm was needed. Dissolved oxygen microelectrode measurement revealed that the biofilm thickness was about 1600 μm, and that oxygen penetrated about 300 to 700 μm, from the outer surface of the membrane. Furthermore, FISH analysis revealed that ammonia-oxidizing bacteria (AOB) were located near the outer surface of the membrane, whereas other bacteria were located from the inner to the outer part of the biofilm. Combining these results demonstrated that simultaneous nitrification and denitrification occurred in the biofilm of the MABR system. In addition, stoichiometric analysis revealed that after 130 d −1, the free ammonia (FA) concentration ranged within the concentration causing inhibition of the growth of nitrite oxidizing bacteria (NOB) and that AOB consumed 86% of the oxygen supplied through the intra-membrane. These results indicate that nitrogen removal not via nitrate but via nitrite was mainly achieved in the MABR system.