Browsing by Author "Kurisu, F."

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Combined effects of EPS and HRT enhanced biofouling on a submerged and hybrid PAC-MF membrane bioreactor
(2013-02) Khan, Mohiuddin M. T.; Takizawa, S.; Lewandowski, Zbigniew; Rahman, M. Habibur; Komatsu, K.; Nelson, Sara E.; Kurisu, F.; Camper, Anne K.; Katayama, H.; Ohgaki, S.
The goal of this study was to quantify and demonstrate the dynamic effects of hydraulic retention time (HRT), organic carbon and various components of extracellular polymeric substances (EPS) produced by microorganisms on the performance of submersed hollowfiber microfiltration (MF) membrane in a hybrid powdered activated carbon (PAC)-MF membrane bioreactor (MBR). The reactors were operated continuously for 45 days to treat surface (river) water before and after pretreatment using a biofiltration unit. The real-time levels of organic carbon and the major components of EPS including five different carbohydrates (D(Ã¾) glucose and D(Ã¾) mannose, D(Ã¾) galactose, N-acetyl-D-galactosamine and Dgalactose, oligosaccharides and L( ) fucose), proteins, and polysaccharides were quantified in the influent water, foulants, and in the bulk phases of different reactors. The presence of PAC extended the filtration cycle and enhanced the organic carbon adsorption and removal more than two fold. Biological filtration improved the filtrate quality and decreased membrane fouling. However, HRT influenced the length of the filtration cycle and had less effect on organic carbon and EPS component removal and/or biodegradation. The abundance of carbohydrates in the foulants on MF surfaces was more than 40 times higher than in the bulk phase, which demonstrates that the accumulation of carbohydrates on membrane surfaces contributed to the increase in transmembrane pressure significantly and PAC was not a potential adsorbent of carbohydrates. The abundance of N-acetyl-Dgalactosamine and D-galactose was the highest in the foulants on membranes receiving biofilter-treated river water. Most of the biological fouling compounds were producedinside the reactors due to biodegradation. PAC inside the reactor enhanced the biodegradation of polysaccharides up to 97% and that of proteins by more than 95%. This real-time extensive and novel study demonstrates that the PAC-MF hybrid MBR is a sustainable technology for treating river water.
Powdered activated carbon and biofiltration improve MF performance: Part I
(2007-05) Khan, Mohiuddin M. T.; Jones, Warren L.; Camper, Anne K.; Takizawa, S.; Katayama, H.; Kurisu, F.; Ohgaki, S.
This article shows how the use of high-dose powdered activated carbon and biofiltration are able to improve the performance of membrane-based microfiltration systems. The first part, which appears here, provides an overview of the study, materials and methods, and experimental design and operational conditions of the reactors.
Powdered activated carbon and biofiltration improve MF performance: Part II
(2007-06) Mohiuddin, Khan T.; Takizawa, S.; Katayama, H.; Kurisu, F.; Camper, Anne K.; Ohgaki, S.
This article shows how the use of high-dose powdered activated carbon and biofiltration are able to improve the performance of membrane-based microfiltration systems. The first part of this feature, which was published in the May 2007 issue of Membrane Technology, provides an overview of the study, materials and methods, and experimental design and operational conditions of the reactors. The second installment, which appears here, discusses the results of this study.