Membrane bioreactor integrated

Danner H, Madzingaidzo L, Thomasser C, Neureiter M, Braun R (2002) Thermophilic production of lactic acid using integrated membrane bioreactor systems coupled with monopolar electrodialysis. Appl Microbiol Biotechnol 59(2-3) 160-169. doi 10.1007/s00253-002-0998 ... 

Figure 7.1 shows the two major treatment options to obtain RO-quality water from sewage and seawater. The key in water reclamation is to first treat the sewage biologically and use MF/UF membrane filtration to remove suspended solids. Two membrane filtration alternatives are available for water reclamation tertiary filtration (TF) of the effluent from a conventional activated sludge (CAS) process and an integrated membrane bioreactor (MBR). For seawater desalination, pretreatment must be provided if the source is open seawater. The current practice involves multimedia filtration, but membrane filtration has also been considered. 

In this section, the options for sewage treatment are investigated, including MF/UF filtration, but without RO. The two primary options shown are conventional activated sludge (CAS) followed by tertiary filtration (TF) and integrated membrane bioreactor (MBR). These options are developed and costed for plants ranging in size between 3800 mVday (1 MOD) and 76,000 mVday (20 MOD). 

Microfiltration and Ultrafiltration are the best available technology for water reuse. Two options are available conventional activated sludge followed by tertiary filtration and an integrated membrane bioreactor. Both provide effluent of high quality suitable for treatment by reverse osmosis. The cost of tertiary filtration can be lower than a membrane bioieactor if the water reclamation plant is designed for constant flow and is located at a different site. 

In the following, a number of integrated reaction-separation systems wiU be discussed, with emphasis on the application of polymeric membranes. As a result, the systems discussed will be Hmited to relatively low temperatures, typically below 120°C. In Section 13.2, appHcations of membranes in chemical synthesis will be described. Subsequently, in Section 13.3 various examples of membrane bioreactors will be discussed. 

In the development of cell or enzyme-based processes, many process configurations exist, including batch, fed batch and continuous operation. In general, the conversion and the separation processes (downstream processing) are regarded as separate units, and most industrial processes are based on this approach. In the last decades, however, more attention is paid to the integration of conversion and separation, leading to the development of membrane bioreactors [49, 50], and some of these concepts have reached an industrial scale. The membranes used for this type of reactors are almost exclusively polymeric, as temperatures seldomly exceed 100 °C for obvious reasons. 

More progresses can be anticipated in the near future by promoting the integration of different membrane operations, including MCs and membrane bioreactor (MBRs), also for wastewater treatment. 

Membrane bioreactors can be easily integrated with other systems, for example, with delivery of drugs or genes to individual cells achieved on the nanoscale using electroporation techniques. In one method developed in a recent patent, a flowthrough bioreactor having an inlet and an outlet connected by a flow chamber and a nanoporous membrane positioned in the flow chamber was used [28]. 

The OHLM systems, integrating reaction, separation, and concentration functions in one equipment (bioreactor), find a great interest of researchers in the last few years. A bioreactor combines the use of specific biocatalyst for the desired chemical reactions, and repeatedly or continuously application of it under very specific conditions. Such techniques were termed as hybrid membrane reactors. In biotechnology and pharmacology, these applications are termed as hybrid membrane bioreactors or simply bioreactors (see Table 13.11). Experimental setup of the bioreactor system is shown schematically in Figure 13.17. 

Gryta [150] conducted integration of fermentation process with membrane distillation for the production of ethanol. The removal of by products, which tends to inhibit the yeast productivity, from the fermenting broth by MD process increased the efficiency and productivity of the membrane bioreactor. The ethanol concentration in permeate was 2-6 times higher than that in the fermenting broth. The enrichment coefficient was found to increase with decrease of ethanol concentration in the broth. 

Figure 3.8 (a) A membrane bioreactor-based system for treating landfill leachates, (b) A multi-staged RO and reject RO integrated membrane system for treating landfill leachates. Source [17]. 

Figure 5.3 Process flow schematics of membrane plants. Process A is single-pass RO process B is double-pass RO process C is high-recovery RO process D is pressurised MFAJF-RO integrated plant process E is membrane bioreactor-RO integrated plant process F is cross-flow MF-RO integrated plant and processes G and HI are RO-EDI integrated high-purity water plants. In process H2, second-pass RO replaces EDI, and no post-treatment after MBIX is required.

Gan Q, Allen SJ, Taylor G. (2005). Analysis of process integration and intensification of enzymatic cellulose hydrolysis in a membrane bioreactor. J Chem Techrwl Biotechnol, 80(6), 688-698. 

Chapter 22 (Uragami, Chakraborty, Piemonte and Di Paola) presents a survey of membrane bioreactor appHcations in pharmaceutical, environmental and biomedical fields. The integration between the separation and the reaction units is demonstrated to highly improve the selectivity and productivity of bioreactors, especially when some factors (inhibition by products or reactants, contamination by xenobiotics) play a key role in the bioreactive systems. In Chapter 23 (Calabrb and lorio membrane bioreactors are described from an economical point of view. Most important rules and parameters have been preliminarily introduced. Some appUcations,... 

Schematic diagram of the integrated membrane process for the treatment of paper mill wastewater. 1 - sedimentation tank 2 - anoxic tank 3 and 4 - aerobic tanks 5 - sludge treatment equipment. MBR = membrane bioreactor UF = ultrafiltration RO = reverse osmosis. (Adapted from Zhang eta ., 2009.)... 

Scheme of a membrane bioreactor integrated system for wastewater treatment. 

In Part I a selection of the types of membrane reactor is presented, together with chapters on the integration of membrane reactors with current industrial processes. To summarize, in Chapter 1 (Calabro) membrane bioreactors are described from an engineering point of view, together with a straightforward description and simulation, with a simple mathematical approach, of the most important configurations and processes in which they are involved. Basic principles of bioconversion, bioreactors and biocatalysis with immobilized biocatalysts are also presented. For all the cited systems the most significant parameters are defined in order to estimate their performances. The best approaches for the preparation of... 

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