Biomass Concentrator Reactor

Venosa, A.D. and Suidan, M.T., Biomass concentrator reactor The answer to the MTBE problem in groundwater, U. S. EPA Science Forum 2003 Partnering to Protect Human Health and the Environment, Washington, DC, May 5-7 2003. 

Another special type of membrane bioreactor, a biomass concentrator reactor (BCR) [42,56] uses gravity to filtrate the suspension containing bacterial mass and groundwater. 

Reactor weight Foam level Off gas composition Biomass concentration... 

Decolorization of azo dye R016 by immobilized cultures of I. lacteus was compared in three different reactor systems [59]. Different size of PuF was used for immobilization in reactors. Biomass concentration was reported to be 11.6, 8.3, and 4.9 g dw/L in Small Trickle Bed Reactor (STBR), Large Trickle Bed Reactor, and Rotating Disk Bioreactor, respectively. Decolorization rate was found high in STBR, where 90% decolorization rates were achieved after 3 days. Dye decolorization was highly efficient, but no direct relationship between the extracellular enzyme activities (laccase and MnP) and dye decolorization capacity was found. 

In a series of controlled experiments, Dosi et al. used the conversion of glucose to lactic acid as a model for the potential of controlling (automatically by computer) the concentrations of the constituents.45 Nice schematics for the reactor setup and connections to the computer/NIR spectrometer/microhltration unit, etc., are shown. Six cases are described, each using a conventional batch process. Transition from batch mode to automatic was triggered by predefined criteria such as degree of substrate conversion or biomass concentration. Control charts and comparisons of NIR data with conventional assays are given for all six cases. 

The reactor is an aerobic, plug flow, packed-bed biofihn reactor. Reticulated polyurethane (PUR), a foam with large surface area, is used as the substrate for microorganisms. The substantial area available on the PUR for contact results in a high biomass concentration and thus high reaction rates at short retention times. Biopur can be used in conjunction with soil vapor extraction technology. 

The resultant equations are non-linear and in this general case numerical solution techniques must be used. However, there exists a special case where an analytical solution may be obtained. If the increase in biomass concentration during flow through the reactor is small then an average value for the biomass concentration, independent of the distance Z along the fermenter, may be used. The material balance for the substrate over the reactor element may then be written ... 

It should be noted that these data were obtained by extracting the relatively small amounts of biomass, which can exagerate the experimental error. The reasons for working with small amounts of biomass are two-fold firstly, the samples were collected here at the steady state directly from the effluent of the system at one day intervals. Samples can degenerate due to the continuing interaction between metals and biomass before the analysis, which can cause changes in the relative amounts of the metal forms in sludge over the time. Secondly, biomass concentrations in the effluent of the reactor are quite low anyhow due to metal inhibition ef-... 

The basic advantage of the suspended biofilm membrane reactors over the suspended biomass system (either with dispersed cells or with floes) is that the former are able to retain much more biomass [22]. It substantially reduces the biomass wash out and allows a more stable operation with higher biomass concentration. A moving-bed-biofilm membrane reactor is illustrated in Figure 14.5. The biomass is immobilized inside and outside of the fluidized particles. The structure of the biofilm continuously... 

CSTR Substrate and nutrients including oxygen are continuously fed so as to achieve the desired steady state. The beer containing ethanol, biomass and unconsumed nutrients is removed continuously. The productivity can reach 6g/l h, about three times of a batch reactor. The yield of ethanol is limited by the inhibition effect Total productivity is also limited by low biomass concentration (10-12g/l). A sugar concentration of 10% in the feed gives the highest productivity. Two or more CSTR in series can be used. 

In the various studies, the different sensors were found to be significantly different with respect to sensitivity, linearity and signal to noise ratio. None of the sensors lost sensitivity completely due to surface growth on the optical window. The signals never correlated perfectly linearly with biomass concentration. Only little disturbance was observed from changing environmental illumination (artificial or sun light when used in glass reactors). 

For an industrial wastewater activated-sludge process, the amount of bsCOD in the influent wastewater is 300 g/m3 and the influent nonbiodegradable suspended volatile solids (nbVSS) concentration is 50 g/m3. The influent flowrate is 1000 m3/d, the biomass concentration is 2000 g/m3, the reactor bsCOD concentration is 15 g/m3, and the reactor volume is 105 m3. If the cell debris fraction, / . 

Fig. 3 Plug-flow activated sludge process schematic. (Note The aeration tank is a plug-flow reactor with an average biomass concentration of Xav and effluent substrate concentration of S.)...

One of the most important processes in the production of biochemicals is the 40,000 tons/yr lactic acid production involving the Lactobacillus oxidation of lactose. The MBR productivity increased eightfold compared to a conventional batch reactor with a 19-fold increased biomass concentration. Even a 30-fold increased production of ethanol was found upon coupling the Saccharomyces cerevisiae fermentation to a membrane separation. Other successful industrial applications involve the pathogen-free production of growth hormones, the synthesis of homochiral cyanohydrins, the production of 1-aspartic acid, phenyl-acetylcarbinol, vitamin B12, and the bio transformation of acrylonitrile to acrylamide. 

Lee, H. Barnett, S.M. A predictive model for the allowable operating velocities and the biomass concentration in a three phase fluidized biofilm reactor. J. Ind. Eng. Chem. 2003, 9, 202-211. 

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