United States
                               Environmental Protection
                               Agency
              EPA/540/F-93/506
              July 1993
 vvEPA
                               SUPERFUND  INNOVATIVE
                               TECHNOLOGY EVALUATION
                  Emerging  Technology  Bulletin

                             Methanotrophic Bioreactor System
                                           BiotroP, Inc.
Technology Description: BioTrol's Methanotrophic Bioreactor
is an above-ground remedial system for water contaminated with
halogenated volatile organic compounds, including trichloroethyl-
ene (ICE) and related chemicals. Its design features circumvent
problems peculiar to treatment of this unique class of chemicals.
First, microorganisms are not known which utilize these chemi-
cals as  a  primary carbon source; so a  specific organism
(Methylosinus trichosporium OB3b, or simply OB3b) is used which
oxidizes these compounds rapidly  while utilizing methane, an
abundant and inexpensive source of carbon, as its growth  sub-
strate. Second, because of the ability of the bacterium to degrade
ICE in the absence of  the growth substrate, growth of the
organism and degradation of the contaminants can take place in
separate reactor vessels. This is important because these  con-
taminants are extremely volatile, and bubbling of methane or air
through the reaction vessel would likely result in stripping of the
contaminants from the water.
A two-stage bioreactor system (diagramed in Figure  1) was
designed which  circumvents  these problems.  The first stage
involves the propagation of OB3b on methane in a continuous-
flow suspended growth reactor (culture vessel). Cells grown in
the culture vessel are supplied to the second stage (plug flow)
contactor where the culture medium is mixed with the contami-
nated water.

For the pilot demonstration, the culture vessel consisted of a 400-
L fermenter which was modified to permit continuous-flow  fer-
mentation and the use  of methane as  the growth substrate.
Methane transfer efficiency to the culture vessel was improved by
addition of a circulating gas-saturation device. The plug flow
                                                                    Ground
                                                                     Water
                                           IPlug Flow
                                           Contactor
                                              v

                                            Effluent
Figure 1. Bioreactor system flow diagram.
                                                                               Printed on Recycled Paper

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                               United States
                               Environmental Protection
                               Agency
              EPA/540/F-93/506
              July 1993
 v>EPA
                                SUPERFUND  INNOVATIVE
                                TECHNOLOGY EVALUATION
                  Emerging  Technology  Bulletin

                             Methanotrophic Bioreactor System
                                           BiotroP, Inc.
Technology Description: BioTrol's Methanotrophic Bioreactor
is an above-ground remedial system for water contaminated with
halogenated volatile organic compounds, including trichloroethyl-
ene (ICE) and related chemicals. Its design features circumvent
problems peculiar to treatment of this unique class of chemicals.
First, microorganisms are not known which utilize these chemi-
cals  as  a  primary carbon source; so a  specific organism
(Methylosinus trichosporium OB3b, or simply OB3b) is used which
oxidizes these compounds rapidly  while utilizing methane, an
abundant and inexpensive source of carbon, as its growth  sub-
strate. Second, because of the ability of the bacterium to degrade
ICE in the absence of  the growth substrate, growth of the
organism and degradation of the contaminants can take place in
separate reactor vessels. This is important because these  con-
taminants are extremely volatile, and bubbling of methane or air
through the reaction vessel would likely result in stripping of the
contaminants from the water.
A two-stage bioreactor system (diagramed in Figure  1)  was
designed which  circumvents  these problems.  The first stage
involves the propagation of OB3b on methane in a continuous-
flow suspended growth reactor (culture vessel). Cells grown in
the culture vessel are supplied to the second stage (plug flow)
contactor where the culture medium is mixed with the contami-
nated water.

For the pilot demonstration, the culture vessel consisted of a 400-
L fermenter which was modified to permit continuous-flow  fer-
mentation and the use  of methane as  the growth substrate.
Methane transfer efficiency to the culture vessel was improved by
addition of  a circulating gas-saturation device. The plug  flow
                                           IPlug Flow
                                           Contactor
                                              v

                                            Effluent
Figure 1. Bioreactor system flow diagram.
                                                                               Printed on Recycled Paper

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