aerobic microbial community and enhances the development of biofilm. It has been
highlighted that polluted soil did not possess necessary endogenous microbial
degrading population or the availability of necessary conditions that could stimulate
the process of biodegradation that might be subjected to ex situ remediation frequently in a reactor.
It has been highlighted that in engineered systems, biofilms are applied in a
bioreactor in an inert support. The biofilm bioreactor is utilized for biochemical
conversion and biosorption of contaminants most especially from municipal wastewater, heavy metals, industrial wastewater and petroleum hydrocarbon (Boon et al.
2002). The bioreactor based on the application of biofilms is applied for the
commercial bioremediation of industrial wastewaters for decades (Qureshi et al.
2005; Bryers 1993).
Some of the merits of biofilm reactors when compared to conventional treatment
processes includes decreased interruption in the bioreactor, enhanced concentration
and retention of biomass for long periods of time, better tolerance to harsh pollutants,
improved volumetric biodegradation capability, improved metabolic action, large
mass transfer area and improved process flow rates. It has been discovered that in
industrial set up, the biofilm reactors are utilized in situation where some freefloating microorganisms do not possess the capability to generate adequate biomass
or the biomass could not be retained for a longer period for effective volumetric
conversion. This happens when the microorganism growth is slower most especially
in the suspensions or when diluted feed streams are utilized in bioreactors. Moreover, in a typical biofilm reactor, there is a need for support medium for development
and adhesion of microbes.
9.5 Different Types of Biofilm Bioreactors
There are different types of biofilm bioreactors which entails biofilm airlift suspension batch reactors, expanded granular sludge blanket, continuous stirred tank,
fluidized bed, trickle bed, air-lift reactors and up flow anaerobic sludge blanket
(Qureshi et al. 2005; Bryers 1993; Rosche et al. 2009; Singh et al. 2006). Biofilm
reactors can be utilized for the bioremediation of off-site or applied for the nearby
contaminated sites. A packed bed reactor is typical designed based on the common
biofilm with solid supports that are arranged together with biofilm to give adequate
supports between the liquid and the biomass. A packed bed reactor entailing a
biofilm mercury-resistant strains has been adequately utilized for the ecorestoration
of mercury (Wagner-Dobler 2003).
Trickle-bed biofilm bioreactor is another type of biofilm-based reactor used for
the treatment of wastewater. Some of the examples of materials used as media in this
type of reactor include ceramics, plastics and rock where the biofilm could develop.
In trickle-bed biofilm bioreactor, waste water normally settles down from the top
through the distribution system over the biofilm surface held on a fixed media.
Normally, the pollutant available in the water will be metabolized as it passes
238
C. O. Adetunji and O. A. Anani
highlighted that polluted soil did not possess necessary endogenous microbial
degrading population or the availability of necessary conditions that could stimulate
the process of biodegradation that might be subjected to ex situ remediation frequently in a reactor.
It has been highlighted that in engineered systems, biofilms are applied in a
bioreactor in an inert support. The biofilm bioreactor is utilized for biochemical
conversion and biosorption of contaminants most especially from municipal wastewater, heavy metals, industrial wastewater and petroleum hydrocarbon (Boon et al.
2002). The bioreactor based on the application of biofilms is applied for the
commercial bioremediation of industrial wastewaters for decades (Qureshi et al.
2005; Bryers 1993).
Some of the merits of biofilm reactors when compared to conventional treatment
processes includes decreased interruption in the bioreactor, enhanced concentration
and retention of biomass for long periods of time, better tolerance to harsh pollutants,
improved volumetric biodegradation capability, improved metabolic action, large
mass transfer area and improved process flow rates. It has been discovered that in
industrial set up, the biofilm reactors are utilized in situation where some freefloating microorganisms do not possess the capability to generate adequate biomass
or the biomass could not be retained for a longer period for effective volumetric
conversion. This happens when the microorganism growth is slower most especially
in the suspensions or when diluted feed streams are utilized in bioreactors. Moreover, in a typical biofilm reactor, there is a need for support medium for development
and adhesion of microbes.
9.5 Different Types of Biofilm Bioreactors
There are different types of biofilm bioreactors which entails biofilm airlift suspension batch reactors, expanded granular sludge blanket, continuous stirred tank,
fluidized bed, trickle bed, air-lift reactors and up flow anaerobic sludge blanket
(Qureshi et al. 2005; Bryers 1993; Rosche et al. 2009; Singh et al. 2006). Biofilm
reactors can be utilized for the bioremediation of off-site or applied for the nearby
contaminated sites. A packed bed reactor is typical designed based on the common
biofilm with solid supports that are arranged together with biofilm to give adequate
supports between the liquid and the biomass. A packed bed reactor entailing a
biofilm mercury-resistant strains has been adequately utilized for the ecorestoration
of mercury (Wagner-Dobler 2003).
Trickle-bed biofilm bioreactor is another type of biofilm-based reactor used for
the treatment of wastewater. Some of the examples of materials used as media in this
type of reactor include ceramics, plastics and rock where the biofilm could develop.
In trickle-bed biofilm bioreactor, waste water normally settles down from the top
through the distribution system over the biofilm surface held on a fixed media.
Normally, the pollutant available in the water will be metabolized as it passes
238
C. O. Adetunji and O. A. Anani