Microbial Bioremediation and Different Bioreactors Designs Applied

*Memory Tekere*

#### **Abstract**

Microbial remediation of pollutants involves the use of microorganisms to degrade pollutants either completely to water and carbon dioxide (for organic pollutants) or into less toxic forms. In the case of nonbiodegradable inorganic compounds, bioremediation takes the form of bioaccumulation or conversion of one toxic species to a less toxic form for example Cr(VI) is converted to less toxic (III). Bioremediation is considered an environmentally friendly way for pollution cleanup. Microbial clean up can be applied *in situ* (in place of contamination) or *ex situ* (off the site of contamination). *In situ* remediation in the natural environment is deemed slow and often times difficult to control and optimize the different parameters affecting the bioremediation. To this end, use of engineered bioreactors is preferred. Engineered bioreactors providing for optimum conditions for microbial growth and biodegradation have been developed for use in bioremediation processes to achieve the different desired remediation goals. Bioreactors in use range in mode of operation from batch, continuous, and fed batch bioreactors and are designed to optimize microbial processes in relationship to contaminated media and nature of pollutant. Designed bioreactors for bioremediation range from packed, stirred tanks, airlift, slurry phase, and partitioning phase reactors amongst others.

**Keywords:** bioremediation, bioreactors, pollution, microorganisms, degradation

#### **1. Introduction**

Bioremediation is a natural process that relies on microorganisms and plants and/or their derivatives (enzymes or spent biomass) to degrade or alter environmental contaminants as these organisms carry out their normal life functions [1, 2]. Bioremediation is considered an economical, versatile, efficient and eco-friendly way of dealing with environmental pollutants as compared to the physico-chemical methods [1–3]. The use of well-designed microbial bioreactors is acknowledged as an efficient way to ensure that microbial growth and processes occur in a controlled environment that provides the necessary optimum conditions [3–5]. This chapter focuses on microbial remediation in bioreactors so phytoremediation as facilitated by plants is not discussed. Several studies describe microbial remediation in designed bioreactors ranging from batch, continuous, and fed-batch operated mode which can be in different designs such as suspended carrier, slurry and fixed bed, membrane and fluidized bed reactors [4–8].

The use of microbial bioreactors in remediation is very attractive in that the bioreactors offer the advantages of providing a controlled environment where it is possible to control critical process parameters to optimize the microbial bioremediation process. Another advantage is that there is flexibility in design of the bioreactor (size and configuration) to suit application or intended purpose of the reactor [6–9]. However, bioremediation in bioreactors if operated *ex situ*, requires relocation of pollutant, a process which can involve excavation for soils and sediments, transportation and possible containment or controlled handling of the contaminated media thus making the process expensive [4–6, 8, 9]. There is a potential for exposing other environments to the contamination. Also some pretreatment of contaminated media, e.g., drying and crushing, maybe required thus adding on to the process cost [8, 9].

#### **2. Microbial bioremediation**

As defined, microbial bioremediation makes use of microorganisms and/or their derivatives (enzymes or spent biomass) to clean-up environmental contaminants [7, 9, 10]. With microorganisms, it is important to note that microorganisms are everywhere and as such pollutants in the different environmental compartments always come into contact with microorganisms [1, 2]. Microbes break down/transform pollutants via their inherent metabolic processes with or without slight pathway modifications to allow the pollutant to be channeled into the normal microbial metabolic pathway for degradation/and biotransformation. Applied bioremediation methods therefore focus on tapping the naturally occurring microbial catabolic capabilities to degrade, transform or accumulate most of the synthetic compounds such as hydrocarbons (e.g., oil), polychlorinated biphenyls (PCBs), polyaromatic hydrocarbons (PAHs), radionuclides and metals [4, 6–8]. The natural existence of a large diversity of microbial species expands the variety of chemical pollutants that are degraded or detoxified.

The advantages of microbial bioremediation are that it has public acceptance, as it is a natural process [8]. It is a low cost technology in most cases when compared to other clean-up methods for hazardous waste [2]. It can be done *in situ* and *ex situ*, instead of contaminants being transferred from one form to another or one medium to another, complete destruction of target organic pollutants is possible [8]. Notable disadvantages are that bioremediation takes relatively long to achieve treatment goals, may not be effective on all contaminants, some products of biodegradation maybe more toxic or persistent than the parent compound, specificity of the biological processes with respect to microbial populations, pollutant and environmental limitations is also a drawback and that specialized expertise are required in designing and implementing.

Bioremediation using microbial bioreactors finds application in soil, air and water environments including:

• Waste water and industrial effluent treatment

Microorganisms are the primary agents of any biological wastewater treatment. Microorganisms are already present in waste water systems and feed on complex substances in the wastewater converting them to simpler substances thus assisting in achieving the treatment. Trickling filters, membrane bioreactors, slurry phase reactors and upflow anaerobic sludge blanket bioreactors (UASB) are some of the reactors that are used in waste water and industrial effluent treatment.

**119**

*Microbial Bioremediation and Different Bioreactors Designs Applied*

Contaminants successfully treated include diesel fuel, fuel oils, oily sludge, wood-preserving wastes (PCP, PAHs, and creosote), coke wastes, and certain pesticides [6, 8, 9]. Soil bioremediation has proven most successful in treating petroleum hydrocarbons and other less volatile, biodegradable contaminants. Slurry phase, stirred tanks, biofilters, partitioning phase and packed microbial reactors find

Microorganisms are used in the bioremediation of organic and inorganic air pollutants in spent gases before release or escape into the atmosphere [5, 9]. Microorganisms oxidize pollutants such as H2S, SO2, VOCs, and reduce pollutants such as NOx to nitrate and this assist to prevent likely environmental, health hazards and nuisances [5]. Bioscrubbers and biofilters are some of the bioreactor

Microorganisms are chiefly responsible for the biodegradation of organic wastes in nature and they drive the decomposition processes that occur in landfills and composts. Anaerobic digesters are often applied mostly in the biotreatment solid

A number of issues are at play in all bioremediation technologies including when bioreactors are used. These are those that concern the contaminant, microbial community and the design, optimization and monitoring of the process [6, 8, 9]. The microbial science of bioremediation is therefore approached from many scientific frontiers: abiotic interactions (solubility, transport, sorption and photolysis), biotic interactions (taxonomic diversity, physiological, genetic and ecological interactions). In the design and operation of bioreactors in remediation, many of these factors have to be optimized and controlled for best reactor performance [5, 10–12]. Variables that affect the operation and efficiency of a microbial bioreactor relate to biotic and abiotic factors that affect microbial growth and those factors that relate to the reactor design and configuration. Factors that affect microbial growth and activities in bioreactors include; environmental factors (temperature, pH, moisture), pollutant mix, pollutant concentration, macronutrient [5, 10–12]. Factors on reactor design include; size, configuration and mode of operation.

Environmental conditions (temperature, pH, oxygen availability/electron, and salinity) affect growth; the metabolic activities of microorganisms and to some extent the behavior of the pollutant such as solubility and volatility [11]. In any process optimization for biodegradation, it is always necessary to investigate the effects of the environmental conditions and optimize the process in relationship to all the relevant environmental conditions. Tekere et al. [13], established the optimum growth conditions with respect to pH, aeration and nutrients in the growth and degradation of pollutants by white rot fungi and found that optimized conditions

*DOI: http://dx.doi.org/10.5772/intechopen.83661*

application in contaminated soil remediation.

types often used in control of air pollution.

**2.1 Factors affecting microbial bioreactor performance**

• Soil and land treatment

• Control of air pollution

• Solid waste management

• Environmental related factors

result in high enzyme and degradation activities.

waste.

• Soil and land treatment

*Biotechnology and Bioengineering*

the process cost [8, 9].

**2. Microbial bioremediation**

are degraded or detoxified.

designing and implementing.

water environments including:

• Waste water and industrial effluent treatment

The use of microbial bioreactors in remediation is very attractive in that the bioreactors offer the advantages of providing a controlled environment where it is possible to control critical process parameters to optimize the microbial bioremediation process. Another advantage is that there is flexibility in design of the bioreactor (size and configuration) to suit application or intended purpose of the reactor [6–9]. However, bioremediation in bioreactors if operated *ex situ*, requires relocation of pollutant, a process which can involve excavation for soils and sediments, transportation and possible containment or controlled handling of the contaminated media thus making the process expensive [4–6, 8, 9]. There is a potential for exposing other environments to the contamination. Also some pretreatment of contaminated media, e.g., drying and crushing, maybe required thus adding on to

As defined, microbial bioremediation makes use of microorganisms and/or their derivatives (enzymes or spent biomass) to clean-up environmental contaminants [7, 9, 10]. With microorganisms, it is important to note that microorganisms are everywhere and as such pollutants in the different environmental compartments always come into contact with microorganisms [1, 2]. Microbes break down/transform pollutants via their inherent metabolic processes with or without slight pathway modifications to allow the pollutant to be channeled into the normal microbial metabolic pathway for degradation/and biotransformation. Applied bioremediation methods therefore focus on tapping the naturally occurring microbial catabolic capabilities to degrade, transform or accumulate most of the synthetic compounds such as hydrocarbons (e.g., oil), polychlorinated biphenyls (PCBs), polyaromatic hydrocarbons (PAHs), radionuclides and metals [4, 6–8]. The natural existence of a large diversity of microbial species expands the variety of chemical pollutants that

The advantages of microbial bioremediation are that it has public acceptance, as it is a natural process [8]. It is a low cost technology in most cases when compared to other clean-up methods for hazardous waste [2]. It can be done *in situ* and *ex situ*, instead of contaminants being transferred from one form to another or one medium to another, complete destruction of target organic pollutants is possible [8]. Notable disadvantages are that bioremediation takes relatively long to achieve treatment goals, may not be effective on all contaminants, some products of biodegradation maybe more toxic or persistent than the parent compound, specificity of the biological processes with respect to microbial populations, pollutant and environmental limitations is also a drawback and that specialized expertise are required in

Bioremediation using microbial bioreactors finds application in soil, air and

Microorganisms are the primary agents of any biological wastewater treatment. Microorganisms are already present in waste water systems and feed on complex substances in the wastewater converting them to simpler substances thus assisting in achieving the treatment. Trickling filters, membrane bioreactors, slurry phase reactors and upflow anaerobic sludge blanket bioreactors (UASB) are some of the reactors that are used in waste water and industrial effluent

**118**

treatment.

Contaminants successfully treated include diesel fuel, fuel oils, oily sludge, wood-preserving wastes (PCP, PAHs, and creosote), coke wastes, and certain pesticides [6, 8, 9]. Soil bioremediation has proven most successful in treating petroleum hydrocarbons and other less volatile, biodegradable contaminants. Slurry phase, stirred tanks, biofilters, partitioning phase and packed microbial reactors find application in contaminated soil remediation.

• Control of air pollution

Microorganisms are used in the bioremediation of organic and inorganic air pollutants in spent gases before release or escape into the atmosphere [5, 9]. Microorganisms oxidize pollutants such as H2S, SO2, VOCs, and reduce pollutants such as NOx to nitrate and this assist to prevent likely environmental, health hazards and nuisances [5]. Bioscrubbers and biofilters are some of the bioreactor types often used in control of air pollution.

• Solid waste management

Microorganisms are chiefly responsible for the biodegradation of organic wastes in nature and they drive the decomposition processes that occur in landfills and composts. Anaerobic digesters are often applied mostly in the biotreatment solid waste.

#### **2.1 Factors affecting microbial bioreactor performance**

A number of issues are at play in all bioremediation technologies including when bioreactors are used. These are those that concern the contaminant, microbial community and the design, optimization and monitoring of the process [6, 8, 9]. The microbial science of bioremediation is therefore approached from many scientific frontiers: abiotic interactions (solubility, transport, sorption and photolysis), biotic interactions (taxonomic diversity, physiological, genetic and ecological interactions). In the design and operation of bioreactors in remediation, many of these factors have to be optimized and controlled for best reactor performance [5, 10–12].

Variables that affect the operation and efficiency of a microbial bioreactor relate to biotic and abiotic factors that affect microbial growth and those factors that relate to the reactor design and configuration. Factors that affect microbial growth and activities in bioreactors include; environmental factors (temperature, pH, moisture), pollutant mix, pollutant concentration, macronutrient [5, 10–12]. Factors on reactor design include; size, configuration and mode of operation.

• Environmental related factors

Environmental conditions (temperature, pH, oxygen availability/electron, and salinity) affect growth; the metabolic activities of microorganisms and to some extent the behavior of the pollutant such as solubility and volatility [11]. In any process optimization for biodegradation, it is always necessary to investigate the effects of the environmental conditions and optimize the process in relationship to all the relevant environmental conditions. Tekere et al. [13], established the optimum growth conditions with respect to pH, aeration and nutrients in the growth and degradation of pollutants by white rot fungi and found that optimized conditions result in high enzyme and degradation activities.

#### • Temperature

There is always a temperature range at which microorganisms grow and survive (i.e., minimum, optimum and maximum survival temperature). In addition, there is always a temperature optimum at which biochemical processes take place to achieve required bio treatment by each microorganism [13]. Extremes of temperature (too low or too high) affect both microbial growth and microbial enzyme catalyzed reactions [2]. With an increase in temperature within appropriate range, microbial metabolism increases and thus the rate of the bioremediation processes.

Increased temperatures lead to higher solubility of many chemicals, and increased fluidity and diffusion rates. For example with pollutants, such as PAHs and heavy metals, their solubility and in turn bioavailability increases with temperature [2, 7]. Temperature is thus a critical factor in the optimum operating efficiency of bioreactors to achieve best biotreatment results. Often specialized bioreactors are designed with provision for temperature control.

• pH

Similar to temperature, pH affects microbial growth and metabolic processes. pH influences microbial cell ionic properties thus microbial growth. Microorganisms have minimum, optimum and maximum pH of growth with most bacteria for example growing optimally at pH 6–7.5, though there are some which thrive best at acidic pHs (acidophiles) or at alkaline pH (alkaliphiles). Fungi generally grow at pHs lower than that of bacteria. Reactor operating pH has to be set to provide the best pH conditions for growth and enzyme activities. Behavior of pollutants is also influenced by pH thus affecting their bioremediation. For example with metals, pH affects the redox and solubility of metals, different forms and valence have different effects on microorganisms [14]. Metal solubility increases with a decrease in medium pH and alkaline pH favor metal ion precipitation. Often lower pH values are required for metal attachment to the microbial cell surface [7, 14]. Microorganisms that produce acids result in increased solubility of the metal ions [10]. To provide for best pH conditions, buffers are used in media formulations, acids and bases can be added during the bioreactor process [13].

• Nutrients

Nutrients are required for growth and metabolism of the microorganisms. Several elements are required in biosynthesis and energy production. Carbon is the most basic element of living forms and is needed in greater quantities than other elements. Other elements that are important in ensuring a balanced nutritional bioreactor environment depending on the type of microorganism include hydrogen, oxygen, nitrogen, sulfur, phosphorus, iron, calcium and magnesium [10, 11]. All necessary macro- and micro- nutrients requirements are provided in reactor media. Microorganisms can use the pollutants they are degrading as primary energy sources or a primary source of energy is provided to the microorganism in the case of co metabolism of the pollutants.

• Moisture

Water is required to support microbial growth and catalysis. Cellular chemical reactions occur in aqueous conditions and water is required to ensure the correct osmotic pressure is maintained for microbial growth. The amount of water available

**121**

*Microbial Bioremediation and Different Bioreactors Designs Applied*

for microbial growth is called (aW). Most microorganisms grow at water activities of 0.98 or higher, osmotolerant species can however grow at a range of low aW [11].

The presence of electron acceptors, e.g., oxygen in aerobic microbes and NO3

Bioreactors have to provide for the best conditions for microbial growth and biochemical process to occur. The reactor size, configuration and mode of operation are key reactor design factors. The reactor should provide favorable physical, biological and the combined physical-chemical conditions for the best biological remediation processes to be achieved. In designing the bioreactor, favorable physical conditions for transport of gases and liquids and solids over time that ensure that the physical entity of the bioreactor is favorably adapted to the biological system that performs the bioreactions are required [12, 15]. On the other hand there is need to ensure that the biophysical and biochemical events taking operate at optimum

Polluted samples for remediation can be fed into the reactor either as dry or slurry matter [9]. Pollutants with hydrophobic properties are often unavailable for microbial degradation, particularly if they are bound to soil matrix [7]. Their degradation is therefore limited by their transfer to liquid [4]. Minimizing mass transfer resistance was found to be a key factor in the degradation of hexachlorocy-

Despite the rapid development of bioreactors due to their widespread use in biotechnology, the aspects of maintaining stability and rates of bioprocesses are still areas to be addressed. Poor bioreactor construction and design, leading to inadequate mixing, may jeopardize the stability and performance of the process [15]. Mixing prevents thermal stratification, help maintain uniform conditions in the reactor, ensure good contact between microbial culture and media reactants. The importance of mixing in bioreactor cannot be over emphasized, poor mixing affect

Hydraulic retention times (HRT) required to achieve the necessary remediation goals in the bioreactor have to be determined and optimized. Longer HRTs result in poor substrate loading which diminishes the microbial population, whereas shorter ones do not allow microorganisms to effectively degrade the pollutant and can result

Organism related factors include population density, composition, inter and intraspecific interaction. Microbes are the most diverse forms of life and have developed a wide range of metabolic pathways that enable them to cope under the varying ecological conditions including exposure to xenobiotics. A whole range of environments ranging from aerobic, anaerobic, acidic, alkaline, and low to high temperature have been utilized as sources of microorganisms for bioremediation [13]. Only certain species of bacteria and fungi have proven their ability as potent pollutant degraders [13]. In the natural environment degradation of pollutants is often achieved through complex microbial population interactions. Single or mixed microbial cultures are used for pollutant remediation in bioreactors. In the event

<sup>2</sup><sup>−</sup> and Fe (III) oxides in case of anaerobic microbes, also affects the biodegrada-

<sup>1</sup><sup>−</sup>,

*DOI: http://dx.doi.org/10.5772/intechopen.83661*

• Reactor design related factors

levels under real situation application.

microbial process efficiency.

• Organism related factors

clohexane (HCH) in slurry batch bioreactors [4].

in microbial wash out from the system [16].

• Electron acceptors

SO4

tion processes.

for microbial growth is called (aW). Most microorganisms grow at water activities of 0.98 or higher, osmotolerant species can however grow at a range of low aW [11].

• Electron acceptors

*Biotechnology and Bioengineering*

There is always a temperature range at which microorganisms grow and survive

(i.e., minimum, optimum and maximum survival temperature). In addition, there is always a temperature optimum at which biochemical processes take place to achieve required bio treatment by each microorganism [13]. Extremes of temperature (too low or too high) affect both microbial growth and microbial enzyme catalyzed reactions [2]. With an increase in temperature within appropriate range, microbial metabolism increases and thus the rate of the bioremediation processes. Increased temperatures lead to higher solubility of many chemicals, and increased fluidity and diffusion rates. For example with pollutants, such as PAHs and heavy metals, their solubility and in turn bioavailability increases with temperature [2, 7]. Temperature is thus a critical factor in the optimum operating efficiency of bioreactors to achieve best biotreatment results. Often specialized

Similar to temperature, pH affects microbial growth and metabolic processes. pH influences microbial cell ionic properties thus microbial growth. Microorganisms have minimum, optimum and maximum pH of growth with most bacteria for example growing optimally at pH 6–7.5, though there are some which thrive best at acidic pHs (acidophiles) or at alkaline pH (alkaliphiles). Fungi generally grow at pHs lower than that of bacteria. Reactor operating pH has to be set to provide the best pH conditions for growth and enzyme activities. Behavior of pollutants is also influenced by pH thus affecting their bioremediation. For example with metals, pH affects the redox and solubility of metals, different forms and valence have different effects on microorganisms [14]. Metal solubility increases with a decrease in medium pH and alkaline pH favor metal ion precipitation. Often lower pH values are required for metal attachment to the microbial cell surface [7, 14]. Microorganisms that produce acids result in increased solubility of the metal ions [10]. To provide for best pH conditions, buffers are used in media formulations, acids and bases can be added during the

Nutrients are required for growth and metabolism of the microorganisms. Several elements are required in biosynthesis and energy production. Carbon is the most basic element of living forms and is needed in greater quantities than other elements. Other elements that are important in ensuring a balanced nutritional bioreactor environment depending on the type of microorganism include hydrogen, oxygen, nitrogen, sulfur, phosphorus, iron, calcium and magnesium [10, 11]. All necessary macro- and micro- nutrients requirements are provided in reactor media. Microorganisms can use the pollutants they are degrading as primary energy sources or a primary source of energy is provided to the microorganism in the case

Water is required to support microbial growth and catalysis. Cellular chemical reactions occur in aqueous conditions and water is required to ensure the correct osmotic pressure is maintained for microbial growth. The amount of water available

bioreactors are designed with provision for temperature control.

• Temperature

• pH

bioreactor process [13].

of co metabolism of the pollutants.

• Nutrients

• Moisture

**120**

The presence of electron acceptors, e.g., oxygen in aerobic microbes and NO3 <sup>1</sup><sup>−</sup>, SO4 <sup>2</sup><sup>−</sup> and Fe (III) oxides in case of anaerobic microbes, also affects the biodegradation processes.

• Reactor design related factors

Bioreactors have to provide for the best conditions for microbial growth and biochemical process to occur. The reactor size, configuration and mode of operation are key reactor design factors. The reactor should provide favorable physical, biological and the combined physical-chemical conditions for the best biological remediation processes to be achieved. In designing the bioreactor, favorable physical conditions for transport of gases and liquids and solids over time that ensure that the physical entity of the bioreactor is favorably adapted to the biological system that performs the bioreactions are required [12, 15]. On the other hand there is need to ensure that the biophysical and biochemical events taking operate at optimum levels under real situation application.

Polluted samples for remediation can be fed into the reactor either as dry or slurry matter [9]. Pollutants with hydrophobic properties are often unavailable for microbial degradation, particularly if they are bound to soil matrix [7]. Their degradation is therefore limited by their transfer to liquid [4]. Minimizing mass transfer resistance was found to be a key factor in the degradation of hexachlorocyclohexane (HCH) in slurry batch bioreactors [4].

Despite the rapid development of bioreactors due to their widespread use in biotechnology, the aspects of maintaining stability and rates of bioprocesses are still areas to be addressed. Poor bioreactor construction and design, leading to inadequate mixing, may jeopardize the stability and performance of the process [15]. Mixing prevents thermal stratification, help maintain uniform conditions in the reactor, ensure good contact between microbial culture and media reactants. The importance of mixing in bioreactor cannot be over emphasized, poor mixing affect microbial process efficiency.

Hydraulic retention times (HRT) required to achieve the necessary remediation goals in the bioreactor have to be determined and optimized. Longer HRTs result in poor substrate loading which diminishes the microbial population, whereas shorter ones do not allow microorganisms to effectively degrade the pollutant and can result in microbial wash out from the system [16].

• Organism related factors

Organism related factors include population density, composition, inter and intraspecific interaction. Microbes are the most diverse forms of life and have developed a wide range of metabolic pathways that enable them to cope under the varying ecological conditions including exposure to xenobiotics. A whole range of environments ranging from aerobic, anaerobic, acidic, alkaline, and low to high temperature have been utilized as sources of microorganisms for bioremediation [13]. Only certain species of bacteria and fungi have proven their ability as potent pollutant degraders [13]. In the natural environment degradation of pollutants is often achieved through complex microbial population interactions. Single or mixed microbial cultures are used for pollutant remediation in bioreactors. In the event

where bioagumentation is applied the introduced organisms need to be able to coexist with indigenous residents.

Different microorganisms often have different metabolic capabilities, to this extend the evaluation of several strains of different microbial players have to be investigated in order to come up with the best degraders [13]. In screening and comparison of the bio-degradation of PAHs by white rot fungi [17], found out that newly screened white rot fungi strains had higher or comparable degradation capacity to the model well applauded *P. chrysosporium*, and these strains did not accumulate the metabolite quinone which accumulates as a dead end metabolite in *P. chrysosporium.*

Polluted environments provide sources of microorganisms resistant or acclimatized to the pollutant [18]. However microorganisms that are known to have certain inherent physiological characteristic, e.g., metabolism of known substrate with structural similarity to xenobiotics of interest and/or adaptation to certain environmental conditions can be selected. This is the case in several studies that used microorganisms for pollutant degradation [11, 17–19].

• Pollutant related factors

Factors that affect bioremediation in bioreactors that are related to the pollutant include: nature of pollutant, i.e., the physical and chemical properties including solubility, volatility, molecular complexity, concentration and toxicity. Investigations for most pollutant biodegradation have centered on how different concentrations, mixed pollutants, solubility and molecular structure can affect microbial bioremediation [17, 20]. In the case of PAHs, degradation decreases in the order alkane> branched chain alkanes>low molecular weight aromatics> cycloalkanes [17]. It should be noted however that some pollutants are resistant to biodegradation (recalcitrant, i.e., resistant to degradation) they are degraded at very low pace even if the right microbial population and conditions are present.

#### **3. Microbial bioreactors in bioremediation**

Several laboratory, and pilot bioremediation studies have been done using microbial (fungi and bacteria) bioreactors [6, 8, 17, 18, 20]. Bioreactor technologies may offer effective means for treatment of many contaminants in groundwater, soil and air [4, 5, 7, 12]. The bioreactor type of choice for any application should be easy to operate and maintain for the selected purpose and application. **Table 1** presents some of the studies that involved the use of bioreactors in bioremediation. Flexibility to design bioreactor tailor made for different processes and remediation applications makes the use of bioreactors in bioremediation attractive [9]. The design should accommodate high biomass from cell growth, supply of necessary nutrients and also removal of waste components from the system. A description of some bioreactor types and their application is given in Sections 3.1–3.7.

#### **3.1 Slurry phase bioreactors**

Slurry phase bioreactors, as the name implies treats polluted media that is within a slurry phase. Alternative names are bio-slurry reactors and slurry phase biological treatment. Slurry bioreactors offer an *ex situ* environmentally friendly way for remediating mostly soils and sediments from petrochemical hydrocarbons, tars, creosotes, chlorinated solvents, herbicides, pesticides and explosives or when a solid substrate that is formulated into a slurry is used [4, 6, 25, 26]. Hydrophobic nature

**123**

accessible for biodegradation.

*Studies that involved the use of bioreactors in bioremediation.*

bioreactors in bioremediation.

**3.2 Partitioning bioreactors**

*Microbial Bioremediation and Different Bioreactors Designs Applied*

compounds

Packed bed Different fungi and bacteria used for remediation of

Slurry phase Bacterial and fungal remediation of soil from VOC,

PAHs, textile dyes.

Membrane bioreactor Textile dye in waste water; pharmaceuticals,

Suspended carrier Fungi used for remediation of organochlorine pesticides,

groundwater; metal recovery

Biotrickling filter Municipal waste water, brewery waste, olive oil mill waste water, VOC contaminated air

effluent, cellulose industry bleaching effluent

Air lift Textile dye effluent decolorization by fungi, olive mill

**Bioreactor type Application details Reference(s)**

Fluidised bed Treatment of pharmaceuticals using fungi [20, 22]

organochlorines, PAHs, 2,4-dichlorophenoxyacetic acid

organochlorine pesticides, PAHs, pharmaceuticals, amines, and textile dyes. Packing material varied from organic material (sawdust, wood chips) to inert solid materials (polyurethane foam, poraver stones); chlorinated aliphatic

Benzene biodegradation by cow dung microflora [24]

Bacterial degradation of tylosin [16]

Potato waste water, BTEX [9, 35]

Nanosilver, Nanofullerenes [36]

PCP and creosote by some Pseudomonas species [37]

Degradation of phenol by fungal laccase [38]

1,2-dichloroethane, 1,2-dichlorobenzene and 2-chlorophenol

[14, 17, 21–23]

[4, 6, 25, 26]

[21]

[27–31]

[15, 32, 33]

[32, 34]

[7, 8]

of most persistent chemicals makes them sorb to soil or sediments and not easily

Operation of the slurry reactor can be in batch, semi-continuous and continuous mode, with the batch process being the most common one [6, 26]. **Figure 1** shows an illustration of a simplified slurry reactor. Water is mixed with the contaminated solid matrix in suitable ratios and this enhances contact between microorganisms, pollutant, media and oxygen. Pollutants that are solubilized become more bioavailable. **Table 2** shows some of the studies that have involved the use of slurry phase

For hydrocarbon-rich industrial wastewater effluents by mixed microbial cultures, petroleum hydrocarbon

Partitioning bioreactors are used in bioremediation when two phases need to be achieved, e.g., such as for organic solvents or water immiscible compounds in

*DOI: http://dx.doi.org/10.5772/intechopen.83661*

Two-phase partitioning

Up-flow anaerobic stage reactor (UASR)

Upflow Anaerobic Sludge Blanket

Sequence batch reactor

Continuous flow Bioreactor

Nonisothermal bioreactors

**Table 1.**

Continuously stirred tank bioreactor (CSTR)

*Microbial Bioremediation and Different Bioreactors Designs Applied DOI: http://dx.doi.org/10.5772/intechopen.83661*


#### **Table 1.**

*Biotechnology and Bioengineering*

exist with indigenous residents.

• Pollutant related factors

**3.1 Slurry phase bioreactors**

*P. chrysosporium.*

where bioagumentation is applied the introduced organisms need to be able to co-

Different microorganisms often have different metabolic capabilities, to this extend the evaluation of several strains of different microbial players have to be investigated in order to come up with the best degraders [13]. In screening and comparison of the bio-degradation of PAHs by white rot fungi [17], found out that newly screened white rot fungi strains had higher or comparable degradation capacity to the model well applauded *P. chrysosporium*, and these strains did not accumulate the metabolite quinone which accumulates as a dead end metabolite in

Polluted environments provide sources of microorganisms resistant or acclimatized to the pollutant [18]. However microorganisms that are known to have certain inherent physiological characteristic, e.g., metabolism of known substrate with structural similarity to xenobiotics of interest and/or adaptation to certain environmental conditions can be selected. This is the case in several studies that used

Factors that affect bioremediation in bioreactors that are related to the pollutant include: nature of pollutant, i.e., the physical and chemical properties including solubility, volatility, molecular complexity, concentration and toxicity. Investigations for most pollutant biodegradation have centered on how different concentrations, mixed pollutants, solubility and molecular structure can affect microbial bioremediation [17, 20]. In the case of PAHs, degradation decreases in the order alkane> branched chain alkanes>low molecular weight aromatics> cycloalkanes [17]. It should be noted however that some pollutants are resistant to biodegradation (recalcitrant, i.e., resistant to degradation) they are degraded at very low

Several laboratory, and pilot bioremediation studies have been done using microbial (fungi and bacteria) bioreactors [6, 8, 17, 18, 20]. Bioreactor technologies may offer effective means for treatment of many contaminants in groundwater, soil and air [4, 5, 7, 12]. The bioreactor type of choice for any application should be easy to operate and maintain for the selected purpose and application. **Table 1** presents some of the studies that involved the use of bioreactors in bioremediation. Flexibility to design bioreactor tailor made for different processes and remediation applications makes the use of bioreactors in bioremediation attractive [9]. The design should accommodate high biomass from cell growth, supply of necessary nutrients and also removal of waste components from the system. A description of

pace even if the right microbial population and conditions are present.

some bioreactor types and their application is given in Sections 3.1–3.7.

Slurry phase bioreactors, as the name implies treats polluted media that is within a slurry phase. Alternative names are bio-slurry reactors and slurry phase biological treatment. Slurry bioreactors offer an *ex situ* environmentally friendly way for remediating mostly soils and sediments from petrochemical hydrocarbons, tars, creosotes, chlorinated solvents, herbicides, pesticides and explosives or when a solid substrate that is formulated into a slurry is used [4, 6, 25, 26]. Hydrophobic nature

microorganisms for pollutant degradation [11, 17–19].

**3. Microbial bioreactors in bioremediation**

**122**

*Studies that involved the use of bioreactors in bioremediation.*

of most persistent chemicals makes them sorb to soil or sediments and not easily accessible for biodegradation.

Operation of the slurry reactor can be in batch, semi-continuous and continuous mode, with the batch process being the most common one [6, 26]. **Figure 1** shows an illustration of a simplified slurry reactor. Water is mixed with the contaminated solid matrix in suitable ratios and this enhances contact between microorganisms, pollutant, media and oxygen. Pollutants that are solubilized become more bioavailable. **Table 2** shows some of the studies that have involved the use of slurry phase bioreactors in bioremediation.

#### **3.2 Partitioning bioreactors**

Partitioning bioreactors are used in bioremediation when two phases need to be achieved, e.g., such as for organic solvents or water immiscible compounds in

**Figure 1.** *Simplified slurry reactor [26].*

aqueous solutions. Reactors are designed with the aqueous and organic phase, and can be single or multiphased [24]. With toxic hazardous waste, toxicity to degrading microorganisms is a problem. In partitioning bioreactors, there is a two-phase system where a water immiscible and biocompatible organic solvent is allowed to float on the surface of a cell containing aqueous phase [45]. This means that high amounts of hazardous waste dissolved in a solvent can be added to the reactor without the microorganism experiencing inhibitory concentrations of the pollutant [24, 45, 46]. A rigorous process involving selection of the solvent, taking into consideration the biological, physical, operational, environmental and economic factors is necessary in developing an efficient partitioning biotreatment system. Partitioning reactors find application in the remediation of toxic compounds from petrochemical industry such as benzene as well as VOC in waste gases of many industrial processes [45, 47, 48]. Angelucci et al. [49], successfully tested a continuous two-phase-partitioning reactor in the treatment of tannery wastewater. Several other studies involving phase partitioning bioreactors are described [24, 45–50].

#### **3.3 Stirred tank bioreactors**

A continuous stirred tank bioreactor consists of a cylindrical vessel with motor driven central shaft that supports one or more agitators (impellers). Stirred tank bioreactors are the predominantly used design for submerged cultures. Stirred tank bioreactors are mechanically agitated where the stirrers are the main gas-dispersing tools and provide high values of mass transfer rates coupled with excellent mixing. Advantages of the STR include the efficient gas transfer to growing cells, good mixing of the contents and flexible operating conditions, besides the commercial availability of the bioreactors. The main shortcoming of the stirred tank bioreactor is its mechanical agitation which requires energy and stirring can cause shear strain on microbial cells.

Gargouri et al. [7] evaluated the use of a continuously stirred tank bioreactor (CSTR) in the treatment of hydrocarbon-rich industrial wastewaters and achieved

**125**

**3.4 Biofilters**

**Table 2.**

*Microbial Bioremediation and Different Bioreactors Designs Applied*

conditions

species

*adusta*

Chlorpyrifos Enriched indigenous soil

*Some examples of remediation studies in slurry phase bioreactor.*

microorganism

PAHs in creosote Degradation by *Pseudomonas* 

Indigenous microbial consortium

Mixed soil bacteria under anoxic/microaerophilic

*fluorescens, Pseudomonas stutzeri,* and an *Alcaligenes*

Selected Gram positive bacterial isolates

White rot fungi *Bjerkandera* 

PAH-degrading consortium Pyrene degraded

**Pollutant Microorganism(s) Bioremediation details Reference(s)**

24% biodegradation of Total Petroleum Hydrocarbon in oily

99% of 10,000 mg kg<sup>−</sup><sup>1</sup> was degraded in 82 days under co-metabolism with molasses

93.4% of creosote degraded in 12 weeks

Complete removal of the explosive after

Maximal degradations of 94.5, 78.5 and 66.1% were attained after 30 days for the-HCH isomers, respectively

> day<sup>−</sup><sup>1</sup> ,

 day<sup>−</sup><sup>1</sup> .

Degradation of 48% in aerobic and 31% in anaerobic soil slurries

80 days

at 19 mg L<sup>−</sup><sup>1</sup>

chrysene and benzo[*a*]pyrene respectively at 3.5 and 0.94 mg L<sup>−</sup><sup>1</sup>

[39]

[40]

[41]

[42]

[4]

[43]

[44]

waste

successful bioremediation using an acclimatized microbial consortium. The residual total petroleum hydrocarbon (TPH) decreased from 320 –8 mg TPH l<sup>−</sup><sup>1</sup>

The reactor used is shown in **Figure 2**. Bi [51], applied a continuously stirred tank reactor for bioremediation of ethanol, toluene and benzyl alcohol by *P. putida*.

A basic biofilter bioreactor consist of a large media bed where pollutants are passed through and get degraded by the microorganisms. Biofilters are amongst the oldest environmental bioremediation techniques. Biofilters are used mostly in waste water treatment as well as in the control of air pollution [34, 52, 53]. A number of materials are used for bed media such as peat, composted yard waste, bark, coarse soil, gravel or plastic shapes. A typical example of a biofilter is the trickling filter which finds extensive application in the treatment of different liquid effluents or waste waters or waste that is constituted into liquid. A trickling filter is usually a round, vertical tank that contains a support rack and is filled with aggregate, ceramic or plastic media and in the middle of the tank is a vertical pipe that has a rotary connection with spray nozzles on the top end [34]. A spray arm is attached to the rotary connection and has spray nozzles installed along its length for

.

*DOI: http://dx.doi.org/10.5772/intechopen.83661*

Petroleum hydrocarbons

2,4,6-trinitrotoluene

in oil sludge

(TNT)

Explosives 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrobenzene

(TNB)

(HCH)

PAH in soil

Hexachlorocyclohexane

High molecular weight


*Microbial Bioremediation and Different Bioreactors Designs Applied DOI: http://dx.doi.org/10.5772/intechopen.83661*

#### **Table 2.**

*Biotechnology and Bioengineering*

aqueous solutions. Reactors are designed with the aqueous and organic phase, and can be single or multiphased [24]. With toxic hazardous waste, toxicity to degrading microorganisms is a problem. In partitioning bioreactors, there is a two-phase system where a water immiscible and biocompatible organic solvent is allowed to float on the surface of a cell containing aqueous phase [45]. This means that high amounts of hazardous waste dissolved in a solvent can be added to the reactor without the microorganism experiencing inhibitory concentrations of the pollutant [24, 45, 46]. A rigorous process involving selection of the solvent, taking into consideration the biological, physical, operational, environmental and economic factors is necessary in developing an efficient partitioning biotreatment system. Partitioning reactors find application in the remediation of toxic compounds from petrochemical industry such as benzene as well as VOC in waste gases of many industrial processes [45, 47, 48]. Angelucci et al. [49], successfully tested a continuous two-phase-partitioning reactor in the treatment of tannery wastewater. Several other studies involving phase partitioning bioreactors are described [24, 45–50].

A continuous stirred tank bioreactor consists of a cylindrical vessel with motor driven central shaft that supports one or more agitators (impellers). Stirred tank bioreactors are the predominantly used design for submerged cultures. Stirred tank bioreactors are mechanically agitated where the stirrers are the main gas-dispersing tools and provide high values of mass transfer rates coupled with excellent mixing. Advantages of the STR include the efficient gas transfer to growing cells, good mixing of the contents and flexible operating conditions, besides the commercial availability of the bioreactors. The main shortcoming of the stirred tank bioreactor is its mechanical agitation which requires energy and stirring can cause shear strain

Gargouri et al. [7] evaluated the use of a continuously stirred tank bioreactor (CSTR) in the treatment of hydrocarbon-rich industrial wastewaters and achieved

**124**

**Figure 1.**

*Simplified slurry reactor [26].*

on microbial cells.

**3.3 Stirred tank bioreactors**

*Some examples of remediation studies in slurry phase bioreactor.*

successful bioremediation using an acclimatized microbial consortium. The residual total petroleum hydrocarbon (TPH) decreased from 320 –8 mg TPH l<sup>−</sup><sup>1</sup> . The reactor used is shown in **Figure 2**. Bi [51], applied a continuously stirred tank reactor for bioremediation of ethanol, toluene and benzyl alcohol by *P. putida*.

#### **3.4 Biofilters**

A basic biofilter bioreactor consist of a large media bed where pollutants are passed through and get degraded by the microorganisms. Biofilters are amongst the oldest environmental bioremediation techniques. Biofilters are used mostly in waste water treatment as well as in the control of air pollution [34, 52, 53]. A number of materials are used for bed media such as peat, composted yard waste, bark, coarse soil, gravel or plastic shapes. A typical example of a biofilter is the trickling filter which finds extensive application in the treatment of different liquid effluents or waste waters or waste that is constituted into liquid. A trickling filter is usually a round, vertical tank that contains a support rack and is filled with aggregate, ceramic or plastic media and in the middle of the tank is a vertical pipe that has a rotary connection with spray nozzles on the top end [34]. A spray arm is attached to the rotary connection and has spray nozzles installed along its length for

**Figure 2.**

*Schematic diagram of the aerobic continuously stirred tank bioreactor (CSTR) used for continuous experiments [7].*

distribution of the waste water. Microorganisms grow in biofilm forms on the packing material surface and are responsible for the degradation of the pollutants from the effluent. Schmidt and Anderson [34] described the use of a trickling biofilter in the removal of high concentrations of 1-butanol from contaminated air. The potential application of the biotrickling filter in industrial off gas treatment was evaluated in the removal of high concentrations of 1-butanol from contaminated air with efficiency exceeding 80% for butanol concentrations of 0.4–1.2 g m<sup>−</sup><sup>3</sup> [34]. The laboratory-scale perlite-packed biotrickling filter was operated for 60 days and demonstrated effective and efficient removal of butanol concentrations up to 4.65 g m<sup>−</sup><sup>3</sup> with a maximum elimination capacity of 100 g m<sup>−</sup><sup>3</sup> h<sup>−</sup><sup>1</sup> [34].

#### **3.5 Packed bed bioreactors**

Packed bed bioreactor systems provide for microbial growth on fixed film substrata. In order to obtain compact reactors and ensure greater treatment reliability, fixed film reactors are used. They offer the advantage that dilute aqueous solutions can be remediated at high biomass without the need to separate biomass and the treated effluent [13, 54]. In packed bed biofilm biotreatment processes, unlike suspension cultures there is no need to incorporate special measures such as centrifugation and membrane filters to retain the biomass. This feature makes the use of packed bed reactors particularly appropriate in bioreactors systems where large substrate—flow through is required. The concentration of cells in a given volume may be increased, a factor that leads to enhanced efficiency/productivity of the bioreactor and decreased volume of bioreactors [55]. While high biomass concentrations can be easily maintained, the medium to biofilm mass transfer of substrate is the rate limiting process in packed bed bioreactors [54, 56]. Within the biofilm there are considerable differences in the microorganisms' microenvironment, depending on the distance from the surface of the biofilm [54]. Substrates such as

**127**

**Table 3.**

Polyurethane foam and alginate beads

*Microbial Bioremediation and Different Bioreactors Designs Applied*

oxygen, carbon and nitrogen sources have to cross the biofilm—liquid interface by diffusion, thus a diffusion gradient occurs. To calculate the kinetics of conversion in the biofilm processes, two important processes that occur in the system are considered and these are (i) transport of solutes over the biofilm and (ii) combined reactions and diffusion inside the biofilm [54]. In the packed bed reactors, development of excess microbial biomass also occurs leading to hydraulic channeling or loss of interstitial fluid volume. To overcome the severe constraints of hydraulic hold up within the interior of the reactor extra-capillary space transverse flow bioreactors

Selection of suitable substances as packing materials is an important consideration. Materials that have been used include nylon web, polyurethane foam, silicone tubing, sintered glass, porous ceramics, propylene, stainless steel, agarose and agar gel beads [58–67]. The ideal support should be chemically inert in physiological growth medium, rigid and porous to facilitate mycelial attachment and re-usable after removal of the fungus. **Figure 4** shows a Simplified diagram of a laboratory based packed bed bioreactor. Examples of remediation studies in packed bed reactors are given in **Table 3**.

Airlift bioreactors can provide an attractive treatment alternative for treatment of gaseous or volatile air pollutants. Frequently, the most limiting factor in the performance of these reactors is that they are susceptible to being limited by gas-liquid mass transfer and by poor mixing of the liquid phase, particularly when they are operating at high cell densities [68, 69]. The bioreactor performance is dependent on the pumping (injection) of air and the liquid circulation. The airlift bioreactor can have a forced

**Support Experimental study details References**

Benzene, toluene, ethylbenzene, and xylene, BTEX removal

bioreactors by *Brevibacillus parabrevis.* A 95.71% removal of in

packed bed bioreactors, removal at 89% for up to 145.4 mg L<sup>−</sup><sup>1</sup>

*weberianum* B-18 immobilized in a lab-scale packed-bed

Benzene biodegradation Bacillus sp. M3 at 84 in alginate beads

at 0.3 h retention time

and 90% on polyurethane foam within 9 days

of simulated effluent dye.

[58]

[59]

[60]

[61]

[64]

[66]

[66]

[67]

reduced to

Polyurethane foam Anaerobic fixed film horizontal flow bench scale reactor.

with efficiency of 75–99% in 11.4 hrs

Laterite stones Microbial consortium anaerobic degradation of textile azo dyes, 61.7% degradation of 55 μg mL<sup>−</sup><sup>1</sup>

Coconut shell bio-char Congo red dye degradation in batch and continuous packed bed

Polyurethane foam Bacterial degradation of malathion in batch and continuous

Sugarcane bagasse Degradation of dyes and industrial effluents by *Garnoderma* 

Celite Perchlorate-Contaminated groundwater 800 μg L<sup>−</sup><sup>l</sup>

Polyurethane foam Biodegradation of an actual petroleum wastewater by an immobilized biomass of *Bacillus cereus*

less than 4 μ−<sup>1</sup>

*Some examples of remediation studies in packed bed reactors.*

Wire Mesh Fungal degradation of textile effluent [62] Wood chips Chlorophenol degradation by *Phanerochaete chrysosporium* [63]

bioreactor. 55–98% for different dyes tested

6 days of 150 ppm dye.

day<sup>−</sup><sup>1</sup>

*DOI: http://dx.doi.org/10.5772/intechopen.83661*

were developed [57].

**3.6 Airlift bioreactors**

#### *Microbial Bioremediation and Different Bioreactors Designs Applied DOI: http://dx.doi.org/10.5772/intechopen.83661*

oxygen, carbon and nitrogen sources have to cross the biofilm—liquid interface by diffusion, thus a diffusion gradient occurs. To calculate the kinetics of conversion in the biofilm processes, two important processes that occur in the system are considered and these are (i) transport of solutes over the biofilm and (ii) combined reactions and diffusion inside the biofilm [54]. In the packed bed reactors, development of excess microbial biomass also occurs leading to hydraulic channeling or loss of interstitial fluid volume. To overcome the severe constraints of hydraulic hold up within the interior of the reactor extra-capillary space transverse flow bioreactors were developed [57].

Selection of suitable substances as packing materials is an important consideration. Materials that have been used include nylon web, polyurethane foam, silicone tubing, sintered glass, porous ceramics, propylene, stainless steel, agarose and agar gel beads [58–67]. The ideal support should be chemically inert in physiological growth medium, rigid and porous to facilitate mycelial attachment and re-usable after removal of the fungus. **Figure 4** shows a Simplified diagram of a laboratory based packed bed bioreactor. Examples of remediation studies in packed bed reactors are given in **Table 3**.

#### **3.6 Airlift bioreactors**

*Biotechnology and Bioengineering*

distribution of the waste water. Microorganisms grow in biofilm forms on the packing material surface and are responsible for the degradation of the pollutants from the effluent. Schmidt and Anderson [34] described the use of a trickling biofilter in the removal of high concentrations of 1-butanol from contaminated air. The potential application of the biotrickling filter in industrial off gas treatment was evaluated in the removal of high concentrations of 1-butanol from contaminated air with efficiency exceeding 80% for butanol concentrations of 0.4–1.2 g m<sup>−</sup><sup>3</sup>

*Schematic diagram of the aerobic continuously stirred tank bioreactor (CSTR) used for continuous* 

The laboratory-scale perlite-packed biotrickling filter was operated for 60 days and demonstrated effective and efficient removal of butanol concentrations up to

Packed bed bioreactor systems provide for microbial growth on fixed film substrata. In order to obtain compact reactors and ensure greater treatment reliability, fixed film reactors are used. They offer the advantage that dilute aqueous solutions can be remediated at high biomass without the need to separate biomass and the treated effluent [13, 54]. In packed bed biofilm biotreatment processes, unlike suspension cultures there is no need to incorporate special measures such as centrifugation and membrane filters to retain the biomass. This feature makes the use of packed bed reactors particularly appropriate in bioreactors systems where large substrate—flow through is required. The concentration of cells in a given volume may be increased, a factor that leads to enhanced efficiency/productivity of the bioreactor and decreased volume of bioreactors [55]. While high biomass concentrations can be easily maintained, the medium to biofilm mass transfer of substrate is the rate limiting process in packed bed bioreactors [54, 56]. Within the biofilm there are considerable differences in the microorganisms' microenvironment, depending on the distance from the surface of the biofilm [54]. Substrates such as

with a maximum elimination capacity of 100 g m<sup>−</sup><sup>3</sup>

[34].

 h<sup>−</sup><sup>1</sup> [34].

**126**

4.65 g m<sup>−</sup><sup>3</sup>

**Figure 2.**

*experiments [7].*

**3.5 Packed bed bioreactors**

Airlift bioreactors can provide an attractive treatment alternative for treatment of gaseous or volatile air pollutants. Frequently, the most limiting factor in the performance of these reactors is that they are susceptible to being limited by gas-liquid mass transfer and by poor mixing of the liquid phase, particularly when they are operating at high cell densities [68, 69]. The bioreactor performance is dependent on the pumping (injection) of air and the liquid circulation. The airlift bioreactor can have a forced


#### **Table 3.**

*Some examples of remediation studies in packed bed reactors.*

flow in an internal or external loop as shown in **Figure 5**. Specific volatile organic chemicals may be completely degraded by a microorganism at normal temperature and pressure without producing a second polluted byproduct [70]. Nikakhtari and Hill [68], applied and External Loop Airlift Bioreactor with a small amount (99% porosity) of a stainless steel mesh packing inserted in the riser section for bioremediation of a phenol polluted air stream. Phenol removal of 100% was achieved using the bacterium *Pseudomonas putida*, and at a phenol loading rate of 22,160 mg h<sup>−</sup><sup>1</sup> m<sup>−</sup><sup>3</sup> , thus demonstrating the novelty and potential VOCs bioremediation application of the reactor at high loading rates. **Figure 5** presents a schematic diagram of airlift bioreactor. Several other studies involving the use of airlift bioreactors [19, 69–71].

#### **3.7 Membrane bioreactor**

Membrane bioreactors (MBR) combine the use of a membrane that forms a filtration system and the biological process. The membrane provides a physical barrier that separates the liquid from the solid and ensures retention of the solids and good quality effluent. The quality of the treated effluent from the membrane bioreactor is of high quality than that achieved by employing other techniques, enabling optimal functioning of the secondary treatment system [72, 73]. MBR offer the advantages that often smaller tank size is used and filtration function of the membrane ensures that solids are separated from treated effluent. Membrane fouling has been recognized however as a major drawback in the application of membrane bioreactors in bioremediation. Also membranes are often expensive thus making the process costly. Development

**129**

**Figure 4.**

**Figure 5.**

*Microbial Bioremediation and Different Bioreactors Designs Applied*

of low cost membrane filters is an ongoing feature in the science of MBR [72]. MBR reactors have been used in the biological treatment of domestic and industrial waste water. MBR have been evaluated in the remediation of pentachlorophenol in concentration ranges that occur in waste water [73], textile waste water [27], 1,2-dichloro-

*Schematic diagram of airlift bioreactor with (a) external recirculation and (b) internal recirculation [15].*

Due to flexibility in bioreactor designs, the configuration of reactors is numerous. While an effort has been made here to describe some of the common

ethane, 1,2-dichlorobenzene and 2-chlorophenol [30].

*Simplified diagram of a laboratory based packed bed bioreactor [21].*

**3.8 Other bioreactors in bioremediation**

*DOI: http://dx.doi.org/10.5772/intechopen.83661*

**Figure 3.** *Schematic diagram of biotrickling filter [34].*

*Microbial Bioremediation and Different Bioreactors Designs Applied DOI: http://dx.doi.org/10.5772/intechopen.83661*

**Figure 4.** *Simplified diagram of a laboratory based packed bed bioreactor [21].*

#### **Figure 5.**

*Biotechnology and Bioengineering*

**3.7 Membrane bioreactor**

flow in an internal or external loop as shown in **Figure 5**. Specific volatile organic chemicals may be completely degraded by a microorganism at normal temperature and pressure without producing a second polluted byproduct [70]. Nikakhtari and Hill [68], applied and External Loop Airlift Bioreactor with a small amount (99% porosity) of a stainless steel mesh packing inserted in the riser section for bioremediation of a phenol polluted air stream. Phenol removal of 100% was achieved using the

bacterium *Pseudomonas putida*, and at a phenol loading rate of 22,160 mg h<sup>−</sup><sup>1</sup>

tor. Several other studies involving the use of airlift bioreactors [19, 69–71].

thus demonstrating the novelty and potential VOCs bioremediation application of the reactor at high loading rates. **Figure 5** presents a schematic diagram of airlift bioreac-

Membrane bioreactors (MBR) combine the use of a membrane that forms a filtration system and the biological process. The membrane provides a physical barrier that separates the liquid from the solid and ensures retention of the solids and good quality effluent. The quality of the treated effluent from the membrane bioreactor is of high quality than that achieved by employing other techniques, enabling optimal functioning of the secondary treatment system [72, 73]. MBR offer the advantages that often smaller tank size is used and filtration function of the membrane ensures that solids are separated from treated effluent. Membrane fouling has been recognized however as a major drawback in the application of membrane bioreactors in bioremediation. Also membranes are often expensive thus making the process costly. Development

 m<sup>−</sup><sup>3</sup> ,

**128**

**Figure 3.**

*Schematic diagram of biotrickling filter [34].*

*Schematic diagram of airlift bioreactor with (a) external recirculation and (b) internal recirculation [15].*

of low cost membrane filters is an ongoing feature in the science of MBR [72]. MBR reactors have been used in the biological treatment of domestic and industrial waste water. MBR have been evaluated in the remediation of pentachlorophenol in concentration ranges that occur in waste water [73], textile waste water [27], 1,2-dichloroethane, 1,2-dichlorobenzene and 2-chlorophenol [30].

#### **3.8 Other bioreactors in bioremediation**

Due to flexibility in bioreactor designs, the configuration of reactors is numerous. While an effort has been made here to describe some of the common bioreactors used for different bioremediation applications, several other bioreactor types have not been discussed. These include the UASB which find major application in anaerobic digestion of waste waters as well as solid wastes, bio-scrubbers which are applied in off gas air pollution control, continuous stirred tank reactors as well as rotating contactor reactors.

### **4. Conclusions**

It is evident that a wide range of microbial bioreactors have been developed and evaluated in the bioremediation of a wide range of pollutants in water, air and soil. Also a wide range of pollutants in physical and chemical properties are amenable to microbial degradation. Very diverse microbial species have the capability of pollutant degradation naturally and the use of well-developed optimized microbial bioreactors ensure improved rates of degradation when compared to degradation that happens *in situ* in the environment under natural environmental conditions.

### **Conflict of interest**

No conflict of interest is declared.

### **Author details**

Memory Tekere Environmental Science Department, University of South Africa, Johannesburg, South Africa

\*Address all correspondence to: tekerm@unisa.ac.za

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

**131**

*Microbial Bioremediation and Different Bioreactors Designs Applied*

bioremediation of hydrocarbonpolluted Niger Delta marine sediment, Nigeria. 3 Biotech. 2012;**2**(1):53-66

[9] Azubuike CC, Chikere CB, Okpokwasili GC. Bioremediation techniques–classification based on site of application: Principles, advantages, limitations and prospects. World Journal of Microbiology and Biotechnology.

[10] Srivastava J, Naraian R, Kalra SJ, Chandra H. Advances in microbial bioremediation and the factors influencing the process. International Journal of Environmental Science and Technology. 2014;**11**(6):1787-1800

[11] Naik MG, Duraphe MD. Review paper on-parameters affecting bioremediation. International Journal of Life Science and Pharma Research. 2012;**2**(3):L77-L80

[12] Mandenius CF. Bioreactors: Design, Operation and Novel Applications. Germany: John Wiley & Sons; 2016

[13] Tekere M, Mswaka AY, Zvauya R, Read JS. Growth, dye degradation and ligninolytic activity studies on Zimbabwean white rot fungi. Enzyme and Microbial Technology.

[14] Liu SH, Zeng GM, Niu QY, Liu Y, Zhou L, Jiang LH, et al. Bioremediation mechanisms of combined pollution of PAHs and heavy metals by bacteria and fungi: A mini review. Bioresource

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[15] Mahmood KA, Wilkinson SJ, Zimmerman WB. Airlift bioreactor for biological applications with microbubble mediated transport processes. Chemical Engineering Science. 2015;**137**:243-253

[16] Chelliapan S, Wilby T, Yuzir A, Sallis PJ. Influence of organic loading on the performance and microbial community

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[1] Kumar A, Bisht BS, Joshi VD, Dhewa T. Review on bioremediation of polluted environment: A management tool. International Journal of Environmental

[2] Sharma S. Bioremediation: Features, strategies and applications. Asian Journal of Pharmacy and Life Science.

[3] Jeon CO, Madsen EL. In situ microbial metabolism of aromatichydrocarbon environmental pollutants. Current Opinion in Biotechnology.

[4] Quintero JC, Lu-Chau TA, Moreira MT, Feijoo G, Lema JM. Bioremediation of HCH present in soil by the whiterot fungus Bjerkandera adusta in a slurry batch bioreactor. International Biodeterioration & Biodegradation.

[5] U.S. Environmental Protection Agency. Using bioreactors to control air pollution—U.S. Environmental Protection Agency, EPA-456/R-03-003. 2003. Available from: http://www.epa. gov/ttn/catc [Accessed: Nov 23, 2018]

[6] Pino-Herrera DO, Pechaud Y, Huguenot D, Esposito G, Van

Hullebusch ED, Oturan MA. Removal mechanisms in aerobic slurry bioreactors for remediation of soils and sediments polluted with hydrophobic organic compounds: An overview. Journal of Hazardous Materials. 2017;**339**:427-449

[7] Gargouri B, Karray F, Mhiri N, Aloui F, Sayadi S. Application of a continuously stirred tank bioreactor (CSTR) for bioremediation of

effluents. Journal of Hazardous Materials. 2011;**189**(1-2):427-434

[8] Chikere CB, Chikere BO, Okpokwasili GC. Bioreactor-based

hydrocarbon-rich industrial wastewater

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2012;**2231**:4423

2013;**24**(3):474-481

2007;**60**(4):319-326

*Microbial Bioremediation and Different Bioreactors Designs Applied DOI: http://dx.doi.org/10.5772/intechopen.83661*

#### **References**

*Biotechnology and Bioengineering*

well as rotating contactor reactors.

**4. Conclusions**

**Conflict of interest**

No conflict of interest is declared.

**130**

**Author details**

Memory Tekere

South Africa

provided the original work is properly cited.

\*Address all correspondence to: tekerm@unisa.ac.za

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

Environmental Science Department, University of South Africa, Johannesburg,

bioreactors used for different bioremediation applications, several other bioreactor types have not been discussed. These include the UASB which find major application in anaerobic digestion of waste waters as well as solid wastes, bio-scrubbers which are applied in off gas air pollution control, continuous stirred tank reactors as

It is evident that a wide range of microbial bioreactors have been developed and evaluated in the bioremediation of a wide range of pollutants in water, air and soil. Also a wide range of pollutants in physical and chemical properties are amenable to microbial degradation. Very diverse microbial species have the capability of pollutant degradation naturally and the use of well-developed optimized microbial bioreactors ensure improved rates of degradation when compared to degradation that happens *in situ* in the environment under natural environmental conditions.

[1] Kumar A, Bisht BS, Joshi VD, Dhewa T. Review on bioremediation of polluted environment: A management tool. International Journal of Environmental Sciences. 2011;**1**(6):1079

[2] Sharma S. Bioremediation: Features, strategies and applications. Asian Journal of Pharmacy and Life Science. 2012;**2231**:4423

[3] Jeon CO, Madsen EL. In situ microbial metabolism of aromatichydrocarbon environmental pollutants. Current Opinion in Biotechnology. 2013;**24**(3):474-481

[4] Quintero JC, Lu-Chau TA, Moreira MT, Feijoo G, Lema JM. Bioremediation of HCH present in soil by the whiterot fungus Bjerkandera adusta in a slurry batch bioreactor. International Biodeterioration & Biodegradation. 2007;**60**(4):319-326

[5] U.S. Environmental Protection Agency. Using bioreactors to control air pollution—U.S. Environmental Protection Agency, EPA-456/R-03-003. 2003. Available from: http://www.epa. gov/ttn/catc [Accessed: Nov 23, 2018]

[6] Pino-Herrera DO, Pechaud Y, Huguenot D, Esposito G, Van Hullebusch ED, Oturan MA. Removal mechanisms in aerobic slurry bioreactors for remediation of soils and sediments polluted with hydrophobic organic compounds: An overview. Journal of Hazardous Materials. 2017;**339**:427-449

[7] Gargouri B, Karray F, Mhiri N, Aloui F, Sayadi S. Application of a continuously stirred tank bioreactor (CSTR) for bioremediation of hydrocarbon-rich industrial wastewater effluents. Journal of Hazardous Materials. 2011;**189**(1-2):427-434

[8] Chikere CB, Chikere BO, Okpokwasili GC. Bioreactor-based bioremediation of hydrocarbonpolluted Niger Delta marine sediment, Nigeria. 3 Biotech. 2012;**2**(1):53-66

[9] Azubuike CC, Chikere CB, Okpokwasili GC. Bioremediation techniques–classification based on site of application: Principles, advantages, limitations and prospects. World Journal of Microbiology and Biotechnology. 2016;**32**(11):180

[10] Srivastava J, Naraian R, Kalra SJ, Chandra H. Advances in microbial bioremediation and the factors influencing the process. International Journal of Environmental Science and Technology. 2014;**11**(6):1787-1800

[11] Naik MG, Duraphe MD. Review paper on-parameters affecting bioremediation. International Journal of Life Science and Pharma Research. 2012;**2**(3):L77-L80

[12] Mandenius CF. Bioreactors: Design, Operation and Novel Applications. Germany: John Wiley & Sons; 2016

[13] Tekere M, Mswaka AY, Zvauya R, Read JS. Growth, dye degradation and ligninolytic activity studies on Zimbabwean white rot fungi. Enzyme and Microbial Technology. 2001;**28**(4-5):420-426

[14] Liu SH, Zeng GM, Niu QY, Liu Y, Zhou L, Jiang LH, et al. Bioremediation mechanisms of combined pollution of PAHs and heavy metals by bacteria and fungi: A mini review. Bioresource Technology. 2017;**224**:25-33

[15] Mahmood KA, Wilkinson SJ, Zimmerman WB. Airlift bioreactor for biological applications with microbubble mediated transport processes. Chemical Engineering Science. 2015;**137**:243-253

[16] Chelliapan S, Wilby T, Yuzir A, Sallis PJ. Influence of organic loading on the performance and microbial community

structure of an anaerobic stage reactor treating pharmaceutical wastewater. Desalination. 2011;**271**(1-3):257-264

[17] Tekere M, Read JS, Mattiasson B. Polycyclic aromatic hydrocarbon biodegradation in extracellular fluids and static batch cultures of selected sub-tropical white rot fungi. Journal of Biotechnology. 2005;**115**(4):367-377

[18] Lladó S, Gràcia E, Solanas AM, Viñas M. Fungal and bacterial microbial community assessment during bioremediation assays in an aged creosote-polluted soil. Soil Biology and Biochemistry. 2013;**67**:114-123

[19] Ryan DR, Leukes WD, Burton SG. Fungal bioremediation of phenolic wastewaters in an airlift reactor. Biotechnology Progress. 2005;**21**(4):1068-1074

[20] Gros M, Cruz-Morato C, Marco-Urrea E, Longrée P, Singer H, Sarrà M, et al. Biodegradation of the X-ray contrast agent iopromide and the fluoroquinolone antibiotic ofloxacin by the white rot fungus Trametes versicolor in hospital wastewaters and identification of degradation products. Water Research. 2014;**60**:228-241

[21] Tekere M, Read JS, Mattiasson B. Polycyclic aromatic hydrocarbon biodegradation by a subtropical white rot fungus in packed bed and suspended carrier bioreactor systems. Environmental technology. 2007;**28**(6):683-691

[22] Svobodová K, Petráčková D, Kozická B, Halada P, Novotný Č. Mutual interactions of *Pleurotus ostreatus* with bacteria of activated sludge in solid-bed bioreactors. World Journal of Microbiology and Biotechnology. 2016;**32**(6):94

[23] Juarez-Ramirez C, Galíndez-Mayer J, Ruiz-Ordaz N, Ramos-Monroy O, Santoyo-Tepole F, Poggi-Varaldo H.

Steady-state inhibition model for the biodegradation of sulfonated amines in a packed bed reactor. New Biotechnology. 2015;**32**(3):379-386

[24] Singh D, Fulekar MH. Benzene bioremediation using cow dung microflora in two phase partitioning bioreactor. Journal of Hazardous Materials. 2010;**175**(1-3):336-343

[25] Plangklang P, Reungsang A. Bioaugmentation of carbofuran by Burkholderia cepacia PCL3 in a bioslurry phase sequencing batch reactor. Process Biochemistry. 2010;**45**(2):230-238

[26] Robles-González IV, Fava F, Poggi-Varaldo HM. A review on slurry bioreactors for bioremediation of soils and sediments. Microbial Cell Factories. 2008;**7**(1):5

[27] Hossain K, Ismail N. Bioremediation and detoxification of pulp and paper mill effluent: A review. Research Journal of Environmental Toxicology. 2015;**9**(3):113

[28] Couto CF, Lange LC, Amaral MC. A critical review on membrane separation processes applied to remove pharmaceutically active compounds from water and wastewater. Journal of Water Process Engineering. 2018;**26**:156-175

[29] Jegatheesan V, Pramanik BK, Chen J, Navaratna D, Chang CY, Shu L. Treatment of textile wastewater with membrane bioreactor: A critical review. Bioresource Technology. 2016;**204**:202-212

[30] Carucci A, Manconi I, Manigas L. Use of membrane bioreactors for the bioremediation of chlorinated compounds polluted groundwater. Water Science and Technology. 2007;**55**(10):209-216

[31] Mack C, Burgess JE, Duncan JR. Membrane bioreactors for metal

**133**

*Microbial Bioremediation and Different Bioreactors Designs Applied*

Molecular Catalysis B: Enzymatic.

[39] Machin-Ramirez C, Okoh AI, Morales D, Mayolo-Deloisa K, Quintero

R, Trejo-Hernández MR. Slurryphase biodegradation of weathered oily sludge waste. Chemosphere.

[40] Clark B, Boopathy R. Evaluation of bioremediation methods for the treatment of soil contaminated with explosives in Louisiana Army Ammunition Plant, Minden, Louisiana.

Journal of Hazardous Materials.

[42] Fuller ME, Manning JF Jr. Microbiological changes during bioremediation of explosivescontaminated soils in laboratory

reactors. Bioresource Technology.

Benachenhou A, Marcoux J, Gauthier E, Lépine F, et al. Two-liquid-phase slurry bioreactors to enhance the degradation of high-molecular-weight polycyclic aromatic hydrocarbons in soil. Biotechnology Progress.

[44] Tiwari MK, Guha S. Kinetics of biotransformation of chlorpyrifos in aqueous and soil slurry environments.

[45] Daugulis AJ. Two-phase partitioning bioreactors: A new technology platform for destroying xenobiotics. Trends in Biotechnology. 2001;**19**(11):457-462

Water Research. 2014;**51**:73-85

[46] Davidson CT, Daugulis AJ. Addressing biofilter limitations: A two-phase partitioning bioreactor

and pilot-scale bioslurry

[43] Villemur R, Deziel E,

2004;**91**(2):123-133

2000;**16**(6):966-972

[41] Lewis RF. Site demonstration of slurry-phase biodegradation of PAH contaminated soil. Air & Waste.

2008;**55**(3-4):177-184

2008;**70**(4):737-744

2007;**143**(3):643-648

1993;**43**(4):503-508

*DOI: http://dx.doi.org/10.5772/intechopen.83661*

recovery from wastewater: A review. Water SA. 2004;**30**(4):521-532

[32] Olivieri G, Russo ME, Giardina P, Marzocchella A, Sannia G, Salatino P. Strategies for dephenolization of raw olive mill wastewater by means of *Pleurotus ostreatus*. Journal of Industrial

[33] Souza ÉS, Souza JV, Silva FT, Paiva TC. Treatment of an ECF bleaching effluent with white-rot fungi in an air-lift bioreactor. Environmental Earth

Microbiology & Biotechnology.

Sciences. 2014;**72**(4):1289-1294

[34] Schmidt T, Anderson WA. Biotrickling filtration of air contaminated with 1-butanol. Environments. 2017;**4**(3):57

[35] Manhokwe S, Parawira W, Tekere M. An evaluation of a mesophilic reactor for treating wastewater from a Zimbabwean potato-

processing plant. African Journal of Environmental Science and Technology.

[36] Yang Y, Wang Y, Hristovski K, Westerhoff P. Simultaneous removal of nanosilver and fullerene in

sequencing batch reactors for biological wastewater treatment. Chemosphere.

[37] Mueller JG, Lantz SE, Ross D, Colvin RJ, Middaugh DP, Pritchard PH. Strategy using bioreactors and specially selected microorganisms for bioremediation of groundwater contaminated with creosote and pentachlorophenol. Environmental Science & Technology.

[38] Georgieva S, Godjevargova T, Portaccio M, Lepore M, Mita DG. Advantages in using non-isothermal bioreactors in bioremediation of water polluted by phenol by means of immobilized laccase from *Rhus vernicifera*. Journal of

2009;**3**(4):091-096

2015;**125**:115-121

1993;**27**(4):691-698

2012;**39**(5):719-729

*Microbial Bioremediation and Different Bioreactors Designs Applied DOI: http://dx.doi.org/10.5772/intechopen.83661*

recovery from wastewater: A review. Water SA. 2004;**30**(4):521-532

*Biotechnology and Bioengineering*

structure of an anaerobic stage reactor treating pharmaceutical wastewater. Desalination. 2011;**271**(1-3):257-264

Steady-state inhibition model for the biodegradation of sulfonated amines in a packed bed reactor. New Biotechnology.

[24] Singh D, Fulekar MH. Benzene bioremediation using cow dung microflora in two phase partitioning bioreactor. Journal of Hazardous Materials. 2010;**175**(1-3):336-343

[25] Plangklang P, Reungsang A. Bioaugmentation of carbofuran by Burkholderia cepacia PCL3 in a bioslurry phase sequencing batch reactor. Process Biochemistry.

[26] Robles-González IV, Fava F, Poggi-Varaldo HM. A review on slurry bioreactors for bioremediation of soils and sediments. Microbial Cell Factories.

[27] Hossain K, Ismail N. Bioremediation and detoxification of pulp and paper mill effluent: A review. Research Journal of Environmental Toxicology.

[28] Couto CF, Lange LC, Amaral MC. A critical review on membrane

separation processes applied to remove pharmaceutically active compounds from water and wastewater. Journal of Water Process Engineering.

[29] Jegatheesan V, Pramanik BK, Chen J,

Navaratna D, Chang CY, Shu L. Treatment of textile wastewater with membrane bioreactor: A critical review. Bioresource Technology.

2015;**32**(3):379-386

2010;**45**(2):230-238

2008;**7**(1):5

2015;**9**(3):113

2018;**26**:156-175

2016;**204**:202-212

[30] Carucci A, Manconi I, Manigas L. Use of membrane bioreactors for the bioremediation of chlorinated compounds polluted groundwater. Water Science and Technology. 2007;**55**(10):209-216

[31] Mack C, Burgess JE, Duncan JR. Membrane bioreactors for metal

[17] Tekere M, Read JS, Mattiasson B. Polycyclic aromatic hydrocarbon biodegradation in extracellular fluids and static batch cultures of selected sub-tropical white rot fungi. Journal of Biotechnology. 2005;**115**(4):367-377

[18] Lladó S, Gràcia E, Solanas AM, Viñas M. Fungal and bacterial microbial

community assessment during bioremediation assays in an aged creosote-polluted soil. Soil Biology and

Biochemistry. 2013;**67**:114-123

Fungal bioremediation of phenolic wastewaters in an airlift reactor. Biotechnology Progress.

2005;**21**(4):1068-1074

2007;**28**(6):683-691

2016;**32**(6):94

[19] Ryan DR, Leukes WD, Burton SG.

[20] Gros M, Cruz-Morato C, Marco-Urrea E, Longrée P, Singer H, Sarrà M, et al. Biodegradation of the X-ray contrast agent iopromide and the fluoroquinolone antibiotic ofloxacin by the white rot fungus Trametes versicolor in hospital wastewaters and identification of degradation products. Water Research. 2014;**60**:228-241

[21] Tekere M, Read JS, Mattiasson B. Polycyclic aromatic hydrocarbon biodegradation by a subtropical white rot fungus in packed bed and suspended carrier bioreactor systems. Environmental technology.

[22] Svobodová K, Petráčková D,

interactions of *Pleurotus ostreatus* with bacteria of activated sludge in solid-bed bioreactors. World Journal of Microbiology and Biotechnology.

Kozická B, Halada P, Novotný Č. Mutual

[23] Juarez-Ramirez C, Galíndez-Mayer J, Ruiz-Ordaz N, Ramos-Monroy O, Santoyo-Tepole F, Poggi-Varaldo H.

**132**

[32] Olivieri G, Russo ME, Giardina P, Marzocchella A, Sannia G, Salatino P. Strategies for dephenolization of raw olive mill wastewater by means of *Pleurotus ostreatus*. Journal of Industrial Microbiology & Biotechnology. 2012;**39**(5):719-729

[33] Souza ÉS, Souza JV, Silva FT, Paiva TC. Treatment of an ECF bleaching effluent with white-rot fungi in an air-lift bioreactor. Environmental Earth Sciences. 2014;**72**(4):1289-1294

[34] Schmidt T, Anderson WA. Biotrickling filtration of air contaminated with 1-butanol. Environments. 2017;**4**(3):57

[35] Manhokwe S, Parawira W, Tekere M. An evaluation of a mesophilic reactor for treating wastewater from a Zimbabwean potatoprocessing plant. African Journal of Environmental Science and Technology. 2009;**3**(4):091-096

[36] Yang Y, Wang Y, Hristovski K, Westerhoff P. Simultaneous removal of nanosilver and fullerene in sequencing batch reactors for biological wastewater treatment. Chemosphere. 2015;**125**:115-121

[37] Mueller JG, Lantz SE, Ross D, Colvin RJ, Middaugh DP, Pritchard PH. Strategy using bioreactors and specially selected microorganisms for bioremediation of groundwater contaminated with creosote and pentachlorophenol. Environmental Science & Technology. 1993;**27**(4):691-698

[38] Georgieva S, Godjevargova T, Portaccio M, Lepore M, Mita DG. Advantages in using non-isothermal bioreactors in bioremediation of water polluted by phenol by means of immobilized laccase from *Rhus vernicifera*. Journal of

Molecular Catalysis B: Enzymatic. 2008;**55**(3-4):177-184

[39] Machin-Ramirez C, Okoh AI, Morales D, Mayolo-Deloisa K, Quintero R, Trejo-Hernández MR. Slurryphase biodegradation of weathered oily sludge waste. Chemosphere. 2008;**70**(4):737-744

[40] Clark B, Boopathy R. Evaluation of bioremediation methods for the treatment of soil contaminated with explosives in Louisiana Army Ammunition Plant, Minden, Louisiana. Journal of Hazardous Materials. 2007;**143**(3):643-648

[41] Lewis RF. Site demonstration of slurry-phase biodegradation of PAH contaminated soil. Air & Waste. 1993;**43**(4):503-508

[42] Fuller ME, Manning JF Jr. Microbiological changes during bioremediation of explosivescontaminated soils in laboratory and pilot-scale bioslurry reactors. Bioresource Technology. 2004;**91**(2):123-133

[43] Villemur R, Deziel E, Benachenhou A, Marcoux J, Gauthier E, Lépine F, et al. Two-liquid-phase slurry bioreactors to enhance the degradation of high-molecular-weight polycyclic aromatic hydrocarbons in soil. Biotechnology Progress. 2000;**16**(6):966-972

[44] Tiwari MK, Guha S. Kinetics of biotransformation of chlorpyrifos in aqueous and soil slurry environments. Water Research. 2014;**51**:73-85

[45] Daugulis AJ. Two-phase partitioning bioreactors: A new technology platform for destroying xenobiotics. Trends in Biotechnology. 2001;**19**(11):457-462

[46] Davidson CT, Daugulis AJ. Addressing biofilter limitations: A two-phase partitioning bioreactor

process for the treatment of benzene and toluene contaminated gas streams. Biodegradation. 2003;**14**(6):415-421

[47] Dorado AD, Dumont E, Muñoz R, Quijano G. A novel mathematical approach for the understanding and optimization of two-phase partitioning bioreactors devoted to air pollution control. Chemical Engineering Journal. 2015;**263**:239-248

[48] Muñoz R, Daugulis AJ, Hernández M, Quijano G. Recent advances in twophase partitioning bioreactors for the treatment of volatile organic compounds. Biotechnology Advances. 2012;**30**(6):1707-1720

[49] Angelucci DM, Stazi V, Daugulis AJ, Tomei MC. Treatment of synthetic tannery wastewater in a continuous two-phase partitioning bioreactor: Biodegradation of the organic fraction and chromium separation. Journal of Cleaner Production. 2017;**152**:321-329

[50] Tomei MC, Angelucci DM, Daugulis AJ. Towards a continuous two-phase partitioning bioreactor for xenobiotic removal. Journal of Hazardous Materials. 2016;**317**:403-415

[51] Bi Y. Bioremediation of volatile organic compounds in a continuous stirred tank bioreactor (doctoral dissertation). Saskatoon: University of Saskatchewan; 2005

[52] Lebrero R, Gondim AC, Pérez R, García-Encina PA, Muñoz R. Comparative assessment of a biofilter, a biotrickling filter and a hollow fiber membrane bioreactor for odor treatment in wastewater treatment plants. Water Research. 2014;**49**:339-350

[53] Rabbani KA, Charles W, Kayaalp A, Cord-Ruwisch R, Ho G. Pilot-scale biofilter for the simultaneous removal of hydrogen sulphide and ammonia at a wastewater treatment plant.

Biochemical Engineering Journal. 2016;**107**:1-10

[54] Van Loosdrecht MC, Heijnen SJ. Biofilm bioreactors for waste-water treatment. Trends in Biotechnology. 1993;**11**(4):117-121

[55] Bisping B, Rehm HJ. Multistep reactions with immobilized microorganisms. Biotechnology and Applied Biochemistry. 1988;**10**(2):87-98

[56] Guieysse B, Bernhoft I, Andersson BE, Henrysson T, Olsson S, Mattiasson B. Degradation of acenaphthene, phenanthrene and pyrene in a packed-bed biofilm reactor. Applied Microbiology and Biotechnology. 2000;**54**(6):826-831

[57] Burton SG, Boshoff A, Edwards W, Jacobs EP, Lfukes WD, Rose PD, et al. Membrane Based Biotechnological System for the Treatment of Organic Pollutants. South Africa: Water Research Commission; 1998

[58] de Nardi IR, Ribeiro R, Zaiat M, Foresti E. Anaerobic packed-bed reactor for bioremediation of gasolinecontaminated aquifers. Process Biochemistry. 2005;**40**(2):587-592

[59] Senan RC, Shaffiqu TS, Roy JJ, Abraham TE. Aerobic degradation of a mixture of Azo dyes in a packed bed reactor having bacteria-coated laterite pebbles. Biotechnology Progress. 2003;**19**(2):647-651

[60] Talha MA, Goswami M, Giri BS, Sharma A, Rai BN, Singh RS. Bioremediation of Congo red dye in immobilized batch and continuous packed bed bioreactor by Brevibacillus parabrevis using coconut shell bio-char. Bioresource Technology. 2018;**252**:37-43

[61] Geed SR, Kureel MK, Giri BS, Singh RS, Rai BN. Performance evaluation of malathion biodegradation in batch and continuous packed bed bioreactor

**135**

*Microbial Bioremediation and Different Bioreactors Designs Applied*

Biochemical Engineering Journal.

[69] Patel BP, Kumar A. Biodegradation of 4-chlorophenol in an airlift inner loop bioreactor with mixed consortium: Effect of HRT, loading rate and biogenic substrate. 3 Biotech. 2016;**6**(2):117

[70] Bertollo FB, Lopes GC, Silva EL. Phenol biodegradation by *Pseudomonas putida* in an airlift reactor: Assessment of kinetic, hydrodynamic, and mass transfer parameters. Water, Air, & Soil

[71] Azeez TO, Onukwuli OD, Araromi DO, Arinkoola AO, Salam KK, Iwuji SC, et al. Optimization of bioremediation of cheese whey with the activity of Klebsiella pneumonia using response surface methodology. International Journal for Science and Engineering Technologies with Latest Trends.

Pollution. 2017;**228**(10):398

[72] Meng F, Chae SR, Drews A, Kraume M, Shin HS, Yang F. Recent advances in membrane bioreactors (MBRs): Membrane fouling and membrane material. Water Research.

2013;**11**(1):10-21

2009;**43**(6):1489-1512

[73] Visvanathan C, Thu LN,

of pentachlorophenol in a

2005;**183**(1-3):455-464

Jegatheesan V, Anotai J. Biodegradation

membrane bioreactor. Desalination.

2005;**27**(2):138-145

*DOI: http://dx.doi.org/10.5772/intechopen.83661*

(PBBR). Bioresource Technology.

Technology. 2000;**21**(2):231-236

[64] Torres-Farradá G, Manzano AM, Ramos-Leal M, Domínguez O, Sánchez MI, Vangronsveld J, Guerra G. Biodegradation and detoxification of dyes and industrial effluents by Ganoderma weberianum B-18 immobilized in a lab-scale packed-bed bioreactor. Bioremediation Journal.

[65] Losi ME, Giblin T, Hosangadi V, Frankenberger WT Jr. Bioremediation of perchlorate-contaminated groundwater

using a packed bed biological reactor. Bioremediation Journal.

[66] Banerjee A, Ghoshal AK. Biodegradation of an actual petroleum wastewater in a packed bed reactor by an immobilized biomass of *Bacillus cereus*. Journal of Environmental Chemical Engineering.

[67] Kureel MK, Geed SR, Giri BS, Rai BN, Singh RS. Biodegradation and kinetic study of benzene in bioreactor packed with PUF and alginate beads and immobilized with bacillus sp. M3. Bioresource Technology.

kinetics of chlorophenols in immobilized-cell reactors using a white-rot fungus on wood chips. Water Environment Research.

1998;**70**(2):205-213

2018;**22**:1(1-2):20-27

2002;**6**(2):97-103

2017;**5**(2):1696-1702

2017;**242**:92-100

[68] Nikakhtari H, Hill GA. Hydrodynamic and oxygen mass transfer in an external loop airlift bioreactor with a packed bed.

[62] Kapdan IK, Kargi F, McMullan G, Marchant R. Biological decolorization of textile dyestuff by Coriolus versicolor in a packed column reactor. Environmental

[63] Yum KJ, Peirce JJ. Biodegradation

2017;**227**:56-65

*Microbial Bioremediation and Different Bioreactors Designs Applied DOI: http://dx.doi.org/10.5772/intechopen.83661*

(PBBR). Bioresource Technology. 2017;**227**:56-65

*Biotechnology and Bioengineering*

2015;**263**:239-248

2012;**30**(6):1707-1720

process for the treatment of benzene and toluene contaminated gas streams. Biodegradation. 2003;**14**(6):415-421

Biochemical Engineering Journal.

[54] Van Loosdrecht MC, Heijnen SJ. Biofilm bioreactors for waste-water treatment. Trends in Biotechnology.

[55] Bisping B, Rehm HJ. Multistep reactions with immobilized

microorganisms. Biotechnology and Applied Biochemistry. 1988;**10**(2):87-98

[56] Guieysse B, Bernhoft I, Andersson BE, Henrysson T, Olsson S, Mattiasson B. Degradation of acenaphthene, phenanthrene and pyrene in a packed-bed biofilm reactor. Applied Microbiology and Biotechnology.

[57] Burton SG, Boshoff A, Edwards W, Jacobs EP, Lfukes WD, Rose PD, et al. Membrane Based Biotechnological System for the Treatment of Organic Pollutants. South Africa: Water Research

[58] de Nardi IR, Ribeiro R, Zaiat M, Foresti E. Anaerobic packed-bed reactor for bioremediation of gasolinecontaminated aquifers. Process Biochemistry. 2005;**40**(2):587-592

[59] Senan RC, Shaffiqu TS, Roy JJ, Abraham TE. Aerobic degradation of a mixture of Azo dyes in a packed bed reactor having bacteria-coated laterite pebbles. Biotechnology Progress.

[60] Talha MA, Goswami M, Giri BS,

[61] Geed SR, Kureel MK, Giri BS, Singh RS, Rai BN. Performance evaluation of malathion biodegradation in batch and continuous packed bed bioreactor

Sharma A, Rai BN, Singh RS. Bioremediation of Congo red dye in immobilized batch and continuous packed bed bioreactor by Brevibacillus parabrevis using coconut shell bio-char. Bioresource Technology. 2018;**252**:37-43

2016;**107**:1-10

1993;**11**(4):117-121

2000;**54**(6):826-831

Commission; 1998

2003;**19**(2):647-651

[47] Dorado AD, Dumont E, Muñoz R, Quijano G. A novel mathematical approach for the understanding and optimization of two-phase partitioning bioreactors devoted to air pollution control. Chemical Engineering Journal.

[48] Muñoz R, Daugulis AJ, Hernández M, Quijano G. Recent advances in twophase partitioning bioreactors for the treatment of volatile organic compounds. Biotechnology Advances.

[49] Angelucci DM, Stazi V, Daugulis AJ, Tomei MC. Treatment of synthetic tannery wastewater in a continuous two-phase partitioning bioreactor: Biodegradation of the organic fraction and chromium separation. Journal of Cleaner Production. 2017;**152**:321-329

[50] Tomei MC, Angelucci DM, Daugulis AJ. Towards a continuous two-phase partitioning bioreactor for xenobiotic removal. Journal of Hazardous Materials. 2016;**317**:403-415

[51] Bi Y. Bioremediation of volatile organic compounds in a continuous stirred tank bioreactor (doctoral dissertation). Saskatoon: University of

[52] Lebrero R, Gondim AC, Pérez R,

[53] Rabbani KA, Charles W, Kayaalp A, Cord-Ruwisch R, Ho G. Pilot-scale biofilter for the simultaneous removal of hydrogen sulphide and ammonia at a wastewater treatment plant.

García-Encina PA, Muñoz R. Comparative assessment of a biofilter, a biotrickling filter and a hollow fiber membrane bioreactor for odor treatment in wastewater treatment plants. Water Research.

Saskatchewan; 2005

2014;**49**:339-350

**134**

[62] Kapdan IK, Kargi F, McMullan G, Marchant R. Biological decolorization of textile dyestuff by Coriolus versicolor in a packed column reactor. Environmental Technology. 2000;**21**(2):231-236

[63] Yum KJ, Peirce JJ. Biodegradation kinetics of chlorophenols in immobilized-cell reactors using a white-rot fungus on wood chips. Water Environment Research. 1998;**70**(2):205-213

[64] Torres-Farradá G, Manzano AM, Ramos-Leal M, Domínguez O, Sánchez MI, Vangronsveld J, Guerra G. Biodegradation and detoxification of dyes and industrial effluents by Ganoderma weberianum B-18 immobilized in a lab-scale packed-bed bioreactor. Bioremediation Journal. 2018;**22**:1(1-2):20-27

[65] Losi ME, Giblin T, Hosangadi V, Frankenberger WT Jr. Bioremediation of perchlorate-contaminated groundwater using a packed bed biological reactor. Bioremediation Journal. 2002;**6**(2):97-103

[66] Banerjee A, Ghoshal AK. Biodegradation of an actual petroleum wastewater in a packed bed reactor by an immobilized biomass of *Bacillus cereus*. Journal of Environmental Chemical Engineering. 2017;**5**(2):1696-1702

[67] Kureel MK, Geed SR, Giri BS, Rai BN, Singh RS. Biodegradation and kinetic study of benzene in bioreactor packed with PUF and alginate beads and immobilized with bacillus sp. M3. Bioresource Technology. 2017;**242**:92-100

[68] Nikakhtari H, Hill GA. Hydrodynamic and oxygen mass transfer in an external loop airlift bioreactor with a packed bed.

Biochemical Engineering Journal. 2005;**27**(2):138-145

[69] Patel BP, Kumar A. Biodegradation of 4-chlorophenol in an airlift inner loop bioreactor with mixed consortium: Effect of HRT, loading rate and biogenic substrate. 3 Biotech. 2016;**6**(2):117

[70] Bertollo FB, Lopes GC, Silva EL. Phenol biodegradation by *Pseudomonas putida* in an airlift reactor: Assessment of kinetic, hydrodynamic, and mass transfer parameters. Water, Air, & Soil Pollution. 2017;**228**(10):398

[71] Azeez TO, Onukwuli OD, Araromi DO, Arinkoola AO, Salam KK, Iwuji SC, et al. Optimization of bioremediation of cheese whey with the activity of Klebsiella pneumonia using response surface methodology. International Journal for Science and Engineering Technologies with Latest Trends. 2013;**11**(1):10-21

[72] Meng F, Chae SR, Drews A, Kraume M, Shin HS, Yang F. Recent advances in membrane bioreactors (MBRs): Membrane fouling and membrane material. Water Research. 2009;**43**(6):1489-1512

[73] Visvanathan C, Thu LN, Jegatheesan V, Anotai J. Biodegradation of pentachlorophenol in a membrane bioreactor. Desalination. 2005;**183**(1-3):455-464

**137**

**Chapter 10**

Species

**Abstract**

Phytoremediation of Effluents

*Cleide Barbieri de Souza and Gabriel Rodrigues Silva*

concentrations of metal when related to Cd, Hg, Zn, Ni and Pb.

heavy metals, floating aquatic macrophytes

planet in a devastating way [1, 2].

**1. Introduction**

Contaminated with Heavy Metals

by Floating Aquatic Macrophytes

The progress of urbanization and technologies led to the rise of anthropogenic activities, which consequently have high production of pollutants, affecting ecosystems, including aquatic biomes. One of the contaminating forms that cause environmental impact is heavy metals, which are produced in large quantities by inappropriate disposal of batteries, residential, industrial, agricultural and mining waste. Such components generate bioaccumulative effects, classifying them as dangerous elements that must be removed from environment. However, in species such as plants, this bioaccumulative effect can be exploited, aiming a biotechnological and bioengineering application to remove metals, called phytoremediation, employing floating aquatic macrophytes, which have high potential due to their properties retaining contaminants. Results obtained were conclusive for adaptation of *Eichhornia crassipes* and *Salvinia auriculata* as better phytoremediation agents, respectively, while *Lemna minor* and *Pistia stratiotes* fit better in biomonitoring, which have resistance to certain

**Keywords:** environmental bioengineering, biotechnology, phytoremediation, water,

In contemporary society, the great amount of harmful elements produced that come to nature has contributed greatly to environmental degradation, such aggressions to the environment are due to several factors, mainly by the pollutants and substances that affect the planet and its spheres (atmosphere, lithosphere, hydrosphere), as well as affect the biosphere, which participates in these different levels and aggregates all life and its different ecological niches. Therefore, it is necessary to find alternatives of reduction and even exclusion of these pollutants that affect our

Since the harmful damages to the environment from human activities were discovered, we look for sources and methods that can maintain sustainability, thinking about ecologically sustainable projects, making biodegradable products, looking for options to reduce pollutants and contaminants, other substitutions for extraction of material resources aimed at less damaging the ecosystem, creating environmental

#### **Chapter 10**
