Doctoral thesis Bioindication and Bioremediation of Landfill Emissions Christian Maurice Department of Environmental Engineering Division of Waste Science and Technology Luleå University of Technology 87 Luleå Sweden. Preface This thesis is the result of research projects on landfill gas, leachate, and contaminated Bioremediation is defined as use of biological processes to degrade, break down, transform, and/or essentially remove contaminants or impairments of quality from soil and water. Bioremediation is a natural process which relies on bacteria, fungi, and plants to alter contaminants as these organisms carry out their normal life functions For my thesis, I propose to review scientific literature related to “low intensity” bioremediation methods, as defined in this proposal. I will also conduct interviews with community organizations that have begun projects using low intensity bioremediation methods. The methods will be analyzed for their effectiveness as a form of remediation;
(PPT) Bioremediation | AVISHEK BHATTACHARJEE - blogger.com
Try out PMC Labs and tell us what you think. Learn More. Department of Microbiology, Faculty of Bioremediation thesis pdf, University of Port Harcourt, East-West Road, PMBChoba, Port Harcourt, bioremediation thesis pdf, Rivers State Nigeria. Environmental pollution has been on the rise in the past few decades owing to increased human activities on energy reservoirs, unsafe agricultural practices and rapid industrialization.
Amongst the pollutants that are of environmental and public health concerns due to their toxicities are: heavy metals, nuclear wastes, bioremediation thesis pdf, pesticides, green house gases, and hydrocarbons. Remediation of polluted sites using microbial process bioremediation has proven effective and reliable due to its eco-friendly features. Bioremediation can either be carried out ex situ or in situ, depending on several factors, which include but not limited to cost, site characteristics, type and concentration of pollutants, bioremediation thesis pdf.
Generally, ex situ techniques apparently are more expensive compared to in situ techniques as a result of additional cost attributable to excavation.
However, cost of on-site installation of equipment, and inability to effectively visualize and control the subsurface of polluted sites are of major concerns when carrying out in situ bioremediation, bioremediation thesis pdf. Therefore, choosing appropriate bioremediation technique, which will effectively reduce pollutant concentrations to an innocuous state, is crucial for a successful bioremediation project.
Furthermore, the two major approaches to enhance bioremediation are biostimulation and bioaugmentation provided that environmental factors, which determine the success of bioremediation, are maintained at bioremediation thesis pdf range.
This review provides more insight into the two major bioremediation techniques, their principles, advantages, limitations and prospects. In the past two decades, there have been recent advances in bioremediation techniques with the ultimate goal being to effectively restore polluted environments in an bioremediation thesis pdf approach, and at a very low cost.
Autochthonous indigenous microorganisms present in polluted environments hold the key to solving most of the challenges associated with biodegradation and bioremediation of polluting substances Verma and Jaiswal provided that environmental conditions are suitable for their growth and metabolism. Environmentally friendly and cost saving features are amongst the major advantages of bioremediation compared to both chemical and physical methods of remediation. Thus far, several good definitions have been given to bioremediation, with particular emphasis on one of the processes degradation.
Nevertheless, in some instances, the term biodegradation is used interchangeably with bioremediation; the former is a term, which applies to a process under the latter, bioremediation thesis pdf. In this review, bioremediation is defined as a process, bioremediation thesis pdf, which relies on biological mechanisms to reduce degrade, detoxify, mineralize or transform concentration of pollutants to an innocuous state.
The process of pollutant removal depends primarily on the nature of the pollutant, which may include: agrochemicals, chlorinated compounds, bioremediation thesis pdf, dyes, greenhouse gases, bioremediation thesis pdf, heavy metals, hydrocarbons, nuclear waste, plastics, and sewage. Apparently, taking into consideration site of application, bioremediation techniques can be categorized as: ex situ or in situ.
Pollutant nature, depth and degree of pollution, type of environment, location, cost, and environmental policies are some of the selection criteria that are considered when choosing any bioremediation technique Frutos et al.
Apart from selection criteria, performance criteria oxygen and nutrient concentrations, temperature, pH, and other abiotic factors that determine the success of bioremediation processes are also given major considerations prior to bioremediation project.
Although bioremediation techniques are diverse Fig. Besides, it is possible that other remediation techniques Pavel and Gavrilescuwhich might as well be more economical, and efficient to apply during remediation, are considered when remediation of sites polluted with pollutants aside from hydrocarbons are involved.
Furthermore, given the nature of activities leading to crude oil pollution, it is likely that pollution of the environment with pollutants excluding hydrocarbons can easily be prevented and controlled.
Moreover, the dependence on petroleum and other related products as major sources of energy seems to have contributed to increased pollution resulting from this class of pollutant Gomez and Sartaj ; Khudur et al. The aim of this review is to provide a comprehensive knowledge on the two major bioremediation techniques with regards to site of application, highlighting their principles, advantages, limitations and possible solutions.
The prospects of bioremediation are also discussed. Bioremediation techniques. The divergence of each technique is hypothetical; therefore, the left to right order of internal nodes are not the order of evolution technique development. Permeable reactive barrier PBR is not the arbitrary tree root. It is a bioremediation thesis pdf remediation technique with some elements of bioremediation, hence the early hypothetical divergence.
These techniques involve excavating pollutants from polluted sites and subsequently transporting bioremediation thesis pdf to another site for treatment. Ex situ bioremediation techniques are usually considered based on: the cost of treatment, depth of pollution, type of pollutant, degree of pollution, geographical location and geology of the polluted site.
Bioremediation thesis pdf criteria, which also determine the choice of ex situ bioremediation techniques, have been described Philp and Atlas Biopile-mediated bioremediation involves above-ground piling of excavated polluted soil, followed by nutrient amendment, and sometimes aeration to enhance bioremediation by basically increasing microbial activities, bioremediation thesis pdf.
The components of this technique are: aeration, irrigation, nutrient and leachate collection systems, and a treatment bed. The use of this particular ex situ technique is increasingly being considered due to its constructive features including cost effectiveness, which enables effective biodegradation on the bioremediation thesis pdf that nutrient, temperature and aeration are adequately controlled Whelan et al. The application of biopile to polluted sites can help limit volatilization of low molecular weight LMW pollutants; it can also be used effectively to remediate polluted extreme environments such as the very cold regions Dias et al.
At the end of the study period 94 days The high percentage of TPH reduction was attributed to synergistic interaction between bioaugmentation and biostimulation, thus demonstrating the flexibility of biopiles for bioremediation. Similarly, Dias et al. The feasibility of biopiles towards bioremediation of different soil samples including clay and sandy soil has been reported Chemlal et al.
The flexibility of biopile allows remediation time to be shortened as heating system can be incorporated into biopile design to increase microbial activities and contaminant availability thus increasing the bioremediation thesis pdf of biodegradation Aislabie et al. Furthermore, heated air can be injected into biopile design to deliver air and heat in tandem, in order to facilitate enhanced bioremediation.
In another study, Sanscartier et al. In addition, it was reported that biopile could be used to treat large volume of polluted soil in a limited bioremediation thesis pdf. Biopile setup can easily be scaled up to a pilot system to achieve similar performance obtained during laboratory studies Chemlal et al, bioremediation thesis pdf. Important to the efficiency of biopile is sieving and aeration of contaminated soil prior to processing Delille et al.
Bulking agents such as straw, saw dust, bark or wood chips and other organic materials have been added to enhance remediation process in a biopile construct Rodríguez-Rodríguez et al. Although biopile bioremediation thesis pdf conserve space compared to other field ex situ bioremediation techniques, including land farming, robust engineering, cost of maintenance bioremediation thesis pdf operation, lack of power supply especially at remote sites, which would enable uniform distribution of air in contaminated piled soil via air pump are some of the limitations of biopiles.
More so, excessive heating of air can lead to drying of soil undergoing bioremediation, which will result in inhibition of microbial activities, and promote volatilization rather than biodegradation Sanscartier et al. The periodic turning of polluted soil, together with addition of water bring about increase in aeration, uniform distribution of bioremediation thesis pdf, nutrients and microbial degradative activities, thus speeding up the rate of bioremediation, which can be accomplished through assimilation, biotransformation and mineralization Barr Windrow treatment when compared to biopile treatment, showed higher rate of hydrocarbon removal; however, the higher efficiency of the windrow towards hydrocarbon removal was as a result of the soil type, which was reported to be more friable Coulon et al.
Nevertheless, due to periodic turning associated with windrow treatment, it may not be the best option to adopt in remediating soil polluted with toxic volatiles. The use of windrow treatment has been implicated in CH 4 greenhouse gas release due to development of anaerobic zone within piled polluted soil, which usually occurs following reduced aeration Hobson et al.
Bioreactor, as the name implies, is a vessel in which raw materials are converted to specific product s following series of biological reactions. Bioremediation thesis pdf are different operating modes of bioreactor, which include: batch, fed-batch, sequencing batch, bioremediation thesis pdf, continuous and multistage.
The choice of operating mode depends mostly on market economy and capital expenditure. Conditions in a bioreactor support natural process of cells by mimicking and maintaining their natural environment to provide optimum growth conditions.
Polluted samples can be fed into a bioremediation thesis pdf either as dry matter or slurry; in either case, the use of bioreactor in treating polluted soil has several advantages compared to other ex situ bioremediation techniques. Excellent control of bioprocess parameters temperature, pH, agitation and aeration rates, substrate and inoculum concentrations is one of the major advantages of bioreactor-based bioremediation.
The ability to control and manipulate process parameters in a bioreactor implies that biological reactions within can be enhanced to effectively reduce bioremediation time.
Importantly, controlled bioaugmentation, nutrient addition, increased pollutant bioavailability, and mass transfer contact between pollutant and microbeswhich are among the limiting factors of bioremediation process can effectively be established in a bioreactor thus making bioreactor-based bioremediation more efficient. Further, it can be used to treat soil or water polluted with volatile organic compounds VOCs including benzene, toluene, ethylbenzene and xylenes BTEX.
The applications of different bioreactors for bioremediation process have resulted in removal of wide range of pollutants Table 1. The flexible nature of bioreactor designs allows maximum biological degradation while minimizing abiotic losses Mohan et al. Short or long-term operation of a bioreactor containing crude oil-polluted soil slurry allows tracking of changes in microbial population dynamics thus enabling easy characterization of core bacterial communities involved in bioremediation processes Chikere et al, bioremediation thesis pdf.
Furthermore, it allows the use of different substances as biostimulant or bioaugmenting agent including sewage sludge. In addition, bioreactor being an enclosed system, genetically modified microorganism GEM can be used for bioaugmentation after which the organism GEM can be destroyed before treated soils are returned to field for landfilling. This containment of GEM in a bioreactor followed by destruction bioremediation thesis pdf help ensure that no foreign gene escapes into an environment after bioremediation.
With bioreactor, the role of biosurfactant bioremediation thesis pdf found to be insignificant due to efficient mixing associated with bioreactor operations Mustafa et al. Despite that bioreactor-based bioremediation has proven to be efficient as a result of different operating parameters, which can easily be controlled, establishing best operating condition by relating all parameters using one-factor-at-a-time OFAT approach would likely require numerous experiments, which is time-consuming.
This particular challenge can be overcome by using design of experiment DoE tone, which provides information on optimal range of parameters using a set of independent variables controllable and uncontrollable factors over a specified region level Mohan et al.
Notwithstanding, understanding microbiological processes is of great importance when optimizing bioremediation processes Piskonen et al.
Moreover, bioreactor-based bioremediation is not a popular full-scale practice due to some reasons, bioremediation thesis pdf. Firstly, due to bioreactor being ex situ technique, the volume of polluted soil or other substances to be treated may be too large, bioremediation thesis pdf, requiring more manpower, capital and safety measures for transporting pollutant to treatment site, therefore, making this particular technique cost ineffective Philp and Atlas Lastly, pollutants are likely to respond differently to different bioreactors; the availability of the most suitable design is of paramount importance.
Above all, cost of a bioreactor suitable for a laboratory or pilot-scale bioremediation makes this technique to be capitally intensive. Land farming is amongst the bioremediation thesis pdf bioremediation techniques owing to its low cost and less equipment requirement for operation.
In most cases, it is regarded as ex situ bioremediation, while in some cases, it is regarded as in situ bioremediation technique, bioremediation thesis pdf. This debate is due to the site of treatment. Pollutant depth plays an important role as to whether land farming can be carried out ex situ or in situ, bioremediation thesis pdf.
When excavated polluted soil is treated on-site, it can be regarded as in situ; otherwise, it is ex situ as it has more in common with other ex situ bioremediation techniques. Generally, bioremediation thesis pdf, excavated polluted soils are carefully applied on a fixed layer support above the ground surface to allow aerobic biodegradation of pollutant by autochthonous microorganisms Philp and Atlas ; Paudyn et al.
Tillage, bioremediation thesis pdf, which brings about aeration, bioremediation thesis pdf, addition of nutrients nitrogen, phosphorus and potassium and irrigation are the major operations, which stimulate activities of autochthonous microorganisms to enhance bioremediation during land farming. Nevertheless, it was reported that tillage and irrigation without nutrient addition in a soil with bioremediation thesis pdf biological activity increased heterotrophic and diesel-degrading bacterial counts thus enhancing bioremediation thesis pdf rate of bioremediation; dehydrogenase activity was also observed to be a good indicator of biostimulation treatment and could be used as a biological parameter in bioremediation thesis pdf farming technology Silva-Castro et al.
Similarly, in a field trial, Paudyn et al. Land farming is usually used for remediation of hydrocarbon-polluted sites including polyaromatic hydrocarbons Silva-Castro et al. Land farming system complies with government regulations, and can be used in any climate and location Besaltatpour et al.
The construction of a suitable land farming design with an impermeable liner minimizes leaching of pollutant into neighbouring areas during bioremediation operation da Silva et al. Over all, land farming bioremediation technique is very simple to design and implement, requires low capital input and can be used to treat large volume of polluted soil with minimal environmental impact and energy requirement Maila and Colete Although the simplest bioremediation technique, land farming like other ex situ bioremediation techniques has some limitations, which include: large operating space, reduction in microbial activities due to unfavourable environmental conditions, additional cost due to excavation, and reduced efficacy in inorganic pollutant removal Khan et al.
Moreover, it is not suitable for treating soil polluted with toxic volatiles due to its design and mechanism of pollutant removal volatilizationespecially in hot tropical climate regions. These limitations and several others make land farming-based bioremediation time consuming and less efficient compared to other ex situ bioremediation techniques.
One of the major advantages of ex situ bioremediation techniques is that they do not require extensive preliminary assessment of polluted site prior to remediation; this makes the preliminary stage short, less laborious and less expensive. Due to excavation processes associated with ex situ bioremediation, pollutant inhomogeneity as a result of depth, non-uniform concentration and distribution, can easily be curbed by effectively optimizing some process parameters temperature, pH, mixing of any ex situ technique to enhance bioremediation process.
These techniques allow modifications of biological, chemical and physico-chemical conditions and parameters necessary for effective and efficient bioremediation.
Importantly, the great influence of soil porosity, which governs transport processes during remediation, can be reduced when polluted soils are excavated.
What is Bio-remediation ? Insitu, Exsitu \u0026 Types
, time: 8:56Bioremediation: an emerging effective approach towards environment restoration | SpringerLink
Aim of the thesis A series of fungal strains were screened for their ability to degrade hydrocarbons. Screenings were carried out at the ACBR, Vienna and at IRTA, Caldes. The aim of the study was to find promising fungal strains, which could be used for bioremediation purposes in soil, water or in biofilters PDF | On Jun 23, , Ritu Raj and others published Microbial Biodegradation and Bioremediation | Find, read and cite all the research you need on ResearchGate Mónika Molnár PhD thesis 6 In case of transformer oil contamination the % of RAMEB was found to be effective for intensification of bioremediation. Removal of transformer oil was –folds higher in the presence of % RAMEB concentration that achieved without RAMEB. So take into account the cost of remediation, it could
No comments:
Post a Comment