However, their practical use in decontamination technologies is not well known.
Some publications deal with relatively low biodegradation of different types of
persistent pollutants rather than focusing on the improvement that has been made
to the technology. Hardly can we find publications dealing with the solutions to
current problems, especially employing alternative approaches to conventional
technologies or methods of risk assessment.
Although modern tools using genetic modifications or nanobiotechnologies are
exploited, classical remediation techniques still play a major role in real-life
applications.
Bioremediation is a method preferred for remediation of petroleum hydrocarbon
contaminated soils because it is considered a cost-effective and sustainable technology (Coulon et al. 2012; Jiang et al. 2016). It is important to investigate and
understand many factors, such as the soil and the contaminant characteristics, the
bioavailability, or the presence of inhibitors to successfully achieve the target limits.
All these factors can significantly influence the efficiency of the bioremediation
process (Jiang et al. 2016).
Bioremediation is not a new concept and it is being increasingly used as a
relatively economical environmental remediation technology. It is an environmentally friendly and cost-effective method of treating soils containing organic
chemicals, thus enabling appropriate reuse of the treated soil and minimising
disposal of waste soil to landfill whilst providing adequate protection for human
health and the environment (EPA 2005).
The ex situ bioremediation treatment of soil is generally used in the biopiles or
by landfarming. Landfarming is an above-ground remediation technology for soils
that reduces concentrations of petroleum hydrocarbons through biodegradation.
This technology usually involves spreading excavated contaminated soils on the
ground surface in a thin layer and stimulating the aerobic microbial activity within
the soils through aeration and/or the addition of minerals, nutrients, and moisture
(US EPA 2017).
From the microbiological point of view, bioremediation is defined as an accelerated process using microorganisms, indigenous or introduced, to degrade and
detoxify organic substances to harmless compounds, such as carbon dioxide and
water, in a confined and controlled environment. Bioremediation is suitable for
treating a variety of organic chemicals, including (i) volatile organic compounds;
(ii) benzene, toluene, ethylbenzene, xylene (BTEX) compounds; (iii) phenolic
compounds; (iv) polycyclic aromatic hydrocarbons (PAHs), particularly the simpler
aromatic compounds; (v) total petroleum hydrocarbons (TPH); (vi) nitroaromatic
compounds. Bioremediation exploits microorganisms’ ability to degrade or transform organic pollutants to harmless products, yet a spontaneous biodegradation
process on a reclaimed site is very slow for the following reasons: (i) absence of a
specific microflora able to decompose present hydrocarbons, (ii) low solubility of
present pollutants, (iii) non-homogenous distribution of organic pollutants,
(iv) deficiency of oxygen and nutrients, etc. To accelerate the natural decontamination process it is convenient to create ideal conditions for the bacterial growth,
438
P. Najmanová and M. Halecký
Some publications deal with relatively low biodegradation of different types of
persistent pollutants rather than focusing on the improvement that has been made
to the technology. Hardly can we find publications dealing with the solutions to
current problems, especially employing alternative approaches to conventional
technologies or methods of risk assessment.
Although modern tools using genetic modifications or nanobiotechnologies are
exploited, classical remediation techniques still play a major role in real-life
applications.
Bioremediation is a method preferred for remediation of petroleum hydrocarbon
contaminated soils because it is considered a cost-effective and sustainable technology (Coulon et al. 2012; Jiang et al. 2016). It is important to investigate and
understand many factors, such as the soil and the contaminant characteristics, the
bioavailability, or the presence of inhibitors to successfully achieve the target limits.
All these factors can significantly influence the efficiency of the bioremediation
process (Jiang et al. 2016).
Bioremediation is not a new concept and it is being increasingly used as a
relatively economical environmental remediation technology. It is an environmentally friendly and cost-effective method of treating soils containing organic
chemicals, thus enabling appropriate reuse of the treated soil and minimising
disposal of waste soil to landfill whilst providing adequate protection for human
health and the environment (EPA 2005).
The ex situ bioremediation treatment of soil is generally used in the biopiles or
by landfarming. Landfarming is an above-ground remediation technology for soils
that reduces concentrations of petroleum hydrocarbons through biodegradation.
This technology usually involves spreading excavated contaminated soils on the
ground surface in a thin layer and stimulating the aerobic microbial activity within
the soils through aeration and/or the addition of minerals, nutrients, and moisture
(US EPA 2017).
From the microbiological point of view, bioremediation is defined as an accelerated process using microorganisms, indigenous or introduced, to degrade and
detoxify organic substances to harmless compounds, such as carbon dioxide and
water, in a confined and controlled environment. Bioremediation is suitable for
treating a variety of organic chemicals, including (i) volatile organic compounds;
(ii) benzene, toluene, ethylbenzene, xylene (BTEX) compounds; (iii) phenolic
compounds; (iv) polycyclic aromatic hydrocarbons (PAHs), particularly the simpler
aromatic compounds; (v) total petroleum hydrocarbons (TPH); (vi) nitroaromatic
compounds. Bioremediation exploits microorganisms’ ability to degrade or transform organic pollutants to harmless products, yet a spontaneous biodegradation
process on a reclaimed site is very slow for the following reasons: (i) absence of a
specific microflora able to decompose present hydrocarbons, (ii) low solubility of
present pollutants, (iii) non-homogenous distribution of organic pollutants,
(iv) deficiency of oxygen and nutrients, etc. To accelerate the natural decontamination process it is convenient to create ideal conditions for the bacterial growth,
438
P. Najmanová and M. Halecký