hydrocarbons from oil waste was used in an oil field in Kazakhstan. This technology
is based on the combination of physical pretreatment (gravity separation in heavy
suspensions) and bioremediation.
Contaminated soil heavily polluted with petroleum substances, including macroscopic petroleum conglomerates with a fraction !1 mm, is initially treated by
screening. The fine-grained fraction is then treated by bioremediation. The coarsegrained fraction is divided by the heavy-suspension separation into a product of high
specific gravity (sink) and a product of low specific gravity (float). The float product
consists of weathered oil particles (tar balls) and conglomerates of oil and soil with
high content of petroleum hydrocarbons (typically over 30%). The sink product,
made up of a less contaminated material, is crushed and mixed with the fine-grain
fraction and sludge generated by the heavy-suspension separation system. The
produced mixture is shipped to an on-site treatment facility and treated by bioremediation. The costly dewatering of sludge generated by the heavy-suspension separation system is not necessary as the watery sludge is utilized as a source of water in
the bioremediation process. This technology will mean considerable cost savings,
making it the main advantage over others.
26.2 Feasibility Lab Test of Bioremediation
The aim of the test performed on a material contaminated with petroleum hydrocarbons
was to determine and propose the most suitable and effective bioremediation process as
well as to specify the optimal technological parameters for the full-scale treatment
process. For the laboratory bioremediation test, a 5 kg sample of soil was collected
on-site from the oil field in Kazakhstan. The homogenized sample was placed into a
plastic container and the mineral nutrients, in the form of NP fertilizer (YaraMila NP
26–14 + 2S), were added in a ratio of 3 g/kg. Every second week a BIOTECH bacterial
suspension containing the following bacterial strains—Pseudomonas fluorescens,
Pseudomonas stutzeri, Pseudomonas veronii, Pseudomonas putida, and Shewanella
haliotis—was applied into the soil (10 mL of mixed solution per kg, with an initial
concentration of 1.0 Â 10
8 CFU/mL). The bioremediation test was performed under
aerobic conditions (mixed every week) at 20
C (Innemanová et al. 2018). The control
variant was only mixed once a week and set at 20
C with no addition of fertilizers or
BIOTECH. The results of the biodegradation lab test are shown in Fig. 26.1.
A significant decrease in a total petroleum hydrocarbons (TPH) concentration in
the soil sample treated by bioremediation was achieved during the test period, which
lasted about three months. From the initial value over 80 g/kg, the contamination
was reduced to approx. 15 g/kg TPH, which represents approx. 81% efficiency.
On the other hand, it is obvious from Fig. 26.1 that the decrease in TPH starts to
stagnate and only a limited additional decrease in the TPH contamination could be
expected. Probably the biodegradation efficiency reachable in this case will approach
90%, which still represents a high level of contamination (approx. 10 g/kg TPH). It
should be taken into consideration that a full-scale bioremediation process is usually
less effective than the process carried out under laboratory conditions.
536
P. Najmanová and R. Raschman
is based on the combination of physical pretreatment (gravity separation in heavy
suspensions) and bioremediation.
Contaminated soil heavily polluted with petroleum substances, including macroscopic petroleum conglomerates with a fraction !1 mm, is initially treated by
screening. The fine-grained fraction is then treated by bioremediation. The coarsegrained fraction is divided by the heavy-suspension separation into a product of high
specific gravity (sink) and a product of low specific gravity (float). The float product
consists of weathered oil particles (tar balls) and conglomerates of oil and soil with
high content of petroleum hydrocarbons (typically over 30%). The sink product,
made up of a less contaminated material, is crushed and mixed with the fine-grain
fraction and sludge generated by the heavy-suspension separation system. The
produced mixture is shipped to an on-site treatment facility and treated by bioremediation. The costly dewatering of sludge generated by the heavy-suspension separation system is not necessary as the watery sludge is utilized as a source of water in
the bioremediation process. This technology will mean considerable cost savings,
making it the main advantage over others.
26.2 Feasibility Lab Test of Bioremediation
The aim of the test performed on a material contaminated with petroleum hydrocarbons
was to determine and propose the most suitable and effective bioremediation process as
well as to specify the optimal technological parameters for the full-scale treatment
process. For the laboratory bioremediation test, a 5 kg sample of soil was collected
on-site from the oil field in Kazakhstan. The homogenized sample was placed into a
plastic container and the mineral nutrients, in the form of NP fertilizer (YaraMila NP
26–14 + 2S), were added in a ratio of 3 g/kg. Every second week a BIOTECH bacterial
suspension containing the following bacterial strains—Pseudomonas fluorescens,
Pseudomonas stutzeri, Pseudomonas veronii, Pseudomonas putida, and Shewanella
haliotis—was applied into the soil (10 mL of mixed solution per kg, with an initial
concentration of 1.0 Â 10
8 CFU/mL). The bioremediation test was performed under
aerobic conditions (mixed every week) at 20
C (Innemanová et al. 2018). The control
variant was only mixed once a week and set at 20
C with no addition of fertilizers or
BIOTECH. The results of the biodegradation lab test are shown in Fig. 26.1.
A significant decrease in a total petroleum hydrocarbons (TPH) concentration in
the soil sample treated by bioremediation was achieved during the test period, which
lasted about three months. From the initial value over 80 g/kg, the contamination
was reduced to approx. 15 g/kg TPH, which represents approx. 81% efficiency.
On the other hand, it is obvious from Fig. 26.1 that the decrease in TPH starts to
stagnate and only a limited additional decrease in the TPH contamination could be
expected. Probably the biodegradation efficiency reachable in this case will approach
90%, which still represents a high level of contamination (approx. 10 g/kg TPH). It
should be taken into consideration that a full-scale bioremediation process is usually
less effective than the process carried out under laboratory conditions.
536
P. Najmanová and R. Raschman