Fiabilitate si Durabilitate – Fiability Durability Supplement No 1 2015 [601898]

Fiabilitate si Durabilitate – Fiability & Durability Supplement No 1/ 2015
Editura “Academica Br âncuși ” , Târgu Jiu, ISSN 1844 – 640X

330 STUDY ON BIODEGRADATION TECHNOLOGY APPLICATION
IN BULK IN THE REMEDIATION OF SOILS CONTAMINATED WITH
POLYCYCLIC AROMATIC HYDROCARBONS

Lect. Irina Ramona PECINGINĂ, Assoc. Prof. Roxana Gabriela POPA
„Constantin Brâncuși” University of Tg -Jiu, irinacornescu yahoo.com

Abstract : Biodecontaminare methods are based on biodegradation in the subsurface presence of
microorganisms capable of degrading most of carbonaceous organic pollutants and much of inorganic
pollutants . Biodegradation in bulk meet that principle biological decontam ination several ways. These methods
are intended solely for solids, and is often used for on -site remediation of soils contaminated with organic
products. Station bioremediation ensure reducing the harmfulness of residues from oil exploitation activities
considered hazardous , using a bioremediation process . Bioremediation process will lead to reduction of oil
content and thus reducing the hazard of waste.

Keywords: technology, soils, polycyclic aromatic hydrocarbons

1. INTRODUCTION
Crude oil and natural g as, as well as their secondary products , can affect all
environmental factors (soil, water and air) and human life , animals and plants.
Among the negative effects that they have on the environment hydrocarbons are listed :
 destruction of vegetation
 destruct ion of soil fertility
 affecting the biological activity of the soil
 increase the toxicity of various substances , due to lack of oxygen in the environmental
 impairment of concrete and reinforced concrete structure laid underground
constructions and install ations
Biodegradation methods are based on biodegradation in the subsurface presence of
microorganisms capable of degrading most of carbonaceous organic pollutants and much of
inorganic pollutants .
Biodegradation is a natural phenomenon , because the soil , subsoil and groundwater is
normal living environment for many microorganisms (bacteria, fungi) that has an action on
biodegradable organic pollutants . Of these, bacteria predominate (Pseudomonas, Bacillus,
Arthrobacter și Flovorbacterium) and fungi (Tricho derma, Penicillium și Asperigillus).
This type of decontamination is suitable for petroleum hydrocarbons (oil, light liquid
fuel, gasoline, kerosene , mineral oils, benzene, toluene , xylene).
The efficiency of the biological decontamination of soils and gr oundwater depends on
various factors :
• pollutants biodegradability is expressed in terms of their ability to degrade under the
action of micro -organisms . The concentration and the distribution of pollutants in
contaminated environment were also crucial in ensuring the biodegradability . Biodegradation
is performing only within certain concentrations of pollutants. If it exceeds a certain threshold
concentration of the pollutant in the environment , microorganisms can remain on the
periphery of the contaminat ed area or be destroyed due to the high toxicity of pollutant .

Fiabilitate si Durabilitate – Fiability & Durability Supplement No 1/ 2015
Editura “Academica Br âncuși ” , Târgu Jiu, ISSN 1844 – 640X

331  Type of microorganisms . Among microorganisms , bacteria ranks
decontamination processes dominant in the soil and groundwater . Indigenous microflora of the
polluted area can be the basis of micro organisms necessary decontamination . În necessary if it
is proved that microorganisms are not native to biodegradation , microorganisms can use
"specialized" that are developed on a mineral support (zeolites, carbon, composite materials )
and then mixed wit h the contaminated environment .
 Choice oxidant and nutrient is always an important point in the feasibility of a
biological decontamination operations .
Biodegradation in bulk meet that principle biological decontamination several ways.
These methods are in tended solely for solids, and is often used for on -site remediation of soils
contaminated with organic products.
The basic principle of biodegradation in contaminated soil excavation consists bulk and
arrangement thereof in the vicinity of the excavation, the technical conditions that favor
natural aerobic biodegradation.
Source of microorganisms typically comes from the bacterial flora present in the soil,
but there are situations where extra proceed to the addition of external microorganisms.
Composting is the oldest and the simplest technique of biodegradation in contaminated
soil loose . For this method the contaminated soil is excavated and mixed with coarse organic
material (straw, bark, manure) which favors aeration and nutrient role.
The resulting mat erial is deposited on the soil by mixing in regular piles neighborhood
have a circumference of several meters and a height of about one meter .
The main conditions to ensure acceleration of degradation are breathable , moisture and
nutrient intake . To accele rate the biodegradation of pollutants proceed to enhancing soil
aeration by regularly turning piles with mechanized equipment . Excavation of contaminated
soil is the easiest physical method of remediation . It applies in cases of accidental pollution
and soil point when pollutant may soon reach the water table .
The contaminated soil is excavated by mechanical means , where possible and where there are
no conditions for the evacuation of mechanized excavation soil will be done manually , after
which it will be transported to where it will apply step of biodegradation in bulk –
composting . (Fig. 1)

Fig. 1 . Scheme for the application of composting in bulk

Fiabilitate si Durabilitate – Fiability & Durability Supplement No 1/ 2015
Editura “Academica Br âncuși ” , Târgu Jiu, ISSN 1844 – 640X

332 Excavation of polluted soil are obvious advantages : simplicity and speed of
implementation, the possibility of full dismantling of the contaminated material and low cost
execution. Some pollutants changing its characteristics after the execution of excavation
work . Because of these issues , remediation method asola and polycyclic aromatic
hydrocarbons is consider ed the most efficient bulk-composting biodegradation

2. MATERIALS AND METHODS . CASE STUDY
The location chosen to be addressed in the case study company OMV Petrom SA
Group Deposits Ticleni area.
In terms of geomorphology, the location is within the area belonging to the common
meadow and belongs Depression Jiu and Gilortului ture. It is located at a distance of over 2
km from the city Ticleni on land fallow, with neighboring forest areas.
From geological point of view, belongs to Getic Depression studied area. Geological
formations which occur in the upper part of the land belonging to the Quaternary, are
generally composed of sandy clays, sands and gravels.
From the terms of soil, analyzed the lens is placed in a common meadow and belongs
Depression Jiu a nd Gilortului ciency, attending classes with specific soils imposed by
regional and local factors, conditions are favorable pedogenetical area argillic brown soil
formation and development luvic and luvic soil.
In terms of hydrological, regional hydrograph ic network is represented by several
major rivers alien and through a network of smaller rivers native, with frequent phenomena of
drying up.
The main waste resulting from oil extraction activity consists of:
– soil contaminated with petroleum products (hydr ocarbons) from the perimeters of
the extraction and primary processing, as a result of accidental circumstances or
due to phasing of wells or other facilities (parks tanks, compressor stations, etc);
– non-recoverable waste results
For processing and dispos al of these waste types, management proposed a scheme that
complies with national legislation in the field of waste management.
Such waste management scheme comprises:
 Treatment of mechanical, thermal and chemical sludge from lagoons and waste from
tanks – will perform with mobile facilities and will contribute to the recovery and reuse
of hydrocarbons contained in oil slurry;
 Treatment for biologically contaminated soil bioremediation role in stations to reduce
oil content, aimed at reducing waste storage k;
 Use of treated soil meeting the limit values on soil quality, as filler in land cleanup
related to oil fields and primary processing ;
 Elimination of non-recoverable final demolition waste and waste treated by
bioremediation which do not meet the quality requirements for use in remediation
works by storing in warehouses for non-hazardous solid waste .
Construction works of the cell will consist mainly bioremediation :
 scraping topsoil and storing it in specially designed areas , inside, in order to use to
restore the land to the objectives of decommissioning subject (well, parks);

Fiabilitate si Durabilitate – Fiability & Durability Supplement No 1/ 2015
Editura “Academica Br âncuși ” , Târgu Jiu, ISSN 1844 – 640X

333  existing land excavation depths varying depending on the target location and the need
to ensure drainage slopes from all directions to the home collector ;
 basic profiling platform bioremediation ;
execution platform layer foundation ;
 realization of asphalt waterproofing layer ;
 prefabricated construction annexes (booth, laboratory , etc.);
 create system for collection, storage , pre -treatment and water circulation inside and
furrow water ing system .
Specific station bioremediation facilities are:
 The reception area and temporary storage of contaminated soil ;
 Material storage area loosening ;
 Bioremediation platform itself ;
 Bioremediation material storage area ;
 Drainage system and storm wate r storage tank for recycling ;
 System of furrow irrigation water collected in the storage tank ;
 Handling areas .
Station bioremediation ensure reducing the harmfulness of residues from oil exploitation
activities considered as dangerous as using bioremediation treatment process . (Fig.2 ).

Fig.2. Overview of a wastewater bioremediation

The main stages that take place in the station bioremediation are:
• reception and temporary storage of contaminated soil
• deposition result of mixing, soil nearby, r egular heaps with a circumference of several
meters and a height of about one meter, the technical conditions that favor natural aerobic
biodegradation (Fig. 2. and fig.3. )
Submission of polluted soil is impermeable surfaces , removing the risk of migratio n of
pollutants from contaminated soil in the ground support ( fig. 4).
• bioremediation (processing – about 3 months). The process of biodegradation are
developed in a chain reaction in which carbon compounds are converted by sequential
degradation in the molecule becoming less complex , simple to obtain by-products , which
include water and carbon dioxide . Waste treatment process involves the arrangement of the
material received received on the platform surface and inducing optimal conditions for the

Fiabilitate si Durabilitate – Fiability & Durability Supplement No 1/ 2015
Editura “Academica Br âncuși ” , Târgu Jiu, ISSN 1844 – 640X

334 prolife ration of microorganisms in the waste stream (bacteria ) to biological degradation
activity and consumption of existing organic product (petroleum hydrocarbons).

Fig.3. The process of mixing / aeration at Fig. 4 Submission of soil material in bulk
a station in bioremediation

Fig.5. Submission soil impermeable platform

For the growth of microorganisms necessary for the biodegradation of soil polluted with
polycyc lic aromatic hydrocarbons , must meet the following conditions: temperature 15 to 45 °
C (being dependent on the type of microorganisms ); high permeability (permeability
coefficient Kf> 10-6), pH = 5.5 -8.5. To accelerate the degradation process of the main
conditions to be met are: aeration , moisture and nutrient intake (nitrogen , phosphorus, organic
substances ). Indigenous microflora of the polluted area can often constitute the basis of
microorganisms necessary decontamination .The microorganisms present i n contaminated soil
are thoroughly examined by laboratory tests to elucidate possible decontamination without an
additional contribution of non-indigenous microorganisms .
If biodegradation of petroleum hydrocarbons taking advantage of existing natural
species in the soil , such as Arthrobacter , Achromobacter , Novocardia , Pseudomonas,
Flovorbacterium . If, however, it turns out that indigenous microorganisms do not meet the
microorganisms biodegradation can call "specialized" that are developed on a mineral su pport

Fiabilitate si Durabilitate – Fiability & Durability Supplement No 1/ 2015
Editura “Academica Br âncuși ” , Târgu Jiu, ISSN 1844 – 640X

335 (zeolites, carbon, composite materials ) and then mixed with the contaminated environment .
• bioremediation temporary storage material . After treatment , depending on the
concentration in petroleum hydrocarbons resulting material will have the characte ristics of
soil that can be used , as appropriate, to: filling cavities resulting from the excavation of
contaminated soil and parks wells and storage tanks decommissioned in final permanent
repository will be arranged in accordance with European standards by OMV Petrom SA at
field cluster .

3. RESULTS AND DISCUSSION
The content of the material to bioremediation of petroleum hydrocarbons is estimated
at around 5 -6%. In carrying out bioremediation process is compulsory humidity by wetting,
using rainwater sto red in special tanks and oxygenation waste permanently placed in
windrows, by loosening and mixing using a special machine.
Station bioremediation ensure reducing the harmfulness of residues from oil
exploitation activities considered hazardous, using a bi oremediation process.
Bioremediation process will lead to reduction of oil content and thus reducing the hazard of
waste. It is expected that for some of the waste processed in hydrocarbon concentration to be
reduced to the stage that will be allowed to us e as filler in areas contaminated soil is
excavated during decontamination operations.

4. CONCLUSIONS
The advantages of the bulk bioremediation are the following :
• pollutants are destroyed by conversion into water and CO2 ; are not transferred
• treatment is complete and aims at the same time soil, groundwater and air content in
the soil
The disadvantages of bulk bioremediation method are as follows:
• technique can be used only for biodegradable substances
• when applied in situ soil permeabili ty is required to be greater than 10-6 m/s
• if the phenomenon of pollution is generated by a mixture of pollutants , biodegradation
can be inhibited because some pollutants can be toxic
• biological processes involved in biodegradation can sometimes genera te toxic
metabolites with an equal to or greater than the substances they come from
• stability metabolites may be greater than the substances they come from
• during decontamination is quite high

REFERENCES
[1] Lazar , M., Ecological rehabilitation , Publi sher Universitas , Petrosani, 2001
[2] Neag , Gh., Clean soil and groundwater , Paper Science Publishing House , Cluj Napoca ,
1997
[3] Pecingină, I.,R., Environmental protection biotechnologies , C.T.E.A. Publishing,
Bucharest, pp. 195 -206, 2010.
[4] Rauta C., Cirstea S, Prevention and control of soil pollution , Ed. Ceres ,
Bucharest in 1989 .