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© 2002 WIT Press, Ashurst Lodge, Southampton, SO40 7AA, UK. All rights reserved. Web: www.witpress.com Email [email protected] Paper from: Brownfield Sites, CA Brebbia, D Almorza & H Klapperich (Editors). ISBN 1-85312-918-6

Economic aspects of polluted bioremediation

J. Troquetl &M. Troquet2 lBiobasic Environnement, control through , France 21nstitut des Sciences de 1!lng&ieur de 1‘Universit4 Blaise Pascal, France

Abstract

Industrialisation in developed country has left many type of pollution during the last 150 years, The end of course is generally soil and groundwater. In the main part of west countries, authorities must list the contaminated sites and have to consider their clean-up. In the same time, the use of biotechnology for the removal of organic pollution from soil and groundwater is in progress and offer new possibilities of cost savings, The main characteristics of bioremediation processes are their capacity to be implemented in-situ, that is to say to avoid great civil engineering works. Nevertheless before to choose this innovative technology, it is necessary to define the best treatment strategy, which is in close relation with local conditions. In this paper we will investigate some specific cases for which it is possible to implement an effective bioremediation process. In addition, the main process variables will be identified in order to keep the competitive price of this biotechnological approach. In this way, it will be emphasised particularly about the whole knowledge of the quality and quantity of the pollutants to be treated and both physical and biological factors active on the bioprocess in the first stage, Secondly, pilot lab experiment will be conducted to identify the different parameters of oxidizer and nutriments supplementation and micro-organisms growth kinetics, This strategy appears surprising, because the real evaluation of bioremediation cost cannot be established without the two steps described above, and this fust

operation could represent 5 to 15 0/0 of the global cost of rehabilitation, © 2002 WIT Press, Ashurst Lodge, Southampton, SO40 7AA, UK. All rights reserved. Web: www.witpress.com Email [email protected] Paper from: Brownfield Sites, CA Brebbia, D Almorza & H Klapperich (Editors). ISBN 1-85312-918-6

268 Browttfield Sites: Assessment, Rehabilitation and De~elopntent

1 Introduction

With the economic and industrial development, all countries in the world faces an enormous task in cleanup , If we promote today clean technologies for industries, it is also necessary to rehabilitate old industrial sites, particularly in urban zone, and remediate rapidly after ecological disasters. Soil, groundwater and marine coast are often subject to by various organic and mineral pollutants from a wide variety of sources. Organic pollutants, like crude oil, are one of the most important in marine environment with the mediated oil spills like the Exxon Valdez and Sea Empress in the United-States and other Amoco Cadiz or Erika in France. It has been estimated that worldwide somewhere between 1,7 to 8,8 x 106 tons of hydrocarbons impact marine waters and coasts each year [1], Around the coast of the UK alone, between the years of 1986 to 1996, 6,845 oil spills were reported [2]. In France 281 pollution reports in 2000 and 347 in 2001 were notified with respectively only 83 and 62 pollution sources identified [3]. This data show the difficulties to really quantify the . For soil and groundwater, the problem is the same but for other reason, especially because the pollution is quite very diffise and no visible. In different countries, the regulation organisation, national administration or industries try to draw up inventories of polluted site through historical studies. Among those, the US Environmental Protection Agency (EPA) and US Air Force in United-States, British Gas in United-Kingdom, the French Agency for Environment and Energy Management (ADEME) and the Ministry of Industry in France are the most active and they have promoted various demonstration programmed for testing land remediation, Economic assessment is not only a key factor for decisions in the field of site rehabilitation, but also one of the integrating tools for damage assessment. Indeed, economic cost induced by accidental, chronic or historical spills, belong to two distinct categories: a costs associated with decrease in servicesrendered by the natural active assets; n costs of rehabilitation or replacement of this asset. Treatment methods are divided into those for soil remediation and for surface and . Further categorization results in the consideration of biological, chemical and physical treatment technologies. Eighteen different methods have been reviewed that pertain to remediation of [4]. Bioremediation appears the simplest and cost effective method for large volumes of contaminated soil by toxic chemicals [5, 6], probably because this process naturally occurs in soil and groundwater and can be easily enhanced by different techniques,

2 The market evaluation

The pollution amount in soil and groundwater is very extensive, accumulated during 150 years of industrial activities. In United-States, thousands of sites have been identified throughout the country, with an estimated cleanup cost over $1.7 trillion using existing technologies [7]. On the other hand, it has been © 2002 WIT Press, Ashurst Lodge, Southampton, SO40 7AA, UK. All rights reserved. Web: www.witpress.com Email [email protected] Paper from: Brownfield Sites, CA Brebbia, D Almorza & H Klapperich (Editors). ISBN 1-85312-918-6

Browtzfield Sites: Assessment, Rehabilitation and De~’elopntent 269 estimated that the bioremediation component of environmental biotechnology will be some $500 million by the year 2000 [8]. This two values show the difficulty to make an inventory of contaminated sites and to estimate the remediation cost. The US Air Force has estimated that it has 2,000 underground tank sites to clean up [9] by this method. In 1986, conservative estimates indicated that they were approximately 3.5 million Underground Storage Tanks (USTS) in the United- States, of which roughly 200,000 to 400,000 are leaking or showing signs of deterioration. By 1994, the estimate of leaking tanks had grown to over 600,000. The average cost of a non-hazardous UST cleanup is estimated at $70,000 [10]. Other evaluation talk about 6 million USTS, with 1.$20% of them are leaking. The associated cleanup costs are estimated to average about $180,000 per site [11]. Always in United-States, the national market for bioremediation has been estimated to be up to $1 billion. Currently there are over 200 f~s in the US that offer bioremediation services [12]. Nevertheless, many other evaluations exist in different countries. In United-Kingdom, it has been estimated that there are some 100,000 sites which will cost between 210,000 and f20,000 million to cleanup [8], For example, British Gas has a major programme of contaminated land remediation involving approximately the 1,000 former gaswork sites, and up to f200,000 can be saved on each site with bioremediation [13]. In France, 896 contaminated sites have been identified in 1996 by different type of pollution [14] :41 YO are contaminated by hydrocarbons, 17 YO by , 16% by polycyclic aromatic hydrocarbons (PAHs), 13 % by halogenated organic compounds, 6940by polychlorobiphenyls (PCBS), 6 ?40 by other volatile organic compounds (VOCS) and lastly 5 ‘Aby . The regulated market is annually evaluated at ~45 million [15]. In this last country, the global market is estimated between ~7,500 and ~10,500 million for the next ten years for 200,000 to 300,000 sites potentially contaminated [15]. In Germany, 110,000 polluted sites are really identified among 200,000 suspected sites for a total remediation cost of ~200,000 million, but actually, a greater financial effort is consented with regard of other European countries [15].

3 Methods of soil treatment

Various technologies are currently available to treat contaminated soils by hazardous chemicals, including excavation and containment in secured , vapor extraction, stabilization and solidification, soil flushing, soil washing, solvent extraction, thermal resorption, and [4,16]. However, many of these technologies are either costly or do not result in complete decontamination of sites and in the actual communication especially devoted to bioremediation, only comparison for treatment costs will be reported.

4 Bioremediation capability

Bioremediation technologies can be broadly classified as ex-situ or in-situ. In both cases, micro-organisms are used because they have an extensive capacity to © 2002 WIT Press, Ashurst Lodge, Southampton, SO40 7AA, UK. All rights reserved. Web: www.witpress.com Email [email protected] Paper from: Brownfield Sites, CA Brebbia, D Almorza & H Klapperich (Editors). ISBN 1-85312-918-6

270 Browttfield Sites: Assessment, Rehabilitation and De~elopntent degrade synthetic compounds; therefore, bioremediation can be applied to various sites contaminated with a wide variety of chemical pollutants. The frost bioremediation technologies that have been developed were ex-situ technologies, i.e. biotreatment of excavated soil in contrast to in-situ technologies which aim is the treatment without excavation and often is taking care of both groundwater and soil pollution [17]. The current practice and perspective of bioremediation have been recently reviewed in terms of processes, efficient micro-organisms and molecular degradation activity, through the molecular microbiological point of view [18], Before evaluating bioremediation potential, it is necessary to explore the different processing ways and the vocabulary associated to this biotechnology. The most commonly techniques include [19] : ■ in-situ bioremediation, ■ landfarming, ■ slurry-phase bioreactors.

4.1 In-situ bioremediation, relies on biological cleanup without excavation and include many processes:

■ Intrinsic bioremediation, or bio-attenuation, which is natural attenuation of organic pollutants by micro-organisms present in soil an groundwater. No actions are taken to enhance the of contaminants beyond the existing capacity of the system. Intrinsic bioremediation is implemented by demonstrating that the native microbial population has the potential to reduce contaminant levels. It is less costly than conventional engineered technologies, but site remediation to regulatory standards generally cannot be accomplished in short time frame. Before intrinsic bioremediation can be implemented at a site, an evaluation is required to determine if it is a viable remediation method. Intrinsic bioremediation is expected to cost around $200,000, whereas the cost of pump and treat for the same pollution configuration can easily reach several million dollars [20]. ■ , consists in the stimulation of microbial growth in-situ by providing extra nutrients: Nitrogen and Phosphorus sources are added in relation with the hydrocarbons concentration according to the ratio carbon 100, nitrogen 10 and phosphorus 1. An electron acceptors such as is also supplied. Other substrates can be added as phenol, toluene or methane. In Japan, the effectiveness of in-situ biostimulation by methane injection into contaminated groundwater was demonstrated by small- scale field experiments tided by the Environmental Agency [21]. It is also possible to supplement the endogenous microbial population after enrichment of this specific microbial community in a Biological Activated Carbon (BAC) reactor for example [22]. ■ , is the addition of extra micro-organisms to enhance a specific biological activity when indigenous are not sufficiently active, As for biostimulation, the cost of bioaugmentation will vary with the nature of compound, of soil, and with the inoculum type and quantity [23]. © 2002 WIT Press, Ashurst Lodge, Southampton, SO40 7AA, UK. All rights reserved. Web: www.witpress.com Email [email protected] Paper from: Brownfield Sites, CA Brebbia, D Almorza & H Klapperich (Editors). ISBN 1-85312-918-6

Browtzfield Sites: Assessment, Rehabilitation and De~’elopntent 271

Determination of the potential success of bioaugmentation requires an understanding of the bioavaibility of the pollutants, the survival and activity of the added micro-organisms and the general environmental conditions that control soil bioremediation rates, The use of indigenous strains is not subject to notification requirement since they already exist in nature. However, researchers are showing an increased interest in the use of genetically- engineered-micro-organisms (GEMs) for remediation of recalcitrant contaminants [24]. = Biosparging, is a process increasing the biological activity by improving the supply of oxygen by air or pure oxygen sparging into the soil layer. Generally, air injection was tried at fust, but was often replaced by pure oxygen in order to increase the biodegradation rates [8]. Although biosparging has been used for soil and groundwater remediation since the mid- 1980s, and the review of published literature reveals only a limited number of field investigations. The main encountered problem is that the injected air probably moved through the subsurface in channels and there was not realIy all the volume of soil that was oxygenated [25]. ■ Bioventing, is defined as the use of induced low volume air movement through the unsaturated soil associated with vapour extraction. A vacuum is applied at some depth in the contaminated soil which drawn air down into the soil from wells drilled around the site and sweeps out any volatile organic compounds [26], The use of bioventing depends on specific conditions but could result in substantial cost savings as compared to current traditional methods of contaminant source treatment. Costs can vary dramatically depending on specific conditions. However costs from Air Force have been estimated for bioventing at $3 to $80 per cubic meter: $80 for 380 cubic meter and less, $3 for pollution volume greater than 15,000 m3. ■ Biofiltration, is particularly well adapted to groundwater bioremediation. This application involves sand mixed with non-indigenous micro-organisms into a trench in the subsurface ahead of the contaminant plume [27]. ■ , consists in the use of plants for contaminants and metals removal fi-om the soil. Many studies have been recently reported on the effects of vegetation on the transformation or stabilisation of organic compounds [28] and also extraction of metals from the environment [29]. These studies show that there are many reasons to investigate the interactions that occur among hazardous compounds, micro-organisms, plants, soil air and water. The plant root zone (rhizosphere) has significantly larger numbers of micro-organisms than soil which do not have plants growing on them; this appears to enhance bioremediation of organic compounds, Phytoremediation has made tremendous gain in market acceptance in recent years. Cost comparisons to other remediation technologies have been reported and the consensus cost of phytoremediation has been estimated at $45-$180 per cubic meter of soil treatment, and $0.15-$1.50 per cubic meter for treatment of aqueous waste stream [30]. The main technical advantages of phytoremediation in comparison with other methods is that it is far less disruptive to the environment and it has potential versatility to treat a diverse © 2002 WIT Press, Ashurst Lodge, Southampton, SO40 7AA, UK. All rights reserved. Web: www.witpress.com Email [email protected] Paper from: Brownfield Sites, CA Brebbia, D Almorza & H Klapperich (Editors). ISBN 1-85312-918-6

272 Browttfield Sites: Assessment, Rehabilitation and De~elopntent

range of hazardous materials. Finally, the process is relatively inexpensive, because it uses the same equipment and supplies that are generally used in , ■ Associated technologies: in order to enhance the remediation of contaminated soil, surfactants and biosurfactants can be used successfidly to increase contaminants volubility, and consequently their bioavailability. The main factors that should be considered when selecting surfactants include effectiveness, cost, public and regulatory perception, biodegradability and degradation by-products, toxicity to humans, animals and plants. Those specifications should be established by previous experience or by laboratory studies prior to the field-scale demonstrations [31].

4.2 Land farming, is an established technique for the remediation of hydrocarbons contaminated soil. Given half-lives of the order of one year, it would take about 7 years of treatment to remove 6,400 ppm of hydrocarbons down the cleanup goal of 50 ppm [19]. The time required for land farming remediation is an important factor in costing of the project, When the remediation can be promoted in ideal conditions, i.e. no liner and the remediation site adjscent to the contaminated one, the cost reported can be very low. For example, in Australia, 2,700 cubic meter of hydrocarbons contaminated soil have been treated in a 12 months operation; the pollution decrease from 4,600 ppm to near 100 ppm, costed $A1O,3O per ton, i.e. $A13,40 per cubic meter (respectively $US5,5 and $US7, 10). This cost can reach $Al 01 per ton ($US54) for an other contaminated site (5,300 cubic meter) [32], Relative costs associated with land farming in USA are reported to vary from $US1Oto $US100 per ton [17]. As in-situ bioaugmentation, extra micro-organisms can be added. For example, a mixed culture obtained from land farming and introduced in a sandy sediment polluted by light Arabian has increased by 31’XOthe bioremediation efficiency of the heavy fraction [33]. This technology generally used ex-situ can be formally divided in 3 classes: ■ , is the oldest method of ex-situ disposal waste; initially most landfill were unsealed so that any derived from the degradation of the contents could be dispersed in the surrounding soil and groundwater. The main problem of landfill disposal is finding suitable sites in term of geology. Today those sites will need to be lined with an impermeable barrier to avoid contamination of groundwater. This method is particularly used for storage and anaerobic biodegradation of domestic wastes. The problem with landfill is that, although the biodegradable materials is broken down, the degradation process is very slow [8]. Environmental regulations can considerably increase the cost of landfill technique by the hardening of specifications, but also by long-term costs for disposal at licensed site and new levy, as in the UK since 1996, both evaluated at f16 per cubic meter, On a direct cost basis the cost of landfill becomes more expensive [13]. ■ Composting, is the low-tech land farming technology and can be somewhat upgraded by mixing the soil with fresh organic residues (). Elevated © 2002 WIT Press, Ashurst Lodge, Southampton, SO40 7AA, UK. All rights reserved. Web: www.witpress.com Email [email protected] Paper from: Brownfield Sites, CA Brebbia, D Almorza & H Klapperich (Editors). ISBN 1-85312-918-6

Browtzfield Sites: Assessment, Rehabilitation and De~’elopntent 273

temperature and increased microbial diversity and activity improve the reaction rates. Moreover, specific co-substrates could favour co-. The US Environmental Protection Agency (EPA) has conducted many demonstration programmed in bioremediation activity for cost and performance comparison. In the Dubose site (Florida), comporting was believed to be approximately equal in cost to in-situ biological treatment: $266 per ton of soil treated (19,705 tons). This cost is relatively high because of the relatively large quantity of soil excavated (58,559 tons) [34]. = Biopile, is an advanced technology for comporting method by the fact that all parameters are monitored in a controlled area. Biopiles refer to the pilling of the material to be biotreated by adding nutrients and air into piles usually to a height of 2-4 m. This method is particularly well adapted to mathematical modelling for parameters analysis [35], Five biopiles performed in field scale (40 cubic meter) during 5 months, with addition of organic matter, show a decrease of oil pollution from approximately 2,400 to 700 ppm [36].

4.3 Slurry-phase bioreactor, In this case, excavated polluted soil, or sediments lagoon are treated under controlled optimal conditions, ensuring effective contact between contaminants and micro-organisms, The latter are, in most cases, specific cultures of adapted micro-organisms. A slurry phase bioremediation application performed at the French Limited Superfund Site, in Crosby, Texas, by the US Environmental Protection Agency (EPA), was a larger full scale application. The aim of the project was the remediation of a lagoon polluted by poly-nuclear aromatic hydrocarbons (PAHs), chlorinated organics, and metals, In 11 months, an innovative oxygenation system has permitted to remediate in-situ approximately 300,000 tons of tar-like sludge and subsoil from the lagoon. The global cost for this slurry-phase bioremediation system including technology development, project management, EPA oversight and backfill of the lagoon were approximately $49,000,000, i.e. $163 per ton, which correspond to $90 per ton for the treatment only, $55 for the before treatment and $18 for post-treatment activities [37]. Those last values emphasise that the indirect costs are very important: 45 ‘Aof the total cost. On other ex -situ application with four closed-top reactors of 680 cubic meter, for remediation of the South-eastern Wood Preserving Superfimd site, in Canton, Mississippi, EPA demonstrate the great potentiality for this technique. Actually the majority of the biodegradation of 8,000 ppm of PAHs occurred during the fust 5 or 10 days of treatment. The total cost for activities directly attributed to treatment corresponds to $170 per ton ($300 per cubic meter) for 14,140 tons of soil and sludges treated, In addition the cost of post-treatment activities is $35 per tons ($46 per cubic meter) [38].

5 Discussion

Table 1 summarize the results encountered in literature for the cost of contaminated soil remediation. We can observe a large distribution depending © 2002 WIT Press, Ashurst Lodge, Southampton, SO40 7AA, UK. All rights reserved. Web: www.witpress.com Email [email protected] Paper from: Brownfield Sites, CA Brebbia, D Almorza & H Klapperich (Editors). ISBN 1-85312-918-6

274 Browtzfield Sites: Assessment, Rehabilitation and De~elopment

for a part, with the amount of soil treated and for other part, with the type of contamination. It appears clearly that the cost is also function of environmental regulations, definitions of cleanup levels [10] and future progress in research. The fust operations reported have supported the cost of development and those indirect costs can represent 45 ‘-Yo of expenses [37]. Unfortunately, many values, in euros equivalent, date from the 90s. Actual costs will be impacted by time and competition but the relative costs given in Table 1 and the research perspectives will give an idea of where bioremediation falls. In our company, we develop also new generation of oxygenation systems, which permit to increase in-situ and for different conditions the biodegradation rates, This new process will allow us to treat soils and groundwater in-situ at a cost of ~7.5 to 15 per cubic meter.

Remediation Rangeof costin References Increasingexpensesfactors method ~ percubicmeter Incineration 305 4 energy Chemical immobilisation 28-70 4 transportation, monitoring Soil Washing 42 13 transportation, solvent disposal Basically Bioremediation 35 13 monitoring, time course of 34-215 10 treatment Bioventing 3.5-90 9 monitoring Landfarming 20.5-205 32 monitoring Landfill 41 13 excavation, transportation 130-215 10 Comporting 542 34 excavation, transportation Biopile 56-102 4 excavation, transportation Phytoremediation 51-203 28 monitoring Slurry-phase 185-392 37-38 excavation, transportation AH cost are converted in ~ with quotation at the April 4U2002, assuming 1 cubic meter =1.8 ton, when it is not indicated in the text, Table 1: Cost comparison for bioremediation and classical methods,

6 Conclusion

Bioremediation methods will play a significant role in the near Mure for remediation of contaminated soil and groundwater. Bioremediation and associated technologies are environmentally friendly technologies, are promoted in-situ and are often more cost effective than conventional treatment methods that are very energy consumer. Nevertheless, the contaminated soil cleanup market ask today numerous questions and the actual limited growth of this market is without common measure with the requirement in term of public safety, Therefore, as key for the next century, the technical and regulatory communities need to continue to ensure that bioremediation will reach its full potential as a treatment method.

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Browtzfield Sites: Assessment, Rehabilitation and De~’elopment 275

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276 Browtzfield Sites: Assessment, Rehabilitation and De~elopment

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