© 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 soil bioremediation J. Troquetl &M. Troquet2 lBiobasic Environnement, Pollution control through biotechnology, 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 pollutants 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 hazardous waste, 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 contamination by various organic and mineral pollutants from a wide variety of sources. Organic pollutants, like crude oil, are one of the most important pollutant 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 marine pollution. 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 groundwater remediation. Further categorization results in the consideration of biological, chemical and physical treatment technologies. Eighteen different methods have been reviewed that pertain to remediation of soils [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 petroleum hydrocarbons, 17 YO by lead, 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 mercury. 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 landfills, vapor extraction, stabilization and solidification, soil flushing, soil washing, solvent extraction, thermal resorption, vitrification and incineration [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