In situ and on-site soil and groundwater remediation technologies

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Contaminated Soil and Groundwater Remediation; Economical in-situ and on-site technologies. Presented at China-Finland co-operation seminar on soil remediation and waste management held 4.-7.11.2008, SHANGHAI, CHINA, Ramada Inn – Shanghai New World

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In situ and on-site soil and groundwater remediation technologies

  1. 1. Contaminated Soil and Groundwater Remediation; economical in-situ and on-site technologies China-Finland co-operation seminar on soil remediation and waste management 4.-7.11.2008, SHANGHAI, CHINA Ramada Inn – Shanghai New World Mr. Jarno Laitinen Deputy Managing Director Doranova Ltd.
  2. 2. Presentation outline <ul><li>Company Overview </li></ul><ul><li>Contaminated Soil Remediation </li></ul><ul><li>In-situ and On-site Technologies </li></ul><ul><li>Soil Washing </li></ul><ul><li>Conclusions </li></ul>
  3. 3. Doranova Ltd. Contracting • Supplying • Partnership <ul><li>Founded 1996 </li></ul><ul><li>Vesilahti (FI) </li></ul><ul><li>Heinola (FI) </li></ul><ul><li>Tallin (ES) </li></ul><ul><li>London (UK) </li></ul><ul><li>15-20 persons </li></ul><ul><li>Parnerships </li></ul><ul><ul><li>International partners </li></ul></ul><ul><ul><li>Import/Export of knowledge </li></ul></ul><ul><li>ISO 9000:2000 </li></ul><ul><li>ISO 14000:2004 </li></ul>
  4. 4. Doranova Ltd. Contracting • Supplying • Partnership <ul><li>Consulting and R&D </li></ul><ul><li>Soil and groundwater remediation </li></ul><ul><li>DoAct ® water and gas purification units </li></ul><ul><li>Municipal water & ww -treatment </li></ul><ul><li>Landfill leachates treatment </li></ul><ul><li>Sludge dewatering and hygienisation </li></ul><ul><li>Biogas fermentation, collection and usage </li></ul><ul><li>(landfill, agriculture & natural -gases) </li></ul><ul><li>Renewable energy production, CHP -systems </li></ul>
  5. 5. R&D - state of the art remediation
  6. 6. In-situ and on-site technologies <ul><li>Risk-based clean-ups are becoming more widespread internationally, resulting in demand for certain types of technologies, enabling more flexibility in site reuse , and encouraging more property owners to remediate their properties. </li></ul><ul><li>In-situ and on-site treatment allows the development and usage of the property during remediation . </li></ul><ul><li>” Technologies aiming at optimising the contaminant removal versus financial costs ” </li></ul>
  7. 7. In-situ and on-site technologies <ul><li>Technologies in this presentation: </li></ul><ul><ul><li>Biological </li></ul></ul><ul><ul><li>Chemical </li></ul></ul><ul><ul><li>Electrokinetic </li></ul></ul><ul><ul><li>Vapour </li></ul></ul><ul><ul><li>Adsorbtion </li></ul></ul><ul><ul><li>Separation </li></ul></ul><ul><li>Main focus in general technology overview </li></ul><ul><li>Short examples </li></ul>
  8. 8. Biological in-situ and on-site <ul><li>The fundamental basis of in-situ bioremediation involves introducing nutrients and electron acceptors/donors to the contaminated area by various methods. </li></ul><ul><li>The main goal of the methods is to induce the natural biological activity to increase contaminant biodegradation. </li></ul><ul><li>The major benefits from of in situ technologies arise from their low intrusion level as noted earlier. </li></ul>
  9. 9. Biological in-situ and on-site <ul><li>Biological in-situ and on-site treatment can be divided to aerobic and anaerobic processes. </li></ul><ul><li>There are differences in which process should be selected per contaminant. </li></ul><ul><li>Aerobic processes are used mainly for </li></ul><ul><ul><li>Petroleum hydrocarabons </li></ul></ul><ul><ul><li>PAHs </li></ul></ul><ul><li>Anaerobic processes are used mainly for </li></ul><ul><ul><li>Chlorinated solvents </li></ul></ul>
  10. 10. Biological in-situ and on-site
  11. 11. Biological in-situ and on-site Monitored Natural Attenuation
  12. 12. Biological in-situ and on-site Aerobic Bioremediation
  13. 13. Biological in-situ and on-site Land Farming / Composting
  14. 14. Biological in-situ and on-site Phytoremediation
  15. 15. Chemical in-situ and on-site <ul><li>The basis of chemical treatment is the addition of a chemical into contaminated groundwater or soil which oxidizes the contaminants into harmless or less harmful compounds. </li></ul><ul><li>The main goal of the technology is to rapidly produce ”radicals” which can react with the contaminant and degrade them to to harmless compaunds. </li></ul><ul><li>The major benefit of chemical treatment is the short er timline than with biological treatment. </li></ul>
  16. 16. Chemical in-situ and on-site <ul><li>Chemical oxidation can be done with different oxidising chemicals: </li></ul><ul><ul><li>Permanganate (MnO 4 - ) </li></ul></ul><ul><ul><li>Fenton (Fe/H 2 O 2 ) </li></ul></ul><ul><ul><li>Ozone (O3) </li></ul></ul><ul><ul><li>Persulfate (S 2 O 8 2- /SO 4 - ) </li></ul></ul><ul><li>Can be applied for petroleum hydrocarbons, BTEX, PAHs, chlorinated solvents </li></ul>
  17. 17. Chemical in-situ and on-site In Situ Chemical Oxidation (ISCO)
  18. 18. Electrokinetic in-situ and on-site <ul><li>The basis of the technology is the addition of an electric current on the subterraean. </li></ul><ul><li>The basic reactions are: </li></ul><ul><ul><li>Electro-osmosis (transportation of water) </li></ul></ul><ul><ul><li>Electrophoresis (transport in pH gradient) </li></ul></ul><ul><ul><li>Electro-migration (transport of ions) </li></ul></ul><ul><ul><li>Electro-oxidation (oxidation of contaminats) </li></ul></ul><ul><li>Electrokinetics can tackle contaminants otherwise difficult, like metals. </li></ul>
  19. 19. Vapour in-situ and on-site <ul><li>The basis of technology is the physico-chemical properties of some chemicals to be easily volatilized. </li></ul><ul><li>The volatilisation can be enhanced by air injection or by vacuum pumping. </li></ul><ul><li>… </li></ul>
  20. 20. Vapour in-situ and on-site Soil Venting and Air Sparging
  21. 21. Adsorption / Mass Removal in-situ and on-site <ul><li>The basis of the technology is to remove and/or adsorb the contaminants. </li></ul><ul><li>Various adsorbent materials can be applied, most widely used are activated carbons </li></ul><ul><li>… </li></ul>
  22. 22. Adsorption / Mass Removal in-situ and on-site LNAPL Pumping / Pump and Treat
  23. 23. Separation, soil washing <ul><li>Soil consists of various fractions, like sand, clay and organic material. The mutual relations of these three fractions determine the type of soil. </li></ul><ul><li>Most contaminants attach mainly to either the organic material or clay particles. Therefore once the soil is separated into the various fractions the greater part can be reused on-site. </li></ul><ul><li>A large fraction of reusable sand can be separated and the much smaller volume of strongly contaminated clay, silt and organic matter can either be treated or delivered to a landfill. </li></ul>
  24. 24. Separation, soil washing <ul><li>The contaminated soil is presieved (dry) on about 10 cm for removal of coarse debris etc. </li></ul><ul><li>The soil is mixed with water and sieved (wet) in a scrubber on a diameter of 25 mm and afterwards on a 4 mm vibrating sieve. The fractions (> 25 mm and > 4 mm) removed in these two steps are often not contaminated and reusable. </li></ul><ul><li>The remaining water/soil mixture is pumped to the jig, where it runs in a thin layer (5 – 10 cm) over a lattice on which a coarse gravel bed (ragging) is placed. </li></ul><ul><li>The water is pulsated vertically using a bellows. By the pulsation and the nett upward flow of clean water (hudge), the sand, which has the largest density, is caught in the ragging. The organic matter and the fine materials (clay and silt) are removed with the water. </li></ul><ul><li>The sand passes through the ragging and is removed at the bottom of the jig, after which it is dewatered by a dewatering sieve. </li></ul><ul><li>The sludge (water/clay/silt) is collected in a storage depot. The sludge can be dewatered either by a natural process or by a sieve belt press. </li></ul><ul><li>The water from the sludge depot is reused after treatment in the process. In this way little fresh water is needed and therefore also less water needs to be disposed of. </li></ul>
  25. 25. Separation, soil washing
  26. 26. Separation, soil washing <ul><li>An example project done in Finland, Leilahti </li></ul><ul><li>The site was an old industrial site , planned for housing </li></ul><ul><li>About 9,000,000.00 kg of contaminated soil was treated </li></ul><ul><li>The average treatment capacity was 20,000.00 kg/h </li></ul>
  27. 27. Separation, soil washing
  28. 28. Separation, soil washing <ul><li>By the treatment the contamination is concentrated in the organic matter and the clay/silt fraction. The sand fraction hardly contains any contaminants. Usually the treatment results in a reusable amount of about 80-90% (depending on the soil type). </li></ul><ul><li>The system is simple and easy to adjust to the material that is treated </li></ul><ul><li>The energy and water consumption are low </li></ul>
  29. 29. Conclusions <ul><li>In-situ and on-site technologies are more widely applied in Europe and North-America. </li></ul><ul><li>Treating the contaminants at site provides undeniable cost savings . </li></ul><ul><li>The technology selection has to be done on case-by-case basis to define the optimum. </li></ul><ul><li>There are solutions for all contaminants </li></ul><ul><li>And also methods that produce new raw materials , like Doranova’s soil washing . </li></ul>
  30. 30. Doranova remediates the value of environment

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