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Prof. Dr. Celal F. Gökçay

Prof. Dr. Celal F. Gökçay

Prof. Dr. Celal F. Gökçay

Professor · Department of Environmental Engineering
E-mail: cfgokcay@metu.edu.tr
 

Education

  • Ph.D., Microbiology, University of Wales (University College Cardiff), UK, June 1978
  • B.Sc., Biology, University of Istanbul, February 1973
  • Istanbul Kabataş Lycee, Science Section, September 1968

Research Interests

  • Biodegradation of unusual compounds
  • Bio-leaching and recovery of mining residues and wastes
  • Bacterial desulfurization of coals; microbial solubilization of lignites
  • Activated sludge kinetics; nutrient removing activated sludge
  • Effect of heavy metals on activated sludge kinetics
  • Biological treatment of paper pulp bleachery effluents
  • Treatability of chlorinated organic compounds

Research Techniques

Techniques Employed

  • Enzyme assays, manometric and respirometric techniques in biochemistry and biological treatment
  • Gas chromatography, atomic absorption spectroscopy, thin layer chromatography
  • Organic chlorine analysis (TOX, AOX)
  • Trace organics analyses (PCBs and organochlorine pesticides) in waters and wastewaters

Laboratories Developed

  • Microbiology research and teaching labs; atomic absorption, gas chromatography, AOX and IR laboratories in METU Environmental Engineering Department

Membership in Professional Societies

  • International Water Association (IWA) — Member
  • Turkish Microbiology Society (TMC) — Member
  • Type Culture Collections and Industrial Microbiology Society (KUKEM) — Board Member and Editor
  • Mediterranean Scientific Association for Environmental Pollution (MESAEP) — Member and Editor

Awards

  • NATO Fellowship for Ph.D. studies in the UK, delivered via TÜBİTAK

Positions Held

Academic Positions

  • February 1992 – present     Full Professor, METU Environmental Engineering Department
  • September 1980 – February 1992   Associate Professor (Docent), METU Environmental Engineering Department
  • September 1978 – September 1980   Assistant Professor, METU Environmental Engineering Department
  • November 1973 – October 1974   Teaching Assistant, METU Environmental Engineering Department

Administrative Positions

  • 1998 – 1999     Head of Environmental Engineering Department, METU
  • 1990 – 1997     Head of Environmental Sciences Section, METU Environmental Engineering Department
  • 1988 – 1991     Executive Board Member, Environmental Research Group, National Scientific and Technical Council of Turkey (TÜBİTAK)
  • February 1983 – July 1988   Assistant Chairman, METU Environmental Engineering Department

International Assignments

  • July–August 1991   Short-term WHO Consultancy Assignment, Regional WHO Office for the Western Pacific — Designed and conducted an intensive course on environmental sanitation and biological treatment for hospital engineers, Kuala Lumpur, Malaysia

Teaching Experience

  • ENVE 205 Environmental Microbiology (lectures and practicals)
  • ENVE 301 Principles of Ecology for Environmental Engineers
  • ENVE 302 Chemical Microbiology
  • ENVE 313 Statistics for Environmental Engineers
  • ENVE 314 Chemical Microbiology Laboratory
  • ENVE 420 Environmental Impact Assessment
  • ENVE 520 Microbial Degradation of Organic Pollutants
  • ENVE 532 Environmental Biotechnology
  • ENVE 535 Advanced Biological Treatment

Directed Thesis Studies

M.Sc. Theses

  1. Yurteri, R., "Microbiological desulfurization of Turkish lignites"
  2. Önerci, S., "Bacterial leaching of copper flotation tailings"
  3. Çağlar, A., "Studies on calcined pyritic fly-ash using microbiological leaching techniques"
  4. Kazancı, N., "Development of a compact bio-disk system for domestic wastewater treatment"
  5. Eldem, M., "Anaerobic biological treatment of high-strength wastes"
  6. Gürol, A., "Effect of Nickel(II) and Chromium(VI) on RBC culture systems"
  7. Lule, M., "Effect of Metals on Respirometric BOD" (Co-supervision with Prof. Dr. Ülkü Yetiş)
  8. Şahin, Ş., "Characterization of Chlorine Dioxide Bleached Pulp Effluents" (Co-supervision with Prof. Dr. Ülkü Yetiş)
  9. Gerçek, A., "Physico-Chemical Treatment of Bleaching Process Effluents from SEKA Kastamonu Pulp and Paper Plant" (Co-supervision with Dr. Gülerman Sürücü)
  10. Yurdagül, S., "Biochemistry of Chlorolignin and Chloropesticide Degradation"
  11. Katmer, P., "Assessment of Toxicity and Biodegradability of Pulping Effluents to Microbial Treatment Community by Electrolytic Respirometry" (Co-supervision with Prof. Dr. Filiz B. Dilek)
  12. Bilgiç, H., "Biological Color Treatment of Pulp and Paper Industry Effluents"
  13. Atabek, S., "Activated Sludge Treatment of AOX from Pulping Wastes"
  14. Baş, G., "Treatment of Chlorinated Compounds by Activated Sludge and Process Microbiology"
  15. Arıcan, B., "Nickel Sorption by Activated Sludge" (Co-supervision with Prof. Dr. Ülkü Yetiş)
  16. Sin, G., "Evaluation and Modeling of Ankara Nutrient Treatment Plant"
  17. Aydoğan, A., "Biological Phosphorus Removal in A/O Process with High Strength Wastewater"

Ph.D. Theses

  1. Yetiş, Ü., "Effect of Nickel(II) and Chromium(VI) on activated sludge"
  2. Dilek, F.B., "Combined effects of heavy metals on activated sludge"
  3. Kılıç, B., "Biological treatment of chlorinated wastes"

Research Projects

  1. Recycling of pyritic fly ash by using microbiological techniques, TÜBİTAK (MAG-539), 1981 — Project Director
  2. Monitoring of microbiological pollution in the Mediterranean coastal zone of Turkey, Mediterranean Action Plan (MED-POL), 1985–1987 — Research Staff
  3. Biological treatment of IMEKS-Abattoir wastewaters (supported by IMEX) — Research Staff
  4. Treatment of MKE-Elmadag Ammunition Factory effluents (supported by MKE) — Project Director
  5. Treatment of pulp and paper industry wastewaters from SEKA Taşköprü Plant (supported by SEKA) — Project Director
  6. Effect of Nickel on activated sludge microbiology and kinetics, METU Research Fund — Project Director
  7. Effects of various parameters on rotating biological contactors, METU Research Fund — Project Director
  8. Consultancy to Ankara Municipality on process selection for the municipal biological treatment unit, ASKİ — Consultant
  9. Environmental impact assessment for Aliağa Thermal Power Plant — Project Staff
  10. Biosolubilization of Turkish Lignites, TÜBİTAK (KTCAG5), completed 1993 — Project Director
  11. Black Sea Land-based Pollutants Project, Turkish Ministry of the Environment (PCB analyses in surface waters), 1993 — Project Staff
  12. Characterization and treatability of chlorinated and coloured effluents from SEKA Pulping Plants (supported by SEKA General Directorate), 1993–1995 — Project Director
  13. Treatment of chlorinated effluents, TÜBİTAK (KTCAG128), 1993–1995 — Project Director
  14. Consultancy to İzmir Municipality for control of the process design of the municipal nutrient-removing biological treatment unit, İzmir Municipality, 1999 — Consultant
  15. Consultancy to the Ministry of the Environment for the assessment of Pamukkale and Akkoy nutrient-removing activated sludge plants, 2000 — Consultant
  16. Consultancy to the Ministry of the Environment for assessment and design modifications for Göçek nutrient-removing activated sludge plant, 2001 — Consultant
  17. Monitoring of chlorinated organics in Kızılırmak, State Planning Organization (DPT), 1998–2001 — Project Director
  18. Short-term projects with durations of three months or less; mainly consultancy work — approximately 20 projects

Publications

  1. Gökçay C.F., "Microbial degradation of ethers", Ph.D. Thesis, University of Wales, Cardiff, UK, 1978.
  2. Gökçay C.F., "Microbial degradation of surfactants", 1st National Environmental Engineering Symposium, Ankara, 26 February 1979. (In Turkish)
  3. Gökçay C.F., "Tracing of waters by using microbial tracers", Industry and the Environment Symposium, Turkish Chamber of Mechanical Engineers, 28–30 November 1979. (In Turkish)
  4. Soyupak S., Yazici A. and Gökçay C.F., "A mathematical model for simulating biofilm formation in completely submerged rotating biodisc reactor", DOGA, Environment Sect., 5: 93–98, 1981. (In Turkish)
  5. Gökçay C.F., "Microbial metal leaching", KUKEM J., 5(2): 24–25, 1982. (In Turkish)
  6. Çağlar A. and Gökçay C.F., "Leaching of copper from Murgul calcined fly-ash by using thermophilic Thiobacilli", KUKEM J., 5(2): 30–31, 1982. (In Turkish)
  7. Gökçay C.F., Doğan Z. and Atabey M.E., "Microbial leaching and recycling of Turkish pyrite cinders", KUKEM J., 5(2): 86–87, 1982. (In Turkish)
  8. Gökçay C.F. and Yurteri R., "Microbial desulfurization of lignites", FUEL (London), 62: 1223–1224, 1983.
  9. Gökçay C.F., "Microbial metal extraction and recycling of mineral wastes". In Industrial Microbiology, ed. E.T. Cetin, Istanbul Bayda Publication, pp. 381–396, 1983. (In Turkish)
  10. Doğan Z., Gökçay C.F. and Atabey M.E., "Bacterial leaching of Turkish pyrite cinders". In Recent Progress in Biohydrometallurgy, ed. G. Rossi and A.E. Torma, Associazione Mineraria Sarda, Iglesias, Italy, pp. 693–704, 1983.
  11. Gökçay C.F., Soyupak S. and Hatipoğlu M.E., "Initial assessment of marine biological fouling and fouling control for a nuclear power plant to be sited in the East Mediterranean", MESAEP Symposium, Iraklion, Greece, 1983.
  12. Gökçay C.F., Soyupak S. and Hatipoğlu M.E., "Initial assessment of marine biological fouling and fouling control — environmental protection aspects", VII Journées Étud. Pollutions, Lucerne, C.I.E.S.M., pp. 721–725, 1984.
  13. Doğan Z., Gökçay C.F. and Atabey M.E., "Bacterial leaching of Turkish pyritic cinders", VIIIth National Congress on Mining and Mining Technology, Ankara, 21–25 February 1983, pp. 349–358. (In Turkish)
  14. Gökçay C.F. and Hatipoğlu M.E., "Study of human-originated bacterial and organic pollution on the Mediterranean coast of Turkey", ENVIRONMENT 84, Vth Turkish-German Environmental Engineering Symposium, İzmir, 11–16 June 1984, pp. E.20–23. (In Turkish)
  15. Doğan Z., Gökçay C.F. and Atabey M.E., "Bacterial leaching of Turkish pyritic cinders", METU Applied Research J., 3(11), 1985. (In Turkish)
  16. Gökçay C.F., "Food industry wastewaters and their discharge and biological treatment alternatives", Recent Advances in Food Technology Symposium, FAO-METU-TÜBİTAK, Ankara, 23–24 October 1985, pp. 217–236. (In Turkish)
  17. Gökçay C.F. and Önerci S., "Microbiological recycling of copper flotation tailings", KUKEM J., 10(2): 116–117, 1987. (In Turkish)
  18. Yetiş Ü. and Gökçay C.F., "Effect of Cr(VI) and Ni(II) salts on BOD experiments", KUKEM J., 10(2): 118–119, 1987. (In Turkish)
  19. Gökçay C.F. and Yetiş Ü., "Effect of Ni(II) on activated sludge", International Symposium on Environmental Management 87, Istanbul, pp. 581–596, 1987.
  20. Gökçay C.F. and Yurteri R., "Bacterial desulfurization of Turkish lignites", Resources Conservation and Recycling, 1: 261–278, 1988.
  21. Yurteri R. and Gökçay C.F., "Bacterial desulfurization of Turkish lignites", Biological Treatment of Coals Workshop, Virginia, July 8–10, 1987, pp. 242–277, 1988.
  22. Yetiş Ü. and Gökçay C.F., "Effect of Nickel(II) on activated sludge", Water Research, 23: 1003–1007, 1989.
  23. Gökçay C.F., "Magnitude of impacts of industry on the environment in Turkey", Symposium on Biology Education Related to Environmental Problems, Ankara, 20–21 December 1989. (In Turkish)
  24. Gökçay C.F. and Yurteri R., "Bacterial desulfurization of lignites". In Bioprocessing and Biotreatment of Coal, ed. D.L. Wise, Marcel Dekker, New York, 1990.
  25. Gökçay C.F. and Yetiş Ü., "Effects of Cr(VI) on activated sludge", Water Research, 25: 65–73, 1991.
  26. Gökçay C.F. and Dilek F.B., "Effects of nickel, chromium and initial feed concentration on the batch growth of a microbial consortium developed from sewage", Environmental Technology, 12: 1–11, 1991.
  27. Dilek F.B., Gökçay C.F. and Yetiş Ü., "Effects of Cu(II) on a chemostat containing activated sludge", Environmental Technology, 12: 1007–1016, 1991.
  28. Gökçay C.F., Dilek F.B., Sürücü G. and Uluğ E., "Biological treatability of wastewaters from pulp and paper industry", Turkish Journal of Water Pollution Control, 9: 245–256, 1992. (In Turkish)
  29. Dilek F.B., Gökçay C.F., Oğuz M., Enüysal M. and Uluğ E., "Characterization and treatability of wastewaters from SEKA Kastamonu pulp and paper plant", Turkish Journal of Water Pollution Control, 9: 257–290, 1992.
  30. Gökçay C.F., Dilek F.B., Sürücü G. and Uluğ E., "Treatability of effluents originating from cellulose production", 9th Turkish-German-Polish Environmental Engineering Symposium, Istanbul, 5–7 October 1992, pp. 469–481.
  31. Gökçay C.F., Kolankaya N., Dilek F.B., Atabey M.E., Oğuz M. and Demirtaş K., "Biological solubilization of Turkish lignites", International Symposium on Energy Efficiency, 16–18 November 1992, pp. 214–223.
  32. Yetiş Ü., Dilek F.B. and Gökçay C.F., "Effects of heavy metals on biological activity in BOD bottle-seed biomass concentration", 2nd International Symposium on Waste Management Problems in Agro Industries (IAWQ), Istanbul, 23–25 September 1992, pp. 141–151.
  33. Yurteri C., Gökçay C.F. and Egemen E., "Overlay technique in assessment of thermal power plant impacts on vegetation: A case study", ENSEC'93, Cracow, Poland, July 5–9 1993, pp. 157–164.
  34. Egemen E., Gökçay C.F. and Yurteri C., "Assessment of terrestrial impacts of sulfur emissions", IInd International Ecology and Environmental Problems Symposium, 5–7 November 1992.
  35. Dilek F.B. and Gökçay C.F., "Effects of selected metals on microbial growth", International Urban Ecology Symposium, İzmir, 5–10 June 1991, pp. 240–265.
  36. Gökçay C.F. and Önerci S., "Recycling of copper flotation tailings and bioremediation of copper-laden dump sites". In Emerging Technology for Bioremediation of Metals, ed. J.L. Means and R.E. Hinchee, Lewis Publishers, pp. 61–73, 1994.
  37. Tuncer G., Güven O., Gökçay C.F., Balkas T. and Tuncel G., "Riverian fluxes of pollutants to the Black Sea along the Turkish coast", Xth National Chemistry Congress, Bursa, 1994. (In Turkish)
  38. Soyupak S., Gökçay C.F., Yerli S., Erden S., Akbay N. and Cilesiz A.F., "Assessment of eutrophication for Keban Dam Reservoir", Fresenius Environmental Bulletin, 3: 181–186, 1994.
  39. Dilek F.B. and Gökçay C.F., "Treatment of effluents from hemp-based pulp and paper industry — I. Waste characterization and physico-chemical treatability", Water Science and Technology, 29: 161–164, 1994.
  40. Gökçay C.F. and Dilek F.B., "Treatment of effluents from hemp-based pulp and paper industry — II. Biological treatability of pulping effluents", Water Science and Technology, 29: 165–168, 1994.
  41. Gökçay C.F. and Kılıç B., "Biological treatability of pulping effluents by using a Penicillium species", Environmental Pollution and Its Impact on Life in the Mediterranean Region, 8th Symposium, 1995.
  42. Gökçay C.F. and Ataberk S., "Biological treatment of organic chlorine compounds from pulping effluents", Environmental Pollution and Its Impact on Life in the Mediterranean Region, 8th Symposium, 1995.
  43. Bayar A., Soyupak S., Mukhallati L., Altınbilek D., Kutoğlu Y. and Gökçay C.F., "Use of modelling for development of management strategies in control of eutrophication in lakes Mogan and Eymir", Environmental Pollution and Its Impact on Life in the Mediterranean Region, 8th Symposium, 1995. (Also published in Fresenius Environmental Bulletin)
  44. Gökçay C.F. and Yetiş Ü., "Effect of Nickel(II) on the biomass yield of the activated sludge", Water Science and Technology, 34(5–6): 163–171, 1996.
  45. Yetiş Ü., Selçuk A. and Gökçay C.F., "Reducing chlorinated organics (AOX) in the bleachery effluents of a Turkish pulp and paper plant", Water Science and Technology, 34(10): 97–104, 1996.
  46. Dilek F.B. and Gökçay C.F., "Microbiology of activated sludge treating wastewater containing Ni(II) and Cr(VI)", IAWQ Biennial 1996, Singapore, pp. 63–69.
  47. Yetiş Ü., Şahin S.M. and Gökçay C.F., "Characterization of effluents from chlorine dioxide substitution bleaching and oxygen-reinforced extraction", 2nd Specialized Conference on Pretreatment of Industrial Wastewaters, IAWQ, Athens, 16–18 October 1996, pp. 659–666.
  48. Taşeli B.K. and Gökçay C.F., "Studies on pre-treatment of coloured effluents from pulping process by using a Penicillium species", 2nd Specialized Conference on Pretreatment of Industrial Wastewaters, IAWQ, Athens, 16–18 October 1996, pp. 667–674.
  49. Gökçay C.F. and Ataberk S., "Treatment of chlorinated organics in bleached kraft mill effluents by activated sludge", 2nd Specialized Conference on Pretreatment of Industrial Wastewaters, IAWQ, Athens, 16–18 October 1996, pp. 771–774.
  50. Albek M., Yetiş Ü. and Gökçay C.F., "Effect of Ni(II) on respirometric oxygen uptake", Applied Microbiology and Biotechnology, 48: 636–641, 1997.
  51. Taşeli B.K. and Gökçay C.F., "Developing fungal reactor for organic chlorine removal from pulping effluents", In-Situ and On-Site Bioremediation Symposium, New Orleans, April 28–May 1, 1997, Vol. 2, pp. 519–525.
  52. Gökçay C.F. and Taşeli B.K., "Biological treatability of pulping effluents by using a Penicillium species", Fresenius Environmental Bulletin, 6: 220–226, 1997.
  53. Demirbas G., Gökçay C.F. and Dilek F.B., "Sequence of microbial populations associated with the treatment of pulping effluents in a model activated sludge plant", MESAEP 1997, Sorrento, Italy.
  54. Bilgiç H., Gökçay C.F. and Hasırcı N., "Color removal by white-rot fungi". In Global Environmental Biotechnology, ed. D.L. Wise, Elsevier Science, pp. 187–198, 1997.
  55. Ataberk S. and Gökçay C.F., "Treatment of chlorinated organics in bleached kraft mill effluents by activated sludge process", Water Science and Technology, 36(2–3): 147–150, 1997.
  56. Yetiş Ü., Ataberk S., Gökçay C.F. and Şahin Ş.M., "Characterization of effluents from chlorine bleaching and oxygen-reinforced extraction", Water Science and Technology, 36(2–3): 353–360, 1997.
  57. Tuncer G., Karakaş T., Balkas T., Gökçay C.F., Aygın S., Yurteri C. and Tuncel G., "Land-based sources of pollution along the Black Sea coast of Turkey: Concentrations and annual loads", Marine Pollution Bulletin, 36(6): 409–423, 1998.
  58. Demirbas G., Gökçay C.F. and Dilek F.B., "Sequence of microbial populations associated with the treatment of pulping effluents in a model activated sludge plant", Fresenius Environmental Bulletin, 7: 114–119, 1998.
  59. Dilek F.B., Gökçay C.F. and Yetiş Ü., "Combined effects of Ni(II) and Cr(VI) on activated sludge", Water Research, 32(2): 303–312, 1998.
  60. Yetiş Ü., Demirer G. and Gökçay C.F., "Effect of chromium(VI) on the biomass yield of activated sludge", Enzyme and Microbial Technology, 25: 48–54, 1999.
  61. Demirbas G., Gökçay C.F. and Dilek F.B., "Treatment of organic chlorine in pulping effluents by activated sludge", Water Science and Technology, 40(1): 275–279, 1999.
  62. Taşeli B.K. and Gökçay C.F., "Biological treatment of paper pulping effluents by using a fungal reactor", 6th IAWQ Symposium on Forest Industry Wastewaters, Tampere, Finland, June 6–10, 1999, pp. 221–229.
  63. Taşeli B.K. and Gökçay C.F., "Biological treatment of paper pulping effluents by using a fungal reactor", Water Science and Technology, 40(11–12): 93–99, 1999.
  64. Gökçay C.F., Kolankaya N. and Dilek F.B., "Biological solubilization of lignites", FUEL (London), 80: 1421–1433, 2001.
  65. Arıcan B., Gökçay C.F. and Yetiş Ü., "Mechanistics of nickel sorption by activated sludge", Process Biochemistry, 37(11): 1307–1315, 2002.
  66. Dilek F.B., Yetiş Ü. and Gökçay C.F., "Water savings and sludge minimization in a beet-sugar factory through re-design of the wastewater treatment facility", Journal of Cleaner Production, 11(3): 327–331, 2003.
  67. Uzal N., Gökçay C.F. and Demirer G.N., "Sequential (anaerobic/aerobic) biological treatment of malt whisky wastewater", Process Biochemistry, 39: 279–286, 2003.
  68. Gökçay C.F. and Sin G., "Modeling of a large-scale wastewater treatment plant for efficient operation", IX. IWA Specialised Conference on Design, Operation, Economics of Large Wastewater Treatment Plants, Prague, September 2003, pp. 193–200.
  69. Taşeli B.K., Gökçay C.F. and Taşeli H., "Upflow column reactor design for dechlorination of chlorinated wastes by Penicillium camemberti", Journal of Environmental Management, 72: 175–179, 2004.
  70. Gökçay C.F. and Sin G., "Modeling of a large-scale wastewater treatment plant for efficient operation", Water Science and Technology, 50(7): 123–130, 2004.
  71. Taşeli B.K. and Gökçay C.F., "Degradation of chlorinated compounds by Penicillium camembertii in batch and up-flow column reactors", Process Biochemistry, 40: 917–923, 2005.
  72. Taşeli B.K. and Gökçay C.F., "Identification of electron acceptor properties of Penicillium camemberti used for effective treatment of chlorinated organic compounds", Fresenius Environmental Bulletin, 14(5): 347–352, 2005.
  73. Taşeli B.K. and Gökçay C.F., "Degradation of low and high molecular weight fractions of softwood bleachery effluents by Penicillium camemberti in up-flow column reactor", Bulletin of Environmental Contamination and Toxicology, 77(3): 481–489, 2006.
  74. Komesli O.T., Teschner K., Hegemann W. and Gökçay C.F., "Vacuum rotation membrane bioreactor (MBR) — performance and sludge characteristics", Desalination, 215(1–3): 22–28, 2007.
  75. Kaya D., Dilek F.B. and Gökçay C.F., "Reuse of lagoon effluents in agriculture by post-treatment in a step feed dual treatment process", Desalination, 215(1–3): 29–36, 2007.
  76. Özkan Yücel U.G. and Gökçay C.F., "Co-treatment of reactive azo-dye with sewage sludge", Facing Sludge Diversities: Challenges, Risks and Opportunities, Antalya, 28–30 March 2007, pp. 165–175.
  77. Komesli O.T., Gürkan Z. and Gökçay C.F., "Sludge characteristics of a vacuum rotation membrane bioreactor (MBR)", Facing Sludge Diversities: Challenges, Risks and Opportunities, Antalya, 28–30 March 2007, pp. 747–755.
  78. Gökçay C.F., "Wastewater potential and reuse standards in Turkey", 6th Conference on Wastewater Reclamation and Reuse for Sustainability, Antwerp, Belgium, 9–12 October 2007.

Short-Term International Contacts

  • Process microbiology and biotechnology advanced course, University of Canterbury, 1980
  • VII. CIESM Marine Pollution Conference, Lucerne, 1984 — Speaker
  • Biological Treatment of Fossil Fuels Workshop, Washington D.C., 1987 — Speaker
  • Academic link, University of London, Birkbeck College, 1988
  • Short-term WHO Consultancy Assignment, Regional WHO Office for the Western Pacific, 1991
  • In Situ and On-Site Bioreclamation, 2nd International Symposium, San Diego, California, April 5–8, 1993 — Speaker
  • IAWQ Biennial 1996, Singapore — Speaker
  • Environmental Pollution and Its Impact on Life in the Mediterranean Region, 8th Symposium, Rhodes, Greece, 8–12 October 1995 — Speaker
  • Environmental Pollution and Its Impact on Life in the Mediterranean Region, 9th Symposium, Sorrento, Italy, October 1997 — Speaker, Session Chairman
  • Olive Oil Wastes Remediation Symposium, 28–30 January 1999 — Speaker
  • 6th IAWQ Symposium on Forest Industry Wastewaters, Tampere, Finland, June 6–10, 1999 — Speaker
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