Yatay deşarj edilen soğuk-yoğun atıksuların bazı deşarj parametrelerinin belirlenmesi

Öz

Termal kirlilik, okyanus, göl veya nehir gibi sucul alanlarda ortam sıcaklığının insan faaliyetleri sonucunda artması veya azalması olarak tanımlanır. Termal kirliliğe, enerji santralleri, sıvılaştırılmış doğalgaz terminalleri (LNG) ve endüstriyel tesislerin ısıtma veya soğutma amaçlı kullanılan daha sonra alıcı ortamlara deşarj edilen suları neden olur. Alıcı ortamlara deşarj edilen termal atıksuların en önemli kaynaklarından biri LNG gazlaştırma terminallerinden kaynaklanan soğuk sulardır. Soğuk sular genellikle kıyısal sulara deşarj edilirler. Bu sular deşarj edildikleri alıcı ortamlara göre yoğunluklarının yüksek olması nedeniyle bir çeşit negatif yüzen (batan) jetlerdir. Alıcı ortam canlı türlerine olumsuz etkilerinden dolayı soğuk sular, yüksek seviyede seyrelme sağlayacak şekilde deşarj edilmelidir. Bu çalışmada, yatay olarak deşarj edilen soğuk-yoğun suyun birinci seyrelme ve çarpma noktası gibi bazı deşarj parametreleri laboratuvar ortamında dairesel deşarj portu kullanılarak belirlenmiştir. Soğuk-yoğun atıksuyun alıcı ortam içerisindeki davranışını (jet geometrisini) belirlemek için renk maddesi olarak Rhodamin B ilavesi yapılmıştır.  Renklendirilmiş soğuk-yoğun atıksuyun anlık fotoğraflarını çekmek için yüksek çözünürlüklü kamera ve atıksu jet merkezinde meydana gelen sıcaklık değişimlerini (seyrelmeler) ölçmek için de hassas termal problar kullanılmıştır. Farklı atıksu yoğunlukları elde etmek için -3 °C, -5 °C ve -7 °C gibi üç değişik sıcaklık fark değerleri uygulanmıştır. Bu çalışmada elde edilen sonuçlara göre soğuk su deşarjlarının tabana çökme eğilimde olan negatif yüzen (batan) jet gibi davrandığı belirlenmiştir. Ayrıca bu çalışmada, ortalama normalize edilmiş çarpma noktası mesafesi ve birinci seyrelmenin 2.333 ve 0.491 olduğu bulunmuştur.

Anahtar Kelimeler

• Termal kirlilik,Yoğun jet,Soğuk su deşarjı,Birinci seyrelme,Negatif yüzen jet

Determination of some discharge parameters of horizontally discharged cold-dense wastewaters

Abstract

Thermal pollution is defined as increase or decrease in temperature of an aquatic environment which may be ocean, lake or river by human influence. A common cause of thermal pollution is the use of water as a cooling and heating system by power plants, liquefied natural gas (LNG) re-gasification terminals and industrial manufacturers. One of the important sources of thermal effluents is cold water discharges, which are mainly originated from LNG re-gasification terminals from open cycle heating units. Cold water can be frequently discharged into coastal waters. Due to its high density, cold water discharge is a kind of negatively buoyant jet. Because of some undesired effects of cold water on receiving water species, should be discharged properly into the marine environment with a high level of initial dilution. Some discharge parameters of horizontally discharged cold-dense wastewater such as initial dilutions, impingement points were   determined in a laboratory system using circular port in this study. To determine the behavior of the cold-dense wastewater (wastewater jet geometry) Rhodamine B as a colorant was added to the wastewater. A high-resolution camera was used to take snapshots of the colored cold-dense wastewater. Temperature changes (dilutions) in the cold-dense wastewater jet centerline were detected with sensitive thermal probes. To gain different densities, three discharge temperature differences were used as -3 °C, -5 °C and -7 °C. According to the results of this study, it was determined that the cold water discharges behaved like a negative buoyant jet. In addition, it was calculated that the averages of the normalized impingement point and initial dilution of the cold water were found 2.333 and 0.491, respectively.

Keywords

• Thermal pollution,Dense jet,Cold water discharge,Initial dilution,Negatively buoyant jet

Kaynakça

1. John JEA. "Thermal pollution: a potential threat to our aquatic environment" Boston College Environmental Affairs Law Review, 1(2), 287-298, 1971.
2. Nemlioglu S, Sezgin N. "Water depth effects on initial dilution of horizontally discharged coldwater from an elevated outfall". International Journal of Global Warming, 6(2-3), 284-294, 2014.
3. Verones F, Hanafiah MM, Pfister S, Huijbregts MJ, Pelletier GJ, Koehler A. "Characterization factors for thermal pollution in freshwater aquatic environments". Enviromental Science & Technology, 44(24), 9364-9369, 2010.
4. Madden N, Lewis A, Davis M. "Thermal effluent from the power sector: an analysis of once-through cooling system impacts on surface water temperature". Environmetal Research Letters, 8, 1-8, 2013.
5. Langford TE. Thermal discharges and pollution. Editors: Steele J, Thorpe S, Turekian K. Encyclopedia of Oceanic Sciences 1st Ed. New York, USA, Academic Press , 2001.
6. De Vries P, Tamis JE, Murk AJ, Smit MGD. "Development and application of a species sensitivity distribution for temperature-induced mortality in the aquatic environment". Environmental Toxicology and Chemistry, 27, 2591-2598, 2008.
7. Hester ET, Doyle MW. "Human impacts to river temperature and their effects on biological processes: a quantitative synthesis". Journal of the American Water Resources Association, 47, 571-587, 2011.
8. Beitinger TL, Bennett WA, McCauley RW. "Temperature tolerances of North American Freshwater Fishes exposed to dynamic changes in temperature". Environmental Biology of Fishes, 58, 237-275, 1999.

9. Caissie D. "The thermal regime of rivers: a review". Freshwater Biology, 51, 1389-1406, 2006.
10. Kikkert GA, Davidson MJ, Nokes RI. "Inclined Negatively Buoyant Discharges". Journal of Hydraulic Engineering, 133, 545-554, 2007.
11. Saeedi M, Aliabadi Farahani A, Abessi O, Bleninger T. "Laboratory studies defining flowregimes for negatively buoyant surface discharges into crossflow". Environmental Fluid Mechanics, 12, 439-449, 2012.
12. Boru Hatları ile Petrol Taşıma AŞ. (BOTAŞ). "BOTAS LNG Terminal Marmara Ereglisi Environmental Impact Report". Ankara, Türkiye, 5377, 1986.
13. Nemlioglu S, Sezgin N. "Use of duckbill valve on horizontal cold water discharge ınitial dilution". 6th International Perspectives on Water Resources& the Environment Conference (IPWE 2013), İzmir, Turkey, 7-9 January 2013.
14. Wikipedia. “List of lng Terminals”. https://en.wikipedia.org/wiki/List_of_LNG_terminals (02.02.2017).
15. Artuz I. "Marine Pollution (in Turkish)". Istanbul Technical University Faculty of Naval Architecture and Ocean Engineering Press No: 1464, Istanbul, Turkey, 1992.
16. Hart Jr CW, Fuller SLH. "Pollution Ecology of Freshwater Invertebrates". New York, USA, Academic Press Inc., 1974.
17. Nielsen E. Marine Photosynthesis with Special Emphasis on the Ecological Aspects. New York, USA, Elsevier Scientific Publishing Company,1975.
18. Sherman B. "Scoping Options for Mitigating Cold Water Discharges From Dams". CSIROLand and Water, Australia, Canberre Consultany Report 00/21, 2000.
19. Öztürk İ. Deniz Deşarjı Tesisleri Tasarımı. İstanbul, Türkiye, Su Vakfı, 2011.
20. Bayat C, Nemlioglu S, Altuncu FF, Berkun M. "Experimental scaling originated differences in cold water outfall design". MESAEP & SECOTOX 12th International Symposium on Environmental Pollution and its Impact on Life in the Mediterranean Region, Antalya, Turkey, 4-8 October 2003.
21. Malacic V, Faganeli J, Malej A. "Environmental Impact of LNG Terminals in the Gulf Trieste (Northern Adriatic). Editors: Coskun HG. et al., Integration of Information forEnvironmental Security. NATO Science for Peace and Security Series C: Environmental Security, 375-395, Netherlands, Springer, 2008.
22. Davis LR. Fundamentals of Environmental Discharge Modeling. New York, NY, USA, CRC Press, 1998.
23. Pincince AB, List EJ. "Disposal of brine into an estuary". Journal Water Pollution Control Federation, 45(11), 2335-2344, 1973.
24. Roberts PJW, Toms G. "Inclined dense jets in flowing current". Journal of Hydraulic Engineering, ASCE, 113, 323-341, 1987.
25. Katano N, Kawamura H, Wada A, Suzuki K, Tanaka K. "Experimental Study on Diffusion of Buoyant Jet of Cold Water". Abiko Research Laboratory of Central Research Institute of Electric Power Industry, Tokyo, Japan, 1979.
26. Sezgin N. "Investigation of horizontal cold water discharge initial dilutions at various temperature differences using duckbill valve". Desalination and Water Treatment, 6, 2437-2445, 2016.
27. US Environmental Protection Agency. "Guideline for fluid modeling of atmospheric diffusion". Rep. No. EPA-600/8/81/O09, , N.C. USA, 1981.
28. Isaacson MS, Koh RCY, Brooks NH."Plume dilution for diffusers with multiport risers". Journal of Hydraulic Engineering, ASCE, 109, 199-220, 1983.
29. Roberts PJW, Snyder WH, BaumgartnerDJ. "Ocean outfalls. I: Submerged waste field formation". Journal of Hydraulic Engineering, ASCE, 115, 1-25, 1989a.
30. Roberts PJW, Snyder WH, Baumgartner DJ. "Ocean outfalls. II: Spatial evolution of submerged wastefield". Journal of Hydraulic Engineering, ASCE, 115, 26-48, 1989b.
31. Roberts PJW, Snyder WH, Baumgartner DJ. "Ocean outfalls. III: Effect of diffuser design on submerged wastefield". Journal of Hydraulic Engineering, ASCE, 115, 49-70, (1989c).
32. Roberts PJW, Snyder WH. "Hydraulic model study for Boston outfall. I: riser configuration". Journal of Hydraulic Engineering, ASCE, 119, 970-987, 1993.
33. Shao D, Law AWK. "Boundary impingement and attachment of horizontal offset dense jets". Journal of Hydro-environment Research, 5, 15-24, 2011.
34. Michas SN, Papanicolaou PN. "Horizontal round heated jets into calm uniform ambient". Desalination, 248, 803-815, 2009.
35. Fischer B, List JE, Imberger J, Brooks HN. Mixing in Inland and Coastal Waters. New York, USA, Academic Press, Inc., 1979.
36. Cederwall K. "Hydraulics of marine wastewater disposal". Report No. 42, Chalmers Institueof Technology, Goteborg, Sweden, Scientific Report 42, 1968.