The Role of Methanogens in Waste Water Treatment: Difference between revisions

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by Melissa Mooradian
by Melissa Mooradian
<br>[[File: Methanogen.jpeg |thumb|300px|right|Filamentous methanogen. Obtained from Maryland Astrobiology Consortium, NASA, and STScI]]<br>
<br>[[File: Methanogen.jpeg |thumb|300px|right|Filamentous methanogen. Obtained from Maryland Astrobiology Consortium, NASA, and STScI]]<br>
As one of the most diverse groups of Archaea known to date, the Methanogens represent the euryarchaeota order which gains energy via methane production.  The methanogens utilize the metabolic process of methanogenesis, which is the methane production pathway that converts carbon dioxide and other bacterial waste products into methane.  Methanogens have become the focus of recent literature due to their large contribution to global methane emissions as well as their role in wastewater treatment.  Methane is a potent greenhouse gas that has a global warming potential of 25 in a 100 year time frame and is estimated to account for 20% of the total radiative forcing from all greenhouse gases (Wang et al., 2011).  The recent increase in methane emissions, from natural systems such as wetlands as well as landfills and agricultural cattle, has made the understanding of methanogens crucial to reducing the effects of climate change.  Although methane emissions have negative environmental impacts, the use of methanogens can be crucial in reducing wastewater and the pollution of water systems across the world.  Methanogens help break down organic material that would otherwise pollute water sources and lead to environmental degradation.  The construction of wetland systems in developing countries has been adopted as a low cost and highly effective method of reducing nutrient concentrations and degrading organic compounds in agricultural as well as urban wastewaters (Johansson, et al., 2004).  The balance of these two impacts is vitally important for the future.


==Methanogens==
==Methanogens==

Revision as of 01:22, 23 April 2014

Introduction

by Melissa Mooradian


Filamentous methanogen. Obtained from Maryland Astrobiology Consortium, NASA, and STScI


As one of the most diverse groups of Archaea known to date, the Methanogens represent the euryarchaeota order which gains energy via methane production. The methanogens utilize the metabolic process of methanogenesis, which is the methane production pathway that converts carbon dioxide and other bacterial waste products into methane. Methanogens have become the focus of recent literature due to their large contribution to global methane emissions as well as their role in wastewater treatment. Methane is a potent greenhouse gas that has a global warming potential of 25 in a 100 year time frame and is estimated to account for 20% of the total radiative forcing from all greenhouse gases (Wang et al., 2011). The recent increase in methane emissions, from natural systems such as wetlands as well as landfills and agricultural cattle, has made the understanding of methanogens crucial to reducing the effects of climate change. Although methane emissions have negative environmental impacts, the use of methanogens can be crucial in reducing wastewater and the pollution of water systems across the world. Methanogens help break down organic material that would otherwise pollute water sources and lead to environmental degradation. The construction of wetland systems in developing countries has been adopted as a low cost and highly effective method of reducing nutrient concentrations and degrading organic compounds in agricultural as well as urban wastewaters (Johansson, et al., 2004). The balance of these two impacts is vitally important for the future.

Methanogens


Classification of the different orders of Methanogens. Obtained from http://dc344.4shared.com/doc/U1tNMdLZ/preview.html


Methanogenesis


The figure represents the main pathways of methanogenesis which convert CO2, acetate, or organic acids into methane gas. Image obtained from http://microbewiki.kenyon.edu/index.php/Black_Sea


Uses in Wastewater Treatment


This diagram shows the CDT and CSRT anaerobic reactors. Obtained from Tabatabaei et al., 2010.
This figure shows the methane fluxes from each part of the A/A/O process. Obtained from Wang et al., 2011.


Possible Environmental Impacts


Include some current research in each topic, with at least one figure showing data.

Conclusion


Overall paper length should be 3,000 words, with at least 3 figures.

References

[1]M. R.J. Daelman, E. M. van Voorthuizen, U. G.J.M. van Dongen, E. I.P. Volcke, M. C.M. van Loosdrecht. "Methane emission during municipal wastewater treatment". Water Research. 2012. Volume 46. p. 3657-3670.

[2]A.E. Johansson, A-M. Gustavsson, M.G. Oquist, B.H. Svensson. "Methane emissions from a constructed wetland treating wastewater-seasonal and spatial distribution and dependence on edaphic factors". Water Research. 2004. Volume 38. p. 3960-3970.

[3]Toprak, Hikmet. "Temperature and organic loading dependency of methane and carbon dioxide emission rates of a full-scale anaerobic waste stabilization pond". Water Research. 1995. Volume 29. p. 1111-1119.

[4]E. Uggetti, J Garcia, S. E. Lind, P. J. Martikainen, I. Ferrer. "Quantification of greenhouse gas emissions from sludge treatment wetlands". Water Research. 2012. Volume 46. p. 1755-1762.

[5]J. Wang, J. Zhang, H. Xie, P. Qi, Y. Ren, Z. Hu. "Methane emissions from a full-scale A/A/O wastewater treatment plant". Bioresource Technology. 2011. Volume 102. p. 5479-5485.

[6]M. Tabatabaei, R. A. Rahim, N. Abdullah, A-D. G. Wright, Y. Shirai, K. Sakai, A. Sulaiman, M. A. Hassan. "Importance of the methanogenic archaea populations in anaerobic wastewater treatments". Process Biochemistry. 2010. Volume 45. p. 1214-1225.

[7]Y. Wang, C. Ye, H. Yang, J. Zhang, C. Huang, B. Xie. "Methane formation in soil-plant systems treating wastewater as influenced by microbial populations". Environmental Earth Science. 2013. Volume 70. p. 1647-1652.

[8][Slonczewski, J.L., and Foster, J.W. "Microbiology: An Evolving Science". W.W. Norton and Company. 2014. Third Edition.]

Edited by student of Joan Slonczewski for BIOL 238 Microbiology, 2009, Kenyon College.