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Volume 2017, Article ID 9231056, 7 pages
Research Article

Biofilm Forming Bacteria during Thermal Water Reinjection

1Department of Mineralogy, Geochemistry and Petrology, University of Szeged, Hungary
2Institute of Biochemistry, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
3Seqomics Biotechnology Ltd., Mórahalom, Hungary

Correspondence should be addressed to Máté Osvald; uh.degezs-u.oeg@etamiso

Received 10 August 2016; Accepted 10 October 2016; Published 9 January 2017

Academic Editor: Francesco Italiano

Copyright © 2017 Máté Osvald et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Reinjection of heat-depleted thermal water has long been in the center of scientific interest in Hungary regarding around 1000 operating thermal wells. While the physical and chemical aspects of reinjection have partly been answered in the past years, the effects of biological processes are still less known. We carried out our investigations in the surface elements of the Hódmezővásárhely geothermal system which is one of the oldest operating geothermal systems in Hungary. About one-third of the used geothermal water has been reinjected since 1998 by two reinjection wells at the end of the thermal loops. During the operation, plugging of the surface system was experienced within a few-day-long period, due to biological processes. The goal of our research was to find the dominant species of the microbial flora and to make a proposal to avoid further bacterial problems. We found that the reinjected, therefore the produced, water’s chemical oxygen demand, phenol index, and BTEX composition basically determine the appearing flora on the surface. When the concentration of these compounds in the thermal water is significant and residence time is long enough in the buffer tank, certain bacteria can be much more dominant than others, thus able to form a biofilm which plugs the surface equipment much more than it is expected.