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Projects / Programmes source: ARIS

Influence of pharmaceutical residues on activated sludge microbial communities in a pilot wastewater treatment plant

Research activity

Code Science Field Subfield
1.03.00  Natural sciences and mathematics  Biology   

Code Science Field
B003  Biomedical sciences  Ecology 
Keywords
wastewater treatment / bioreactor / pharmaceuticals / activated sludge / microbial community structure
Evaluation (rules)
source: COBISS
Researchers (1)
no. Code Name and surname Research area Role Period No. of publicationsNo. of publications
1.  22492  PhD Barbara Kraigher  Biology  Head  2008 - 2011  123 
Organisations (1)
no. Code Research organisation City Registration number No. of publicationsNo. of publications
1.  0481  University of Ljubljana, Biotechnical Faculty  Ljubljana  1626914  67,254 
Abstract
New emerging contaminants have long been present in the environment, however, only recently they have raised scientific and general public attention. A group of new emerging contaminants are pharmaceutical residues. Due to the increasing consumption of different drugs, pharmaceutical residues are accumulating in the environment and hence, raising concerns because of their biological activity at very low concentrations. Recently, new methods for determination of very low concentrations (ng/L) of pharmaceutical residues have been developed, however, the influence of pharmaceutical residues on the environment is still largely unknown. Non-degraded or partially degraded pharmaceuticals accumulate in wastewaters (pharmaceutical industry, municipal sewage) and the function of wastewater treatment plants (WWTPs) is to remove these residues in order to prevent environmental contamination. Wastewater treatment processes rely on the composition and activity of their microbial communities in activated sludge. There is lack of knowledge about the microbial community structure of activated sludge in WWTPs and responses to various contaminants in these systems. The objective of the proposed project is to assess the influence of pharmaceuticals on the structure and diversity of activated sludge microbial communities, the activity of which is reflected in degradation efficiency of contaminants in wastewater treatment plants. In the last years, we have in our laboratory introduced and established methodology to study microbial community structure in soil ecosystem using molecular-biology approaches, which will be applied in the investigation of the wastewater system. The studies will be conducted in small-scale pilot wastewater treatment plants. From the results, potential wastewater treatment operational failures due to detected shifts in microbial community structure will be predicted.
Significance for science
There is lack of knowledge about the microbial community structure of activated sludge in WWTPs and responses to various contaminants in these systems. It is not known how different pharmaceuticals affect microbial communities in activated sludge, do they influence the removal efficiency of other pollutants, and which species of bacteria are capable of degrading different commonly detected pharmaceuticals in wastewaters. Despite the fact that environmental contamination with different pharmaceutical residues is increasing and raising concerns because of their unknown biodegradability and influences on different ecosystems, to our knowledge our studies are the first reported attempts to investigate the microbial community structure of activated sludge in relation to the presence of the commonly present pharmaceutical residues in wastewater. In our studies, culture-independent molecular techniques have been used which are faster and capture much higher portion of the natural, in situ activated sludge community, as compared to culture-dependent methods. Our results indicated that the selected pharmaceuticals caused changes in bacterial community structure. Specifically, according to our findings, they influence the structure of Nitrospira sp., which was recognized as a very important group of nitrifying bacteria in treatment plants. Our experiments have also shown that the structure of the genus Nitrospira could be changed which would not neccessarily be reflected in the abundance of these bacteria. However, this could not be observed with real-time PCR when using primers specific for the whole genus Nitrospira (which could only be found in literature). Since most wastewater treatment processes rely on the structure and activity of their microbial communities in activated sludge, a fundamental understanding of the microbial community shifts in response to different parameters and presence of different chemicals (including pharmaceuticals) could be an essential component of designing and operating stable and efficient treatment systems. The results of our studies could be important for future predictions of the effects of environmentally present pharmaceuticals on the wastewater treatment operation. Microbial community shifts in response to pharmaceuticals could potentially be sensitive indicators of presence and toxicity of the pharmaceuticals in water systems. In addition, the maintenance of stable nitrifying bacterial communities in these treatment systems is critical to their proper functioning, therefore further studies of the observed influences are needed.
Significance for the country
Biological wastewater treatment using activated sludge is one of the most significant biotechnological processes with important ecological and economic aspects. The results of our studies are the first indications of impact of pharmaceuticals on bacterial communities and essential processes that are important in wastewater treatment plants. In our experiments, activated sludge from real Slovenian WWTP has been used as an inoculum for pilot WWTPs which increased the relevance of our investigations. Since microorganisms represent the key components in wastewater treatment systems and the effects of changes in microbial community structure and activity affect the wastewater treatment system as a whole, the results of these analyses are important for future predictions of the effects of environmentally present pharmaceuticals on wastewater treatment plant operation and on their release to the environment. In collaboration with appropriate field experts this knowledge could eventually be applied in improving the operation and design of the real wastewater treatment plants. The findings could be interesting for the companies operating WWTPs and thereby contributed to an ever closer collaboration between research institutions and economy. The project theme is up-to-date and it could be incorporated into more extensive EU research projects where the projects concerning pharmaceuticals in the environment and improving of wastewater treatment plants are frequently supported. Environment protection is becoming one of the most important guidelines in the national development program. As municipal wastewater is a major source of pharmaceuticals in the aquatic environment, the improvement of wastewater treatment is a viable option to significantly reduce the release of these compounds into the environment. With the optimized utilization of pharmaceuticals’ biodegradation in wastewater treatment plants their entering into environment would be reduced which means better environmental protection. The findings from the research work have been presented at relevant international conference in Slovenia. The indirect intention of presenting the results was to alert the people about the widespread distribution of potentially toxic pharmaceutical residues in the environment, even in drinking water, and encourage them to use and dispose even the frequently used non-prescribed drugs with caution.
Most important scientific results Annual report 2008, final report, complete report on dLib.si
Most important socioeconomically and culturally relevant results Annual report 2008, final report, complete report on dLib.si
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