In Germany, 1452 tons (t) veterinary antibiotics were distributed in 2013. After application, the compounds are partly excreted unchanged. By using (liquid) manure as soil fertilizer, antibiotics enter the environment. Approx. 200 mio. t of liquid manure are applied in Germany per year. Thus, a mean antibiotic content of 1 mg per kg manure would correspond to 200 t antibiotics spread in the environment.

The experiments are conducted in semi-continuous fermenters with daily substrate addition (maize silage, liquid manure fortified with sulfonamides and tetracyclines) to simulate biogas plants in laboratory scale. Factors such as temperature, substrate pretreatment (acidic hydrolysis) and addition of enzymes are varied. The elimination pattern of the antibiotics and parameters like methane yield are analyzed. Latter one is used for an economic process assessment.

By in vitro studies, the influence of temperature, pH value and enzymes on the stability of antibiotics is investigated. Combined with sorption studies in fermenter matrix, these experiments will be the basis for possible mechanisms of the observed elimination.

The project delivers a comprehensive investigation of the fate of antibiotics during anaerobic fermentation. This will finally lead to recommendations for biogas plant processes based on both economic aspects and the reduction of antibiotics in the environment.

Project Operation:

Dr. Astrid Spielmeyer (Projektleitung)
Justus-Liebig-Universität Gießen
Institut für Lebensmittelchemie und Lebensmittelbiotechnologie
Heinrich-Buff-Ring 58
35392 Gießen
Tel.: 0641 99 34953

Bettina Breier
Fritzmeier Umwelttechnik GmbH & Co. KG
Abteilung inocre®
Dorfstraße 7
85653 Großhelfendorf
Tel.: 08095-87339-483
E-Mail: b.breier@fritzmeier.de

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