Study of amoxicillin affecting the species composition of activated sludge on single and repeated exposure

Summary

Sustainable operation of wastewater treatment facilities is important to prevent the spread of antibiotics and resistance genes into the environment. In this investigation antibiotic amoxicillin affecting activated sludge, a key element of biological wastewater treatment, was studied. The work objective was studying the effect of two amoxicillin dosage forms (dispersible tablets and active pharmaceutical ingredient) under different entry modes (single and multiple) on the structure and function of the activated sludge biocenosis. In the process of laboratory simulations of the wastewater treatment facilities operation, the changes in the species composition of the indicator organisms were estimated by microscoping technique. It was found that repeated entry of amoxicillin, especially in the form of an active pharmaceutical ingredient, produced the most negative impact on the treatment system, namely: inhibition of ciliates and rotifers, degradation of floccules, and the dominance of filamentous bacteria, resulting in sludge bulking and reduced wastewater treatment efficiency. It was shown that the form and mode of the antibiotic entry are the key environmental risk factors for the operation of wastewater treatment facilities.

Key words

activated sludge , wastewater biological treatment , antibiotics , ampicillin , species composition of the activated sludge , general properties of activated sludge

Study of the effect of ampicillin on the functional state of activated sludge at multiple exposure

Summary

The widespread use of antibiotics in medicine and veterinary science results in an increase in their production, which contributes to the occurrence and accumulation of these drugs in the surrounding aquatic environment. Antibiotics, getting into wastewater, disturb the degradation of organic matter by microorganisms of activated sludge which results in a decrease in the functional state of activated sludge, and also contributes to the development of multiresistant strains of bacteria. In this regard, it is important to estimate the impact of antibiotics on the hydroecosystem of the treatment facilities. Estimation of the functional state of activated sludge of biological treatment facilities is possible using hydrobiological analysis. Hydrochemical indicators of activated sludge, quantitative calculation of activated sludge organisms provides for monitoring the state of the biological wastewater treatment process. The results of estimating the effect of ampicillin on the functional state of activated sludge at multiple exposure are presented. Activated sludge of the Samara wastewater treatment facilities was used as test organisms. The betalactam antibiotic ampicillin served as the material for the study. The antibiotic was added every 24 hours at a concentration of 100 mg per 1g of activated sludge. Incubation of activated sludge was carried out at a temperature of 25°C for 72 hours at continuous aeration. Samples of activated sludge without antibiotic addition served as a control. During the experiment, the hydrochemical characteristics and species composition of the activated sludge biocenosis were estimated. It was shown that ampicillin added multiple times, had a negative effect on the functional state of activated sludge aggravating the sedimentation properties and reducing the species diversity of activated sludge.

Key words

activated sludge , antibiotics , ampicillin , species composition of the activated sludge , general properties of activated sludge