An activated sludge model for xenobiotic organic micro-pollutants (ASM-X): factors influencing the solid-liquid partitioning in wastewater treatment

Benedek Plósz, K. Lehnberg, W. Dott, K.H. Thomas

Research output: Chapter in Book/Report/Conference proceedingArticle in proceedingsResearchpeer-review

1 Downloads (Pure)


In this paper, we present an evaluation of the process model developed by Plósz et al. (2010a) to predict the fate of antibiotics xenobiotic organic micro-pollutants (XOMs) in activated sludge systems. Instead of spiking the batch reactors with reference substances, observations were made using the XOMs content of pre-clarified municipal sewage. Evaluation of the model structure is carried out in dynamic simulations using data obtained in samples taken in a measuring campaign in a full-scale activated sludge wastewater treatment plant (WWTP). Our results suggest that the sorption of the antibiotic ciprofloxacin (CIP) can significantly differ under aerobic and anoxic conditions that agrees well with results obtained with other two antibiotics, sulfamethoxazole and tetracycline. Additionally, for CIP, results obtained suggest that its solid-liquid partitioning behaviour can intermittently deteriorate; thereby hindering the effluent quality of secondary treatment step, and thereby increasing the XOM mass load on the tertiary treatment step. Besides the impact of different redox conditions, divalent iron-salt dosing used for enhanced phosphorus removal and pH have been identified as potential factors in influencing CIP speciation in biological treatment, and were further investigated in targeted batch experiments. Results obtained suggest that CIP sorption is influenced by ionic interactions between sludge components and dissolved Fe-ions or bounding between cations and charged CIP molecules. We additionally show that the impact of Fe-salt added can vary under aerobic, anoxic and anaerobic conditions, and that the presence of nitrate can significantly influence CIP partitioning under aerobic conditions. The possible depletion of nitrate in the pre-anoxic effluent can additionally deteriorate the sorption capacity, in the presence of Fe(II).
Original languageEnglish
Title of host publication2nd IWA/WEF Wastewater Treatment Modelling Seminar : Conference Proceedings
PublisherInternational Water Association & Water Environment Federation
Publication date2010
Publication statusPublished - 2010
Event2nd IWA/WEF Wastewater Treatment Modelling Seminar - Mont-Sainte-Anne, Canada
Duration: 28 Mar 201030 Mar 2010
Conference number: 2


Seminar2nd IWA/WEF Wastewater Treatment Modelling Seminar


  • Biotransformation, sorption, mathematical modelling
  • Activated sludge
  • Wastewater treatment; activated sludge; xenobiotic organic micro-pollutants; biotransformation, sorption, mathematical modelling
  • Xenobiotic organic micro-pollutants

Cite this

Plósz, B., Lehnberg, K., Dott, W., & Thomas, K. H. (2010). An activated sludge model for xenobiotic organic micro-pollutants (ASM-X): factors influencing the solid-liquid partitioning in wastewater treatment. In 2nd IWA/WEF Wastewater Treatment Modelling Seminar: Conference Proceedings (pp. 297-305). International Water Association & Water Environment Federation.