Mònica Escolà Casas, Kai Bester

1. January 2014 Slow Sand Filtration (Biofilm reactors):a solution to remove micro-pollutants in small WWTP’s effluents? Mònica Escolà Casas, Kai Bester Department of Environmental Science, Aarhus University, Roskilde, Denmark moes@dmu.dk kb@dmu.dk

2. Disposition • Background • Objectives • The Set-up and Results • Discussion and Conclusion

3. Background: The Problem XENOBIOTICS CONVENTIONAL WATER TREATMENT MICRO-POLLUTANTS

4. Background: Possible Solutions • Activatedcarbon and ReverseOsmosis • Advanced Oxidation Processes • BiologicalProcesses TRAB act. carbon Bouillides WTP Rielli.com

5. Background: Biofilm Reactors • Biofilm Reactors = porous media + biofilm (Biofilters) (Sand) • Affordable, robust and suitable for small WWTP’s • Constructed soil biofilters eliminate micro-pollutants from wastewater effluents. • Effectiveness: hydraulic residence-time, compounds residence time and biological activity. • Mechanisms and most efficient biofilm reactor configuration?

6. Disposition • Background • Objectives • The Set-up and Results • Conclusion

7. Objective: Efficiency BIOFILM REACTOR XENOBIOTICS (Filter media and biofilms) Sorption or degradation? Transport? Aerobic or anaerobic? CONVENTIONAL WATER TREATMENT SORPTION + DEGRADATION %? MICRO-POLLUTANTS

8. Aim: Understanding mechanisms What is happening in the reactor? • Adsorption or degradation? • Observed removal in soil = adsorption + degradation • Observed removal in sand ≈ degradation • Transport? • Observedtransport in soil = adsorption + porosity • Observed transport in sand ≈ porosity • Sand particles knownsize and even distribution • Aerobic or anaerobic? • Aerobic degradation >> Anaerobicdegradation • Sand-based biofilm reactoroperatedaerobically Quartz-sand biofilm reactor

9. Disposition • Background • Objectives • The Set-up and Results • Conclusion

10. The Set Up: Which compounds? Pharmaceuticals Diclofenac and propranolol Detected in WWTP’s effluents (ng L-1 ) Fungicides Propiconazole and tebuconazole. Detected in WWTP’s effluents (ng L-1 ) X-ray contrast media Iopromid, iohexol and iomeprol Detected in WWTP’s effluents (µg L-1 ) Diclofenac Tebuconazole Iohexol

11. The Set-up: Biofilm reactor TRANSPORT On-Linemeasurements Ø = 5 cm2 REMOVAL 29 cm Tank ”WWTP” Effluent Tank ”clean” Off-linemeasurements +Oxygen consumption + TOC

12. Transport: Results

13. The Set Up: Biofilm reactor TRANSPORT Off-linemeasurements Ø = 5 cm2 REMOVAL 29 cm Tank ”WWTP” Effluent Tank ”clean” Off-linemeasurements +Oxygen consumption + TOC

14. Removal: Oxygen and TOC 27% 0% 60% 27% Oxygen consumption and TOC removal for min. and max. flows

15. Removal: Method

16. Removal: kinetics (k’s) Agrees with O2 and TOC… ln(Coutlet/Cinlet) Hydraulic Residence Time (h)

17. Disposition • Background • Objectives • The Set-up and Results • Discussion and Conclusion

18. Similar studies

19. Similar studies

20. Similar studies

21. Comparing data Sand reactor, getting started

22. Conclusions • Sand biofilm reactors are easy to control due to hydraulics and minimized sorption processes • Micro-pollutants (some considered reclacitrant) can be eliminated by the sand biofilm reactor • Operation over 10 months without signs of clogging • Low flows (1000 m 3 h -1 )  filter-area of 85.000 m2 • Biofilter thickness can be increased (meaning less filter-area)

23. Acknowdledgements • AUFF grant: Advanced water purification using bio-inorganic nanocatalysts and soil filters. • The personnel of WWTP Bjergmarken that was always extremely helpful considering provisions of samples and data on their WWTP. • Aasbjørn Haaning Nielsen and Jes Vollertsen of Aalborg University helped with setting up the oxygen sensing.

24. Thanks for your attention LITERATURE • Hapeshi, E., Lambrianides, A., Koutsoftas, P., Kastanos, E., Michael, C. and Fatta-Kassinos, D. (2013) Investigating the fate of iodinated X-ray contrast media iohexol and diatrizoate during microbial degradation in an MBBR system treating urban wastewater. Environ SciPollut Res Int. • Kadlec, R.H. and Knight, R.L. (1996) Treatment Wetlands, Lewis Publishers, Boca Raton, New York, London, Tokyo. • Matamoros, V., Arias, C., Brix, H. and Bayona, J.M. (2007) Removal of Pharmaceuticals and Personal Care Products (PPCPs) from Urban Wastewater in a Pilot Vertical Flow Constructed Wetland and a Sand Filter. Environmental Science & Technology 41(23), 8171-8177. • Reungoat, J., Escher, B.I., Macova, M. and Keller, J. (2011) Biofiltration of wastewater treatment plant effluent: Effective removal of pharmaceuticals and personal care products and reduction of toxicity. Water Research 45(9), 2751-2762. • Ribeiro, A.R., Afonso, C.M., Castro, P.M.L. and Tiritan, M.E. (2013) Enantioselective biodegradation of pharmaceuticals, alprenolol and propranolol, by an activated sludge inoculum. Ecotoxicology and Environmental Safety 87(0), 108-114. • Scheytt, T.J., Mersmann, P. and Heberer, T. (2006) Mobility of pharmaceuticals carbamazepine, diclofenac, ibuprofen, and propyphenazone in miscible-displacement experiments. Journal of Contaminant Hydrology 83(1–2), 53-69. • Zearley, T.L. and Summers, R.S. (2012) Removal of Trace Organic Micropollutants by Drinking Water Biological Filters. Environmental Science & Technology 46(17), 9412-9419.

25. January 2014 Slow Sand Filtration (Biofilm reactors):a solution to remove micro-pollutants in small WWTP’s effluents? Mònica Escolà Casas, Kai Bester Department of Environmental Science, Aarhus University, Roskilde, Denmark moes@dmu.dk kb@dmu.dk