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Slow Sand Filtration (Biofilm reactors): a solution to remove micro-pollutants in small WWTP’s effluents? 1 Mònica Escolà Casas, Kai Bester Department.

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Presentation on theme: "Slow Sand Filtration (Biofilm reactors): a solution to remove micro-pollutants in small WWTP’s effluents? 1 Mònica Escolà Casas, Kai Bester Department."— Presentation transcript:

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

2 Sand Biofilm Reactors: a solution to remove micro-pollutants in small WWTP’s effluents? Mònica Escolà Casas January 2014 Disposition › Background › Objectives › The Set-up and Results › Discussion and Conclusion

3 Sand Biofilm Reactors: a solution to remove micro-pollutants in small WWTP’s effluents? Mònica Escolà Casas January 2014 Background: The Problem XENOBIOTICS CONVENTIONAL WATER TREATMENT MICRO- POLLUTANTS

4 Sand Biofilm Reactors: a solution to remove micro-pollutants in small WWTP’s effluents? Mònica Escolà Casas January 2014 Background: Possible Solutions › Activated carbon and Reverse Osmosis › Advanced Oxidation Processes › Biological Processes Bouillides WTP Rielli.com TRAB act. carbon

5 Sand Biofilm Reactors: a solution to remove micro-pollutants in small WWTP’s effluents? Mònica Escolà Casas January 2014 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 Sand Biofilm Reactors: a solution to remove micro-pollutants in small WWTP’s effluents? Mònica Escolà Casas January 2014 Disposition › Background › Objectives › The Set-up and Results › Conclusion

7 Sand Biofilm Reactors: a solution to remove micro-pollutants in small WWTP’s effluents? Mònica Escolà Casas January 2014 BIOFILM REACTOR (Filter media and biofilms) Objective: Efficiency XENOBIOTICS CONVENTIONAL WATER TREATMENT MICRO- POLLUTANTS SORPTION + DEGRADATION Sorption or degradation? Transport? Aerobic or anaerobic? %?

8 Sand Biofilm Reactors: a solution to remove micro-pollutants in small WWTP’s effluents? Mònica Escolà Casas January 2014 Aim: Understanding mechanisms What is happening in the reactor? › Adsorption or degradation? › Observed removal in soil = adsorption + degradation › Observed removal in sand ≈ degradation › Transport? › Observed transport in soil = adsorption + porosity › Observed transport in sand ≈ porosity › Sand particles  known size and even distribution › Aerobic or anaerobic? › Aerobic degradation >> Anaerobic degradation › Sand-based biofilm reactor operated aerobically Quartz-sand biofilm reactor

9 Sand Biofilm Reactors: a solution to remove micro-pollutants in small WWTP’s effluents? Mònica Escolà Casas January 2014 Disposition › Background › Objectives › The Set-up and Results › Conclusion

10 Sand Biofilm Reactors: a solution to remove micro-pollutants in small WWTP’s effluents? Mònica Escolà Casas January 2014 The Set Up: Which compounds? Iohexol Diclofenac Tebuconazole 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 )

11 Sand Biofilm Reactors: a solution to remove micro-pollutants in small WWTP’s effluents? Mònica Escolà Casas January 2014 The Set-up: Biofilm reactor 29 cm Tank ”WWTP” Effluent Tank ”clean” On-Line measurements Ø = 5 cm 2 TRANSPORT Off-line measurements REMOVAL + Oxygen consumption + TOC

12 Sand Biofilm Reactors: a solution to remove micro-pollutants in small WWTP’s effluents? Mònica Escolà Casas January 2014 Transport: Results

13 Sand Biofilm Reactors: a solution to remove micro-pollutants in small WWTP’s effluents? Mònica Escolà Casas January 2014 The Set Up: Biofilm reactor 29 cm Tank ”WWTP” Effluent Tank ”clean” Off-line measurements Ø = 5 cm 2 TRANSPORT Off-line measurements REMOVAL + Oxygen consumption + TOC

14 Sand Biofilm Reactors: a solution to remove micro-pollutants in small WWTP’s effluents? Mònica Escolà Casas January 2014 Removal: Oxygen and TOC Oxygen consumption and TOC removal for min. and max. flows 60% 27% 0%

15 Sand Biofilm Reactors: a solution to remove micro-pollutants in small WWTP’s effluents? Mònica Escolà Casas January 2014 › Removal: Method 15

16 Sand Biofilm Reactors: a solution to remove micro-pollutants in small WWTP’s effluents? Mònica Escolà Casas January 2014 Removal: kinetics ( k ’s) ln(C outlet /C inlet ) Hydraulic Residence Time (h) Agrees with O 2 and TOC…

17 Sand Biofilm Reactors: a solution to remove micro-pollutants in small WWTP’s effluents? Mònica Escolà Casas January 2014 Disposition › Background › Objectives › The Set-up and Results › Discussion and Conclusion

18 Sand Biofilm Reactors: a solution to remove micro-pollutants in small WWTP’s effluents? Mònica Escolà Casas January 2014 Similar studies ParameterPresent study Reungoat et al. (2011) Scheytt et al. (2006) Matamoros (2007) Water type Real wastewater effluent Real wastewater effluent Syntetic wastewater Raw wastewater Hydraulic loading rate [m 3 m -2 h -1 ] Filter (particle size [mm]) Quartz sand ( ) Sand (2.25) Sandy sediment ( ) (f oc =0.13%) Coarse gravel (8-16) Gravel(0-4) Initial TOC/DOC [mg C L -1 ] 4.86 and ± 0.4 (DOC)Not tested HRT [h] (unsaturated) 342 Diclofenac Removal (%) 41.7 ± 220 ± 10 (graph)3539 ± 22 Diclofenac Degr. Rate [h -1 ] (k A = m/h*) Not tested0.37k A =0.004 m/h*

19 Sand Biofilm Reactors: a solution to remove micro-pollutants in small WWTP’s effluents? Mònica Escolà Casas January 2014 Similar studies ParameterPresent study Reungoat et al. (2011) Scheytt et al. (2006) Matamoros (2007) Water type Real wastewater effluent Real wastewater effluent Syntetic wastewater Raw wastewater Hydraulic loading rate [m 3 m -2 h -1 ] Filter (particle size [mm]) Quartz sand ( ) Sand (2.25) Sandy sediment ( ) (f oc =0.13%) Coarse gravel (8-16) Gravel(0-4) Initial TOC/DOC [mg C L -1 ] 4.86 and ± 0.4 (DOC)Not tested HRT [h] (unsaturated) 342 Diclofenac Removal (%) 41.7 ± 220 ± 10 (graph)3539 ± 22 Diclofenac Degr. Rate [h -1 ] (k A = m/h*) Not tested0.37k A =0.004 m/h*

20 Sand Biofilm Reactors: a solution to remove micro-pollutants in small WWTP’s effluents? Mònica Escolà Casas January 2014 Similar studies ParameterPresent study Reungoat et al. (2011) Scheytt et al. (2006) Matamoros (2007) Water type Real wastewater effluent Real wastewater effluent Syntetic wastewater Raw wastewater Hydraulic loading rate [m 3 m -2 h -1 ] Filter (particle size [mm]) Quartz sand ( ) Sand (2.25) Sandy sediment ( ) (f oc =0.13%) Coarse gravel (8-16) Gravel(0-4) Initial TOC/DOC [mg C L -1 ] 4.86 and ± 0.4 (DOC)Not tested HRT [h] (unsaturated) 342 Diclofenac Removal (%) 41.7 ± 220 ± 10 (graph)3539 ± 22 Diclofenac Degr. Rate k A k A = m/hNot tested nd k A =0.004 m/h

21 Sand Biofilm Reactors: a solution to remove micro-pollutants in small WWTP’s effluents? Mònica Escolà Casas January 2014 Comparing data Target compound k [h -1 ] % Removal at 98 µl/min Other studies Propranolol ±2 Incubated sludge K : h h -1 (S- and R-enantiomers) Ribeiro et al Diclofenac ±2 % Removal sand filters (Matamoros et al Scheytt et al. 2006) Propiconazole - 17±3 No previous data Tebuconazole - 58±4 No previous data Iohexol ±3 % Removal MBBR 79 (Hapeshi et al.2013) Iomeprol ±0.2 No previous data Iopromide ±0.3 % Removal sand filter - drinking water 13 (Zearley and Summers 2012) Sand reactor, getting started

22 Sand Biofilm Reactors: a solution to remove micro-pollutants in small WWTP’s effluents? Mònica Escolà Casas January 2014 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 m 2 › Biofilter thickness can be increased (meaning less filter- area)

23 Sand Biofilm Reactors: a solution to remove micro-pollutants in small WWTP’s effluents? Mònica Escolà Casas January 2014 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 Sand Biofilm Reactors: a solution to remove micro-pollutants in small WWTP’s effluents? Mònica Escolà Casas January 2014 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 Sci Pollut 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), › 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), › 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), › 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), › Zearley, T.L. and Summers, R.S. (2012) Removal of Trace Organic Micropollutants by Drinking Water Biological Filters. Environmental Science & Technology 46(17),

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


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