POTENTIAL AND LIMITATIONS OF (ADVANCED) OXIDATION PROCESSES IN WATER AND WASTEWATER TREATMENT

Titelmasterformat durch Klicken bearbeiten POTENTIAL AND LIMITATIONS OF (ADVANCED) OXIDATION PROCESSES IN WATER AND WASTEWATER TREATMENT Torsten C. Schmidt, Holger Lutze Cairo, February 19, 2013

Outline Introduction/Overview of Oxidative Processes Examples of our Recent Work: Lab Scale: Mechanistic Investigations with Probe Compounds: Degradation of Micropollutants Pilot Scale: Implementation of Ozonation in Drinking Water Treatment (Full Scale: Advanced Treatment of Wastewater Effluents) Conclusions and Outlook

Use of Oxidation Processes in Water Treatment Advantages: Constant process performance No disposal of concentrates or solids (compared with AC sorption or membrane filtration) Areas of Use: Drinking water Disinfection, Decolorization, Fe(II) and Mn(II) Removal, Micropollutant Elimination Municipal wastewater Disinfection, Further elimination of micropollutants Industrial wastewater High purity industrial process waters

Modified after U. von Gunten, eawag Important Considerations in Oxidative Treatment Processes Oxidation Lifetime Pollutants Oxidation Mechanisms CO 2, H 2 O Kinetics Prediction of elimination based on properties possible? Scavenging by matrix components Possible loss of efficiency, Oxidation byproducts Transformation products Biodegradability D Toxicological effects Energy Demand/Carbon Footprint?

Effect of Oxidative Transformation: Reduction of Estrogenicity Estrogenically active compound Transformation product Oxidation 17b-Estradiole (E2) binds binds? Effect Effect? Estrogen Receptor Modified after U. von Gunten, eawag

Reduction of Estrogenic Effects (EEEQ) of 17a- Ethinylestradiole by Oxidative Processes Relative EE2 or EEEQ 1.0 0.8 0.6 0.4 0.2 EE2 EEEQ Relative EEEQ 1.0 0.8 0.6 0.4 0.2 0.0 0.0 0.2 0.4 0.6 0.8 1.0 Relative EE2 0.0 0 5 10 15 20 25 30 dose, M Chlorine r 2 = 0.96 0.8 r 2 = 0.99 0.6 1 Relative EEEQ 1.0 0.4 0.2 0 5 10 15 20 25 30 dose, M Bromine 0.0 0.0 0.2 0.4 0.6 0.8 1.0 Relative EE2 Relative EEEQ 0.2 0 5 10 15 20 25 30 dose, M Ozone 0.6 1 0.4 1 1.0 0.8 r 2 = 0.99 0.0 0.0 0.2 0.4 0.6 0.8 1.0 Relative EE2 Relative EE2 or EEEQ 1.0 0.8 0.6 0.4 0.2 Relative EEEQ 1.0 0.8 0.6 0.4 OH radical r 2 = 0.99 1 0.2 0.0 0.0 0.2 0.4 0.6 0.8 1.0 Relative EE2 Relative EEEQ Chlorine dioxide 1.0 0.8 0.6 0.4 r 2 = 0.99 1 0.2 0.0 0.0 0.2 0.4 0.6 0.8 1.0 Relative EE2 Relative EEEQ 1.0 0.8 0.6 0.4 Ferrate r 2 = 0.99 1 0.2 0.0 0.0 0.2 0.4 0.6 0.8 1.0 Relative EE2 0.0 0 100 200 300 400 UV fluence, mj/cm 2 0 5 10 15 20 25 30 dose, M 0 10 20 30 40 dose, M Lee et al. 2008 17a-Ethinylestradiole (EE2) Reduction of estrogenicity is proportional to concentration decline of EE2 Modified after U. von Gunten, eawag

Oxidation + Biological Filtration: Reduction of Toxic Effects in Whole Effluents Adapted from S. Zimmermann, EPFL Data from WWTP Regensdorf, CH: Bioluminescence suppression Algae test (photosynthesis) Algae test (growth) YES Assay Acetylcholinesterase suppression Elimination by ozonation and slow sand filtration in %

Overview Advanced Oxidation Processes UV based Ozone based H 2 O 2 based No Chemicals UV/TiO 2 UV/H 2 O 2 UV/O 3 O3/H2O2 Vacuum UV (VUV) Fenton Ultrasound O 3 /AC Ozonation H 2 O+Ultrasound OH +H H 2 O + VUV(120-160nm) OH +H TiO 2 + hn h + + e - OH + O 2 - H 2 O 2 + UVC 2 OH (F = 1) Also direct photolysis H 2 O 2 OH O 3 +UVC H 2 O 2 OH+O 2 OH- yield: 50% [Jarocki et al., in prep.] 2O 3 + HO - 2 2 OH +3O 2 O 3 + AC OH + O 2 O 3 + (OH -, NOM) OH Fe(II) Fe(III) [Fe(III)HO 2 ] 2+ HO 2 H 2 O 2 ph < 4

Comparison of Advanced Oxidative Processes No Chemicals Ultrasound Vacuum UV UV based Ozone based H 2 O 2 based UV/H 2 O 2 (TiO 2 ) Fenton UV/O 3 O 3 /H 2 O 2 Energy demand O 3 /AC Ozonation O 3 Br - HOBr/OBr - H 2 O 2 Br - Negative Effects - BrO 3-3 NDMA O 3 / OH Loss of oxidation efficiency via matrix scavenging, assimilable organic carbon formation, unknown transformation products

Modified after U. von Gunten, eawag Describing Pollutant Removal Typical second order kinetic constants for a pollutant P: dp = dt 0 k ox P ) ) ln P k ox t P = Oxidant Ozone ~ 500 OH Radicals ~ 2000 Chlorine ~ 300 Chlorodioxide ~ 100 Ferrate(VI) ~ 50 No. of publ. kinetic const. k (ca. 2008) ph, T! Determination kinetic constants: Direct measurements Indirect measurements (Competition kinetics) Quantitative structure activity relationships (QSARs) Estimation from similar oxidants Quantification oxidant exposure: Matrix dependent Dosage dependent Consideration of secondary oxidants

Mechanistic Investigations

Degradation of Micropollutants: Example Diclofenac HOOC H N O 3 Diclofenac (Non-Steroidal Anti- Inflammatory Drug) HOOC O 3 H N Possible sites of ozone attack Ref.: Sein et al. (2008), Environ. Sci. Technol. 42, 6656

Degradation of Micropollutants: Example Diclofenac O C CH 2 OH H N O 3 O O C OH O CH 2 O N H O C OH CH 2 - O 3. N - H + O 3 + H 2 O OH + O 2 + OH Ref.: Sein et al. (2008), Environ. Sci. Technol. 42, 6656

[Diclofenac] and [Products] / µm Diclofenac Degradation in Presence of t-buoh 50 45 COOH 40 35 CH 2 N 30 25 20 O 15 10 5 0 0 50 100 150 200 250 [Ozone] / µm ([Diclofenac] 0 = 50 µm) Diclofenac Iminoquinone (major intermediate) 2,6-Dichloroaniline Ref.: Sein et al. (2008), Environ. Sci. Technol. 42, 6656

Suggested Reaction Mechanism for the Formation of the Iminoquinone Intermediate CO 2 H CH 2. N CO 2 H CH 2 O 3 / - O N 2. O H 1,2 H-shift HO. CO 2 H CH 2 N O 2 Iminoquinone O CO 2 H CH 2 N - HO 2. HO O O CO 2 H CH 2 N Ref.: Sein et al. (2008), Environ. Sci. Technol. 42, 6656

Pilot-Scale Study

SEBES Syndicat des Eaux du Barrage d'esch-sur-sûre Provides drinking water for ca. 80% of the population of Luxemburg The drinking water treatment plant was build up in 1969 SEBES Modernization of treatment and increase of water production to 100 000 m 3 /d planned Surface area: 3,8 km 2 Capacity: 60 Mill. m 3

Simplified Scheme of the Pilot Plant Raw Water Preozonation ph Adjustment/Flocculation Membrane Filtration ph Adjustment/Flocculation Membrane Filtration Postozonation Biological Filtration

Pilot Study SEBES

t[s] Accompanying Lab Studies: Ozone Scavenging 800 700 600 500 400 300 200 206 402 230 573 260 701 523 RW O3 UF O3 UF AOP 100 0 26 63 57 58 46 1 2 3 5 c(o3) [mg/l] Ozone half life time vs. ozone dose preozonation (RW O 3 ), postozonation (UF O 3 ) and AOP O 3 /H 2 O 2 (UF AOP)

Ozone exposure [M s] Accompanying Lab Studies: Disinfection Efficiency 0,03 0,025 0,02 0,015 0,01 99% inactivation B. subtilis spores RW O3 UF O3 UF AOP 0,005 0 1 2 3 4 5 c(o 3 ) [mg/l] Ozone exposure vs. ozone dose; preozonation (RW O 3 ), postozonation (UF O 3 ) and AOP O 3 /H 2 O 2 (UF AOP); reaction time 500 s, DOC: raw water 2 mg/l, UF filtrate 1 mg/l, alkalinity: 0.4 mm, ph: 7

Accompanying Lab Studies: Bromate Formation Potential c(bro 3 - )[µg/l] 25 UF O 3 20 15 Bromate drinking water standard Bromate TLV RW O 3 UF AOP 10 5 0 1 2 3 5 c(o 3 ) [mg/l] Bromate formation vs. ozone dose, c(br - ): 20 µg/l, complete ozone depletion, preozonation (RW O 3 ), postozonation (UF O 3 ) and AOP O 3 /H 2 O 2 (UF AOP), DOC: RW 2 mg/l, UF 1 mg/l, Alkalinity: 0.4 mm, ph: 7

Design of Postozonation

Design of Postozonation Q = 1 m 3 /h c(o 3 ) = 1, 3, 5 mg/l c(h 2 O 2 ) = ca. c(o 3 ) Reaction time = 10 min PN 2 PN 3 PN 1 H 2 O 2

Residual conc. in % Pilot: Micropollutant Elimination Ozon dose UF O 3 1 mg/l O 3, PN 3 MTBE Dichlorobenzamide Bentazone Carbamazepine Diclofenac Sulfadiazine 100 90 80 70 60 50 40 30 20 10 0 Raw water Flocculation/UF UF O3 AC filter k O3 : < 10, 700, > 10 3 M -1 s -1

Concentration [µg/l] Pilot: Micropollutant Elimination 1,2 1 0,8 0,6 0,4 OH 0,2 H 2 N O S O 0 1 2 3 4 PN1 PN2 PN3 Sampling point Complete ozone consumption O No transformation of Chlorthalonil M12 by O 3 or OH N AOP O 3 /H 2 O 2, O 3 4 mg/l, H 2 O 2 17 mg/l DOC 1 mg/l, Alkalinity: 0.4 mm, ph: 7

Summary of Pilot Study Reservoir O 3 (Preozonation) Intermediate disinfection Intermediate oxidation efficiency Flocculation + UF Bromate formation at high ozone doses O 3 (Postozonation) Good disinfection Lowered oxidation efficiency Increased bromate formation Disinfection modus Synergy via switch between two modi O 3 + H 2 O 2 (Post AOP) Poor disinfection High oxidation efficiency Bromate formation can be controlled Oxidation modus

Full-Scale Implementation

Research projects Reine Ruhr Elimination of pharmaceutical residues in municipal wastewater treatment plants (WWTP: Schwerte, Bad Sassendorf & Duisburg-Vierlinden) Final report: http://www.lanuv.nrw.de/wasser/abwasser/forschung/abwa sser.htm Project management: Dr. Thomas Grünebaum (Ruhrverband, Essen) Lehrstuhl für Siedlungswasserwirtschaft und Umwelttechnik Institut für Siedlungswasserwirtschaft und Abfalltechnik Abteilung für Hygiene, Sozial- und Umweltmedizin 45

Elimination [%] Elimination of Selected Target Compounds in Large Scale WWTP Elimination [%] Jochen Türk, IUTA 100 90 80 70 60 50 2 mg Ozone/L, z spec = 0.36 40 30 20 10 0 n.d. 100 90 5 mg Ozone/L, z spec = 0.91 80 70 60 50 40 30 20 10 0

Take-home Messages Oxidative Processes can be used to meet (additional) goals of water and wastewater treatment Optimized technical use requires a profound understanding of chemistry of oxidant species including formation of oxidation byproducts For micropollutant elimination detailed knowledge of transformation reaction is needed but enormous effort needed Comprehensive economical and effect-orientied evaluations are still largely lacking

Acknowledgements Current and Previous Coworkers in Oxidative Processes: Alexandra Jarocki, Alexandra Beermann, Maike Cyris, Agnes Tekle- Rötering, Sebastian Kowal, Alaa Salma, Myint Sein, emens von Sonntag, Jochen Türk, numerous students Collaborators: Urs von Gunten, Georges Kraus, Jean-Paul Lickes, Stefan Panglisch, André Tatzel Funding: Deutsche Forschungsgemeinschaft, BMWi/AiF, BMBF, Deutsche Bundesstiftung Umwelt, Wasserchemische Gesellschaft, EU MC-ITN ATWARM ANAKON 2011, Zürich Wasser 2012, Neu-Ulm