Effect of NOM Characteristics on the Removal of Pharmaceutically Active and Endocrine Disrupting Compounds by Coagulation

Transcription

1 Effect of NOM Characteristics on the Removal of Pharmaceutically Active and Endocrine Disrupting Compounds by Coagulation Sabrina Diemert (M.A.Sc. Candidate) Robert C. Andrews Department of Civil Engineering University of Toronto

2 PhACs & EDCs: Intro Pharmaceutically active compounds (PhACs) Chemicals designed to generate a biological response for the diagnosis, treatment, and prevention of diseases Endocrine disrupting compounds (EDCs) Chemicals which interfere with hormones 2

3 PhACs & EDCs: Concerns No conclusive evidence of health risks, but many knowledge gaps in research Not currently regulated in Canada or the U.S. However, many compounds listed on US EPA s Contaminant Candidate List 3 (CCL 3) Therefore, cost-effective drinking water treatment methods for these emerging contaminants will be of interest e.g. chemical coagulation 3

4 PhAC/EDC Removal Via Coagulation Previous studies indicate coagulation generally ineffective for EDC/PhAC removal (<20%), BUT: Higher removals observed in presence of NOM No links in literature between NOM characteristics and EDC/PhAC reduction NOM characteristics can be measured using novel analytical technique: liquid chromatography organic carbon detection (LC-OCD) 4

5 NOM Characterization: LC-OCD Using LC-OCD, NOM can be chromatographically separated and detected at low concentrations (µg/l scale) Identifies and quantifies NOM fractions by: Size Ionic character Hydrophobicity 5

6 NOM Characterization: LC-OCD

7 NOM Characterization: LC-OCD Bypass peak (total DOC)

8 NOM Characterization: LC-OCD Bypass peak (total DOC) Biopolymers

9 NOM Characterization: LC-OCD Humic substances Bypass peak (total DOC) Biopolymers

10 NOM Characterization: LC-OCD Humic substances Bypass peak (total DOC) Biopolymers

11 NOM Characterization: LC-OCD Humic substances Bypass peak (total DOC) Biopolymers Low molecular weight (LMW) acids

12 NOM Characterization: LC-OCD Humic substances Bypass peak (total DOC) Biopolymers Low molecular weight (LMW) acids LMW neutrals

13 Project Objective Assess the effectiveness of chemical coagulation (at bench-scale) for EDC/PhAC removal in waters with different NOM compositions (lake, river, and laboratory produced)

14 Methods JAR TESTS Otonabee River (Peterborough, ON) Lake Ontario (Ajax, ON) Grand River (Waterloo, ON) Laboratory-produced water (Suwannee River NOM + Milli-Q ) Polyaluminum chloride (PACl) Alum GC/MS and LC/MS/MS LC-OCD

15 PhACs & EDCs Studied Here Compound Acetaminophen Gemfibrozil Oxybenzone Carbamazepine Estrone Classification Analgesic, antipyretic (PhAC) Lipid regulator (PhAC) Sunscreen ingredient (EDC) Antiepileptic, antidepressant (PhAC) Natural hormone, metabolite (EDC) 15

16 Experimentation Issue: Solvents Studies assessing EDC/PhAC removal through drinking water treatment often artificially spike EDC/PhACs to environmentally relevant concentrations Usually use stock solutions in organic solvents Often do not test impact of solvent on treatment method Secondary aim of our study: Does acetone concentration in test waters affect coagulation processes?

17 Experimental Set-up: ANOVA Two-way (two treatment factor), three level, replicated factorial design Screening for effects of PACl dose and acetone concentration on EDC/PhAC and NOM fraction concentrations Treatment factors and levels for experimental runs: Level PACl dose (mg/l) Low Mid-point High Acetone concentration (mg/l) Statistical analysis of variance (ANOVA) applied at confidence level of 95%

18 ANOVA: Effect of PACl Coagulation Compound Significant impact on concentration (95% confidence) Lake Ontario Otonabee River Grand River SRNOM water Acetaminophen No Yes ( ) No No Gemfibrozil Yes ( ) No No Yes ( ) Oxybenzone No No a Yes ( ) No Carbamazepine No No a No No Estrone No No No No Total DOC No Yes ( ) Yes ( ) No Hydrophobic DOC No Yes ( ) No No Biopolymers Yes ( ) Yes ( ) Yes ( ) N/A Humic Substances No Yes ( ) Yes ( ) No Building blocks Yes ( ) Yes ( ) Yes ( ) No Low molecular weight acids No No Yes ( ) No Low molecular weight neutrals No No No a No a = not significant at 95% but yes at 90%

19 ANOVA: Effect of Acetone Compound Concentration Significant impact on concentration (95% confidence) Lake Ontario Otonabee River Grand River SRNOM water Acetaminophen No No No No Gemfibrozil No No No No Oxybenzone No No No No Carbamazepine No No No No Estrone No No Yes ( )* No Total DOC Yes ( ) Yes ( ) Yes ( ) Yes ( ) Hydrophobic DOC Yes ( ) Yes ( ) Yes ( ) Yes ( ) Biopolymers No No No N/A Humic Substances No No No No Building blocks No No No No Low molecular weight acids No No No No a Low molecular weight neutrals Yes ( ) Yes ( ) Yes ( ) Yes ( ) a = not significant at 95% but yes at 90%, * = irregular residuals plot

20 Treatment Factor PACl dose Acetone dose ANOVA Results: Summary Significant negative effect Various NOM fractions (primarily biopolymers, building blocks & humic substances) Gemfibrozil in low DOC waters (<4 mg/l): Lake Ontario and laboratoryproduced water None (estrone discarded) Significant positive effect Oxybenzone in Grand River water Acetaminophen in Otonabee River water Hydrophobic DOC and LMW neutral NOM fractions To examine coagulation trends in more detail, additional coagulant doses were added at lowest acetone concentration

21 Coagulation and NOM Removal: Lake Ontario

22 Coagulation and NOM Removal: Lake Ontario Small (<0.5mg/L) decrease as PACl

23 Coagulation and NOM Removal: Otonabee River Decrease as PACl No clear trend Small (<0.5mg/L) decrease as PACl

24 Coagulation and NOM Removal: Grand River Decrease as PACl Small (<0.5mg/L) decrease as PACl Little change in concentration

25 Coagulation and NOM Removal: Suwannee River NOM Quick decrease with PACl, then steady concentrations

26 Coagulation and NOM Removal: All Waters

27 Coagulation and NOM Removal: Summary Humic substances well removed in Otonabee and Grand River waters Concentrations too low in Lake Ontario (<1 mg/l) to be influenced by coagulation Removed at low PACl doses in laboratory produced water but no benefit with higher doses Low (<0.5 mg/l) removals of building blocks and biopolymers in natural waters Next, examine EDC/PhAC removal at lowest acetone dose

28 Coagulation and Gemfibrozil Concentration 28 28

29 Coagulation and Gemfibrozil Concentration 29 29

30 Coagulation and Gemfibrozil Concentration - As PACl dose, gemfibrozil concentration in Lake Ontario and SRNOM waters - May be removed by sorption to NOM - But, differences in NOM fractions indicate charge neutralization mechanisms more likely PhAC - PhAC NOM EDC 30 30

31 Coagulation and PhAC/EDC Concentrations

32 Coagulation and PhAC/EDC Concentrations

33 Coagulation and PhAC/EDC Concentrations As PACl dose : - oxybenzone concentration in Grand River water - acetaminophen concentration in Otonabee River water Potential cause: coagulant causes conformation changes in NOM, leading to desorption of EDCs/PhACs NOM EDC PhAC 33

34 Coagulation and EDC/PhAC Concentrations: Summary Gemfibrozil removal not correlated to NOM fraction concentrations Likely removed through charge neutralization by PACl, not coordination with NOM Oxybenzone concentration increases in Grand River water and acetaminophen concentration increases in Otonabee River water potentially due to desorption from NOM Finally, the effects of acetone concentration can be examined more thoroughly

35 Total DOC: Effects of Acetone and PACl DOC as PACl dose

36 Total DOC: Effects of Acetone and PACl DOC as acetone dose

37 Total DOC: Effects of Acetone and Grand River PACl Otonabee River -DOC : due to acetone addition -DOC : due to coagulation of humic substances, building blocks and biopolymers -Acetone concentration effects can be examined for specific NOM fractions

38 Acetone: Contribution to LMW Neutrals Water Slope Intercept Otonabee River SRNOM water Grand River Lake Ontario

39 Acetone: Contribution to LMW Neutrals Water Slope Intercept Otonabee River SRNOM water Grand River Lake Ontario

40 Acetone: Contribution to LMW Neutrals Water Slope Intercept Otonabee River SRNOM water Grand River Lake Ontario

41 Acetone: Contribution to LMW Neutrals r 2 all >0.99 Water Slope Intercept Otonabee River SRNOM water Grand River Lake Ontario

42 Acetone: Contribution to Hydrophobic DOC r 2 range: Water Slope Intercept Otonabee River SRNOM water Grand River Lake Ontario

43 Acetone Contributions to NOM: Summary Acetone concentration has similar contributions to NOM fractions in all waters: Major contribution LMW neutrals Minor contribution hydrophobic DOC 43

44 Next Steps Repeat tests using alum for 4 water types Add 15 additional EDCs/PhACs (analyzed via LC/MS/MS) Add NOM characterization techniques: Fluorescence Excitation-Emission Matrices (FEEM) Zeta potential Compare to parallel experiments: Emerging DBPs (haloquinones, MX, iodo-thms) Mutagenicity Impact of chlorination/chloramination 44

45 NSERC Chair Partners: Calgon Carbon Corporation Durham Region Environmental Bio-Detection Products (EBPI) GE Water & Process Technologies Hydromantis Environmental Software Solutions Lake Huron and Elgin Area Primary Water Supply Systems (London) Pathogen Detection Systems Peterborough Utilities Commission Regional Municipality of Halton Regional Municipality of York Regional Municipality of Peel Toronto Water Town of Parry Sound 45

46 LC-OCD: Sample Chromatogram Huber,