CEE 697z Organic Compounds in Water and Wastewater

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1 Print version CEE 697z rganic Compounds in Water and Wastewater NM and DBPs Special Lecturer: Rassil El Sayess Lecture #9 Dave Reckhow - rganics In W & WW Formation of 2 -driven DBPs 2 Na -, I- -, I 3 - The alogenated DBPs TMs AAs and other haloacids aloaromatics N-halo compounds alo-nitriles, aldehydes, nitros, etc N 3 ~1% N 2 The nonhalogenated DBPs Natural rganic Mater Anthropogenic Chemicals 2 (PPCPs, Ag & industrial products) ~9% C 2 + xidized rganic Compounds Acids Aldehydes Ketones Nitrosamines 1

ther Compounds The DBP Iceberg TMs, TAAs DAAs ICR Compounds 5 MWDSC DBPs

Compounds Non-halogenated Compounds The Trihalomethanes (TMs) C C C C

Dutch journal 2, Aug 19, 1972 issue Deduced that they were formed as

2 ther Compounds The DBP Iceberg TMs, TAAs DAAs ICR Compounds 5 MWDSC DBPs Stuart Krasner AWWA ~7 Known DBPs Susan Richardson USEPA alogenated Compounds Non-halogenated Compounds The Trihalomethanes (TMs) C C C C Chloroform omodichloromethane Chlorodibromomethane omoform Published in Dutch journal 2, Aug 19, 1972 issue Deduced that they were formed as byproducts of chlorination Proposed chemical pathways 4 Rook, 1974, Water Treat. & Exam., 23:

3 Treated Waters: TTMs from US Surveys ccurrence Assessment for the Final Stage 2 DBPR, 12/5, USEPA 5 5 The aloacetic Acids (AAs) AA5 include the two monohaloacetic acids (MCAA & MBAA) plus ne of the trihaloacetic acids: C C C C C C C C Trichloroacetic omodichloroacetic Chlorodibromoacetic Tribromoacetic Acid Acid Acid Acid (TCAA) And 2 of the dihaloacetic acids C C C C C C 6 6 Dichloroacetic omochloroacetic Dibromoacetic Acid Acid Acid (DCAA) (DBAA) 3

4 Regulated Compounds TMs AA5 omate Chlorite The regulated compounds are Common end products produced by almost all precursors Chemically very stable This is not typical of other DBPs DBP Precursor Materials General Groups Bulk NM ydrophobic NM Acids (Fulvics & umics) Neutrals Bases ydrophilic NM Acids, Bases, Neutrals Mesophilic NM Acids, Bases, Neutrals Soluble Metabolics Specific Structures Lignin Carbohydrates Proteins & Amino Acids Terpenoids Fatty Acids Tannins Anthropogenics Ranitidine 4

5 DBP Data - Availability Based on precursors Bulk NM: most data, from raw & treated waters NM Fractions: some data Specific Structures: far less data Based on type of DBP Regulated compounds (TMs & AAs) Extensive Data, especially for bulk NM Common unregulated compounds Moderate level, especially from ICR and selected studies Emerging unregulated compounds Very little data 13 6 Fulvic Acid 12 2 mg/l chlorine dose p 7. 2 o C TX TX Concentration (g/l) TCAA TTM TM, AA Concentration (g/l) DCAA (from: Reckhow & Singer, 1984) Time (hrs) 5

6 Some Common Unregulated DBPs Many decrease with time Degradation Chemical Biological Not shown Concentration (g/l) DCAN 1,1,1-TCP Chlorinated Raw Drinking Water from New Jersey (MacNeill's UMass thesis, 1994) 2 Chloropicrin 1,1-DCP Time (hrs) Model Compound Studies Model compounds Synthetically prepared in the lab: water that has been spiked with certain compounds Most have been used to assess formation of regulated DBPs (TMs & AAs) Some have been conducted to find new DBPs and especially intermediates formed along the way to the final byproducts 6

7 Lignin: alobenzoquinones (BQs) Many pathways Plants to Qs Toxicity Lignin? Qs are known to be reactive and damaging to DNA Postulated to be bladder carcinogen of high potency 4 5 Bull et al., alobenzoquinones (cont.) Identified following QSAR deductive reasoning SPE - LC/MS/MS method: Zhao et al., 21 Little occurrence data: U Alberta: 7 samples in 2 publications Dichloro (DCBQ): 14 ng/l median (165 ng/l max) thers much lower UMass: several dozen samples - unpublished Dichloro: 36 ng/l high value 14 7

8 Formation Potential Experiments designed to maximize exposure of water to chlorine (in this case) under optimal conditions and measure the concentration of DBP for a specified duration Disinfection by-product formation potential (DBP-FM): 72 hr, 2 mg/l 2 dose, p 7, 2C Simulated distribution system (SDS) test: 24 hr, 4 mg/l 2 dose, 2C and p 7 Dave Reckhow - rganics In W & WW TM-FP From: Reckhow et al., 27 WRF Report # Surface Waters Groundwaters From: Reckhow et al., 26 AWWARF report (in press) Formation Potential conditions: 72 hrs, 2 mg/l 2, p 7, 2C Specific TM-SDS (g/mg-c) Specific TMFP (g/mg-c) µg-tm/mg-c Median Value Cumulative Frequency 8

9 FP and SDS for NM Fractions Cumulative Frequency Plot for TM Precursor Content in Major RW Fractions 6 12 Untreated Waters nly.6 Specific TM-SDS (g/mg-c) Specific TMFP (g/mg-c) Philic Phobic Trans Pre-exponential Term (a) Cumulative Frequency Formation Potentials of NM Fractions 7 6 TTMFP (µg/mg-c) umic Acid Fulvic Acid Weak Acids Bases ydrophobic Neutrals Acids Bases Neutrals ydrophilic 9

10 TX Formation NM NM -DBPs -DBPs TX I I NM I-DBPs TX=T + T + TI ther disinfectants: N 2, 3, 2 From: Guanghui ua; 24 WQTC David Reckhow What do we know so far? Approximately 5% of the TX formed by drinking water chlorination is not accounted for concern about the identity and concentrations of DBPs Not feasible to account for each and every compound that might be formed in disinfected water TX: A surrogate measure for organically-bound halogenated DBPs in a disinfected water sample. Comparing the TX vales with the halides attributed to the identified DBPs: allow for the estimation of the unidentified TX TX analyzers: used to quantify amounts of organically-bound chlorine, bromine and iodine in raw and disinfected water samples 1

TX: Known & Unknown Data from the Mills Plant (CA) August 1997 (courtesy of Stuart Krasner) aloketones Chloropicrin Trihalomethanes 2% Regulated DBPs But, the Bad Stuff is probably somewhere here?

11 TX: Known & Unknown Data from the Mills Plant (CA) August 1997 (courtesy of Stuart Krasner) aloketones Chloropicrin Trihalomethanes 2% Regulated DBPs But, the Bad Stuff is probably somewhere here? Unknown rganic alogen 64% Unknown TX TTMs aloacetonitriles 2% Chloral ydrate 1% Sum of 5 aloacetic Acids 1% omochloroacetic Acid 3% 21 Cyto- and Geno-Toxicity of DBP classes ccurrence, genotoxicity, and carcinogenicity of regulated and emerging disinfection by-products in drinking water: A review and roadmap for research. (Richardson et al., 27) 11

12 C- and N-based DBPs ccurrence, genotoxicity, and carcinogenicity of regulated and emerging disinfection by-products in drinking water: A review and roadmap for research. (Richardson et al., 27) Final disinfectant Drinking water treatment plants usually employ a chemical as a final disinfectant Common oxidative chemicals Free chlorine Chloramines Chlorine dioxide Manganese oxide Potassium permanganate Dave Reckhow - rganics In W & WW 12

13 Use of chloramine vs chlorine as final disinfectant Less formation of regulated DBPs TMs & AAs ydrolysis and oxidation is slow which minimizes further oxidation to TXAA Dihalo products, but little trihalo R'' C C 2 C R'' C C 2 Substitution (free chlorine only) TM ydrolysis C 3 NM R' ydrolysis ydrolysis & xidation R'' C C 3 Slow xidation & Substitution (chlorine & chloramines) R'' C C 2 C 2 C C C xidative ydrolysis 3 C ydrolysis TCAA DCAA Use of chloramine vs chlorine as final disinfectant.2%.18% TM Yield (mole/mole).16%.14%.12%.1%.8%.6%.4%.2%.% Chlorination Chloramination colloids hydrophilic bases hydrophilic A+N transphilic NM Fraction hydrophobic Normalized per micromole of DC DBP Formation Reactivities of NM Fractions of a Low-umic Water by wang, Sclimenti & Krasner 13

14 Use of chloramine vs chlorine as final disinfectant AA Yield (mol/mol) colloids.6 hydrophilic bases.4 hydrophilic A+N.2 transphilic NM Fraction hydrophobic Chlorination Chloramination Normalized per micromole of DC DBP Formation Reactivities of NM Fractions of a Low-umic Water by wang, Sclimenti & Krasner Final Thought US federal and state environmental agencies still only regulate four TMs and five AAs (none of which include iodinated species) in addition to bromate and chlorite. ow to change that? Literature is lacking in studies conducted on treated drinking waters that are not spiked with model compounds attention should be put in that direction. Focus on quantifying more harmful compounds or TI/T in drinking water With the recent advances in analytical techniques, it is possible to have data that will supplement existing and ongoing epidemiological/toxicological evidence. nce enough concrete evidence is generated, regulatory agencies will have no choice but to improve on current regulations. 14

15 To next lecture Dave Reckhow - rganics In W & WW 15

CEE 697z Organic Compounds in Water and Wastewater

CEE 697z Organic Compounds in Water and Wastewater Print version CEE 697z rganic Compounds in Water and Wastewater NM and DBPs Special Lecturer: Rassil El Sayess Lecture #9 http://www.ecs.umass.edu/eve/research/nyc_chloramines/literature.html Dave Reckhow