Disinfectant and disinfectant by- product formation · • Chlorine dioxide is degraded to...

Wasserversorgung

Disinfectant and disinfectant by-

product formationStrategic Exercise Drinking Water

Hans-Peter Kaiserex Water Works Zurich

Stadt Zürich

Wasserversorgung Page 2

Content of presentation

Introduction

Approach of Water Works Zurich to control disinfectants

and disinfectant by-products

Monitoring drinking water quality

Stadt Zürich


City of Zurich

- 400 000 inhabitants

67 communities

- 506 000 inhabitants

- 660 km2 supply area

I. Introduction

Zürich

Bachs Hoch-

felden Bülach

Rorbas

Uitikon

Killwangen

Embrach

Dättlikon

Pfungen

Wiesen-

dangen

Elsau

Elgg

Schlatt

ZellKyburgTurbenthal

Wila

Sternenberg

WeisslingenWild-

berg

Russikon

Fehraltorf Bauma

PfäffikonHittnau

Bäretswil

Wetzikon

HinwilGossau

Rüti

Dürnten

Bubikon

Egg

Hombrechtikon

Mönch-

altorf

Grüningen

Stäfa

Oetwil a.S.Meilen

Herrliberg

Ober-

EmbrachBrütten

Lindau

WinterthurHöri

Nieder-

weningen

Ober-

weningen

Rümlang

KlotenNürens-

dorf

Lufingen

Bachen-

bülach

Winkel

Bassers-

dorfOpfikon-

Glattbrugg

Wallisellen

Illnau-

Effretikon

Dietli-

kon

Uster

See-

gräben

Volketswil

Wangen-

Brüttisellen

Dübendorf

Greifen

-see

Schwerzen-

bachFällanden

MaurZumikon

Zollikon

Wädenswil

Horgen

Hirzel

Wollerau

Hütten

Schönen-

berg

Menzingen

Baar Neuheim

Thalwil

Kappel a.A.

Hausen

a.A.

Rifferswil

Zug

ChamStein-

hausen

Hünenberg

Masch-

wanden

Knonau

Obfelden

Ottenbach

Mettmen-

stetten

Langnau

a.A.

Aeugst

a.A.

Richters-

wil

Uetikon

a.S.

Affoltern

a.A.

Adliswil

Hedingen

Bon-

stetten

Stallikon

Arni

Jonen

IslisbergUnterlunkhofen

Oberlunkhofen

Zufikon

Berikon

Oberwil-

Lieli

Wettswil

a.A.Aesch

Birmensdorf

Oberglatt

Nieder-

glatt

Eggenwil

WidenRudolfstetten-

Friedlisberg

Urdorf

Schöfflis-

dorf

Neer-

ach

Steinmaur

Dielsdorf

Buchs

Regens-

berg

Schlei-

nikon

Boppelsen

Nieder-

hasli

RegensdorfDän-

ikon

Würenlos

Otelfingen

Hüttikon

Ober-

engstringen

Schlieren

Weiningen

Untereng-

stringen

Gerolds-

wil

Oetwil

a.d.L.

Spreitenbach

Dietikon

Bergdietikon

Dällikon

Küsnacht

Oberrieden

Rüschli-

kon

Kilch-

berg

Männe-

dorf

Erlenbach

Stadt Zürich

Wasserversorgung Seite 4

Task of the water works Zurich (WVZ)

To supply drinking water

and water for fire fighting to

the city

– anytime good quality

– anytime in sufficient quantity

– with sufficient pressure

– as cost-efficient as possible

280 employees

Stadt Zürich


Lengg

Lake Water Plant

(250 000 m3/day)

Sihlbrugg

Spring Water Plant

Moos

Lake Water Plant

(80 000 m3/day)

Hardhof

Groundwater Plant

(150 000 m3/day)

Water treatment plants

Stadt Zürich


Lake water treatment in the Lengg plant

Raw water

from lake ZurichOxidation/disinfection with ozone (O3)

pH adjustment with sodium carbonate (Na2CO3)

Two layer rapid sand filtration

Disinfection with ozone (O3)

Biological activated carbon filtration

Biological activated slow sand filtration

Drinking water

Stadt Zürich


Lake water treatment in the Moos plant

Raw water

from lake Zurich

Oxidation/disinfection with a mixture of

chlorine/chlorine dioxide (Cl2/ClO2)

pH adjustment with sodium hydroxide (NaOH)

Two-layer rapid sand filtration

Disinfection with ozone (O3)

Biological activated carbon filtration

Biological activated slow sand filtration

Drinking water

Flocculation with aluminum sulfate (Al2(SO4)3

Stadt Zürich

Wasserversorgung

Why disinfection is so important?

Definition of drinking water disinfectionMeasure to reduce the number of infectious pathogenic microorganisms by

inactivation.

Diseases caused by pathogenic microorganisms in drinking water: WHO: Worldwide approx. 2 million illnesses per year and approx. 800000 deaths

(600000 children).

But also diseases caused by pathogenic microorganisms in drinking

water in the US and Europe:

1993 Milwaukee Wisconsin 400000 sick people (Cryptosporidia)

2010 Östersund, Sweden 27000 sick people (Cryptosporidia)

2015 Le Locle 1000 sick people (Norovirus)

In Europe, the WHO estimates about 14 deaths per day

25.03.2018

Stadt Zürich


Regulated disinfectant and disinfectant by-products (CH: TBDV)

Disinfectant / DBPs Reaction Health effects

Ozone (O3) Ozone is immediately reduced

after ingestion.

Not considered to be toxic

when ingested at

concentrations applied in

drinking water treatment.

Highly toxic when inhaled

Bromate (BrO3-) Ozone + Bromide → Bromate carcinogenic, genotoxic

(bladder cancer)

II. Disinfectants and disinfectant by-products

Ozone

DBP: Disinfection By-Product

TBDV: Ordinance for drinking water in Switzerland (Verordnung des EDI über Trinkwasser sowie Wasser in öffentlich

zugänglichen Bädern und Duschanlagen)

Stadt Zürich


Emerging disinfectant by-products

DBPs Reaction Health effects

Nitrosoamines

NDMA

(+NDPA, NMEA),

NMOR, NPIP, NPYR,

NDBA, NDEA, NDMA)

Ozone + N,N-Dimethylsulfamide

(DMS; degradation product of the

pesticide Tolylfluanide) →Nitroso-

dimethylamine (NDMA)

Carcinogenic, genotoxic

(bladder cancer)

Aldehydes

Organic acids(not analyzed at WVZ)

Ozone + NOM Some of them

carcinogenic, genotoxic

Iodate (IO3-)

(not analyzed at WVZ)

Ozone + Iodide No health effect known

Ozone

i

NOM: Natural Organic Matter (DOC/POC: Dissolved/Particulate Organic Carbon)

Stadt Zürich


Compound Analytical method Höchst-

wert CH

Guideline

value WHO

LOQ of

WVZ

Regulated compounds (TBDV)

Ozone -Amperometry (cont.)

-Indigo method(DEV G3/DIN 38408 part 3)

50 µg/L - 0.02 mg/L

0.01 mg/L

Bromate (BrO3-) IC (post-column derivatization)

(WVZ-method, Salhi et al.

(1999), Wat. Res. 33: 3239-45)

10 µg/L 10 µg/L 0.5 µg/L

Emerging disinfection by-products

Nitrosamines(8 compounds)

SPE LC HRMS(WVZ method, Kraus et al.

(2008) Anal. Chem. 80: 834-842

- 100 ng/L(BRDproposed:

10 ng/L)

2-5 ng/L

N,N-dimethyl-

sulfamide

LC MS/MS(WVZ method)

- - 24 ng/L

Ozone - Analytical methods

i

DEV: Deutsche Einheitsverfahren (usually also DIN/EN/ISO norms)

LOQ: Limit of Quantification

WVZ: Water Works Zurich

Stadt Zürich


Chlorine


Chlorine Chlorine (hypochlorous

acid / hypochlorite) is

immediately reduced after

ingestion.


when ingested at


drinking water treatment

Toxic when inhaled

Trihalomethanes (THMs) (CHCl3, CHBrCl2, CHBr2Cl,

CHBr3)

Chlorine (bromine) + NOM carcinogenic and partly

genotoxic

Regulated disinfectant and disinfectant by-products (CH: TBDV)

Stadt Zürich


Chlorine

DBPs Reaction Health effects

Haloacetic acids Chlorine (iodine, bromine) + NOM carcinogenic and or

genotoxic

Halonitromethanes ditto genotoxic

Iodo-trihalomethanes ditto cytotoxic

Halofuranones (MX) ditto genotoxic and carcinogenic

Haloamides ditto genotoxic

Haloacetonitriles ditto genotoxic

Haloaldehydes (Di- and

Trichloracetaldehyde)

ditto genotoxic

2,4,6-trichlorophenol ditto possibly carcinogenic

Emerging disinfectant by-products

i

Stadt Zürich


Compound Analytical method Höchstwert

CH

Guideline

value WHO

LOQ of

WVZ


Chlorine Amperometry

(continuous)

DPD method(DEV G4-2,

EN ISO 7393-2)

100 µg/L 5000 µg/L 0.02 mg/L

0.01mg/L

Trihalomethanes

(THM)

Chloroform

Bromdichlormethane

Chlordibromomethane

Bromoform

HS SPME GC/MS (DIN 38407-41)

50 µg/L -

0.3 mg/L

0.06 mg/L

0.1 mg/L

0.1 mg/L

0.5 µg/L

Chlorine - Analytical methods

HS: Head Space SPME: Solid Phase MicroExtraction

Stadt Zürich



Compound Analytical

method

proposed

WHO Guideline

value

LOD reported

Emerging disinfection by-products (not analyzed at WVZ)

Mono, di- and trichloroacetic acid GC(ECD) after

esterificationEPA Method 552.1

20/50/200 µg/L 12-17 ng/L

Halonitromethanes

(trichloronitromethane, chloropicrin)

SPME GC-MS1 - 1-50 ng/L

Iodo-trihalomethanes SPME GC-MS1 - 1-50 ng/L

Halo acetonitrils

(Dichloro-/Dibromoacetonitrile)

SPME GC-MS1

20 µg/L/70µg/L

1-50 ng/L

Haloamides GC-MS/MS after liquid/liquid

extraction2

- 0.1-0.3 µg/L

1: Luo et al., J. Chromatogr. A 1365 (2014). EPA: US Environmental Protection Agency2: Templeton et al., Report of project DWI 70/2/268 (2012). LOD: Limit of Detection

SPME: Solid Phase MicroExtraction

Stadt Zürich



Compound Analytical method

proposed

WHO Guideline

value

LOD

reported

Emerging disinfection by-products (not measured at WVZ)

Halofuranones (MX compounds) LC ESI MS/MS after

liquid/liquid extraction1

-* 7-35 ng/L

Haloaldehydes (Di- and

Trichloroacetaldehyde)

GC MS2 or

GC(ECD)

-* 0.5 µg/L

2,4,6-trichlorophenol GC MS (EPA method 604)

200 µg/L 5 µg/L

* WHO: Concentrations well below those of health concern

ESI: ElectroSpray Ionization

1 Padilla (2015),, thesis University of Washington.2 Jeong et al. (2015), Environ. Sci. Technol. 49: 13749-59

Stadt Zürich

Wasserversorgung

Chlorination disinfectant by-products

25.03.2018

Source: Barcelo, Emerging Organic Contaminants, Springer 2012

Stadt Zürich


Chlorine dioxide

Emerging disinfectant by-products: None under evaluation


Chlorine dioxide (ClO2) Chlorine dioxide is instantly

reduced to chlorite and

chloride after ingestion.


when ingested at


drinking water treatment

Toxic when inhaled

Chlorite (ClO2-) Chlorine dioxide + NOM Changes in red blood cells

Chlorate (ClO3-) Disproportion of chlorite to

chlorine dioxide and

chlorate(Formation of chlorate in

hypochlorite solutions after long

storage times)

Changes in thyroid histology

an thyroid hormones

Changes in red blood cells

Regulated disinfectants and disinfectant by-products (CH: TBDV))

Stadt Zürich


Chlorine dioxide - Analytical methods

Compound Analytical method Höchstwert

CH

WHO Guideline

value

LOQ

WVZ


Chlorine dioxide Amperometry

(continuous)

DPD(DEV G5 DIN 38408-5)

TMB(Hach-Lange method)

50 µg/L - 10 µg/L

20 µg/L

2 µg/L

Chlorite IC (DEV D25/D20) 200 µg/L 700 µg/L 6 µg/L

Chlorate IC (DEV D25/D20) 200 µg/L 700 µg/L 6 µg/L

DPD: N,N-diethyl-p-phenylenediamine TMB: : 3,3′,5,5′-tetramethylbenzidine

Stadt Zürich


How to control disinfectant by-product formation

Lab analysis are spot tests: Monthly, a 100 µL to 100 mL sample is analyzed. In the same period, the Lengg

plant produces 3 billion L of drinking water.

Amount of DBP formed depends mainly on the concentrations of the

precursor and the disinfectant.

Approach to control the formation of disinfectant by-products:

Measuring the variation of the concentration of precursors in lake Zurich

(bromine, NOM) minor variation

Control the disinfection process based on continuous measurements in a way to

never exceed a defined maximum disinfectant concentration

The formation of DBPs is limited at anytime

Stadt Zürich


Lengg: Sampling locations and frequency

Rapid filtration

Pre-ozonation

Ozonation

Activated

carbon

filtration

Pumping

station

Clean water

reservoir

to the

reservoirs

pH-

adjustment

Pumping

station

Lake Zurich

Slow sand

filtration

Ozone

Ozone

Ozone (cont.)

Bromide (m)

NOM (m)

Bromate (m)

NDMA (q)

Ozone (cont.)

Bromate (m)

NDMA (q)

Bromate (m)

NDMA (q)

Ozone (cont.)

Ozone (cont.)

Bromate (m)

NDMA (q)

(cont.): continuous

(m): monthly

(q): quarterly

Stadt Zürich


Moos: Sampling locations and frequency

Rapid

filtration

Chlorination

(Cl2/ClO2)

Ozonation

Activated

carbon

filtrationPumping

station

Clean water

reservoir

to the

reservoirs

pH-adjustment

(NaOH)

Pumping

stationLake Zurich

Slow sand

filtration

Ozone

Chlorine (cont.)

Bromide (q)

Bromate (q)

NDMA (q)

THM (m)

Chlorite (m)

Chlorate (m)

Ozone (cont.)

(cont.): continuous

(m): monthly

(q): quarterly

THM (m)

Chlorite (m)

Chlorate (m)Flocculation

Aluminium

-sulfate

Bromide (q)

NOM (m)

Bromate (q)

NDMA (q)

Stadt Zürich


• With chlorine a wide variety of disinfection by-products are formed.

• Chlorine dioxide is degraded to chlorite, chlorate and chloride.

• With ozone, bromate and many other DBPs are formed.

→ Too many DBPs to analyse them all

→ Bioassays of water before and after disinfection (Ames microplate

fluctuation test Ames-MPF, bioassays with Daphnia,Thamnocephalus

→ Replacing the chlorine/chlorine dioxide step in the Moos plant to reduce

DBPs in drinking water

New Moos treatment chain:

Summary and Outlook

Pre-

filtrationLake

Zurich

Ultra-

filtrationOzonation

Activated

carbon

filtration

UV-

disinfection

NaOH

Drinking

water

Stadt Zürich


III Quality monitoring at water works Zurich

Quality Control with 25 employees

(ISO 17025)

Stadt Zürich


Chemical parameters

• Temperature, pH el. conductivity

• Water constituents (Ca, Mg, nitrate, etc.

• 30 metals and other elements (ICP-MS),

• UV-absorbance 254 nm

• NOM (DOC, POC, TOC)

• Bromate, chlorate, chlorite

Micropollutants

• Pesticides (approx. 50)

• Pharmaceuticals (approx. 40)

• Volatile org. carbon (approx. 40, VOC; DBPs)

• Polychlorinated biphenyls (PCB)

• Fuel additives and solvents

• Complexing agents (NTA, EDTA)

• Fluorinated hydrocarbons

• Artificial sweeteners (Acesulfam)

• Odours and flavours

ICP-MS : Inductively coupled plasma - mass spectrometry

Stadt Zürich


Microbiological and limnological parameters

In addition to the chemical monitoring parameters, microbiological and

linmological monitoring is essential for water works Zurich.

Parameters:

• Heterotrophic plate counts (HPC; cfu)

• E.coli (fecal indicator)

• Enterococcus (fecal indicator)

• Algae

• Plankton

• Total cell counts (flow cytometry)

http://www.google.ch/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwihpq7c-ffPAhVCVhoKHYARC3AQjRwIBw&url=http://www.moldbacteriaconsulting.com/bacteria/heterotrophic-plate-count-what-is-hpc-and-when-is-the-right-time-to-use-it.html&bvm=bv.136593572,d.ZGg&psig=AFQjCNFXdL8c-4Cy_icn_cW_b6-m2QMD7Q&ust=1477553419955017

http://www.google.ch/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwihpq7c-ffPAhVCVhoKHYARC3AQjRwIBw&url=http://www.moldbacteriaconsulting.com/bacteria/heterotrophic-plate-count-what-is-hpc-and-when-is-the-right-time-to-use-it.html&bvm=bv.136593572,d.ZGg&psig=AFQjCNFXdL8c-4Cy_icn_cW_b6-m2QMD7Q&ust=1477553419955017

Stadt Zürich


III Quality Control

http://www.zueriwasser.ch/

Stadt Zürich


Continuous online monitoring

Physical-chemical parameters (temperature, pH, redox potential, turbidity,

particles, conductivity, UV-absorbance, fluorescence, residuals of disinfectants)

Stadt Zürich


Early warning system with bio sensors

Sensitive organisms, like Daphnia sp. to detect poisonous compounds

after chemical accidents or sabotage.

Stadt Zürich


Daphnia test

Stadt Zürich


Zurich’s drinking water

is safe at any time!

Thank you for your

attention

www.zueriwasser.ch

http://www.zueriwasser.ch/

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