week 3 hwts treatment options

8/12/2019 WEEK 3 HWTS Treatment Options

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Heat

Introduction to Household Water Treatment and Safe Storage, Modu

Dr. Richard Johnston


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Heat kills Enzymes denature Proteins change shape Cell pressure increases

Boiling Pasteurization

Introduction

DisinfectFiltrationSedimentation


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Higher pressure, high

temperature Autoclave, steam sterilizati 121 C at 1 bar for 15 minut

Lower pressure, lowe

temperature

Temperature and pressure


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Dose = Heat * Time

Thermal death kinetic First-order kinetics assume D = time required at 121 C

Canning 12 D reduction ofClostridiu

Thermal death kinetics


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Oldest method of HW

Estimated 600 millionusual practice >90% in Uzbekistan, Mong

Indonesia

Effective against all vand protozoa

Turbidity is not a problem Prone to recontamina Flat taste

Boiling


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Country Reduction inTTC

% samples< 1 CFU/100 mL

% samples< 10 CFU/100 mL

Re

India 2 LRV 60% 65% Clasen et

Vietnam 1.5 LRV 37% 75% Clasen et

Guatemala 0.9 LRV 71% 82% Rosa et al

Indonesia -- 49% Sodha et

Cambodia 2 LRV 44% 73% Brown and So

Effectiveness in field studies


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If biomass is used as fuel

Health impacts Environmental impac

Costly (India, Viet Na

Fuel: 0.5%-1.5% monthly i Time: 20 min/d wood colle

minutes extra/day for treatm Another 2-5% of monthly in

Fuel and time


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Not necessary to reac

Protein damage Milk pasteurization 72 C for 15 seconds 63 C for 30 minutes

Heat-up and cool-dow

Difficulty of knowingwhen water is 70C

WAPI

Pasteurization


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System developed in

Readily available was Inefficient stoves 600 C internal, >80% heat w

Inexpensive flow-throexchanger

Chulli system


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System developed in



Chulli system

Credit: Islam and Johnston, 2006


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System developed in



Evaluation: (Gupta et Microbiologically effective Low use: 20%

Chulli system

Credit: Islam and Johnston, 2006


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Disinfection effectiveness

Protozoa Giardia

Bacteria E. coli,

Viruses Adenovirus, poliovir Lab waters, Indian w

Protozoa 6-9+

Crypto cystsafter 1 min

Bacteria 6-9+ B. anthrax c

boilingViruses 6-9+ L Easily killed


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Protozoa

Giardia

Bacteria E. coli,

Viruses Adenovirus, poliovir Lab waters, Indian w

Protozoa 6-9+

Crypto cystsafter 1 min

Bacteria 6-9+ B. anthrax c

boilingViruses 6-9+ L Easily killed

Islam, M. F. and R. B. Johnston (2006)."Household pasteurization of drinking water: thechulli water-treatment system." Journal ofHealth, Population and Nutrition 24(3): 356-362.

Ericsson, C. D., R. Steffen and H. Backer(2002). "Water disinfection for internationaland wilderness travelers." Clinical infectiousdiseases 34(3): 355-364.


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Some key elevations

Dbendorf 440

Zermatt 1608

Addis Ababa 2355

La Rinconada, Peru5101

La Paz, Bolivia3640

Mt. Everest 8848

Kilimanjaro 5895

Mt. Fuji 3776

Aspe

-2000

0

2000

4000

6000

8000

10000

E l e v a t i o n

, m

The Dead Sea -427

Mean sea level 0


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Some key boiling points (Celsius)

Dbendorf 98.6

Zermatt 94.4

Addis Ababa 92.1La Paz, Bolivia

87.8 Aspe

-2000

0

2000

4000

6000

8000

10000

E l e v a t i o n

, m

The Dead Sea 101.5

Mean sea level 100


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Some key boiling points (Celsius)

Dbendorf 98.6

Zermatt 94.4

Addis Ababa 92.1

La Rinconada, Peru83.2

La Paz, Bolivia87.8

Mt. Everest 72.0

Kilimanjaro 80.9

Mt. Fuji 87.3

Aspe

-2000

0

2000

4000

6000

8000

10000

E l e v a t i o n

, m

The Dead Sea 101.5

Mean sea level 100


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Some key boiling points (Relative oxygen)

Dbendorf 96

Zermatt 82%

Addis Ababa 77%

La Rinconada, Peru54%

La Paz, Bolivia66%

Mt. Everest 33%

Kilimanjaro 48%

Mt. Fuji 63%

Aspe

-2000

0

2000

4000

6000

8000

10000

E l e v a t i o n

, m

The Dead Sea 106

Mean sea level 100% relative = 20.9% actual oxygen


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How long do you need to boil water?


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Advantages Challenges

Highly effective Takes long time, including cooling

Not affected by turbidity Changes taste of water

Simple operation, no special equipmentneeded

Possibility of recontamination

Widely accepted, understood, promoted High energy and time costs

Considerations for heat treatment


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Heat kills Effective against all classes

Boiling is very widesp Recontamination is w Pasteurization works

Summary


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Ultraviolet radiation

Introduction to Household Water Treatment and Safe Storage, ModuDr. Richard Johnston


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Ultraviolet radiation Artificial radiation Natural radiation (sol

Introduction: Ultraviolet Radiation

DisinfectiFiltrationSedimentation


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CosmicRays

GammaRays

X-rays Ultraviolet Visible Infrared Mwav

0.1 0.1 1 nm 100-400nm

400-700nm

Up to 1mm

1 cm

Electromagnetic spectrum

Vacuum UV UV-C UV-B UV-A

400 315280200100

GermicidalPeak

260

ff


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Dose = Intensity * Tim 1 mJ/cm2 = 10 J/m2

DNA absorbs in 200- Peak at 260 nm

Most effective agains Bacteria, then Protozoa cysts, then Viruses, bacterial spores

Typical dose 400 J/m2

Efficacy against pathogens

Effi i h


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Source: USEPA 2006, UV Disinfection Guid

UV C G i


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UV-C generated by la Low-pressure mercury lam Medium-pressure lamps, 20 LED lamps developing rap

Effective in water No impact of pH

Turbidity can shield particl Modest temperature effect,

at low temperatures

UV-C Generation

UV C i i M i A l


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Baja California, Mexi Small UV-C lamp (ele

1200 J/m2

5 litres per minute, sto

Evaluation: water quapre-intervention, thanalternative disinfectio

Exclusive use: 40%

UV-C interventions: Mesita Azul

Credit: F. Reygadas, 2012

S l Di i f ti (SODIS)


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Use natural sunlight PET bottles

Six hours exposure 2 days if cloudy

> 20 countries, 5 mill www.sodis.ch www.fundacionsodis.

Solar Disinfection (SODIS)

S l i di ti
http://www.sodis.ch/http://www.fundacionsodis.org/http://www.fundacionsodis.org/http://www.sodis.ch/


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Solar irradiation

SODIS Mechanisms


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Direct inactivation UV-B Much removed by PET

Indirect inactivation UV-A Generation of Reactive Ox Internal: chromophores in c External: organic matter, ir

Heat

SODIS Mechanisms

Factors affecting SODIS


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UV Radiation Sun height Latitude Cloud cover Altitude Ozone Ground reflection Water column


Credit: www.sodis.ch

http://www.sodis.ch/http://www.sodis.ch/


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UV Radiation Sun height Latitude Cloud cover Altitude Ozone Ground reflection Water column

Temperature At 50C, one hour exposure

Turbidity < 30 NTU


Credit: www.sodis.ch

http://www.sodis.ch/http://www.sodis.ch/


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Protozoa 2-4+ L Giardiacysts Cryptosporidi

Bacteria 3-5+ L Salmonella > E

Shigella > V. c

Viruses 1-5+ LR Adenovirus, p

echovirus, MS

SODIS in Bolivia


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Since 2001 Eawag + Fondacion S Piloted in Cochabamb Training by NGOs, lo

promoters, schools, hprofessionals, women

700 000 users

Evaluation: 32% mea

Source: Musezahl, 2009, PLoS M

SODIS in Bolivia

Credit: Fundacin SODIS

Is SODIS safe?


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PET = polyethylene t

Antimony Adipates, phthalates Acetaldehydes, forma Bisphenol A

Genotoxicity

http://www.sodis.ch/methpublikationen/index_EN

Is SODIS safe?

Considerations for UV treatment
http://www.sodis.ch/methode/forschung/publikationen/index_ENhttp://www.sodis.ch/methode/forschung/publikationen/index_ENhttp://www.sodis.ch/methode/forschung/publikationen/index_ENhttp://www.sodis.ch/methode/forschung/publikationen/index_ENhttp://www.sodis.ch/methode/forschung/publikationen/index_ENhttp://www.sodis.ch/methode/forschung/publikationen/index_EN


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Highly effective (UV-C > SODIS) Limited to low turbidity

UV-C requires electricity

Simple (SODIS) Dependent on climate

Inexpensive (SODIS) Takes significant time

Low risk of recontamination (SODIS) Small volumes

Considerations for UV treatment

Summary


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What UV radiation is Efficacy against pathogens

How UV-C interventican be adapted for HW

How solar disinfectioworks and is applied imiddle income countr

Summary


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Chemical disinfection



Introduction: Chemical disinfection


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Chlorine Chemistry and dosing Forms Example application

Introduction: Chemical disinfection

DisinfectFiltrationSedimentation

Chlorine disinfection


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Since 1890s in Englanearly 20th century

Used in 98% of US utilities

Second most reported 5.6% of households Latin America and Caribbe

Strong oxidant Devastates cell wall, DNA, Mechanisms not fully unde

Chlorine disinfection

Chlorine speciation


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Elemental Chlorine (C High Test Hypochlori Calcium hypochlorite Sodium hypochlorite Electrolytic generatio

All generate Free Ch hypochlorous acid (HOCl) hypochlorite (OCl-) pKa 7.54

Aim for pH < 8

p

Chlorine dose and demand


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Dose = Demand + Re

Chlorine demand Organic carbon Iron and manganese Ammonia

Target 0.5 mg/L resid Usually need 1-5 mg/L dos If turbid, double dose Guideline value for chlorin

Safe Water System (CDC, PAHO)


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Household water trea Safe storage Behavior change com

Dilute liquid chlorine pH 11+ Water Guard, Clorin, Claro

One capful per 20 L w Dose of at least 1.9 mg/L (e Double if turbid

y ( , )

www.cdc.gov/safewater/

NaDCC Tablets
http://www.cdc.gov/safewater/http://www.cdc.gov/safewater/


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Sodium Dichloroisocy About 60% free chlorine Reservoir chlorine Guideline value of 40 mg/L

Consistent free chlori Less taste and odour

Effervescent tablets, l

10 litres: 1x33 mg tablet if 20 litres: 1x67 mg tablet if

Easy to useSource: www.medentech.com

http://www.medentech.com/http://www.medentech.com/


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Dose = Concentration min-mg/L

Recommended 0.5 m Ct = 15 min-mg/L Equivalent to 1 mg/ for 15

HWTS, minimum dos Ct = 56 min-mg/L

y g g



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0.01 0.1 1 10 100Ct99 , mg-min/L

Bacteria0.04 0.08

Viruses2 30

Protozoa25 - 245

Source: WHO Guidelines for Dr



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0.01 0.1 1 10 100Ct99 , mg-min/L

Bacteria0.04 0.08

Viruses2 30

Protozoa25 - 245




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0.01 0.1 1 10 100Ct99 , mg-min/L

Bacteria0.04 0.08

Viruses2 30

Protozoa25 - 245




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Protozoa 2-5 LR Cryptosporidi

Bacteria 3-6+ L Spores may b

Viruses 2-5 LRV Longer time r

Combined chlorine


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Free chlorine + AmmChloramines

Monochloramine Dichloramine Trichloramine

Less efficient disinfec

Stronger odour

Note: Disinfection By-products


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Organic carbon Trihalomethanes (e.g. chloro

Haloacetic acids Carcinogenic in laboratory a

concentrations

Guideline values, 1 in 1cancer cases


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Example: Gadyen Dlo in Haiti


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Credit: M. Ritter, Deep Sprdeepspri

Gadyen Dlo evaluation


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Conducted in Norther Not in the earthquake zone

75% report current us 56% had free chlorine resid

Expansion to earthqua Massive free distribution High uptake, uncertain sust

Source: Harshfield, Am. J. Trop. MCredit: M. Ritter, Deep Springs Internationaldeepspringsinternational.org

Other disinfectants


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Chloramines Chlorine dioxide Ozone

Bromine Silver

Considerations for chlorination


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Highly effective against bacteria Ineffective against protozoa

Residual protection Taste and odour

Simple to use Requires low turbidity

Low cost Requires supply chain

Misunderstanding about by-produ

Summary


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Chlorine is widely usconventional treatmen

A variety of sources, achlorine in water

Highly effective again Effective against viru

protozoa NotCryptosporidium


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Safe Storage



Introduction: Safe Storage


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1

Water Resource

2 Delivery system

3 Collection and Transport

4

Household storage

5 Consumption

Characteristics of safe storage


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Opening Small enough to discourage ha Large enough for easy filling Cap Possible to clean

Tap or spigot for withdra

Portable Stable (flat bottom), rob (Size appropriate for tre

Inexpensive, available lo

Source: UNICEF Water Quality Handbook,

Safe storage containers


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CDC Container, 20 L Oxfam bucket, 14 L

Credit: www.nrs-international.com Credit: www.cdc.gov/safewater

Jerrycans
http://www.nrs-international.com/http://www.cdc.gov/safewaterhttp://www.cdc.gov/safewaterhttp://www.nrs-international.com/http://www.nrs-international.com/http://www.nrs-international.com/


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Credit: DFID, Jess SeldonCredit: UNICEF, Pierre Holz

Buckets and jars


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Credit: M. Ritter, Deep Springs Internationaldeepspringsinternational.org

Credit: D. Lantagnewww.cdc.gov/safewa

Water storage in refugee camps


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Malawi refugee cam Repeated outbreaks of dia

Well water, high micrbobi

Improved 20 L stora Provided free to 25% of in Exchanged for previous c

53% reduction in tot 69% reduction in geometr

Finger rinse: high coSource: Roberts et al, Bulletin of the WHO, 2001http://www.who.int/bulletin/archives/79(4)280.pdf

Improved water storage in Benin
http://www.who.int/bulletin/archives/79(4)280.pdfhttp://www.who.int/bulletin/archives/79(4)280.pdf


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Rural Benin, high leve At least 40% using public p

Randomized interventcontainer with tap

72 villages, 50% selected fo 50% plastic, 50% ceramic. Cost $24-$33, no cost recov

88% continued use aft Clay containers prone to br

70% lessE. coli contamSource: Gnther and Schipper, Health Econo

Summary


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Safe storage containdesigned to minimiz

recontamination Desired characteristics

Examples Intervention studies


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Combinations


Introduction


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DisinfectioFiltrationSedimentation

Multiple barriers

Informal combination Commercial combina

Informal combinations


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Sedimentation, roughceramic filtration, or b

Heat, SODIS, or chlo

Safe storage containe

Typical combination: filtration + chlorine + safe

Source: CAWST - The Centre for Affordable Water and Sanitation Technology (www.cawst.org)

Coagulation and chlorination


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Informal combination

P&G Purifier Watermaker

Good for turbid water Requires stirring cont

Separate safe storageCredit: Procter & Gamble

Filtration and disinfection
http://childrensafedrinkingwater.typepad.com/.a/6a00d83452215469e2015437e112bf970c-pi


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Source: www.eurekaforbes.com Source: www.pureitwater.com Source: www.tataswach.com

Minera Aquasure Pureit Swach

Source: biosi
http://www.eurekaforbes.com/http://www.pureitwater.com/http://www.tataswach.com/https://biosil.wordpress.com/https://biosil.wordpress.com/http://www.tataswach.com/http://www.pureitwater.com/http://www.eurekaforbes.com/


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Key Messages, Week 3


Introduction


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Disinfection

Heat Ultraviolet Chemical

Safe storage

Combined systems

Heat


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Boiling

Pasteurization

Effective against all cpathogens

Ultraviolet radiation


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CosmicRays

GammaRays

X-rays Ultraviolet Visible Infrared Mwav

0.1 0.1 1 nm 100-400nm 400-700nm Up to 1mm 1 cm

Vacuum UV UV-C UV-B UV-A

400 315280200100

GermicidalPeak260

Chemical disinfection


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Chlorination Liquids Tablets

Different effectivenespathogens

Safe water system Disinfection Safe storage Behaviour change communwww.cdc.gov/safewater/

Safe storage
http://www.cdc.gov/safewater/http://www.cdc.gov/safewater/


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Characteristics of safecontainers Examples Intervention studies

Combined systems


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Multiple barriers

Informal combination

Commercial combina
http://childrensafedrinkingwater.typepad.com/.a/6a00d83452215469e2015437e112bf970c-pi


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week 3 hwts treatment options

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