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Drinking Water Treatment

in Rural Peru

Agua Para TodosBrittany Coulbert

April 26, 2004

Agua Para Todos

• Purpose: develop effective household water purification technologies and evaluate existing efforts

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Peru

Population: 28.4 million

Project Sites: Arequipa & Tacna

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The Water Problem

•Many rural residents are drinking from polluted irrigation canals

•Small water treatment plants are often inadequate

Drinking Water Sources:

Irrigation Canals

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Streams

Household Taps & Storage Devices

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Water Treatment Plants

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Water Vending Trucks

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Total Coliform Concentration in Source Waters - LOG Scale

1.7E+05

1.5E+03

6.4E+04 7.1E+043.7E+04

8.4E+03

1.1E+03

2.8E+02

2.4E+05

2.3E+04

1

100

10000

1000000

CBV W

TP inf

low

CBV W

TP eff

luent

El Triun

fo WTP

inflow

El Triu

nfo W

TP eff

luent

La Joy

a Cana

l

CBV H

ouseho

ld Tank

CBV H

ouseh

old Ta

p

CBV Unfil

tered

CBV Unfilt

ered

La Jo

ya Ho

spital

Tap

Water Location

CFU

/100

mL

Lo

g S

cale

Disaster Intervention7.9 earthquake in Southern Peruin June 2001

CEPIS (Center for Sanitary Engineering

and Environmental Sciences)

Peruvian Ministry of Health

&

Source: BBC News

disseminated household filtration and chlorination programs to rural villages, where water was negatively affected by the earthquake.

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Household Table Filter

Container for Chlorinating

Water

Chucatamani, TacnaSome of the towns receiving the

intervention program:

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Cerrito Buena Vista, Arequipa

Cruz de Mayo, Arequipa

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Alto La Cano, Arequipa

Chlorination System

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Chlorine Solution

Bidon (Storage Container)

Chlorination System

• 20-L safe storage containers (“bidones”)• 0.5% chlorine solution generated at local

hospital & distributed to towns in 200mL bottles of chlorine solution

• Add “half cap” of solution to 20 L of water• Distributed free to 400 families

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Small Scale Chlorine Generator

Chlorine Residual Found in Bidones

(Goal: between the red lines)

0.15

0.05 0.05

0.28

0.10.04

0.8

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1 2 3 4 5 6 7

Bidones

Fre

e C

hlo

rine

Conc.

[mg/L

]

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Pros & Cons of Chlorination

Pros• Percent removal of total

coliform from one household = 99.7%

• Very Inexpensive: $4 each• Easy to use• Local chlorine generation

possible

Cons• Turbidity & organic content

of source water high (particle removal step needed)

• Chlorine residual dosing too low

• Chlorine solution sometimes difficult to obtain due to poor technical support

• People don’t like the taste

Peruvian “Table Filter”

• Indigenous filter created by CEPIS

• Made of two 20-L plastic buckets

• Distributed for freeto 300 families

SandCeramic Candle Filters

Geotextile Cloth

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Pros & Cons of the Table Filter

Pros• Average percent removal

of total coliform = 97%• Average percent removal

of turbidity = 93%• Provides relatively

consistent and significantly improved drinking water

• Inexpensive: $12 each• Easy to use

Cons• Broken spigots• Cleaning is bothersome • Fragile ceramic candles• Parts not easily available• Sand sifting (during filter

assembly) is time-consuming

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Microbial Contamination

• Initial testing indicates that filters significantly reduction of coliform

• Coliform concentration still too high for safe drinking water

Total Coliform Before & After Chlorination at One House in Peru

LOG Scale

3.7E+04

7.1E+04

9.5E+01

1

10

100

1000

10000

100000

Water Source

CFU

/100

mL

Log S

cale

Household Tap Holding Tank Bidon

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Average Total Coliform Before & After Filtration

LOG ScalePeru Data

1.E+02

6.E+04

5.E+03

1

10

100

1000

10000

100000

Various Sources Before Filter After Filter

Water Type

CF

U/1

00m

L

Cost versus Willingness To Pay

0

10

20

30

40

50

60

70

80

90

Filter Clorine system 20% Plant

US

D $

Cost WTP

Slide prepared by C. Liu & A. Obizhaevafor G-Lab presentation

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People Affected by this Intervention & Evaluation:

Users

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People Affected by this Intervention & Evaluation:

Technical Support

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Local Health Center in Arequipa

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Program Support Technicians in Tacna

Local & International Engineers Evaluating the Program

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Politicians working with engineers to provide clean drinking water