“Tackling bacteriological quality problems in drinking water at HH level"

www.cosi.org.lkAbstractWhile long-term water distribution infrastructure might be a community's ideal, the realityis that the investment level needed is not always immediately present. Often, a watersource is too far a distance from homes to make conventional pipe distribution feasible.According to the World Health Organization, one sixth of humanity currently lacksaccess to any form of improved water supply within one kilo meter of their homes.Fortunately, recent research demonstrates that simple, low-cost point-of useinterventions at the household and community level are capable of dramaticallyimproving the microbial quality of water stored in the home and reducing the risk ofdiarrhoeal disease.Simple household-level water treatment and safe storage interventions can lead todramatic improvements in drinking water quality and typical reductions in diarrhoealdisease of 30 to 50 percent or more — making an immediate difference to the lives ofthose who rely on water from polluted rivers, lakes and, in some cases, unsafe wells orpiped water supplies.There are various household level water treatment methodologies available and COSIhas intervened in disseminating 2 major technologies.1. Solar Water Disinfection ( SODIS)2. Bio Sand Filter ( BSF)

This paper discusses the outcome of the above two technoclogies.

Paper presented for Symposium on November 29, 2006 at PGIA, University of Peradeniyawww.cosi.org.lk

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01. Introduction

Lot of rural and urban communities rely on unsafe drinking-water sources. Even more

are likely to be using microbiologically contaminated water if one takes into account recontamination

during water collection and transport, the use of unsafe storage vessels

and poor hygiene. Lot of people also face chronic poisoning from naturally occurring

chemical pollutants in water, such as arsenic and fluoride. Effective technologies for

household water treatment and storage, in combination with improved hygiene

behaviour, can help reduce water-related diseases much more quickly than it will take to

design and implement piped community water supplies.

Current estimates of the number of people using microbiologically unsafe water are

probably low. This is because the assumptions about the safety or quality of water based

on its source, extent of treatment or consumer handling do not take into consideration

several well-documented problems. One problem is that co-called protected or improved

sources, such as boreholes and treated urban supplies, can still be fecally contaminated

and deliver microbiologically unsafe water. In some cities the water systems abstract

unsafe water from unprotected or contaminated sources and deliver it to consumers with

no or inadequate treatment, yet these water systems are classified or categorized as

improved and safe. Another problem contributing to the underestimation of the

population served by unsafe water is contamination of water during distribution whether

water is piped or carried into the home.

There are various household level water treatment methodologies available and COSI

took the initiative to disseminate two such appropriate technologies in Sri Lanka. Those

are;

• Solar Water Disinfection ( SODIS)

• Bio Sand Filter ( BSF)

02. Bio-Sand Filter

The major benefits of slow sand filtration are due to the microbiology of the filter. The

microbiological community must be kept alive for the filter to be effective. In a

conventional slow sand filter, oxygen is supplied to the organisms through dissolved

oxygen in the water. Consequently, they are designed to be operated continuously. Also,

because the water moves through at a slow rate, the filter beds tend to be very large.

The bio-sand water filter is an invention that modifies the traditional slow sand filter in

such a way that the filters can be built on a smaller scale and can be operated

intermittently. These modifications make the filter suitable for use at the household or

small group level. Household use would simply not be possible with conventional slow

sand filtration because of the size requirements and the mode of operation.

A bucket of contaminated water can be poured into the top of the Bio-Sand filter as

necessary. The water simply flows through the filter and is collected in another bucket or

container at the base of the spout. It normally takes a few minutes for the entire bucket

to make its way through the filter. There are no valves or moving parts and the design of

the outlet pipe ensures that a minimum water depth of five centimetres is maintained

over the sand when the filter is not in use.

Paper presented for Symposium on November 29, 2006 at PGIA, University of Peradeniyawww.cosi.org.lk

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When water is flowing through the filter, oxygen is supplied to the biologic layer at the

top of the sand by the dissolved oxygen in the water. During pause times, when the

water is not flowing, the oxygen is obtained by diffusion from the air and by slow

convective mixing of the layer of water above the sand. If this layer is kept shallow,

enough oxygen is able to pass through to the micro organisms to keep them alive and

thus effective.

The filter is made up of five distinct regions; the influent reservoir, the supernatant, the

schmutzdecke, the biologically active zone, and the sand support and under-drain, as

shown below.

Paper presented for Symposium on November 29, 2006 at PGIA, University of Peradeniyawww.cosi.org.lk

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02.01 Project Objectives

Overall Objective:

To disseminate, facilitate & strengthen the use of BSF among the community members

and development of partners in Sri Lanka.

Specific Objectives:

1. Identify the communities/organizations who have the potential to use/likelihood to

sustain BSF in the long run

2. provide backup support services to the BSF users and the organizations involved

in BSF dissemination

3. disseminate BSF technology among non BSF users and with other influential

partners & monitor the progress

4. influence the decision makers (especially the health authorities) to consider BSF

as a viable water treatment method at household level

SUPERNATANT – The standing

water layer present during pause

periods - Oxygen can diffuse into

the water

INFLUENT RESERVOIR –

Volume above the filter media

which allows for a full pail of

BIOLOGICAL ZONE –

5-10 cm deep – living

layer of micro-organisms

SAND BED – Contains

virtually no living microorganisms

GRAVEL – No living

mirco-organisms present

SCHMUTZDECKE – Layer of

slime, mud and micro-organisms

which develops at the sand

f

Paper presented for Symposium on November 29, 2006 at PGIA, University of Peradeniyawww.cosi.org.lk

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02.02 Methods used (training & Demonstration)

Two 2 staff members from 7 partner organizations who are currently engaged in the

WATSAN sector were selected for the initial training for BSF. BSF technology,

dissemination strategies, training the community level staff were discussed & taught in

the training.

Another training was held recently for 23 PHI from Kalutara district and Regional PHI

Training Centers.

02.03 Monitoring and Follow up support

COSI assists the partner organizations in water quality tests, advisory services on

technicalities and providing training when & where necessary.

COSI will follow up and monitor the implementation of BSF filters at community level

which will be conducted by the partner organizations.

02.04 Results

This technology is field tested in many of the developing countries and proved to be

successful. However, in Sri Lanka, filed testing has just begun. Present interventions are

coupled with awareness programmes as well as hygiene education programmes.

03. SOlar water DISinfection (SODIS)03.01 Introduction

The Solar Water Disinfection (SODIS) process is a simple technology used to improve

the microbiological quality of drinking water. SODIS uses solar radiation to destroy

pathogenic microorganisms which cause water borne diseases.

SODIS is ideal to treat small quantities of water. Contaminated water is filled into

transparent plastic bottles and exposed to full sunlight for six hours.

Sunlight is treating the contaminated water through two synergetic mechanisms:

Radiation in the spectrum of UV-A (wavelength 320-400nm) and increased watertemperature. If the water temperature rises above 50°C, the disinfection process is

three times faster.

The poor bacteriological quality of drinking water, immensity of water related diseases

and plenty of sunshine received were considered as positive factors to introduce SODIS.

Apart from North Western, Eastern and dry part of the Uva province, COSI selected two

more organizations from the dry part of the North Central and Southern provinces.

Several Local organizations involved with SODIS project in central and southern part of

the country & the participation in northern east and west is fully by international

organizations. Traveling and organizing the training programmes in northern Sri Lanka

was easier as the security conditions have come back to normal due to the peace

process. The involvement of the schools in SODIS was promising & was as a better

Paper presented for Symposium on November 29, 2006 at PGIA, University of Peradeniyawww.cosi.org.lk

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way of promoting since they adopt the method with a good understanding of the

technicality.

Treating water before drinking was not common in most of the places. In some places,

people said that they drink boiled water but they were not aware on how to boil water in

order to destroy the germs. People were more concerning about the taste, odour and the

clearness of water and not much aware of the bacteriological contamination and its

consequences. Also, some people saw additional benefits of using SODIS such

as reducing cooking time and the cost for fuel/fire wood.

COSI suggested a target of 1010 SODIS regular users by the end of the project. This

target was achieved without any difficulty by June & progressed better afterwards.

In addition to the above targets & partner organizations, another organization working in

the Estate sector started SODIS with their small-scale water supply schemes in Tea

Estates in Nuwara Eliya district. Further, several units of NWS&DB (National water

Supply & Drainage Board) introduced SODIS in their rural water supply projects. For all

these organizations, the training and training/promotional material were supplied by

COSI.

03.02 Project Objectives

Overall Objective:

To disseminate, facilitate & strengthen the use of SODIS among the community

members and development partners in Sri Lanka.

Specific Objectives:

1. Screening and reviewing present SODIS users/organizations and identify the

communities/organizations who have the potential to use/likelihood to sustain

SODIS in the long run

2. provide backup support services to the present SODIS users and the

organizations involved in SODIS dissemination

3. disseminate SODIS technology among non SODIS users and with other

influential partners & monitor the progress

4. influence the decision makers (especially the health authorities) to consider

SODIS as a viable water treatment method at household level

03.03 Monitoring and Follow up support

COSI assists the partner organizations in supplying bottles, water quality tests, advisory

services on technicalities and providing training, training/promotional materials in

particular & when & where necessary.

Field visits, interviews and discussions with management, field staff and beneficiaries

were carried out initially to monitor the progress. Further, a proper plan was developed

for monitoring after the interactive discussion held in the mid–term review meeting.

03.04 Summary of Results

Total Target households (proposed) = 1010 by June 2003

Paper presented for Symposium on November 29, 2006 at PGIA, University of Peradeniya

5000 by June 2004

Analysis of users (by September 2003):

1. Households actually covered 2288

2. Regular users 2148(93.9%)

3. Irregular users 97 (4.2%)

4. Non users 43 (1.9%)

TOTAL (100 %)

The main reasons why the regular users are using SODIS daily are

1. To be free from water related diseases

2. To reduce the cost for fuel/fire wood

3 To reduce Housewife’s cooking time

03.05 Lessons learned and Conclusion

• Making the state officials in the water & health sections at provincial level aware

on SODIS is helpful in convincing people.

• Introducing both glass bottles & PET bottles together & making the users to

choose what is best is appropriate especially in places where the PET bottles are

not abundant.

• Though SODIS would be incorporated in other integrated projects, there should

be at least one full time field officer only for SODIS recruited either by COSI or

the partner organization.

• SODIS activities should be started in parallel or initially with the schools in the

area. Introducing SODIS in schools is more promising & this should be done by

interactive discussion with students incorporated in similar subject matter like

science, health.

• Each advantage of using SODIS should be highlighted when promoting SODIS

since reducing water related diseases in not the only fact that strike users

accord.

04. Summary

SODIS and bio-sand filter is proved to be efficient but need further research and

promotion. It is the responsibility for the government, NGOs, Universities and other

relevant organizations to take this further which will certainly improve the livelihood of

the Sri Lankans.

Further technical information can be obtained from;

Bio-sand filter www.cawst.org

SODIS www.sodis.ch