Water Quality & Intermittent Water Water Quality & Intermittent Water SuppliesSupplies

Dr. Nawal Sunna’Water Authority, Ministry of Water & Irrigation

Amman, Jordan

Consultation on Minimum Household Water Security Requirement and HealthCEHA, Amman

1-3 December 2003

Household Water SecurityHousehold Water Security The safe quality of water supplied to communities is

an important consideration in the protection of human health and well being, However, it is not the only factor that affects consumers. Other important factors include access to water and population served, Quantity and reliability of the supply and cost to the consumers.

  “All peoples, whatever their stage of development

and social and economic condition, have the right to have access to drinking water in quantities and of a quality equal to their basic needs", United Nations conference, Mar del Plata, 1977.

 

Intermittent Supply in JordanIntermittent Supply in Jordan

Jordan has a severe water shortage problem, the drinking water per capita is less than 100 liter per day. The water per capita is estimated to be 145 CM per year.

Water is rationed by intermittently supplying drinking water to consumers.Water is distributed once per week ( as a minimum).

Water is stored in household water storage tanks. Tanks are made either from Galvanized steel, polyethylene, fiber glass , PVC or cement.

Impacts of Intermittent Water Impacts of Intermittent Water Supply on QualitySupply on Quality

Un-pressurized distribution system is subject to infiltration and contamination

Stagnant water in distribution system will be the first flush to flow into the consumers tanks.

Water in the storage tanks may deteriorate due to:1. Microbial re-growth2. Chemical & Physical changes3. Loss of chlorine residual4. Accumulation of sediments5. Vulnerability to outside sources of contamination

and poor hygiene

Impacts on QuantityImpacts on Quantity

Inequitable supply availability despite available access.

The rich can afford more and better types of storage reservoirs and tanks.

Benefits: Reduce water loss due to leakage in distribution

system. Better management and conservation of water at

water supply and household level.

Water Source

Water Treatment

Distribution System

Storage Tanks

Impacts on Surveillance Programs to Impacts on Surveillance Programs to Ensure Safety of Drinking WaterEnsure Safety of Drinking Water

Samples from Distribution system are non-representative of what people drink.

Variable water quality during pumping. What representative is the composite water in

tanks. No regulation governing quality in tanks. Responsibility of the consumers. Only can be addressed by Public awareness

programs. Inapplicability of confirming positive

bactertiological results and take actions as needed.

Storage Impact on Microbial Storage Impact on Microbial QualityQuality

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cfu/mlin

fluen

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ater

2 da

ys

4 da

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7 da

ys

14 d

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log heterotrophic platecount (cfu/ml)

Figure 1. Log heterotrophic bacterial count of the influent water and water after being stored for different periods in house-hold storage tanks. This increase was accompanied by a decrease in turbidity and chlorine residual and an increase in TOC and pH

 

  Log bacterial plate count at the different storage periods in the different types

of house-hold storage tanks used in the study (Fiber-glass, coated fiber-glass, polyethylene and cast iron tanks).

Effect of the tank material on Effect of the tank material on water qualitywater quality

Bacterial growth in the Different House-hold Storage Tanks

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influentwater

2 Days 4 Days 7 Days 14 DaysStorage Period

Lo

g H

ete

rotr

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hic

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fu/m

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All Tanks

Polyethylene

Cast Iron

Fiber-Glass

Coated Fiber-Glass

Affect of SedimentsAffect of Sediments

Results showed that the water contains a high count of nematodes, which indicate that the sediments play a major role in providing the nutrients needed for their reproduction and growth .

The polyethylene and Fiber-glass house-hold tanks contained the highest concentration of TOC and Chlorophyll-a per tank sediment and they also contain the highest numbers of

nematodes .

Biofilm StudyBiofilm Study

Pressure Guage

Polyethylene

Galvanized cast iron

Valve

Tap (Sampling Point)

Distribution System

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.

.

Biofilm ImpactBiofilm Impact Samples were collected at once after the water flow, from

the inlet and outlet point of the two types of pipes, the polyethylene and the cast iron pipe.

Samples were taken also after the water flow for periods of 8-32 hours in the distribution system. Samples were tested for HPC, temperature, turbidity and residual chlorine.

The results showed a significant difference between the total bacterial count at the starting time and after the water flow for period’s of 8-32 hours. However no significant difference was found in the total bacterial count between the inlet and outlet water.

RecommendationsRecommendations

Study how to statistically represent safety of water distributed to consumers in intermittent water supplied systems.

Design monitoring program for water in tanks. Risk Assessment of storing water on public

health. Identify virulence factors in environmental and

water bacterial isolates. Enhance the design of storage tanks. Public awareness programs.