Presentation on theme: "Water Quality & Intermittent Water Supplies Dr. Nawal Sunna’ Water Authority, Ministry of Water & Irrigation Amman, Jordan Consultation on Minimum Household."— Presentation transcript:
Water Quality & Intermittent Water Supplies Dr. Nawal Sunna’ Water Authority, Ministry of Water & Irrigation Amman, Jordan Consultation on Minimum Household Water Security Requirement and Health CEHA, Amman 1-3 December 2003
Household 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 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 Supply 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-growth 2. Chemical & Physical changes 3. Loss of chlorine residual 4. Accumulation of sediments 5. Vulnerability to outside sources of contamination and poor hygiene
Impacts 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 Ensure 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 Quality 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 water quality
Affect 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 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.
Recommendations 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.