W A TER SANITATION AWARENESS PROGRAM An IEEE UP SECTION – SIGHT Initiative
Natural water Supplies Surface water River & lacks Easily polluted so needs purification. Underground water 2 layers: shallow & deep Sterile if sanitary precautions are followed Rain water Pick impurities Spring Pure if protected Sea water Desalination is expensive
Large scale Small scale Water intake Coagulation-sedimentation Filtration Disinfection “Chlorination” Distribution Boiling Filtration Disinfection
Water intake Place selected in the course of river or (canal) to draw water for purification Must be protected & away from any source of pollution especially fecal materials. Coagulation- sedimentation Water is pumped from intake to sedimentation tanks & left for some hours so that greater part of suspended matter settles down. For better sedimentation in a shorter period of time, a coagulant (commonly alum) is added Filtration Mechanical sand filter made of layers of sand on top of gravel. Alum & rest of impurities form a surface film, which is responsible for the filtration process. Water gets filtered on passing through the surface film. Removes all bacteria, cysts and suspended matter but virus can pass through the filter. Max. efficiency of filtration for micro- organism removal is 95%. Frequent washing of the filter is needed by passing a reverse current of water under high velocity. Disinfection Necessary to destroy the remaining 5% pathogenic organisms that may be found in filtered water. Chlorine is the gas commonly used in disinfection. Chlorine is added to filtered water in a proper dose “0.6 ppm“& left for ½ an hour. Residual chlorine “0.2 ppm” is to safe guard against pollution during distribution of water to final consumers. Super chlorination of water occur in cases of water borne epidemic. Distribution Through a network of pipes, water is distributed to the different parts of the areas to be supplied. Presence of residual chlorine in water is a safeguard against contamination from breaking or leaking through pipes
Boiling Reliable method. Kills all pathogens Specially needed for preparing bottle feeding of young infants. Filtration Domestic filter is the simplest. Water passes through a candle, which is made of clay, porcelain. Requires regular cleaning & if not properly cared for, it may become a source of infection itself Disinfection lime Chlorine of (bleaching powder). It contains 20- 35 % of its weight available chlorine. Destroys most of microorganisms if proper dose & contact time are allowed. Small Scale purification: used in villages, small confined areas. It is used for water supply at the individual levels in case of absence of large- scale purification
1- River water: - A popular source where people go to the canal to fill utensils. - They used for domestic purposes without purification and may be kept in porous containers (e.g. zeer, kolla) for cooling purpose not for purification. - Water is unsafe and thus can expose consumers to infection.
2-Shallow wells: - Used by some houses for private water supply. Shallow underground water, which is located in the superficial layers of the soil, is raised to the surface by a pump. Advantages: Bacteriologically safe if sanitary measures are taken. Disadvantages: - Exposed to pollution, from the surface & nearby sources (latrines, cesspits & refuse heaps) with the risk of spreading water-borne infection. Potential sources of pollution must be eliminated with an area of 20 meters radius all around the well. - A shallow well is 1 st licensed after sending water sample for lab analysis & should be continuously licensed to ensure safety.
3- Deep wells: - Underground water in the deep layers is obtained by constructing a deep well at a depth of more than 20 meters to reach the deep underground water layer. - Pumped water is raised up to fill a high tank reservoir of suitable size. - Water is distributed from the tank to a number of public taps located at different spots of the village. Advantages: - Deep water is clear, but not tasty, it is hard (not forming foam with soap). - Bacteriologically sterile but pollution is possible through cracks or leakage through pipes. Disadvantages: In certain localities, deep underground water contains excess chemicals, from strata of earth, which may cause: *Dental fluorosis: Excess fluorine (>1.5 ppm) causes mottling of the enamel of teeth. *Methemoglobinaemia: Excess nitrates (>20 ppm) lead to the formation of nitrites which is absorbed, and affects Hb leading to a serious and fatal disease in infants.
Physical Biological Chemical Water examination for physical, chemical & bacteriological standards is carried out at each step of water purification.
Physical standards: Must be odorless, colorless, agreeable taste and clear. Presence of organic matter, algae, silt and mud can alter water's physical characteristics (becomes turbid, changes odor) but not necessarily cause harm.
Chemical standards: pH must be neutral or slightly alkaline. With a moderate degree of hardness. Hardness is the presence of insoluble salts of calcium & magnesium in water. It can cause GIT disturbance, waste of soap and explosion of boilers. It is removed by boiling, addition of lime or precipitation. Permissible hardness is 20 degrees. Safety limits for some chemicals are determined such as nitrate 1.0 ppm, fluoride 1.5 ppm, iron 0.3 ppm, arsenic & lead must be nil.
Bacteriological standards: - It concentrates on evidence of faecal pollution. - Water is inoculated on agar & other special media. - Coliform organisms are used as indicators for presence of bacteria. - A high coliform count of ≥ 100 ml is regarded as being suspicious of fecal pollution. - E. coli must be totally absent. No ova, no cysts or parasites.
Water pollution is any physical, biological & chemical changes in water quality that adversely affects living organisms (man, animal and fish) or make water unsuitable for desired uses
Bacteria: enterica, cholera, dysentries Viruses: hepatitis, poliomyelitis. Parasites: Gardia, schistosomiasis. entamebahistolytica. Biological Acids, Salts, Mercury and Lead Minamata disease caused by mercury intoxication. Water soluble inorganic chemicals Pesticides & Oils Organic chemicals Organic wastes decomposed by bacteria which deplete water from its oxygen thus causing death of fish & aquatic plants. Oxygen demanding wastes Insoluble particles that are suspended and thus cloud water and reduce photosynthesis of aquatic plants. Sediment or suspended matter Cause birth defects, cancer, genetic damage. Radioactive isotopes
- Sudden or explosive onset. - Large number of cases is reported in few days. - All cases having common water supply. - All ages, both sexes and different social groups are affected. - More than one case may be simultaneously found in same family. - May occur in any season. - Cases of diarrhea & other GIT manifestations may appear before epidemic wave due to associated infection with other pathogenic organisms of shorter IP. - When water supply is controlled cases drop suddenly but take time to return to the pre-epidemic level due to occurrence of 2ry cases.
Control of water borne epidemic: Control of the water source that caused the epidemic. Increase the amount of chlorine added to the water & then neutralize the excess.