Water Quality Control PDF

L4 WATER QUALITY CONTROL  INTRODUCTION:- Water is a basic nutrient of human body and is critical for human life; it supports transportation, and the use of nutrients and the elimination of toxins and waste from the body. Water is also essential for the preparation of foodstuffs and...

L4 WATER QUALITY CONTROL  INTRODUCTION:- Water is a basic nutrient of human body and is critical for human life; it supports transportation, and the use of nutrients and the elimination of toxins and waste from the body. Water is also essential for the preparation of foodstuffs and requirement for food preparation included the consumption requirement.  INTRODUCTION:- Water is also a good solvent and many substances, some is useful and others are harmful to life as these substances may dissolve in drinking water. WHO mentioned that around 1.1 billion people do not have access to improved water supply sources.Also about 2.4 billion people do not have access to any type of improved sanitation facility.  INTRODUCTION:- The WHO estimated that water intake for adult person is varies 2-2.5 Liter per day, but the daily consumption per day for each person’s purpose 120-400 Liters. Also water is important in many uses such as in agriculture, recreation, industry, street cleaning, and other commercial purposes.  WATER RELATED DISEASES:- 1) Water shortage diseases: Scabies, trachoma and skin infection.. 2) Water borne diseases: Such as Cholera, bacillary dysentery, typhoid, polio, hepatitis A, thread worm, amoebiasis...etc. 3) Water related vector life’s cycle: such as Malaria, Schistosomiasis , and Onchocerciasis.  WATER RELATED DISEASES:- 4) Diseases caused by lack or excess of water elements: Such as the following elements; Nitrate above 50 mg/Liter Blue baby syndrome. Fluoride above 1.5mg/Liter Fluorsis ,and dental caries) Lead above 0.1mg/Liter Lead poisoning. Arsenic above 0.01mg/Liter Arsenicosis (black foot diseases).  WATER SUPPLY SYSTEM: Classified into two major systems; 1) Public water supply system( Aqueducts) ; Usually done in urban areas, it consist of different parts as the following;  WATER SUPPLY SYSTEM: 1) Sources of supply (surface water or ground water). 2) Catchment system (such as ponds and dams). 3) Conduction system (means of pipes).  WATER SUPPLY SYSTEM: 4) Treatment plant (aims to improve quality of water). 5) Storage tanks (to obtain adequate pressure in certain distribution network) 6) Distribution system ( network of water pipes to consumers).  WATER SUPPLY SYSTEM: 2) Private water supply system; Usually in rural and sub rural areas has two types of wells: a) Shallow wells. b) Deep wells or Artesian wells.  WATER POLLUTION: Pollutants in water may be broadly classified as follow; 1) Natural pollutants; as dissolved N2, CO2, H 2S, salts of calcium, magnesium, sodium, suspended impurities and microorganisms. 2) Manmade pollutants; are sewage, industrial wastes, agriculture pollutants and physical pollutants.  Sanitary protection of the well: Special precaution is required to assure that wells are protected from contamination; the protective measures are the following: 1) The privy must be located down stream of water and 20 meters far from the well.  Sanitary protection of the well: 2) Location of domestic animals, also located down stream of water and at least 20 meters far a way. 3) Handle or electric pump should be used to get out water. 4) The lining of the well should be made water proof by cementing.  Sanitary protection of the well: 5) The opening must be protected with concrete cover so that water split does not back into the well. 6) Elevated edge with a lateral sloping floor and built above the ground level. 7) To disinfected wells after have been built or repaired.  How the distribution network get drinking water pollution? 1) Points of defects in drinking water network(Pipes). 2) Differences of pressure inside the pipes of water system and atmospheric pressure. 3) Cross-connection pipe system and sewerage system. 4) Inadequate location of sewerage or rain pipes in relation to drinking water network.  WATER QUALITY CONTROL:- Pure water is a clear, tasteless, and odorless fluid, but this observation not guarantees the safety of water for drinking. So the quality of water and its suitability for particular purposes such as drinking, it need laboratory tests to assess its components and presence of harmful elements in the water. There are three types of tests; physical, chemical, and bacteriological examinations, also there are three terms refers to the quality of water;  WATER QUALITY CONTROL:- 1) Potable water: Is the one which is free from harmful substances of any sources including pathogenic organisms and its more pleasant to eye as well as taste. 2) Polluted water: Is the one which has received any foreign substances, which tends to degrade its quality or its usefulness. 3) Contaminated water: Is the one whose quality is threatened by the presence of pathogenic or toxic substances.  LABORATORY EXAMINATIONS OF WATER:- The quality of water and its suitability for particular purpose are assessed by carry out physical, chemical and biological examinations as follow;  LABORATORY EXAMINATIONS OF WATER:- 1) Physical examination: Physical parameters are turbidity, colour, taste, odour, and temperature. Turbidity is due to organic matter, plantation and algae (particulate matter). Turbid water decreases efficiency of water disinfection, the acceptable standards of drinking water turbidity is 5 NTU (Nephelometric Turbidity Unit). The lower temperature decreases efficiency of water disinfection, higher temperature may cause growth of pathogens.  LABORATORY EXAMINATIONS OF WATER:- 2) Chemical examination: The aim is to analysis the presence of chemical elements in the drinking water because its effects on human health appear after a long period of consumption. Water pollution caused by natural or industrial waste products which may be disposal to river or wells. The chemical tests of drinking water are very important such as PH value, hardness, corrosive, nitrate, BOD, COD, lead, fluoride arsenic…etc.  LABORATORY EXAMINATIONS OF WATER:- 3) Bacteriological examination: Many micro-organisms can lives in a water and caused different diseases to man and animals including bacteria, virus, algae, parasites..etc. This bacteriological test is very importance test for any drinking water which may contaminated by human or animal fecal material, the presence of coliform group in the water is an indicator of contamination of water with fecal coliform as primary indicator is fecal E. coli.  PURIFICATION OF WATER. Purification of water is of great importance in community medicine ,the methods of water treatment are varies according to the source of that water, usually the surface water sources such as rivers are contaminated with industrial and sewage wastes and needs more management to improve its quality. While, the underground water may contains heavy elements but less bacteriological contaminations.  PURIFICATION OF WATER. The methods of water treatments may be considered under two headings: a) Purification of water on a large scale: 1) Sedimentation: Simple or by coagulation such as Aluminum sulphate.  PURIFICATION OF WATER 2) Filtration (Slow or rapid filtration): This is a useful technique that aims to remove the unacceptable color, odor, turbidity, and microorganisms. There are slow sand filters (the structure of sand filter consists of first layer-water bed (1-105 deep) the second layer sand bed, third layer-under drainage valves, filter control valve system is also an integral part of slow sand filter. Commercial filters available as UV filter, carbon filter, and reverse osmosis technology.  PURIFICATION OF WATER 3)Disinfection: The aim of disinfection is to kill the pathogenic agents, there are many disinfectants substances including chlorine , iodine, ozone..etc. Before distribution of drinking water the technique adopted on a large scale are: a) Chlorination. b) Ozonisation. c) Ultraviolet irradiation.  PURIFICATION OF WATER b)Purification of water on small scale: 1) Boiling (heat): Collected and stored water when boiled for 5 to 10 minutes ( Rolling boiling) is sufficient to kill most organisms. 2) Filtration: 3) Disinfection: Chlorine is an ideal disinfectant.  Surveillance of drinking water quality: Potable waters should be subjected to strict ongoing surveillance for maintaining quality standards. Public health labs should be utilized for maintaining and testing standards of water quality.  Surveillance of drinking water quality: Steps of a good surveillance system; 1) Sanitary survey. On the spot inspection and evaluation of water quality by trained person as per WHO guide lines.  Surveillance of drinking water quality: 2) Bacterial surveillance. Usually done using pre-sterilized bottles (McCartnet bottle) available from the national public laboratory. 3) Chemical surveillance. Done for the chemicals and inorganic constituents according to the recommended WHO standards for potable water.  Surveillance of drinking water quality: 4) Biological examination. This includes examination of water under the microscope for the presence of microscopic substance (excluding bacteria) such as algae, protozoa, ova, cyst, yeast, , small worm, insect larvae, etc.