1. Subject: Environmental Engineering GROUP No: 03 SUBMITTED TO: Dr. Reena Popawala Sr. NoNameEnrollment NoRoll No 1Bhavik Gheewala130090106010130610 2Pooja Halvawala130090106011130611 3Hardik Jariwala130090106012130612 4Harsh Patel.J130090106013130613 5Harsh Patel.P130090106014130614 BRANCH : B.E. CIVIL 3 rd year SEMESTER : V

2.  IMPURITIES IN WATER Impurities in water are classified into three heads:  Suspended impurities.  Dissolved impurities.  Colloidal impurities

3. 1)SUSPENDED IMPURITIES. This impurities are dispersion of solid particles that are large enough to be removed by filtration on surface and heavier one settles down. The suspended particles which have the same specific gravity as hat of water, are mixed in the water. Suspended impurities include, Clay, silts Algae, fungi Organic and inorganic matters Mineral matters etc. These all impurities are macroscopic and cause turbidity in the water. The concentration of suspended matter in water is measured by its turbidity. The size of suspended impurities ranges from 0 to 10 -3 mm.

4. 2) Dissolved Impurities Some impurities are dissolved in water when water flows over the rocks, soils etc. Solids, liquids and gases are dissolved in natural water. This dissolved impurities may contain organic compounds, inorganic salts and gases. The concentration of total dissolved solids is usually expressed in ‘ppm’ and is obtained by weighing the residue after evaporation of the water sample from a filtered sample.

5. 3) Colloidal Impurities It is very finely divided dispersion of particles in water. This particles are so small that these can not be removed by ordinary filters and are not visible to the naked eye. All the colloidal impurities are electrically charged and remain in continuous motion. The electric charge is due to the presence of absorbed ions on the surface of the solids. These electric charge is on the surface of the particles are large enough in comparison with their mass to cause the particle to repel one another when they move within the sphere of action of each others charge. Most of the color of the water is due to colloidal impurities. Their quantity is determined by color tests. The size of colloidal particles is between ‘1 micron to 1 milli-micron’.

6.  Characteristic properties of natural water in hydrologic cycle. 1. Sea WaterSalts 2. PrecipitationGases, vapours, particulates, salts nuclei, radio active fall out 3. Surface runoffParticulates, organic matter, nitrates, phosphates, biocides 4. Ground water & spring H2SCarbonates, chlorides and sulphates of calcium and magnesium, iron etc 5. Lake waterAlgae, odours, tastes 6. Swamp waterOdours, tastes, color 7. River waterParticulates, organic matter, waste water

7.  Potable water (Wholesome water) The water which is suitable for drinking is known as potable water. The potable water should have the following qualities: 1.It should be odourless and colorless. 2.It should be free from suspended solids and turbidity. 3.It should be free from toxic substances. 4.It should be free from pathogenic organisms. 5.It should be moderately soft. 6.It should be aesthetically pleasant, i.e cool and fresh. 7.Having pH preferably between 7 & 8.5.

8. Types of water. Pure form of water : in the from of H2O, also known as distilled water. Mineral water : water with acceptable limits of minerals specified by potable water standards. Tap water : water supplied by the concerned authority available at home. Polluted water : water containing impurities not suitable for drinking. Contaminated water : water containing harmful impurities, not suitable for any purpose nor even can be thrown in water bodies.

9.  WATER BORNE DISEASES AND THEIR CONTROL: Water borne diseases are those diseases which spread primarily through contaminated waters. Water borne diseases are caused by pathogenic organisms.(bacteria, viruses, protozoa) carried by water containing sewage contamination. The important water borne diseases are : Typhoid fever. Paratyphoid fever. Cholera. Dysenteries. Gastro- enteritis. Infectious hepatitis, etc.

10. The water borne diseases may be grouped in four heads: 1)Bacterial diseases. 2)Virus diseases. 3)Protozoal diseases. 4)Worm(helminthic) diseases.

11. 1)Bacterial diseases. Diseases caused by bacterial infections are: 1.Typhoid fever: typhoid fever is the most important endemic and epidemic water borne disease of regions where supplies are drawn from surface sources contaminated by human faeces or urine. 2.Paratyphoid fever: this fever is mostly due to ingestion of contaminated food, specially milk, dried or frozen eggs, and other dairy products. This is caused by salmonella paratyphi A, B or C. 3.Cholera: usually this infection is contracted by ingestion of water contaminated by infected humans faecal materials. Sometimes it may be contracted by contaminated food or personal contact. 4.Bacillary dysentery: this disease is mostly contracted due to ingestion of food contaminated by flies or by unhygienic food handlers. This is caused by shigella, S.flexneri, S. sonneri, and S. boydii.

12. 2) Virus diseases: Those virus that can multiply in the intestinal wall and that are discharged in large numbers in faeces are more concern. The recognised viruses of serious concerned and diseases are: 1.Infections hepatitis or infections jaundice – caused by hepatitis virus. 2.Poliomyelitis – caused by polio virus.

13. 3) Protozoal diseases: Diseases caused by protozoa are: 1.Amebic dysentery- caused by entamoeba 2.Giardiasis – caused by giardia lamblia.

14. 4) Worm(helminthic) diseases: Worm infections are sporadic and occur only under grossly insanitary conditions or through gross mismanagement of sewage disposal system. Major worm diseases are: 1.Schistosomiasis (blood fluke disease)- caused by schistosoma. 2.Echinococcosis – caused by echinococcous. 3.Dracontiasis – caused by dracunculus.

15. Control of water-borne diseases 1.The water supply of the town or the city must be checked and disinfected before suppling to the public. 2.The water pipelines should be frequently tested, checked and inspected, so as to detect any leakage and possible source of contamination. 3.While laying or designing the water distribution system, attempts should be made as to keep the sewer lines and water lines as far as possible. 4.Proper disposal and treatment of domestic and the medical waste also helps in controlling water borne diseases. 5.The general habit of cleanliness must be inculcated among the people. People should not be allowed to urinate or defecated as and where desired. 6.The fly nuisance in the city should be checked and reduced to minimum by general cleanliness and by using insecticides. 7.The people should be advised and encouraged to eat hot fresh foods and to avoid raw foods. They should also try to use their own utensils while travelling.