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Unit II Environmental Engineering - II.  Pure water is a chemical compound with each molecule containing two hydrogen atoms and one oxygen atom (H 2.

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Presentation on theme: "Unit II Environmental Engineering - II.  Pure water is a chemical compound with each molecule containing two hydrogen atoms and one oxygen atom (H 2."— Presentation transcript:

1 Unit II Environmental Engineering - II

2  Pure water is a chemical compound with each molecule containing two hydrogen atoms and one oxygen atom (H 2 O).  Pure water can never be available in nature.  When precipitation reaches to earth’s surface, impurities added by physical, chemical or bacterial in it. Quality control

3  As the rain water flows over the surface of the earth, it picks up or dissolves particles of soil, garbage, sewage, pesticides and other human, animal and chemical wastes.  It may also pick up and dissolved certain decayed organic material, such as plants and dead animals.

4  As the surface water seeps into the “Ground – Water Reservoir”, most of the suspended particles are filtered out, but on the other hand, the water dissolved the minerals and salts present in the earth’s layers, through which it travels before joining the water table.

5  The impurities which dissolves or picks up a suspended matter, may sometimes make it more useful and potable for public uses and specially for drinking and some times it may render it harmful and unfit

6  Sometimes the water may contain toxic or poisonous substances such as arsenic, barium, cadmium, chromium, cyanides, lead, selenium silver, copper etc. which may be harmful for public health, even if present in low quantities.

7  The water may contain too much of common salt, there by rendering it brackish and making it undrinkable and less useful for cloth washing or irrigation and farming.

8 1.Physical characteristics:  Physical analysis of water is carried out to determine the physical characteristics of water.  This includes tests for determining turbidity, color, tests or odour, temperature, specific conductivity etc. Characteristics of water

9 i.Turbidity :-  If a large amount of suspended matters such as clay, silt or some other finely divided organic materials are present in water, it will appear to be muddy or cloudy or turbid in appearance.

10  The turbidity depends upon the fineness and concentration of particles present in water.  Clay or other inert suspended particles may not harmful to health, yet they are to be removed or reduced for aesthetic and psychological reasons.

11  The turbidity is measured by a turbidity rod or by turbidi meter with optical observations.  It is expressed as the amount of suspended matter in mg/l or ppm.  The standard units is that which is produced by 1 milligram of finely divided silica in 1 litre of distilled water.

12  The terms of “parts per million”(ppm) is currently being replaced by the term milligrams per litreb(mg/l).  Milligrams per litre is defined as the quantity of matter in milligrams (10 -3 gm) present in one litre of water.  For water, ppm and mg/l are approximately equal.

13  Turbidity can be measured easily by turbidity rod.  It consist of an aluminium rod which is graduated, as to give the turbidity directly in silica units (mg/l). Turbidity Rod

14  Jackson’s turbidity:-  It is also called as Jackson’s Candle turbidimeter.  It consist of a calibrated glass tube which can be placed on metallic cylindrical tube holder fixed over a metallic stand provided with a fixed standard candle at its bottom as shown in fig. Turbiditymeters

15  With the glass tube in place over the lighted candle, the water sample is gradually added to the glass tube increase the height of the water column in the tube and the candle flame is observed from the top.

16  The addition of water is stopped as soon as the image of the candle flame ceases to be seen.  At this stage, the height of the turbid water will provide enough just enough turbidity for preventing the candle light to pass through it.

17  Lower limit of Jackson’s Tubidimeter is 25 JTU

18  It consist of a closed galvanised iron box, on one side of which, two glass tube can be held vertically side by side. On the other side, in front of the tubes as 250 watts electric bulb is located with a reflector, so as to through light on the tubes. Bayli’s Turbidimeter

19  The glass tube are supported at bottom by a white opal glass plate and by blue cobalt plate as shown.  One of the two glass tube is filled with water and other is filled with standard water solution of known turbidity.

20  The electric bulb is lighted and blue color in both tubes is observed from top of the instrument.  If the colour of both tubes differ, the standard solution tube is replaced by another standard tube of different turbidity.  The process is continued till a matching is obtained in the colours of both the tubes.

21  The turbidity of standard solution will then corresponds to the turbidity of the sample of water.  Bayli’s turbidimeter can precisely record low turbidities (of the order of 0 to 2 ppm).

22  It is also called as Nephelometers.  It is used to measure very low turbidities of drinking waters (up to less than one unit).  Light intensity is measured at right angles to the incident light.  Photometer is used to measure the intensity of light passing through the turbid water, after the same is scattered at right angles to the incident.  Nephelometric turbidity units are abbreviated as NTU (Nephrometric Turbidity Units) Modern commercial turbidimeter

23  Occasionally, the Nephelometric turbidity units are referred as FTU ( Formazine Turbidity Units )  Since formazine Turbidity Units), Since formazin polymer is used as a reference turbidity standard suspension in place of silica suspension.

24  It can measure the ratio of 90 0 scattered light as shown in fig.  Light is focused by a lens before passing horizontally through the water sample.  It detects the transmitted light Ratio Turbidimeter

25  At low or moderate turbidity levels, the forward scatter signal is negligible compared to the transmitted signal, and the output is simply ratio of the 90 0 scattered light to the transmitted light.  This relation is stabilizes the instrument and negate the effect of colour, if present in water.  At high turbidity levels, the instrument records the ratio of the 90 0 scattered light, thus allowing linearity over the entire range.

26  Dissolved organic matters from decaying vegetation or some inorganic materials, such as coloured soils, etc. may impart colour to the water.  Colour can be measured by comparing the colour of water sample with other standard glass tube (called Nessels Tubes) containing solutions different standard colour intensity Colour

27  The standard unit of colour is that which produced by one milligram of platinum cobalt dissolved is one litre of distilled water.  The maximum permissible colour for domestic supplies is 20 ppm( based on cobalt scale).  Different standard colour intensities reprenting as 1 ppm, 2ppm, 3ppm,…. Respectively of platinum cobalt in 1 litre of water.  For public supplies, the colour number on cobalt scale should not exceed 20, and should be preferably less than 10.

28  The dissolved organic materials or inorganic salts or the dissolved gases may impart taste and odours, which are generally occur together.  Taste and odour may caused by the presence of: dissolved gases such as H2S, CH4, CO2, O2 etc.  It combined with organic matter: mineral substances like NaCl, iron compounds, carbonates and sulphate elements. Tastes and Odors

29  For drinking purpose, the water must not contain any undesirable or objectionable taste & odour. For public supplies, the water should generally be free from odour. i.e., the threshold number should be 1 and should never exceed 3.

30  For potable waters, temperature about 10 0 C are highly desirable, while temperature above 25 0 C is objectionable. Temperature

31  The total number of dissolved salts presents in water can be easily estimated by measuring the specific conductivity of water.  The specific conductivity of water is determined by means of a portable dionic water tester and is expressed in micro-mhos per cm at 25 0 C. [Mho is the unit of and equal 1ampere / 1 volt] Specific Conductivity

32  The specific conductivity of water in micro-mhos per cm at 25 0 C is multiplied by the coefficient( generally 0.65) so as to directly obtained the dissolved salt contain in milligrams per litre (mg/l) or ppm.

33  Total solids and Suspended solids  The total amount of solids (suspended as well as dissolved solids) present in water can be determined by evaporating a sample of water and weighing the dry residue left.  The suspended solids can be found by filtering the water sample and weighing the residue left on the filter paper. Chemical characteristics

34  The difference between the total solids and suspended solids will then represent nothing but dissolved solids.  The total permissible amount of solids in water is generally limited to 500 ppm, although the heigher amounts upto 1000 ppm are also sometimes permitted

35  pH of water more than 7, it will be alkaline.  pH of water less than 7, it will be acidic.  pH of water equal to 7, it will be neutral.  The maximum acidity will be at zero value of pH.  The maximum alkalinity value of pH equal to 14.  pH can be measured automatically with Potentiometer. pH value of water

36  Hardness in water is that characteristics which prevents the formation of sufficient leather or foam, when such waters are mixed with soap.  It is usually caused by the presence of calcium and magnesium alts present in water which form scum by reaction with soap. Hardness of water

37  Hardness is generally defined as the calcium carbonate equivalent of calcium and magnesium ions present in water, and is expressed in mg/l.  After determining the amount of calcium and magnesium ions present in water by titration with versnate solution (EDTA method). Measurement of Hardness of water

38  = [ Ca ++ in mg/l x Combining wt. of CaCO3/ Combing w. of Ca ++ ] + [ Mg ++ in mg/l x Combining wt. of CaCO3/ Combing w. of Mg ++ ] Total Hardness in mg/l as CaCO3 (T.H.)

39  Cholride Chloride content

40 Micro-Organism in Water  A micro-organism that requires living tissue to grow is called a pathogens and they are parasite – which must depend upon host organixm as a proper environment for growth and reproduction.  Pathogenic micro-organism are harmful to man. Micro- organism can be either plant or animal.

41  When assemblages of aquatic organisms drift more or less passively with waves and current constituent plankton.  If they change their position or location due to their own efforts they are called as nekton.  If they maintain their stability due to surface tension are called as neuston.  1] Aquatic Plants  2] Aquatic animals  3] Aquatic molds, bacteria & virus Micro Organism

42 Forms of Microorganisms 42

43 Bacteria‘s

44 Size of Microorganisms

45 Common Waterborne Bacteria

46 Quality of Water DiseaseSpecific Agent ReservoirSymptoms in Brief Bacteria Enteropathogen ic Escherichia coli O157:H7 Intestines of animals and infected persons Cramping, vomiting, diarrhea (occasionally bloody), fever, dehydration Salmonellosis Salmonella typhimurium Animal s and eggs Abdominal pain, diarrhea, chills, fever, vomiting and nausea Typhoid Fever Salmonella typhosa or typhi Feces and urine of typhoid carrier or patient Fever, usually rose spots on the trunk, diarrheal disturbances Paratyph oid Fever Salmonella paratyphi (ABC) Feces and urine of carrier or patient Fever, diarrheal disturbances, sometimes rose spots on trunk, other symptoms

47 Common Waterborne Bacteria 47 Quality of Water DiseaseSpecific Agent ReservoirSymptoms in Brief Bacteria Shigellosis (Bacillary dysentery) Shigella Feces of carrier and infected persons Acute onset diarrhea, fever, tenesmus, frequent stools containing blood and mucus Campylobact er Enteritis Campyloba cter Jejuni Chickens, swine, dogs, cats, human, raw milk, contaminated water Watery diarrhea, abdominal pain, fever chills, nausea, vomiting, blood in stool Cholera Vibrio cholerae, Vibrio comma Feces, vomitus; carriers Diarrhea, rice-water stools, vomiting, thirst, pain, coma

48 COMMON WATERBORNE PATHOGENS Q DiseaseSpecific Agent ReservoirSymptoms in Brief Protozoa Amebiasis (Amebic dysentery) Entamoeba histolytica Bowel discharges of carrier, and infected person; possibly also rats Diarrhea or constipation, or neither; loss of appetite, abdominal discomfort; blood, mucus in stool Cryptosporidiosis Cryptospori dium Farm animals, human, fowl, cats, dogs, mice Mild flulike symptoms, diarrhea, vomiting, nausea, stomach pain Giardiasis Giardia lambli a Bowel discharges of carrier and infected persons; dog, beaver Prolonged diarrhea, abdominal cramps, severe weight loss, fatigue, nausea, gas, fever is unusual uality of Water by PVK 47

49 COMMON WATERBORNE Viruses DiseaseSpecific Agent ReservoirSymptoms in Brief Viruses Viral Gastroenteritis Rotaviruses, Norwalk agent, Human, feces, or sewage Nausea, vomiting, diarrhea, abdominal pain, low fever Infectious Hepatitis Hepatitis A Feces from infected persons Fever, nausea, loss of appetite; possibly vomiting, fatigue, headache, jaundice Helminths Schistosomiasis Schistosoma Venous circulation of human; urine, feces, dogs, cats, pigs, cattle, horses, field mice, wild rats, water buffalo Dysenteric or urinary symptoms, rigors, itching on skin, dermatitis

50 Forms of Microorganisms

51 Micro organisms details

52 Algae Microorganisms

53 Purpose of Microbiological /Bacteriological Examination ■ ■ To detect and assess the degree of excremental pollution in the sources of supply ■ To assess the amount of treatment required to render a source of supply safe for consumption ■ To ascertain the efficiency of purification treatment at various stages To locate the cause of any sudden deterioration in quality ■ To establish the bacterial purity of final water as it leaves the purification works and to demonstrate the persistence of this high quality in distribution system and in the premises of consumers

54 Quality of Water 54 Microbiological test ■ A] Bacteriological examination: to determine fitness of water for use for human consumption, and for industry for food processing, dairy work. ■ B] Biological Examination: to determine presence of microscopic organisms other than bacteria, such as algae, moulds, fungi, yeasts, protozoa, rotifers etc. ■ Indicator Organism: The indirect evidence of presence of pathogenic bacteria in water is obtained by testing water for indicator organisms. ■ The Coliforms and Eschericha coli (E-coli) are normally used as indicator organisms, since they are present in large in numbers than pathogens, they lend to numerical evaluation, qualitative distinction, easily identifiable by analytical procedure, providing quick information and economical ■ Crude sewage contains millions of E-coli per 100 ml, but no. of pathogens are very less. The absence of E-coli almost justifies asumption that water is free from pathogens.

55 Microbiological test  Total Count or Agar plate count test  Coliform Test A.Multiple tube fermentation technique  i) Presumptive test, ii) Confirmed test, iii) Completed Test B.Membrane Filter Technique  Test for E-coli

56  Plate Count Agar (PCA), also called Standard Methods Agar (SMA), is a microbiological growth medium commonly used to assess or to monitor "total" or viable bacterial growth of a sample. PCA is not a selective medium.Agargrowth medium  The composition of plate count agar may vary, but typically it contains (w/v)w/v  0.5% peptonepeptone  0.25% yeast extractyeast extract  0.1% GlucoseGlucose  1.5% agaragar  pH adjusted to neutral at 25 CC

57 Coli Has Many Sources

58 Method of water sampling ■ Sample should be collected in sterile, clear glass bottle having ground glass stoppers protected with sterile linen, oiled silk or paper tied around neck of bottle. ■ Bottle should be sterilized in hot air oven @ 160 0 C for one hour ■ Bottle should not be open until sample is collected, when stopper is withdrawn, it should be kept in its covering pointing downward. ■ If water sample likely to be contain chlorine,.1ml of sodium thiosulphate is added before sterilization. ■ Testing is done immediately after sample collection. ■ If not possible sample should be kept in ice or refrigerator till testing carried out. ■ All such samples should be tested before 48 hours.

59 Nuisance causing Bacteria ■ There are some types of bacteria which with present in water may cause pitting and tuberculation in pipes, and render the water unsuitable for building construction, air conditioning, paper industry, food and other industries ■ They may cause odour, tests, frothing, color, and increase in turbidity. ■ i) iron bacteria ■ ii) sulphur bacteria, ■ iii) geletin liquefying bacteria, ■ iv) slime forming bacteria.

60 Nuisance Bacteria 1Iron Bacteria Capable of withdrawing iron present in water and depositing it in morphologically distinct way. Oxidize ferrous to ferric ions die to which frictional loss in water mains get increased. Produce slimy reddish brown deposits causing discoloration and turbidity. Pitting and tuberculation in pipe occur, Make water unsuitable for industrial use. 2Sulphur Bacteria Autotropic bacteria which oxidize elemental suphur or reduce sulphur compounds taking carbon from CO 2. make water acidic, unsuitable for concrete structure. Sulphate reducing bacteria reduce sulphate to H 2 S. Involve in bacterial corrosion of iron & steel pipes in s s o o i i l l..

61 Nuisance Bacteria 3Gelatin Liquefying Bacteria Microorganisms which are capable of producing proteolytic ferments which digest and liquefy gelatin. Make water unsuitable for industry such as photographic films, edible gelatin, glue & food processing. 4Slime Forming Bacteria Non pathogenic bacteria which may produce slime which will adhere to structures and increase either by growth or by collecting and holding insoluble debris from water supply. Undesirable for water in condenser system, paper mills, food processing plants etc.

62  Water-borne diseases are those diseases spread primarily through contaminated water.  water is the chief medium for spread of these diseases and hence they are termed as water-borne diseases.  Though these diseases are spread either directly or through flies or filth.  Water Borne Diseases

63 List of Water Borne Diseases 60 A] Diseases Caused By Bacterial Infections 1)1) Typhoid fever & Paratyphoid fever They are Caused by Salmonella Typhi Bacteria. 2) Cholera It is caused by Vibrio Cholerae Bacteria. 3)3) Bacillary Dysentery It is caused by Shiga bacillus or Flexneri bacillus or Sonnie bacillus.

64 60 B] Diseases Caused By Viral Infections 1)1) Hepatitis A,B,E It is Caused by Hepatitis virus. 2) Jaundice It is Caused by Hepatitis virus. 3)3) Poliomyelitis It is Caused by Polio virus.

65 60 C] Diseases Caused By Protozoal Infections 1)1) Amoebic Dysentry They are Caused by Hystolytic Germ. 2) Amoebiasis Dysentry

66 60 D] Diseases Caused By Helminthic/Worm 1)1) Swimmer’s Itch It is Caused by Trematode Worms.

67  Precaution’s From Water Borne Diseases  ???  ??  ?

68  Standard of Purified Water 1)Indian Standard (IS) 2)Indian council of Medical Research (ICMR) 3)World Health Organizations (WHO) 4)United States Public Health Society (USPHS)

69 7)American Water Works Association (AWWA) 8)Environmental Hygiene committee. 9)Ministry of Urban Development (MUD)

70 Standards of Water CharacteristicsAcceptable LimitRejection Limit 1Turbidity (JTU)2.510 2Color (platinum cobalt scale)52.5 3Taste & Odour UnobjectionableObjectionable 4pH7 to 8.5 66..55 ttoo 99..2266..55 ttoo 99..22 5Total Dissolved Solid5001500 mg/lit 6Total Hardness (CaCo3)200600 7Chlorides as Cl2001000 8Sulphates200400 9Fluorides11.5 10Nitrates45 11Calcium75200 12Magnesium30150 13Iron0.11.0

71 Standards of Water CharacteristicsAcceptable LimitRejection Limit 14Manganese0.050.5 15Copper0.051.5 16Zinc515 17Phenolic compound0.0010.002 18Anionic detergent0.21 19Mineral Oil0.010.3 20Arsenic0.05 21Cadmium0.01 22Chromium0.05 23Cynides0.05 24Lead0.1 25Selenium0.01 26mercury0.001

72 Basic principals in treatment units 1) Screening:- to remove all floating matter 2) Aeration:- to remove objectionable tastes & odors, and to remove dissolved gases such as CO 2, H 2 S etc. 3) Sedimentation with or without coagulant:- to remove suspended impurities, silt, sand, fine particles & some bacteria.

73  4) Filtration:-  To remove very fine suspended impurities and colloidal impurities & microorganisms.  5) Disinfection:-  To eliminate or reduce to same minimum limit, remaining micro-organisms and to prevent contamination of water during its transit from plant to consumer.

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75 Flow diagram of Conventional water treatment plant Screening Primary Settling Tank Silt well Aeration Chemical mixing Flocculation Channel Secondary settling tank Distributio n network ESR Pump House Filtration unit Disinfectio n

76 Purpose of Water Treatment ■ i) To remove color, dissolved gas and murkiness in water ■ ii) To remove objectionable taste and odor ■ iii) To remove disease producing micro- organism so that water is safe for drinking purpose ■ iv) To remove hardness of water ■ v) to make it suitable for a wide variety of industrial purposes.

77 Water Treatment Plant

78 Conventional WTP

79 70

80 WTP for Well Water

81 Conventional WTP (river source)

82 Conventional WTP (lake source)

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87 Thanks!


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