Permissible limits of water pollutants in drinking water.

ishan_trivedi2005 57,078 views 41 slides Mar 14, 2011
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About This Presentation

Permissible limits of various water pollutants in drinking water according to ISI and WHO. Presented by me at TIFAC.


Slide Content

Permissible limits of water pollutants according to ISI & WHO Ishan Trivedi . TIFAC.

The need to establish limits….. What is the need to establish permissible limits ? That is because…..

Water is Precious and scarce Resource Only a small fraction (about 3%) is fresh water India is wettest country in the world, but rainfall is highly uneven with time and space (with extremely low in Rajasthan and high in North-East) On an average there are only 40 rainy days Out of 4000 BCM rainfall received, about 600 BCM is put to use so far Water resources are over-exploited resulting in major problems. To enable proper legislation by establishing standards and punish the polluting industries . 3

The Water (Prevention and Control of Pollution) Act, 1974 The need for legislating the act was felt in the year 1962, it was the same year when Independent India fought its first war with China. A committee was set up in 1962 to draw a draft enactment for the prevention of water pollution. The reason for legislating the act was given as “ The problem of pollution of rivers and streams has assumed considerable importance and urgency in recent years as a result of the growth of industries and the increasing tendency to urbanization”. The object for legislating the act was given as “ It is, therefore, essential to ensure that the domestic and industrial effluents are not allowed to be discharged into the water courses without adequate treatment as such discharges would render the water unsuitable as sources of drinking water as well as for supporting fish life and for use in irrigation. Pollution of rivers and streams also causes increasing damage to the country’s economy.”

‘Pollution’ defined in the Act It means such contamination of water or such alteration of the physical, chemical or biological properties of water or such discharge of any sewage or trade effluent or of any other liquid, gaseous or solid substance into water (whether directly or indirectly) as may, or is likely to, create a nuisance or render such water harmful or injurious to public health or safety, or to domestic, commercial industrial agricultural or other legitimate uses, or to the life and health of animals or plants or of aquatic organisms . (section 2(e) of the Act)

Safe drinking water Free from pathogenic organisms Clear Not saline Free from offensive taste or smell Free from compounds that may have adverse effect on human health Free from chemicals that cause corrosion of water supply systems

WATER QUALITY PARAMETERS Physical parameters Chemical Bacteriological

BUREAU OFINDIAN STANDARDS IS 10500-1991 Drinking water standards Parameters Desirable limit Permissible limit Colour Hazen unit 5 25 Turbidity-NTU 5 10 pH 6.5-8.5 6.5-8.5 Hardness (as CaCO 3 )mg/l 0.3 1 TDS 500 2000

BUREAU OFINDIAN STANDARDS IS 10500-1991 Parameters Disirable limit Permissible limit Nitrate mg/l 45 45 Chloride mg/l 250 1000 Flouride mg/l 1 1.5 Arsenic mg/l 0.05 0.05 Aluminium mg/l 0.03 0.2

Essential bacteriological Standards, ISI & WHO Characteristics Number / 100 ml Treated water in distribution system Faecal coliform zero Total coliform not more than 10 Total coliform should not be detectible in two consecutive samples

WHO standards, Drinking water, 1993.

Reasons of various pollutants in water and related issues….

Colour Reason: May be due to the Presence of organic matter,metals (iron, manganese) or highly coloured industrial waste. Issues: Aesthetically displeasing. Desirable that drinking water be colourless . Desirable limit, 5 Hazen unit. Permissible limit 25 Hazen Unit.

Taste and Odour Reason: Mainly due to organic substances ,Biological activity, industrial pollution Issues: Taste buds in the oral cavity specially detect inorganic compounds of metals like magnesium, calcium, sodium, copper, iron and zinc Water should be free from objectionable taste and odour .

Turbidity Reason: Caused by suspended matter Issues: High level turbidity shield and protect bacteria from the action of disinfecting agents Desirable limit-5 NTU should be below 1 NTU when disinfection is practiced Permissible limit-10 NTU In picture: 5,50, 500 NTU

pH It is the measure of hydrogen ion concentration Neutral water pH-7 Acidic water has pH below 7 Basic water has pH above 7 Desirable limit 6.5-8.5 Issues: Beyond this limit the water will affect the mucous membrane and water supply system

Reasons: Substances that change pH of water Acidic Industries Sugar - 5 – 6 Distillery 3 - 4 Electro- Plating unit 2.5-4 Pickle 2 - 3 Basic Paper 8 – 10 Textile 8.5-11 Fertiliser 6.5- 9 Oil Refine- ries 6.5-9.5

HARDNESS Capacity of water for reducing and destroying the lather of soap It is total concentration of calcium and magnesium ions Types and reasons: Temporary hardness – Bicarbonates of Calcium and Magnesium Permanent hardness – Sulphates , chlorides and nitrates of calcium and magnesium

Hardness – contd … 0 – 50 mg/l - soft 50 – 150 mg/l - moderately hard 150 – 300 mg/l - hard 300 above - very hard Surface water is softer than ground water Issues: Causes encrustations in water supply structures Hard water is difficult to drink.

ALKALINITY Capacity to neutralise acid Presence of carbonates, bi-carbonates and hydroxide compounds of Ca, Mg, Na and K Alkalinity = hardness, Ca and Mg salts Alkalinity > hardness - presence of basic salts, Na, K along with Ca and Mg Alkalinity < hardness – neutral salts of Ca & Mg present

IRON One of the earth’s most plentiful resource. Issues: High iron causes brown or yellow staining of laundry, household fixtures. Metalic taste, offensive odour , poor tasting coffee Cause iron bacteria. Acceptable limit – 0.3 mg / l

CHLORIDE Reasons: Dissolution of salt deposit Discharge of effluents Intrusion of sea water Issues: Not harmful to human beings Regarding irrigation – most troublesome anion Acceptable limit - 250 mg/l

NITRATE Reasons: Increasing level of nitrate is due to Agricultural fertilizers, manure,animal dung, nitrogenous material ,sewage pollution Issues: (blue baby diseases to infants) Maximum permissible limit 45 mg / l

FLUORIDE Reasons: Occurs naturally Issues: Long term consumption above permissible level can cause – dental fluorosis (molting of teeth) Skeletal fluorosis Acceptable limit – 1 mg / l Maximum permissible limit – 1.5 mg / l Remedy – 1) Defluoridation 2) Mixing Fluoride free water 3) Intake of vitamin C,D, calcium, antioxidants

FLUORIDE CAUSES Three types of Fluorosis 1. Dental Fluorosis 2. Skeletal Fluorosis 3. Non-skeletal Fluorosis

ARSENIC Reasons: Occur in ground water from arseniferous belt Industrial waste, agricultural insecticide Issues: High arsenic causes 1) various type of dermatological lesions, muscular weakness, paralysis of lower limbs, can also cause skin and lung cancer Acceptable limit – 0.05 mg / l

Pesticides Reasons: Uncontrolled, excessive use. Issues: Cancer Birth defects Blood disorder Nervous disorder Genetic damage

Heavy Metals Reasons: Present as mineral in soil and rocks of earth Human activities : Battery – Lead & Nickel Textile - Copper Photography – Silver Steel production – Iron Issues: The most pollutans heavy metals are Lead, Cadmium, Copper, Chromium, Selenium and Mercury. Lead In humans, Long term exposure can occur acute or chronic damage to the nervous system on humans. Cadmium In humans, long-term exposure is associated with renal disfunction . High exposure can lead to obstructive lung disease and has been linked to lung cancer,and damage to human’s respiratory systems. Copper is an essential substance to human life, but in high doses it can cause anemia, liver and kidney damage, and stomach and intestinal irritation. Effect of the Mercury is to cause damage to the brain and the central nervous system.

RESIDUAL CHLORINE Chlorine added to water forms hypochlorite ions and hypochlorite acids Chlorine demand – Quantity required for killing micro-organisms and reacting with ammonia, organic compounds etc. To take care of post contamination Desirable – 0.2 mg / liter

Common problems Visible effects Reason Iron taste, change in colour after exposure to atmosphere, change in colour of cloths,utensils Oily appea - rance on top of water body Iron Soap not lathering hardness Brownish black streaks on teeth `Fluride Growth of Algae Nitrate, phosphate Fish kills Low pH less DO Salty taste chloride

Common problems contd. Visible effects Reasons water turns black, smell Waste water Acidic taste Low pH Alkaline taste High pH Boiled Rice hard and yellow High Alkalinity White deposits on boiling Hardness

Issues with Industrial pollutants on aquatic ecosystem. Dissolved Solids : Scale buildup in pipes, valves, and filters, reducing performance and adding to system maintenance costs. Suspended Solids : Decrease in penetration of light at ocean beds (Benthic zone) can cause destruction of photosynthetic plants and bacteria at ocean bed which in turn can destroy entire ecosystem. pH: Destruction of pH sensitive aquatic life. Destruction of pH sensitive rocks. Temperature: Destruction of temperature sensitive organisms in local beds. Decrease in DO, killing temperature resistant organisms too. Oil: Decrease in DO can cause destruction aquatic animals and birds.

Issues with Industrial pollutants on aquatic ecosystem contd …. Ammoniacal nitrogen: Hatching and growth rates of fishes may be affected. In the structural development, changes in tissues of gills (Hyperplasia), liver, and kidneys may also occur. Toxic concentrations of ammonia in humans may cause loss of equilibrium, convulsions, coma, and death. Organic carbon: Causes increase in BOD, COD and thus decrease in DO killing aquatic life. Pesticides: Direct destruction. Bioaccumulation Biomagnification

Issues with Industrial pollutants on aquatic ecosystem contd …. Heavy metals: The most pollutans heavy metals are Lead, Cadmium, Copper, Chromium, Selenium and Mercury. Lead In humans, Long term exposure can occur acute or chronic damage to the nervous system on humans. Cadmium In humans, long-term exposure is associated with renal disfunction . High exposure can lead to obstructive lung disease and has been linked to lung cancer,and damage to human’s respiratory systems. Copper is an essential substance to human life, but in high doses it can cause anemia, liver and kidney damage, and stomach and intestinal irritation. Effect of the Mercury is to cause damage to the brain and the central nervous system. Selenium causes to damage to circulatory tissue, and more severe damage to the nervous system. Nitrates and nitrites: Eutrophication. Dissolved phosphates: Eutrophication. Cyanide: weight loss, thyroid effects, nerve damage to humans.

Eutrophication

Thus, It is necessary to establish the limits…

Thank you.

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