Water Pollution

Lectured by-
Dr. Rajendra Singh Thakur
Dr. Rajendra Singh Thakur 1

 Water
 Earth’s surface is covered by 71% water
 Essential for life – can survive only a few days
without water

Small fraction (.014%) is readily available for human use

 Humans directly or indirectly use about 54% of
reliable runoff
 Withdraw 34% of reliable runoff for:
 Agriculture – 70%
 Industry – 20%
 Domestic – 10%
 Leave 20% of runoff in streams for human use:
 transport goods, dilute pollution, sustain fisheries
 Could use up to 70-90% of the reliable runoff by
2025

 Generally speaking, water pollution is a state deviation from the pure condition, whereby
its normal properties and function are affected .
 The presence of some foreign substances or impurities in water in such quantity.
 So constitute a health hazards by lowering the water quality and making it unfit for
use.
 Water pollution are offensive odours from rivers, streams, lakes and ocean beaches,
oily and greasy material floating on surfaces of water bodies.
 Unchecked growth of aquatic weeds .
 Bad taste of drinking water , decrease of aquatic life (fish) in fresh water bodies
and many more.

1. Natural Pollution –
 Aerial contaminants entering the water body due to rainfall or melting
of ice.
 Plants, animals and organic matters- leachates from animal excreta
will introduce micro-organism in water.
2. Agricultural Pollution -
 Soil and silt washing from land surface,
 Fertilizers
 Insecticides
 Pesticides and
 Weed killings

3. Mining Pollution –
 Fines and tailings from washing,
 Inert suspended solids,
 Soluble toxic materials and acid drainage.
4. Municipal Pollution –
 Sewage obtained from domestic premise, institutions, commercial and
industrial building.
5. Industrial Pollution –
 Effluent from food and drugs, chemicals, materials, energy etc.
6. Accidental spillage -
 Chemicals during loading and transit, accidental leakage from
industrial storages tanks, oil refineries etc.

 Point source = pollution comes from single, fixed, often large identifiable sources
 Industries
 Municipal
 Sewage and combine overflow
 Treatment plant
 Raw sewage discharge
 Discharge drains
 Tanker spills
 Non-point (Diffused ) source = pollution comes from dispersed sources
 Agricultural runoff
 Forestry
 Mining
 Construction
 Street runoff

NONPOINT SOURCES
Animal feedlot
Urban streets
Suburban
development
Wastewater
treatment
plant
Rural homes
Cropland
Factory
POINT
SOURCES
Fig. 22-4 p. 494

Water used as various purpose
 Bathing,
 Excretion,
 Washing,
 Food preparation,
 Cleaning of floors and
 Industrial operations,
 Agriculture need and many more.

 The main food stuff – fats, proteins and
carbohydrates
 Materials and substances necessary e.g.
cotton, petroleum, rubber, plastic, antibiotics,
etc.

 Natural Organic Pollutants –
 Breakdown of occurring organic material e.g. decays of leaves, plants, dead
animals etc.
 Various types of algae and vegetation.
 Sewage and Industrial Effluent –
 Municipal sewage and industrial effluents – food processing units, paper
mills, tanneries, slaughter etc.
 Synthetic Organic Pollutant – man made (anthropogenic)- sewage & other
waste
 Volatile organic chemicals (VOCs) -from industrial solvent,
 Carbon tetrachloride (used fire extinguisher, cleaning agent ) and
 Tetrachloroethelene (used solvent and raw material )
 Synthetic organic chemicals (SOCs)-
 Pesticides & Herbicides
 Industrial process
 Ethylene, benzene & styrene.
 Polychlorinated Biphenyl's (PCBs) & dioxins-
 toxic to plant, animals and human being cause cancer at low
concentration.

 Micro-biological Pollutants –
 Different organism & micro-organism e.g. Bacteria, viruses,
protozoa, algae & helminthes .
 Water born disease for responsible.
 Human waste from- point sources (sewage outfall)
 Non- point sources (over the ground failed septic system)
 Oil – mixture of thousand of different HC compound.
 Through originate from waste deposit of plants
 Animal material buried & compressed by deep layer
 Carbon, Hydrogen
 Hydrogen may content O2, S, N2, Ve, Ni, & other atoms
 Crud oil- paraffin's, cycloparafins, aromatic, neptheno-aromatic
etc.
 Transportation by tanker accidental in sea
 Sewage

 Geological formation contact
 Industrial & agriculture runoff
 Inorganic salts
 Mineral or metal compound
 Trace element
 Complex of metals with organics
 Organo-metalic compound
 May be highly or middy toxic

 In natural sources
 Industrial & medical process
 Responsible for man activities-
 Power plant
 Nuclear weapons
 Isotopes in medical, industrial & research application
 Mining process and ore to produced
 Carcinogenic effect on all- radium, uranium, radon and
thorium

 Soil, sand and other solid mix in water
 Soil erosion (naturally, mining, agriculture & construction
activities)
 Disposal of sewage & industrial effluent
 Organic or inorganic radical
 Oil & grease causes-
 Turbidity in water
 Reducing the photosynthesis of plant
 Suffocation of aquatic habitats
 Erosion of pumping equipment
 Power turbines

 From power plant & industries
 Harmful effect-
 Increases temp. of water reduces amount of DO, increases
biological activities
 Create anaerobic condition
 Toxicity of chemical pollutant increases with increases
temperature.
 Rise in the temperature of water (and air) to a harmful level
due to heat from power plants and industries is called
“Thermal Pollution”.

 Water is vital resource essential for sustaining
life
 Contamination has immediate
 Effect on the health and environment of living
being

 Suspended par ticle solids
 Cooling water from power station
 Oily surface of film
 Solid may be inert material wastes or insoluble finally divided
organic solids
 Accumulate on vegetation foliage
 Deposited on river bed
 Effects will cause a disturbance of balance ecosystem-
 Turbidity causes reduce light penetration than effect on plant synthesis and growth
 Turbidity causes reduce food gathering and respiratory efficiency of animals
 Organic solids will be biodegraded and will cause reduction of the DO in water
 Waste oil, fats and grease cause effects on oxygen saturation decrease from
atmosphere
 Spillage from oil tanker in sea level cause marine pollution

 Oxidation by the action of bacteria upon organic pollutant
 Chemical oxidation of other pollutant
 Depend on DO
 Increases BOD than deficiency of oxygen in water
 Bacterial oxidation-
Sulphides Sulphates
Ammonia Nitrte Nitrate
 Chemical oxidation-
Ferrous salt Ferric salt

 It may be Organic And Inorganic chemicals
 Toxic to plants, animals and humans
 Absorbed in tissues from water cause death of living organism
 Effects depend upon –
 Concentration
 Period of action
 Metabolism of organism
 Toxic chemicals-
 Metal and salts
 Pesticides,
 Acid and alkalis
 Organic compound-
 Phenol, cyanide etc.
Very small/trace of metals required for human
growth and metabolism in limiting value for-
 Physiological poisoning,
 Respiration deficiency,
 Reduce photosynthesis,
 Growth

 Metallic toxicity- feeding on polluted marine (bony & fish)
 Cadmium, mercury, lead, chromium etc. cause damage to liver, kidneys & brain.
 Pesticides pollution- leachate from agriculture & horticulture land
 Acid and alkalis- change in pH value may affect physiological process and action of
toxins.
 Polychlorinated biphenyls – stable, insoluble in water and soluble in oil, and
 harmful to fishes, predatory birds, marine & shore birds
 By products of plastic
 Lubricant
 Rubber & paper industries
 Cyanides-
 Toxic to biological life
 Enzyme action & immobilized in nervous system in animal & humans.

 Required for plants and animal for maintaining growth & metabolism.
 Nitrates & phosphates occur in small quantity,
 Balanced biological growth
 Decreases level cause biodegradation of dead organic material
 Increases level called “Ageing or Eutrophication”
 Phosphorous - for photosynthetic process in plant, respiration and
production of DNA
 Nitrogen – essential constituent of protein
 Effects-
 Unicellular green and blue green algae and blanket weed reduce light penetration and
restrict re-oxidation of water.
 Nitrates- cause blood diseases and gastric cancer

Pathogenic organism in waste causes transmitting human
diseases.
 Bacteria – cholera, typhoid fever, bacillary
dysentery, gastroenteritis.
 Virus – poliomylities, infective hepatitis, echo &
consackil fever.
 Round warm – beef and pork tape worm

Radio nucleoside effect on human body through dust & aerosols absorbed
by plant and animals

 Eutrophication refers to an excessive amount of nutrients in a body of
water, usually caused by runoff of nutrients (mainly phosphorous in
freshwater and nitrogen in saltwater) from the land, which causes
a dense growth of plant life, leading to a decrease in oxygen supply, which
causes the death of animals.
 Eutrophic – well-fed, high nutrient levels present in a lake or river
 Oligotrophic – poorly-fed, low nutrient levels
 Water bodies can be naturally eutrophic or oligotrophic, but can also be
human-caused

1. Input control
2. Output control
3. Development of proper sewage and industrial
effluent system
4. Extensive afforestation
5. Domestic and industrial waste water should be
disposed of after treatment
6. Strict enforcement of pollution control laws

i. No intermixing of solid and effluent in water source
ii. Treatment plant for domestic sewage
iii. Prevention of waste entry in sources of water e.g. pond, river, lakes etc.
iv. Bathing , washing etc. should be prohibited in sources.
v. Treated effluent from the industries discharged into sources.
vi. Excess use of fertilizers, pesticides, insecticides should be discourage.
vii. Pond, lakes etc. should be cleaned of auaitic weeds and plants.
viii. Special type of fish breeding
ix. Public awarness
x. Legislation control should be punitive.

 Domestic waste water or sewage is liquid
 Sanitary convenience of residential
 Commercial
 Institutional
 Industrial and
 Public areas
 Sewage-
 Water = 99.9%
 Solid = 0.01% (organic and inorganic matters may be suspended,
colloidal, dissolved state)

 Inorganic matters- ash, cinder, sand, grit, mineral, salts,
mud etc.
 Industrial effluent- toxic substances e.g. Pb, As, Hg, CN etc.
 Organic matter s – carbohydrates, fats, proteins, urea,
amines, amino acid and products of decomposition.
 Nitrogenous – urea and protein
 Nitrogen-free – carbohydrates, fats, and soap
 Addition of solid – sewage contains living organism such as
algae, fungi, bacteria, protozoa, virus, rotifer etc.

 The composition or constitution of sewage
mainly depends upon the sources from where it’s
formed
 Classification-
 Strong
 Medium
 Week

 The principal elements- Carbon, Hydrogen, Nitrogen, Sulphur,
Phosphorous
 The principal organic substance- Protein, Carbohydrates, Fats, Urea,
Amines, Amino acids, Products of decomposition.
 Organic substance in waste water are unstable and decompose thought
combine chemical and biological action
 Organic matters Bacteria Decompose
(Biological action)
Called “Biological organic matter”

1. Aerobic Bacteria-
Flourish in present of DO Consume organic matter as food
Oxidizing it to stable end products
2. Anaerobic Bacteria-
Flourish in absence of DO Bounded molecular oxygen (Nitrates,
Sulphates etc) Stable end products foul gases e.g. Methane, H2S
etc
3. Facultative Bacteria- (Aerobic or Anaerobic)
Flourish and carry out decomposition, in present and absence of DO
anaerobic decomposition Can be oxidized

Air or O2 is freely available in dissolved form
Aerobic decomposition
Biodegradable organic matters
if Unstable organic matters
Aerobic & facultative bacteria
Stable and harmless inorganic matter
 Organic matter decomposed presence Aerobic Bacteria when-
 Carbonaceous + OCO--
2 2
 Nitrogenous + O2 NO3
--
 Sulphurous + O2 SO4
--
 Phosphorous + O2 PO4
--
Stable and
inoffensive

 Water, heat and additional bacteria will also
produce in aerobic decomposition.
 Aeration thanks
 Trickling filters
 Oxidation ponds
 Oxidation ditches
 Contact bed etc

Aerobic decomposition
Facultative bacteria Free DO is exhausted
(An aerobically)
Anaerobic decomposition begins in absence of DO and light
 Hydrolysis process-
Hydrogen and oxygen in water molecule
Separated and combine
Carbon, Nitrogen, Sulphur
End product
Methane, Hydrogen, Nitrogen, Ammonia, Carbon dioxide, Hydrogen sulphide,
Organic acids etc.

 Organic matter decomposed in of presence Anaerobic
Bacteria when-
 Carbonaceous CO2
 Nitrogenous N2 + NH+ Organic acids
3
 Organic acids CH4
+ CO2
 Sulphurous H2S
 First phase decompose large complex - Amino acids, Fatty
acids, Sugar and Glycerol
 End products- odour and toxic to organism themselves

 Septic tanks
 Imhoff tanks
 Sludge digestion tanks etc

 Most of impurities and microscopic in nature
 Waste analysis in laboratory
 Main objectives or need of analysis -
 Evaluate the quality (type of impurities & harmful)
 Pollution effects and harmful effect?
 Required treatment unit, size and capacity?
 Optimum chemical dose?
 Standard waste reached or not?
 Operational efficiency
 Effective and economical waste management
 To prevent pollution of natural water bodies and lands

I. Colour and odour – fresh state or septic
 Fresh sewage is slightly soapy or oily odour and
cloudily appearance
 Biological and chemical characteristics
 Odour of H2S and dark gray colour
 Change state in 2 – 6 hrs at 20C (depend on
concentration)

 Slightly higher than the water
 It is influence-
 Solubility of oxygen
 Oxygen transfer
 Capacity of aeration
 Viscosity
 Rate of biological activity
 Influence the efficiency of sedimentation
 Sludge digestion
Average temperature (INDIA)= 20C (near about biological activities)

 Present of suspended solid and colloidal solids e.g.
faecel matter, fruit, vegetable waste, oil, grease, soap,
paper, pieces etc.
 Measured by Turbidity Rod

 Contain about 0.05 to 0.1%
I Suspended Solids – <1.0 mm remain flouting
II Dissolved Solids – >10-3mm remain dissolved
III Colloidal Solids - 1.0 to 10-3mm solution or suspension
IV Settable Solids - 10mm settle out in 2 hrs
Sub divided-
Organic – Volatile i.g. Carbohydrates (cellulose, starch, sugar, file), Fats and
oil, Nitrogenous compound (protein, animal waste, urea, fatty acids)
Inorganic – Fixed solid i.g. Minerals (sand, gravel) and Salts (chloride,
sulphites), not harmful

Selection and operation of various types of treatment-
I. pH value-
 Know the degree of acidity and alkalinity?
 Fresh sewage pH 7.3 to 7.5
(Bacterial action) Time
Acid formation
 Efficiency of treatment, availability at suitable pH, calculate
of the coagulation and disinfection of dose for control
corrosive.

II. Chlorides-
 Mineral salts.
 Not affected by biological action of sewage.
 A person discharged 8gm of chloride – urine, night soil,
sweating.
 Average sewage flow of 150 lpcd in chloride content of 50
mg/L
 Main sources- ice cream plants, meat salting works, etc.

III. Nitrogen-
 Indicates the presence of organic matter
 Nitrogen compound – Protein, amines, amino acids and urea
 Types (depend upon waste water)- Ammonium nitrogen, Organic nitrogen,
Nitrites and Nitrates.
 Ammonium nitrogen Ammonium hydroxide and Ammonium salts
presence
 Organic matter decompose when organic nitrogen and nitrogenous matter
(Ammonium, Nitrogen, Nitrites, Nitrates and Ammonia) in An aerobically
 Nitrite/Nitrate in Aerobically

IV. Hydrogen Sulphide –
 Indicates anaerobic decomposition
 Large amount of corrosion of concrete and bad odours.
V. Fats, Grease and oil – from kitchen, garage and industries
 Clog sewer –
 Trapped or remove the sources
 Treatment units – skimming tank to biological
 Heavy sewer –
 Sedimentation tank & streams
 Clog the filter media and aeration in activated sludge.

1 Atmospheric Pressure
VI. Dissolve Oxygen-
 Dissolved gases in water
 Support for fish and other aquatic life
 Naturally - enter directly from atmosphere
 Algae through photosynthesis
 Mechanical equipment (aerators)
 Solubility of atmospheric oxygen in fresh water –
14.6 mg/L at 0°C
7 mg/L at 35°C
Oxidation reduction process by Winkler's Method

VII. Biological oxygen demand (BOD)-
 BOD: Oxygen is removed from water when organic matter is consumed by
bacteria.
 Low oxygen conditions may kill fish and other organisms.
Sources of organic matter
 Natural inputs-- bogs, swamps, leaf fall, and vegetation aligning
waterways.
 Human inputs-- pulp and paper mills, meat-packing plants, food
processing industries, and wastewater treatment plants.
 Nonpoint inputs-- runoff from urban areas, agricultural areas, and
feedlots.

 BOD measures- the oxygen uptake by bacteria in a water sample at a temperature of
20°C over a period of 5d in the dark. The sample is diluted with oxygen saturated de-ionized
water, inoculating it with a fixed aliquot of microbial seed, measuring the
(DO) and then sealing the sample to prevent further oxygen addition. The sample is
kept at 20 °C for five days, in the dark to prevent addition of oxygen by photo-synthesis,
and the dissolved oxygen is measured again.
 The difference between the final DO and initial DO is the BOD or, BOD5.
 Once we have a BOD5 value, it is treated as just a concentration in mg/L
 BOD can be calculated by:
 Diluted: (Initial DO - Final DO + BOD of Seed) x Dilution Factor
 BOD of seed (diluted activated sludge) is measured in a control: just deionized water
without wastewater sample.
 Significance: BOD is a measure of organic content and gives an indication on how
much oxygen would be required for microbial degradation.

BBOODD EEffffeeccttss oonn WWaatteerr QQuuaalliittyy
All streams have some capability to degrade organic waste. Problems occur
when stream is overloaded with biochemical oxygen-demanding waste.
http://www.lcusd.net/lchs/mewoldsen/Water_Pollution_LCHS.ppt

VIII. Chemical oxygen demand (COD)-
 Amt. of O2 that certain organisms & chemicals will consume
 Interferences
 [Cl-] > 1000 mg/l
 VOCs might be lost prior to oxidation
 Method Summary
 Most organics & oxidative inorganic are oxidized by addition of
K2Cr2O7 / H2SO4
 xs. (Cr2O7)-2 is titrated w/Fe(NH4)2(SO4)2.6H2O
 COD (mg/L) = 8000 (mL blank – mL sample) [Fe2+]
mL sample

 The environmental engineer must have considerable knowledge of the biological
of waste water because it is a very important characteristics factor in wastewater
treatment.
 The Engineer should know:-
1. The principal groups of micro-organisms found in wastewater.
2. The pathogenic organisms.
3. Indicator organisms (indicate the –presence of pathogens).
4. The methods used to amount the micro-organisms.
5. The methods to evaluate the toxicity of treated wastewater
 The main micro-organisms of concern in wastewater treatment are Bacteria,
Fungi, Algae, Protozoa, Viruses, rotifers and pathogenic micro-organisms groups.

Next- Treatment Processes
THANK YOU

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