WATER POLLUTION
                     WATER POLLUTION
ANALYTICAL MINDS
-A UNIT OF BHUBAN ENTERPRISES
Overview
o Introduction
o Types of Water Pollution
• Sewage
• Disease-causing agents
• Sediment pollution
• Inorganic plant and algal nutrients
• Organic compounds
• Inorganic chemicals
• Thermal pollution
o Water Quality Today
o Improving Water Quality
o Laws Controlling Water Pollution
o Conclusion
INTRODUCTION
   Water pollution is the contamination of 
water bodies, usually as a result of 
human activities. Water bodies include 
for example lakes, rivers, oceans, 
aquifers and groundwater. Water 
pollution results when contaminants 
are introduced into the natural 
environment.
Types of Water Pollution
o Water pollution
• Any physical or chemical change in water 
that adversely affects the health of humans 
and other organisms 
• Varies in magnitude by location
o Major water pollution issue globally
• Lack of disease-free water
o Eight categories
• Sewage, disease-causing agents, sediment 
pollution, inorganic plant and algal 
nutrients, organic compounds, inorganic 
chemicals, radioactive substances, and 
thermal pollution 
Sewage
o The release of wastewater from drains or 
sewers 
• Includes human wastes, soaps, and detergents 
o Causes 2 serious environmental problems:
• Enrichment
• Fertilization of a body of water by high levels of plant 
and algal nutrients (nitrogen and phosphorus)
• Increase in Biological Oxygen Demand (BOD)
• Amount of oxygen needed by microorganisms to 
decompose biological wastes
• As BOD increases Dissolve Oxygen (DO) decreases
Sewage
Sewage- Eutrophication
o Oligotrophic
• Unenriched, clear water that supports 
small populations of aquatic 
organisms 
Sewage- Eutrophication
o Eutrophic-
• Slow-flowing stream, lake or estuary 
enriched by inorganic plant and algal 
nutrients such as phosphorus 
• Often due to fertilizer or sewage runoff
Disease-causing Agents
o Infectious organisms 
that cause diseases
• Originate in the 
wastes of infected 
individuals 
o Common bacterial or 
viral diseases:
• Typhoid, cholera, 
bacterial dysentery, 
polio, and infectious 
hepatitis
Disease-causing Agents
o Monitored by testing for presence of E. 
coli in the water via a fecal coliform 
test
• Indicates the presence of pathogenic 
organisms
Sediment Pollution
o Excessive amounts of suspended soil 
particles
• Originates from erosion of agricultural 
lands, forest soils exposed by logging, 
degraded stream banks, overgrazed 
rangelands, strip mines, and construction 
o Problems
• Limits light penetration
• Covers aquatic animals and plants
• Brings insoluble toxins into waterways

Inorganic Plant and Algal 
Nutrients
o Chemicals such as nitrogen and 
phosphorus that stimulate the growth of 
plants and algae
• Harmful in large concentrations
o Sources:
• Human and animal wastes, plant residues, 
atmospheric deposition, and fertilizer runoff
o Causes:
• Enrichment, bad odors, and a high BOD 
Inorganic Plant and Algal Nutrient- 
The Dead Zone

The Great Pacific 
Patch of Garbage
Organic Compounds
o Chemicals that contain carbon atoms
• Natural examples: sugars, amino acids, 
and oils 
• Human-made examples: pesticides, 
solvents, industrial chemicals, and plastics 
Inorganic Chemicals
o Contaminants that contain elements 
other than carbon
• Examples: acids, salts, and heavy metals 
o Do not degrade easily
o Lead
• Found in old paint, industrial pollutants, 
leaded gasoline
o Mercury
• Mercury bioaccumulates in the muscles of 
top predators of the open ocean 
Radioactive Substances
o Contain atoms of unstable isotopes that 
spontaneously emit radiation 
o Sources
• Mining
• Processing radioactive materials
• Nuclear power plants
• Natural sources
Thermal Pollution
o Occurs when heated 
water produced 
during industrial 
processes is released 
into waterways 
o Organisms affected
• Temperature affects 
reproductive cycles, 
digestion rates, and 
respiration rates 
• Warm water holds less 
DO than cold water
Water Quality Today
o Two Types of Water Pollution
o -Point Source Pollution
• water pollution that can be traced to a 
specific origin 
• Discharge via pipes, sewage, and ditches
o -Non-point Source Pollution
• Pollutants that enter bodies of water over 
large areas rather than being concentrated at 
a single point of entry 
• Diffuse, but its cumulative effect is very large
• Ex: runoff from agricultural fields or parking 
lots
Water Pollution from 
Agriculture
o Agriculture is leading source of water 
pollution in US
• Animal wastes and plants residues have 
high BOD
• Chemical pesticides can leach into 
groundwater
o Almost all streams and rivers are 
polluted with agricultural pesticides
Municipal Water Pollution
Industrial Wastes in Water
o Different industries generate different 
pollutants
• Food processing plants- high BOD
• Paper mills- High BOD and toxic compounds
o Many industries recover toxins before they go 
into the waste stream
Case-In-Point Green Chemistry
Groundwater Pollution
Water Pollution in Other 
Countries
o Lake Maracaibo, Venezuela
• 10,000 oil wells tap lake bottom
• Leak oil into lake
• Agricultural 
wastes from 
local fields
• Unit recently 
raw human 
waste polluted 
the lake
Water Pollution in Other 
Countries
o Po River, Italy
• Similar to Mississippi River
• Pollutants: Sewage, industrial wastes, 
sediment
• >16 million Italians depend on the river for 
drinking water
• Pollution is high
• Swimming and fishing prohibited
• Cleanup will require a national 
management plan and may take decades
Water Pollution in Other 
Countries
o Ganges River, India
• Used for bathing and 
washing clothing
• Sewage and industrial 
waste discharged into 
river
• Ganga Action Plan 
initiated by government
• Construction of 29 
sewage treatment plants
Improving Water Quality-
Purification of Drinking Water
o In US most 
municipal water 
supplies are 
treated 
o Collected from 
water or 
reservoir
o Treated
Improving Water Quality-
Purification of Drinking Water
o Treated water 
distributed to 
customers
o Sewer lines bring 
sewage to 
treatment plant
o Sewage treated at 
sewage treatment 
plant
Purification of Drinking Water
o Chlorine Dilemma
• Chlorine kills disease causing organisms
• Chlorine byproducts are linked to numerous 
cancers, miscarriages and birth defects
• Peru stopped using chlorine
• 1991- huge cholera epidemic that infected 
300,000 people
o Fluoridation
• Prevents tooth decay
• Linked to cancer, kidney disease
Municipal Sewage Treatment
o Primary treatment
• Removing suspended and floating particles by 
mechanical processes 
o Secondary treatment
• Treating wastewater biologically to decompose 
suspended organic material; reduces BOD 
Municipal Sewage Treatment
o Sewage Sludge
• Solids remaining after primary and 
secondary sewage treatment has been 
completed 
o Tertiary treatment
• Advanced wastewater treatment methods 
that are sometimes employed after primary 
and secondary treatments 
• Reduce phosphorus and nitrogen
Municipal Sewage Treatment
Individual Septic System-
Septic Tank
Individual Septic System-
Drain Field
Laws Controlling Water 
Pollution
o Citizen Watchdogs to Monitor Pollution
o Safe Drinking Water Act (1974)
• Set uniform federal standards for drinking 
water
• Maximum contaminant level
o Clean Water Act (1972)
• EPA sets up and monitors National 
Emissions Limitations
• Effectively improved water quality from 
point sources
Laws that Protect Groundwater
o Safe Drinking Water Act
o Resource, Conservation and Recovery 
Act
Conclusion
    The stress on our water environment as a result of 
increased industrialization, which aids urbanization, is 
becoming very high thus reducing the availability of clean 
water. Polluted water is of great concern to the aquatic 
organism, plants, humans, and climate and indeed alters 
the ecosystem. The preservation of our water environment, 
which is embedded in sustainable development, must be 
well driven by all sectors. While effective wastewater 
treatment has the tendency of salvaging the water 
environment, integration of environmental policies into the 
actor firms core objectives coupled with continuous 
periodical enlightenment on the present and future 
consequences of environmental/water pollution will greatly 
assist in conserving the water environment.
Presentation Credits:
Mr. Shivam Saha
Dr. Tathagata Deb
THANK YOU
ANALYTICAL MINDS
-A UNIT OF BHUBAN ENTERPRISES