ENVIRONMENTAL
ENGINEERING
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The Environment and its
domains
Solid and
Hazardous
Air Pollution Waste
and Control Management
Atmosphere Lithosphere
Hydrosphere Biosphere
Water and
wastewater Public
treatment Health and
Ecology 2
Sustainable development
• Development that meets the needs of the present
without compromising the ability of future
generations to meet their own needs
• Implications:
• Societal emphasis has to shift from a
destructive, exploitative philosophy (The Tragedy
of the Commons) to one that fosters long-
long-term
protection of the environment and its inhabitants
(we have to protect The Golden Goose!)
• Two conflicting objectives have to be reconciled
– improving quality of life vs. protecting the
environment 3
Driving forces for sustainability
• Health and safety: human and other
organisms
• Financial: property values, profits, taxes
• Aesthetics
• Civic pride and values
• THE LAW
– All the good intentions in the world are not
equal to the arm of law
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What is environmental engineering?
Environmental engineering is the
application of science and engineering
principles to
• Protect public health and the health of
other organisms,
• Preserve or improve the environment
(air, water, and/or land resources),
• Remediate polluted sites.
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Scope of environmental engineering
Pollution Control
identify sources of pollutants,
understand fate and transport of pollutants, and
design and engineer solutions
Environmental Impact Assessment
Assess short-
short-term and long
long--term impacts of current
and proposed projects
Environmental Auditing
Inventory of mass and energy for any facility to
minimize waste and inefficiency
Environmental Risk Assessment
Minimize risks to public health and environment
Environmental Management
Optimization of systems with due regard to user
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expectations
Evolution of the discipline
Lothal, Wikipedia 2010
The Law and its course
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More about the law……..
Year of Amend
Regulations notice ment
Water (Prevention and Control of Pollution) Act 1974 1988
Air (Prevention and Control of Pollution) Act 1981 1987
Environment Protection Act 1986 1991
Hazardous Waste (Management and Handling) Rules 1989
Biomedical Waste Handling Rules 1998
Flyash Rules 1999
Recycled Plastics Usage Rules 1999 2003
Municipal Solid Waste (Management and Handling) Rules 2000
Batteries (Management and Handling) Rules 2001
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What is a pollutant or contaminant?
– A pollutant is a chemical species in the
environment that causes undesirable
effects on the environment or any of its
components.
– Can be natural or anthropogenic
– Undesirable effects
• Endangers health of human and other
organisms
• Endangers safety
• Causes financial and aesthetic losses
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Population growth
• World Population = 6.86 billion (US Census
Bureau)
• India’s population = 1.186 billion (Wikipedia)
• West Bengal’s population = 90 million
• Kharagpur’s population = 2.07 lakhs
India’s current annual growth rate = 1.34%
(World Bank, 2008)
If data from 1921 to 2001 is used
• Average annual total population growth rate = 1.8%
• Average annual urban population growth rate = 3.0%
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All figures for 15 Aug 2010
Population growth in India
1.000E+10
Total Population
y = 2E-07e0.018x
Urban population
R² = 0.985
Expon. (Total Population)
log Population, persons
1.000E+09 Expon. (Urban population)
1.000E+08
1910
1920
1930
1940
1950
1960
1970
1980
1990
2000
2010
y = 2E-18e0.03x
R² = 0.995 12
1.000E+07
Time, years
Resource consumption
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http://www.eia.doe.gov/cabs/India/Full.html
Power generation
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http://www.eia.doe.gov/cabs/India/Full.html
WASTE
SOLID WASTE WASTEWATER AIR POLLUTANTS
Municipal Solid • Municipal • Industrial
Waste (MSW) wastewater sources
Ash from Thermal • Industrial • Motor Vehicles
Power Plants wastewater • Other sources
Agricultural waste
HAZARDOUS WASTE
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Waste Management Hierarchy
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Integrated Solid Waste Management
Integrated
Solid Waste
Management
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‘Zero Pollution’
• Closed loop systems
• Waste from one process or
industry is used in another
process or industry within the
same facility or industrial estate
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Environmental Auditing
• Required by the law [EPA]
• Mass and energy balances
• Complete inventory of mass and energy for
the plant, facility or industry
• Helps detect inefficiencies, losses, and
waste generation points
• Evaluate options for minimizing waste
– Technical, environmental or economic
options
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Waste – to – energy (WTE) conversion
WASTE PROCESSING
FOR ENERGY
CHEMICAL BIOLOGICAL
PROCESSING PROCESSING
AEROBIC
COMBUSTION COMPOSTING
ANAEROBIC DIGESTION
GASIFICATION [BIOFUELS]
ANAEROBIC
PYROLYSIS
COMPOSTING
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BIOFUELS
Sources of biofuels are crops
like
• Sugarcane [Brazil]
• Cassava, jatropha [India]
• Corn [US]
Waste materials can also be
used
• Wastewater [industrial or
agricultural]
• Solid waste [agricultural] for
WTE
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http://keetsa.com/blog/eco-friendly/biofuels-answer-fuel-issues-what-about-food/
Plug flow anaerobic digester - US
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http://web2.msue.msu.edu/manure/FinalAnearobicDigestionFactsheet.pdf
Bhadreswar Biogas
plant, Bhadreswar, West Bengal
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Bhadreswar Biogas plant, Bhadreshwar, West Bengal
Exposure assessment:
Fate and transport of pollutants in the environment
• Pollutants can be released into different
environmental compartments
– Soil, Sediment, Air, Water
• Pollutants are transported and transformed by
different processes
Transport processes
– Physical processes:
convection, diffusion, dispersion, settling, volatilization
Transformation processes
– Chemical processes:
adsorption, oxidation, reduction, photooxidation, hydrolysis
– Biological processes: pollutants serve as food for
microbes, and/or are bioconcentrated through the food web;
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transformation of compounds by microbial processes
Sediment-water contamination –
Sediment-
exposure pathways
Food
Air
Water
Bioconcentration
in flora and fauna
Water
Heavy metal
containing
Soil ore tailings
Contaminated Sediment 26
Ground water-
water-soil contamination
– exposure pathways
Volatilization
Leaking
Underground
Inhalation Storage Tank
Ingestion of contaminated water (LUST)
Ground water Contamination
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Calculating cancer risk
If drinking water contains ≥100 ppb of arsenic, and a person weighing 70 kg
drinks 2 L of this water every day over a lifetime of 70 years, what is the
incremental lifetime cancer risk?
CDI = 0.1 mg/L x 2 L/d = 2.86 x 10-3 mg/kg-
mg/kg-d
70 kg
Risk = CDI x SF = 2.86 x 10-3 mg/kg- (mg/kg-d)-1
mg/kg-d x 1.75 (mg/kg-
= 5.005 x 10-3 = incremental lifetime cancer risk
• This implies that 5 cancers per thousand persons over a 70- 70-year period
can be attributed to arsenic in drinking water.
water.
• For a population of approx. 60 million people that drink water with arsenic
content of 100 ppb or more, we estimate that on an annual basis, arsenic
contributes to
= 6 x 107 persons x 5.005 x 10-3 cancers/ persons exposed x 1/70 yr
≥ 4286 cancers/year
• If water treatment brings the level of arsenic down to ≤ 50 ppb, the
number of cancers due to arsenic ingestion are expected to be
≤ 2143 cancers/year
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Calculating non-
non-cancer risk
• Hazard quotient (HQ)
= Average daily dose
Reference dose (RfD
(RfD)
RfD)
• If hazard quotient is <1.0, there is no significant risk of
toxicity
• When exposure involves more than one chemical or more
than one exposure route or more than one environmental
medium,
Sum of the individual HQs = hazard index (HI)
• The five environmental media accounted for in HI calculations
are air, water, food, soil and consumer products
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Bioconcentration factors
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Risk characterization:
Overall cancer risk due to As in water
What is the cancer risk for a person eating fish contaminated with
arsenic?
• Arsenic has a fish BCF of 44 L/kg
• Concentration in fish = C(water) x BCF
C(fish) = 0.1 mg/L x 44 L/kg = 4.4 mg/kg
• If an average 70 kg person eats 50 g of fish for 300 days/yr for
30 years, the chronic daily intake of fish is
CDI = 0.05 kg/d x 4.4 mg/kg x 300 d/yr x 30 yr
70 kg x 365 d/yr x 70 yr
= 1.1 x 10-3 mg/kg-
mg/kg-d
• Cancer risk = CDI x SF
(mg/kg-d)-1 x 1.1 x 10-3 mg/kg-
= 1.75 (mg/kg- mg/kg-d
= 1.925 x 10-3 or approx. 2 cancers per thousand people
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Risk characterization
• For a population of 60 million people that are living in As
affected areas;
areas; we assume
• half the population eats fish regularly, i.e., 30 million
• Annual cancer risk is = 3 x 107 x 1.925 x 10-3 x 1/70
≥ 825 cancers/year
• Adding cancer risks from two pathways
• Ingestion of water ≥ 4286 cancers/year
• Ingestion of fish ≥ 825 cancers/year
Total cancers each year that can be attributed to As
≥ 5111 cancers/years
This is an example of ‘how to’ calculate overall risk, and is not
As…………
a complete characterization of risks due to As …………
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Risk management
• Calculate costs of average As concentration in untreated water
– Cost of loss of livelihood, decrease in productivity of victims
– Cost of medical care of victims (cancers and other effects to
be included)
• Calculate costs of treating water to remove As
– Cost of As removal to different possible MCLs
• Technology-
Technology-based costs have to be determined
• Weigh costs of all options
• Decide
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Environmental Risk Management
Contaminant concentration
or risk level
Acceptable risk level
Detection limit
Cost of cleanup
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Civilization began with the felling of the
first tree and will end before the fall of
the last one
THANK YOU
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