Atmosphere. Lithosphere. Hydrosphere. Biosphere

Transcription

1 ENVIRONMENTAL ENGINEERING 1

2 The Environment and its domains Air Pollution and Control Solid and Hazardous Waste Management Atmosphere Lithosphere Hydrosphere Biosphere Water and wastewater treatment Public Health and Ecology 2

3 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-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

4 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 4

5 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. 5

6 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-term term and 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 expectations 6

7 Evolution of the discipline 7 Lothal, Wikipedia 2010

8 The Law and its course 8

9 More about the law.. Regulations Year of notice Amend ment Water (Prevention and Control of Pollution) Act Air (Prevention and Control of Pollution) Act Environment Protection Act Hazardous Waste (Management and Handling) Rules 1989 Biomedical Waste Handling Rules 1998 Flyash Rules 1999 Recycled Plastics Usage Rules Municipal Solid Waste (Management and Handling) Rules 2000 Batteries (Management and Handling) Rules

10 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 10

11 Population growth World Population = 6.86 billion (US Census Bureau) India s population = 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% 11 All figures for 15 Aug 2010

12 log Population, persons 1.000E E E E Population growth in India Total Population Urban population Expon. (Total Population) Expon. (Urban population) Time, years y = 2E-07e 0.018x R² = y = 2E-18e 0.03x R² =

13 Resource consumption 13

14 Power generation 14

15 WASTE SOLID WASTE Municipal Solid Waste (MSW) Ash from Thermal Power Plants Agricultural waste WASTEWATER Municipal wastewater Industrial wastewater AIR POLLUTANTS Industrial sources Motor Vehicles Other sources HAZARDOUS WASTE 15

16 Waste Management Hierarchy 16

17 Integrated Solid Waste Management Integrated Solid Waste Management 17

18 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 18

19 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 19

20 Waste to energy (WTE) conversion WASTE PROCESSING FOR ENERGY CHEMICAL PROCESSING BIOLOGICAL PROCESSING COMBUSTION GASIFICATION AEROBIC COMPOSTING ANAEROBIC DIGESTION [BIOFUELS] PYROLYSIS ANAEROBIC COMPOSTING 20

21 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 21

22 Plug flow anaerobic digester - US 22

23 Bhadreswar Biogas plant, Bhadreswar, West Bengal 23

24 24 Bhadreswar Biogas plant, Bhadreshwar, West Bengal

25 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; 25 transformation of compounds by microbial processes

26 Sediment-water contamination exposure pathways Food Air Water Bioconcentration in flora and fauna Water Soil Heavy metal containing ore tailings Contaminated Sediment 26

27 Ground water-soil contamination exposure pathways Volatilization Inhalation Ingestion of contaminated water Leaking Underground Storage Tank (LUST) Ground water Contamination 27

28 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-d 70 kg Risk = CDI x SF = 2.86 x 10-3 mg/kg-d x 1.75 (mg/kg-d) -1 = x 10-3 = incremental lifetime cancer risk This implies that 5 cancers per thousand persons over a 70-year period can be attributed to arsenic in drinking 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 10 7 persons x 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 28

29 Calculating non-cancer risk Hazard quotient (HQ) = Average daily dose Reference dose (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 29

30 Bioconcentration factors 30

31 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-d Cancer risk = CDI x SF = 1.75 (mg/kg-d) -1 x 1.1 x 10-3 mg/kg-d = x 10-3 or approx. 2 cancers per thousand people 31

32 Risk characterization For a population of 60 million people that are living in As affected areas; we assume half the population eats fish regularly, i.e., 30 million Annual cancer risk is = 3 x 10 7 x x 10-3 x 1/ 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 a complete characterization of risks due to As 32

33 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-based costs have to be determined Weigh costs of all options Decide 33

34 Environmental Risk Management Contaminant concentration or risk level Acceptable risk level Detection limit Cost of cleanup 34

35 Civilization began with the felling of the first tree and will end before the fall of the last one THANK YOU 35