Ch 2 Water Air and Their Impurities 2

Ch 2 Water, Air and Their Impurities 2. A Water and the Hydrosphere Environmental Engineering Science 1

Water and hydrosphere • Hydrologic cycle – Characteristic residence times • Physicochemical properties – Density (1 g/cm 3, 55. 6 M, Temp. , Composition) – Density of ice 0. 92 g/cm 3 – Viscosity (0. 6 -1. 8 g/m. s in 0 -40 o. C) – Water and Life • O 2 → H 2 O Environmental Engineering Science 3

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• Density of freshwater, as a function of temperature 6

• Density of seawater (a) as a function of salinity (mass percentage of total salts in water) for various temperatures and (b) as a function of temperature for various salinities. 7

• Dynamic viscosity, μ, of freshwater as a function of temperature. 8

2. B Air and the Atmosphere • Five major gases Environmental Engineering Science 9

Physicochemical properties of air • Ideal gas – n/V = P/RT (1 atm, 293 K, gas conc. =41. 6 mol/m 3) – Partial pressure = Mole fraction – Molecular weight (dry, moist) – Density (Temp. , Pressure) • Atmosphere Environmental Engineering Science 10

• PV=n. RT PM=ρRT • Density of dry air versus temperature at several pressures (P) 12

Ci = MW．ni / V ↓ Ci = Yi. MW．ni / V ( PV = n. RT ) ↓ Ci = Yi. MW．P / RT And ρair= MW．n / V = MW．P / RT Environmental Engineering Science 13

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• Typical dependence of temperature, pressure, and air density on height through the lower portion of the troposphere. The given altitudes range from sea level to near that of the tallest mountains on earth. 15

2. C Impurities in Environmental Media – 2. C. 1 Gases Dissolved in water – 2. C. 2 Water in Air – 2. C. 3 Acids, Bases, and the Hydrogen Ion – 2. C. 4 Inorganic Impurities – 2. C. 5 Organic Impurities – 2. C. 6 Radio nuclides – 2. C. 7 Compounds Causing Odor, Taste, or Color – 2. C. 8 Particulate Matter – 2. C. 9 Microorganisms Environmental Engineering Science 16

• 2. C. 1 Gases Dissolved in water – O 2, CO 2, SO 2, HNO 3, NH 3, CH 4 • 2. C. 2 Water in Air • 2. C. 3 Acids, Bases, and the Hydrogen Ion – p. H = -log [H+] – p. H = 1 -14, p. H = 0 (? ) Environmental Engineering Science 17

• 2. C. 4 Inorganic Impurities – Ions in water • Electroneutrality, • Ionic strength, • Hardness, • Alkalinity, A=[OH- ]+[HCO 3 -]+2[CO 32 - ]- [H+ ] – Inorganic gaseous pollutants • CO, NOx, SOx, O 3 – Toxic metals • Cadmium (Cd), Chromium (Cr), Lead (Pb), Mercury (Hg) Environmental Engineering Science 18

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Na. Cl 之電導度 Environmental Engineering Science 22

Mg. SO 4 之電導度 Environmental Engineering Science 23

• 2. C. 5 Organic Impurities – Specific organic impurities • HCHO, CFCs, Benzene, PCE, Dioxin, PAHs – Aggregate measurement of organic compounds • OD, TOD (Th. OD), BOD, COD, TOC • NMHC Environmental Engineering Science 24

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• 2. C. 6 Radio nuclides • 2. C. 7 Compounds Causing Odor, Taste, or Color • 2. C. 8 Particulate Matter – Aerosol and Hydrosol – Small Colloids (10 -3 μm) – Particles in Air: fine and coarse – Particles in Water: settleable, suspended and colloidal solid Environmental Engineering Science 27

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• 2. C. 9 Microorganisms Environmental Engineering Science 33

• Prokaryotic • Bacteria • Archaea • Viruses • Eukaryotic • Algae • Fungi • Protozoa

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Problem assignments #2 In textbook: • 2. 3 Volume occupied by air • 2. 14 Electroneutrality • 2. 15 River water quality • READING: Chapter 2: Section 2. C (pp. 41 -69) Chapter 3: Sections 3. A and 3. B (pp. 76 -106) Appendix C (pp. 613 -619 Environmental Engineering Science 37