Environmental Engineering: Key Concepts

Environmental Engineering Fundamentals

• Environmental engineering applies math and science to solve problems related to environmental sanitation.

Learning Objectives Chapter 1

• Be able to define environmental engineering and its scope
• Identify the traditional and modern goals of environmental engineering
• Understand the historical evolution of water treatment, wastewater treatment, air pollution control, and solid waste management
• Understand the significance of sustainability and the role of the Sustainable Development Goals (SDGs)
• Understand the APEGA Code of Ethics and its relevance to professional practice

Environmental Engineering Definition

• The application of mathematics and science to utilize the properties of matter and energy
• Solves problems related to environmental sanitation.

Traditional Environmental Engineering Goals

• Protect public health
• Restore and protect the natural environment
• Improve environmental quality

Modern Environmental Engineering Focus

• Focus is on sustainability

Sustainability Topics

• Further discussion provided in Chapter 5

Key Dates for Sustainable Development Goals

• 1992: UN Conference on Environment and Development (UNCED) in Rio de Janeiro; Agenda, (Agenda 2021)
• 2000: Millennium Summit adoption of the Millennium Development Goals (MDGs)
• 2012: Rio+20 Summit establishes a draft for Sustainable Development Goals (SDGs) continuing MDGs
• 2015: Adoption of the 2030 Agenda and the Sustainable Development Goals (SDGs) by all UN member states
• 2016: Agenda 2030 begins, taking effect with a term of 15 years
• 2021: SDG Decade of Action begins

United Nations Sustainable Development Goals

• Consists of seventeen goals that address various economic, social, and environmental challenges
• Goal is to design a better future where products, processed and systems are more sustainable
• Engineers address challenges relating to economic growth as well as awareness for a potential better design

History of Environmental Engineering

• Mid-1800s: Engineering societies are formed
• Early 20th Century: Environmental Engineering=sanitary engineering (water and wastewater)
• Late 1960s: Rebrands as Environmental Engineering to address pollution and solid waste

Rachel Carson

• Known as the "Mother of Environmental Movements"
• Wrote "Silent Spring" in 1962, identifying that the biocide/pesticide DDT (initially WWII), is very persistent and bioaccumulates

Water Treatment History

• 3750 BC: Sewer constructed in Nippur, India
• 97 AD: 9 aqueducts carried 3 x 105 m³/d of water into Rome
• 1804: Water filtration process (sand filters) installed in Scotland
• 1833: Parisian sewers were constructed
• 1842: Hamburg sewers were built
• 1854: Relationship between contaminated water and cholera infection demonstrated by John Snow
• 1873: William Budd proposed that typhoid fever was a waterborne disease
• 1830s: Primary water treatment in the United States/North America is through sedimentation
• Filtration started in late 1880's
• 1902: Chlorination started in Belgium
• 1905: England followed chlorination that began in Belgium
• 1908: New Jersey follows chlorination technique
• 1960s: Water treatment advancements occurred using synthetic membranes for filtration

Brief History of Wastewater Treatment

• 1840: Sewage was irrigated onto agricultural land
• 1850-1900: Septic tanks, aeration and filtration was implemented
• 1908, 1916: Trickling filters and activated sludge were developed
• 2000's: Pharmaceuticals personal care products and micropollutants were of concern
• Endocrine disrupting compound may cause fish feminization

Brief History of Air Pollution Control

• Development proceeded from the latter part of the 19th century, and the early part of the 20th centuries
• Recognition of connection between air pollution and disease, late 18th to early 19th century
• 1852: Fabric Filters were first used to trap particulates
• 1895: Cyclone collectors improve trapping of particles
• 1899: Venturi scrubbers begin mass transfer of airborne contaminants into solution
• 1952: Killer Fog in London claimed 4,000 lives and stimulated positive legislation
• 1987: Montreal Protocol result of CFCs and Ozone depletion

Solid Waste Management History

• 1297: Homeowners in London were obligated to keep pavements clear
• 1875: Refuse collection began using horse buggies
• Waste was either incinerated (1885 in the US) or went to landfill (beginning in the 1930s)

APEGA Code of Ethics

• Professional engineers and geoscientists shall hold paramount the health, safety, and welfare of the public/regard for the environment.
• Undertake only work that they are competent to perform by virtue of their training and experience
• Conduct themselves with integrity, honesty, fairness and objectivity in their professional activities
• Professional engineers and geoscientists shall comply with applicable statutes, regulations and bylaws in their professional practices
• Uphold/enhance the honor, dignity and reputation of their professions to serve the public interest

Basic Concentration Concepts

• Chemical concentration is a determinant of chemical fate, transport, and treatment in natural and engineered systems
• Has a variety of units depends on what chemical it is in (air, water, soil/sediments)

Common Unit of Concentrations in Environmental Measurements

• Mass chemical/total mass = mg/kg in soil, measured in mg/kg or ppmm
• Mass chemical/total volume=mg/L in water or air, measured in ppm or mg/L or ug/m³
• Volume chemical/total volume=Volume fraction in air, measured in ppmv
• Moles chemical/total volume=Moles/L in water, measured in M
• Common Prefixes: nano (10^-9), micro (10^-6), milli (10^-3),kilo (10^3)

Mass/Mass Units

• Parts per million, parts per billion, parts per trillion
• 1 mg solute placed in 1kg solvent = 1 ppmm (part per million, by mass)
• ppmm= mix10^6 , with here=mass m total mi
• Similar definitions for ppbm, pptm, percent by mass m total

Mass(Volume units

• Mg/L or Ug/L commonly used for concentration of chemicals in water
• Mg/m^3 or Ug/m^3 more commonly uesd for air concentration
• ppm=mg/L
• ppb=ug/L and ppt=ng/L
• Only works because pure water density is approximately 1000 g/L

Volume Volume units

• Volume fraction is often used for for gas concentrations
• Volumes will be given in parts per million (ppmv)
• Concentrations will not change as the gas is compressed or expanded

Gas Laws

• The ideal gas laws states that the Pressure(P) times Volume(V) == Number of Moles(n) times the gas constant(R) times the absolute temperature(T)
• p =(Pm)/RT

Partial Pressure units

• In 1801, John Dalton founded that total pressure of a gaseous mixture was the sum of partial pressures exerted by the total mixture
• Partial pressures are mole fractions that are identical to pressure fractions for a given temp and volume

Normality

• If molarity is moles of substance per L, then Normality is the moles of REACTIVE species per L of a solution
• 1 Reactant will in turn react with 1 equivalent of another
• Normality= mass concentration/equivalent weight

Equivalent Weight

• Equivalent Weight (EW) is the substance mass for substance and is calculated as:
• EW = Molecular mass/n, and units are g/eg
• Knowing this normality calculated
• g concentration is units =Leq
• Mass concentration is units L g/normal weight

Finding Number of Equivalents

• Acid/Base, #moles or protons exchanged per mol of reactant
• Precipitate/Dissolution, #moles of protons needed to replace cation involved in dissolution
• Oxidation/Reduction, #electron moles tramsferred

Chemical Reactions

• Reactants react to form products with rates proportional to their stoichiometric constants
• Four types exist
  • Oxidation-Reduction: Electron Exchanges
  • Complexation: Reaction with Metals
  • Precipitate-Dissolution: Reaction w/a solid
  • Acid-Base : H+ exchange

Solving Equilibrium for Reactions

• At equilibrium, the dissociation constant is equal to the products divided by the reactants
• In activity problems y=1
• Environmental problems we use concentrations instead as they're in dilute solution

Solubility with Precipitation Distillation

• All Solutions still soluble in water
• Most solutions limited in how soluble they are based on how well it can dissolve. The solution remains unsaturated in the initial stage
• At a saturation level, solute is solved
• A super saturation level is reached
• Then precipitation forms

The Ksp

• The higher the Ksp, the more soluble the compound is

Acid Base Chemistry

• Bronze-Lowry acids are proton dontars while bronze Lowry bases serve as proton receptors
• Acid-Base Rxns involve proton donors and pro receptors
• Diprotic acida have 2 acidic protons and Triprotic have 3 acidic protons

Reaction Rates

• The strong acids have equilibrium reactions with their products shifted right, the weak acids have theirs shifted left

Defining Water Reactions

• Waters reactions include H+ and OH-
• Using these we can find pH if necessary

Sustainability

• Using Resources that are NOT permanently damaged
• Considers a just society that produces wealth and provides jobs WITHOUT degrading wealth
• Focuses On:
  • Reducing Renewable and NonRenewable Resources
  • Provides Market Based Solutions

Projecting the Population

• Population growth may depend on crude estimates
• Factors:
  • Constant
  • Slow Fertility
  • Fast Fertility
  • Slow Ferility

Global Warming

• Vulnerability, the ability to cope with rapid enviro change is key for global warming
• Can assess by assessing available capacity for strong farmland/resources/adaptability
• Resources depend in the future on:
  • Drought
  • Flooding

Defining Drought

• Define as period of time with constant deficincy in water supply from below average precip

Explore the core principles of environmental engineering, including water quality, pollution control, and hazardous waste management. Understand the field's evolution from end-of-pipe solutions to a focus on sustainability and environmental impact. Learn about the key role of environmental engineers in protecting the environment and public health.