ENST233 - Final exam

Water Stress

When the demand for water exceeds the available amount during a certain period or when poor quality restricts its use

• Quantity and quality decreases

What percentage of the world’s water is available for human use?

• 97% salt water

• 3% freshwater, ⅔ in glaciers, ice caps etc (inaccessible), ⅓ in groundwater, surface water, etc (accessible)

Population growth affect on water supply

Increase in consumption, agriculture, and industrial use

Climate change affect on water supply

Alterations in precipitation, less snow, wetter areas become more wet, dry areas become more dry

Pollution affects on water supply

Untreated sewage, purification is expensive and inaccessible

3 factors that put water supply in jeopardy

population growth, climate change, pollution

What human activities are the largest users of freshwater?

45% power generation, 32% agricultural, 9% domestic, 7% industrial

Unconfined aquifer

directly under the permeable soil, open to atmosphere, more susceptible to contamination

Confined aquifer

bounded by layers of impermeable rock or clay, under large amounts of pressure, protected from contamination

Saltwater intrusion

 the movement of ocean saltwater into freshwater aquifers, occurs after an aquifer has been excessively drained

Public water

• Used when houses are close together, from a municipal system

• High quality but incredibly expensive, fluoridated, but quality is monitored

Strategies to protect drinking water

• Protection of source water - prevention

  • Limiting contaminants

  • Sourcing water correctly

  • Limiting runoff

• Water treatment

  • Municipal water treatment - sewage treatment plant

Point source water pollution

municipal, industrial, from a pipe

Non point source water pollution

ag runoff, urban runoff, atmospheric deposition (PCBS, biomagnification), contaminants from other countries (national level)

Groundwater contamination

septic systems, underground storage systems, municipal/industrial landfills, abandoned hazardous waste sites, purposeful pesticides/fertilizers

Chemical pollutants (can enter both surface and ground) -

heavy metals and organic, generally long lasting

Biological pollutants (mainly enter surface water)

 fecal coliforms (intestinal bacteria that indicated the presence of fecal contamination)

Biological oxygen demand

• decomposition needs dissolved oxygen for the microorganism , too much organic waste suffocates oxygen

Wastewater Treatment Plant

• Primary - screens, remove large matter, sludge removal, grit chamber, primary settling tank

• Secondary - activated sludge (bacteria), trickle filtration, ponds and lagoons with bacteria

• Tertiary - chlorination, enhanced nutrient removal then dechlorination

Particulate Matter (PM₁₀ and PM_2.5)

• PM10 - large gets lodged in lungs, PM2.5 - small penetrates lungs and blood

• Stay suspended in atmosphere

Nitrogen Oxides (NOx)

• NO and NO2

• Sources - volcanos, lightning, bacterial fixation, fossil fuels

• Acid rain, acute and chronic health effects

Sulfur Dioxide (SO₂)

• Sources - combustion of fuels, smelting metals

• Health effects - inhalation, eyes burning, asthma

Ozone - Ground Level (O₃)

• Good in the stratosphere → reduced UV penetration

• Bad in the troposphere → respiratory irritant and part of photochemical smog

  • Sunlight + NOx + VOCs → O3

• Health effects - acute respiratory response (body does not breathe O3), chronic repeated exposure

More on PM

• Sources - volcanic ash, forest fires, dust, fossil fuels, wood burning

  • Reduced overall due to less coal, but increase in forest fires

• Solutions - wet scrubbers and electrostatic participates

• Health consequences - respiratory symptoms, blood stream, lung disease

Acid rain

• SO2 + NOx + H2O → H2SO4 + HNO3

• wet deposition as rain snow fog, dry deposition as gas/particles

• Noticed

Smog

mixture of particulates and SO2 from coal burning, wet areas

Photochemical smog

 sunlight interacting with emissions to form complex secondary pollutants, dry areas

Thermal inversion

due to convection and the release of heat in urbanized areas, a layer of heat is created which traps pollutants and particulates from releasing into the atmosphere

mechanism of action (MOA) of carbon monoxide (CO)

CO attaches to hemoglobin which makes it so oxygen can’t be attached, blocking oxygen from entering the body

Principle sources of lead exposure

paint and gasoline (not anymore)

Catalytic converter

•  Reducing NOx by turning it into O2 and N2, but this can form both CO2 and N2O which are harmful greenhouse gases

Bhopal India in 1984 event

massive leak of methyl gas from a pesticide plant, instantly killed thousands, addressed the issues of industrial safety systems.

Varieties of Municipal Solid Waste

• Paper, yard trimmings, food waste, plastics, metals

• Either commercial waste or residential waste

  • Commercial - paper, packaging, waste foods

  • Residential - garbage, trash, durable goods, yard waste

Extended Producer Responsibility (EPR)

All costs associated with a produced are included in the initial market price, manufactures are held responsible for waste after products useful life is over

Polluter Pays Principle (PPP)

Polluting party (end user) pays for disposal/ impact to the environment

Market based motives

- works when recycled material is cheaper than raw material, subject to market pressures and fluctuations

Legislation based motives

mandating min recycled content in products

Operation of a Modern Landfill

• Bottom liner composed of layers of clay and flexible membrane

• Cells covered to minimize pests

• Impermeable cap to shed water 

• Vegetation to prevent erosion

• Leachate recovery system, gas recovery, monitoring wells

Cradle to grave

technique to assess every impact associated with a product from creation to destruction

Cradle to cradle

 holistic framework that seeks to create systems that are waste free, continuously reusing things

What is renewable vs. non-renewable fuel?

Renewable fuel can come back through nature (hydro, wind, biomass to some extent), non-renewable does not come back (fossil fuels, natural gas)

Combustion fuels are solar energy concept

Combustion fuels are all from organic materials which once gained there energy from the sun, that same energy has just been transformed into fuel

Coal origins

• plant materials buried under sediments decay to form peat, compaction forces water out which forms lignite (soft brown coal), further compression turns into bituminous (soft black coal), and then anthracite (hard coal mostly carbon)

Simple biomass fuel

• wood, crop residues, peat, animal waste (simply burning all of this stuff and producing fuel

Technological biomass fuels

• ethanol (corn), garbage, landfill, biodigesters

U.S. energy use per capita

• U.S. is at 500 GJ/year whereas england, france, germany, and japan are at 150-180

• World average is 85

What countries are rapidly increasing their amounts of energy use?

China and India

What is the principle energy source for transportation in the US?

Petroleum, “energy dense”

What is the biggest recent change in US electricity generation and what activity has allowed it to happen?

• Shift from coal to natural gas and renewable energy sources 

• More technological innovations that have allowed for the extraction of natural gas from tight rock formations (hydraulic fracturing and horizontal drilling)

Effects of coal extraction

mining disasters (suffocation), lung disease (PM), community impacts (rockslides, slurry pong leaks, regional poverty)

Environmental impacts of coal extraction

eliminates vegetation, topography/soil profile gone, acid mine drainage

Oil/natural gas origins

hydrocarbons, began as algae and bacteria, remains consolidated within the sediment, used up most of it already (more BDE than coal)

Hydraulic fracturing problems

pre-existing fault lines, takes up a lot of land, almost 2 million active wells, earthquakes, waste from fracking can go into aquifers

Natural gas issues

can not be smelled (led to the addition of thiols (sulfides) to be able to smell the natural gas), liquified natural gas (on ships and in pipes, both can blow up)

Nuclear power issues

dangerous and dirty uranium extraction, radiation, release carcinogens, contaminate water

Hydroelectric issues

flooded areas above dams (flooding, loss of towns, mudslides), changes down stream (physical, chemical, and biological)

Temperature trends

• Average surface temperature has increased 1.4 degrees C over the past century

• More heat waves, more warm days, less cold nights

Sea level rise trends

• Risen 20 cm (8inches) over the past century due to melting glaciers, thermal expansion 

• Will ultimately be unevenly distributed due to countercurrents and uneven land

Precipitation trends

Overall precipitation will decrease but more natural disasters

Retreating glaciers

• Albedo - reflection coefficient 

  • Higher with white, lower with black - rock will absorb the heat and warm the surface more

• Alters seasonal availability to water

Himalayas issue

greatest area of glaciers and feed into all surrounding rivers, all of Asia (loss of water, food production, etc), more rapid heat rising in this area

Shifts in areas suitable for food production

• As areas become warmer - some areas will become more suitable, some will become unsuitable for agriculture

  • Some areas will have longer growing seasons due to warmth

Increases in wildfires

• Higher temperatures, changes in precipitation = more droughts/heat waves

• Earlier spring snow melt

• Reduce yield in agricultural areas due to burning,

Expanding ranges of pathogens and/or vectors

• More heat, more areas that are suitable for mosquitoes and common pests which will spread more diseases

• Less cold nights where insects can die

• More pests, more pesticides in ag