Engineering in the Environment

Lec 3: Engineering in the Environment

• Environmental management involves laws, regulations, natural environmental standards, district plans, and consultation.
• An environmental code of practice includes using resources efficiently, minimizing waste generation, recognizing adverse impacts, prioritizing long term, and practicing kaitiakitanga (guardianship/stewardship).
• An Environmental Impact Assessment (EIA) encompasses identification, prediction, and evaluation of magnitude, avoidance, and minimization, as well as other components.
• Ecosystem services include regulating (clean air), supporting (soil), provisioning (materials), and cultural (recreation) aspects.
• The biosphere is a global ecological system that integrates all living beings and their relationships.
• Major components of the biosphere are the hydrosphere (water), lithosphere (soil), and atmosphere (air).

Ecosystem vs. Environment

• An ecosystem is a community of interacting organisms with their abiotic environment.
• The environment comprises multiple, different ecosystems that have evolved due to their location's conditions.

Ecosystem Principles

• Mass conservation dictates that mass is neither created nor destroyed.
• Energy conservation means energy is neither created nor destroyed, only transformed.
• Diversity serves as a buffer against disruptions.
• Dynamic ecosystems adapt to external disturbances while retaining functionality.
• Interdependence describes that all life forms are interconnected.
• Carrying capacity is the upper limit of an ecosystem.

Self Design

• Ecosystems organize, develop, and maintain themselves.
• Species constantly adapt.

Biomimicry Designs

• Biomimicry designs copy and integrate what ecosystems already do naturally into engineering designs.

Lec 4: Population and Systems Ecology

• Terrestrial ecosystems are also called biomes.
• Biomes are classified by climate (precipitation and temperature).
• Vegetation (plants) is also used in classification.

Producers, Decomposers, and Consumers

• Producers, like vegetation, manufacture material through photosynthesis.
• Photosynthesis uses 6CO2 + 6H2O + light to produce C6H12O6 + 6O2.
• Decomposers are waste converters.
• Heterotrophs obtain food from others.

Consumers

• Primary consumers, or herbivores, only consume vegetation.
• Secondary consumers, or carnivores, only consume moving things.
• Tertiary consumers, or omnivores, consume both vegetation and other things.

Species Types

• Indicator species tell us the status of other species (e.g., lichen).
• Keystone species have a greater effect on ecological processes than predicted by their abundance (e.g., honey bees).
• Umbrella species involve protecting these species (predators), which indirectly protects others (e.g., bears).
• Link species transfer matter and energy across trophic levels (e.g., birds, butterflies).
• Foundation species create and maintain a habitat (e.g., coral reefs).
• Ecological species alter the habitat (e.g., beavers creating dams).

Population Growth

• Exponential growth is where dN/dt = rN.
• Logistic growth involves dN/dt = rN(1 - (N/k)).
• N(t) = (k * No) / ((k - No) * e^(-rt)).

Relationships Between Species

• Equilibrium occurs when prey and predator populations balance.
• Extinction occurs when the predator causes prey extinction, followed by the predator also becoming locally extinct.

Lec 5: Energy Flows and Material Cycles

• Primary production (PP) is the process where plants and algae produce organic compounds from CO2 through photosynthesis.
• PP forms the foundation of the food web.
• Gross primary production (GPP) is the total energy converted.

Net Primary Production (NPP)

• Energy converted minus respiration.
• NPP = GPP - R, where R is respiration.

Bioaccumulation

• Bioaccumulation is the uptake and accumulation of contaminants via a food web.
• Key organs and hydrophobic compounds accumulate contaminants.

Ecosystem Terms Related to Material Dynamics

• Standing stock is the amount present (tonnes, hectares, water).
• Material flux rate is the input or output of material from a system as it changes form.
• Residence time = standing stock / flux rate.
• It's the avg time material spends in a form.
• Forcing functions drive the rate of change (consumption, climate, economics).
• Products of ecosystems are results, like clean water or food stocks.

Most Abundant Materials on Earth

• Nitrogen: 78.08%.
• Oxygen: 20.95%.

Materials for Biota

• Main materials: oxygen, carbon, and water.
• Macro nutrients: nitrogen, phosphorus, potassium, calcium, and magnesium.
• Micro nutrients: iron, magnesium, zinc, copper, boron, and chlorine.

Nutrient Cycles

• Water cycle consists of the transfer of water: land to atmosphere (evaporation), atmosphere to land (precipitation), and surface runoff/streams to lakes/ocean (percolation).
• Evapotranspiration: Earth surface to atmosphere (sublimation), solid to gas (evaporation), and liquid to gas (transpiration/biopumps).

Water Movement on Land

• Lateral flow over ground (surface runoff).
• Vertical movement into soil (infiltration).
• Lateral movement in soil (interflow).
• Vertical movement through soil/rock to ground (percolation).

The water cycle global budget

• Residence time = Total Stock / Total Flow In.

Example water amounts

• Atmosphere: 0.013 x 10^15 m^3
• Land: 33.6 x 10^15 m^3
• Oceans: 1350 x 10^15 m^3

Reservoirs Influx

• PPT=324 * 10^12 m^3/year
• Runoff= 37 * 10^12 m^3/year
• Total Sum = 361 * 10^12 m^3/year

Residence time

• Residence Time = 1383 *10^15 m^3 / year / 361 * 10^12 m^3 /year = 3832.7 years

Carbon Removed from the Atmosphere

• The natural process is photosynthesis, ocean absorption, and soil sequestration.
• Anthropogenic process: Direct air capture, capture and underground storage, and capture to biogas.

Carbon Dynamics

• Photosynthesis (consumes carbon): 6CO2 + 6H2O -> C6H12O6 + 6O2
• Respiration (releases carbon): C6H12O6 + 6O2 -> 6CO2 + 6H2O
• Reactions are reversed and interdependent.

Nitrogen Emissions

• Natural: Lightning and soil respiration.
• Anthropogenic: Combustion, construction (cement), transport (diesel), and gardening.

Nitrogen Dynamics

• Nitrogen fixation converts atmospheric N to ammonia (NH3).
• Nitrification converts ammonia (NH3) to nitrites (NO2-) then to nitrates (NO3-), through bacteria in the soil.
• Assimilation absorbs nitrates (NO3-) in plants for plant proteins and nucleic acids.
• Ammonification occurs when plants/animals die, decomposers (bacteria) convert organic N back into NH3.
• Denitrification converts NO3- into N, releasing it back into the air.

Phosphorus Dynamics

• Weathering of rocks releases phosphorus (P) into soil.
• Plants absorb inorganic P.
• When plants/animals die, P goes back to the soil.
• In water, P is in sediments and can form rocks.

Learning Objectives

• Different ways civilians use water.
• Why water quality is important for engineers.
• How water is classified & diff quality signatures.
• Terms relevant to water quality.
• Engineering decisions affect water quality.
• Understand diff sources, classification and impacts of solids.
• Solid fractions, what they are and Calc.
• Definitions, sources and relevance of alkanlinity and hardness
• How can engineers use alkalinity and hardnes.
• Definitions, sources, measurment and Relevana of dissolval Os and Or demands
• How can enchance dissolved Or to help enviro problems.

L7 Water Quality Affects Structures

• Structural concern: corrosion and mass loss.
• Source of pollutants: ground water, rainfall runoff and deposition

L7 Key water quality

• Solids, O demands, pathogens, and nutrients