ELA Revision Notes Flashcards
Define environmental engineering
Branch of engineering concerned with the application of scientific and engineering principles for:
- protection of human populations
- protection of environments
- improvement of environmental quality
What is the triple bottom line
Social, environmental and economic factors
- Social and enviro - bearable
- Enviro and econ - viable
- Social and econ- equitable
Current paradigm
Fossil fuels, energy intensive processes, waste generating chem
Ideal vision
Renewable feedstocks, renewable energy, atom economy
Eight grand challenges for sustainability
- Energy intensive chemical processing
- Transition from oil and gas to coal
- Opportunities in separation processes such as alternatives to distillation, catalytic activity and tribology - Sustainability education
- Separation, sequestration and utilisation of CO2
- LCA
- Toxicology
- REACH European regulations 2007 which controls users of chemical over 1 ton per year who must register - Green and sustainable chemistry
- It is better to prevent waste than to clean up afterwards
- Excessive by products
- Atom efficiencies, use of reagents and catalysts, selectivity, toxic waste - Renewable feedstocks
- Chemicals from biomass, energy crops
- Development of new production pathways - Renewable fuels
- Nuclear, biomass, solar, wind, waves
Define LCA
The measure of the environmental impact of a product throughout it’s lifecycle ‘cradle to grave’
LCA uses
Measurement of impact Comparison Decision making Marketing Strategic management Public policy making
Improvements in LCA
Quality and quantity of data
Using methodology
Interpreting results
Complexity of systems
LCA methodology ISO 14040
- Goal and scope definition
- Inventory analysis
- Impact assessment
- Interpretation
Define FU
A quantitative measure of the output of products or services which the system delivers to
Define allocation
The system under study produces more than one functional output then the environmental burdens must be allocated among these outputs.
System expansion
The emissions from waste incineration are offset by calculating emissions from an alternative heat/power process of the same amount of energy
Different ways to allocated products that are recycled
- Cut-off
- Value
- Associate waste with raw material acquisition
- Associate need to replace waste with raw material
- Closed loop
- 50/50
LCA impact assessments steps
- Classification
- Characterisation
- Normalisation
- Valuation
Reports and bodies for climate change
IPCC - intergovernmental panel on climate change
Stern report (2006) UK Gov report on economics of climate change
George Mombiot Guardian 2007 on reduces to 2’C by 2050
Kyoto protocol 1997 legally binding
Paris agreement 2015 bottom up approach
IPPC methodology
- Define objective
- Quantify emissions
- Quantify environmental impact
- Compare abatement options and rank
- Evaluate costs of implementing
- Identify BAT
Air pollution control options
- Process change
- Abatement
- Dispersion
Air pollution control philosophy
Emission taxes
Cost-benefit standards
Emission standards
Air quality standards
MAC and MDC
Marginal abatement cost and marginal damage cost
Routes for capture in a combustion plant
Post-combustion capture
Pre-combustion capture
Oxy-fuel combustion
Air sucking
CO2 storage techniques
Geological formations - Depleted oil and gas reservoirs - Deep saline aquifers - Unmineable coal seems Deposition into water on deep ocean floor Conversion into solid materials
Carbon trading phases
Phase 1: over allocated prices peaked then plummeted
Phase 2: also peaked then drops, due to decline in manufacturing and companies cashing in and selling to ease cash flow
Phase 3: expected to lead to a steady rise in value of allowances and the hope is to force the adoption of clean technology
The challenges of waste water management
Increase the residence time of fresh water
Retention of fresh water affected by deforestation as roots retain soil/moisture
Concreting cities reduces ground water and increases sewage volume
Sources of water pollution
Agricultural, industry and households
Measurements of water pollution
Biological oxygen demand Chemical oxygen demand Total solids Total suspended solids Nutrients
Waste water treatment stages
Pre treatment (chem or phys) Primary treatment (phys) Secondary treatment (bio) Tertiary treatment (phys or bio)
Check notes for more information
What is aerobic treatment (waste water treatment)?
Activated sludge is mixed with waste water in presence of oxygen, the cleaned water is then separated from the sludge
What are the options for sludge disposal?
Use as fertiliser, incineration for energy recovery
Options for aeration in aerobic digester?
mechanical, coarse bubble, fine bubble, jet
must consider the ads and disads of using oxygen instead of air, oxygen can be produced by cryogenic distillation or pressure swing adsorption
