ELA Revision Notes

Question 1

Define environmental engineering

Answer 1

Branch of engineering concerned with the application of scientific and engineering principles for:

• protection of human populations
• protection of environments
• improvement of environmental quality

Question 2

What is the triple bottom line

Answer 2

Social, environmental and economic factors

• Social and enviro - bearable
• Enviro and econ - viable
• Social and econ- equitable

Question 3

Current paradigm

Answer 3

Fossil fuels, energy intensive processes, waste generating chem

Question 4

Ideal vision

Answer 4

Renewable feedstocks, renewable energy, atom economy

Question 5

Eight grand challenges for sustainability

Answer 5

1. Energy intensive chemical processing
   - Transition from oil and gas to coal
   - Opportunities in separation processes such as alternatives to distillation, catalytic activity and tribology
2. Sustainability education
3. Separation, sequestration and utilisation of CO2
4. LCA
5. Toxicology
   - REACH European regulations 2007 which controls users of chemical over 1 ton per year who must register
6. 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
7. Renewable feedstocks
   - Chemicals from biomass, energy crops
   - Development of new production pathways
8. Renewable fuels
   - Nuclear, biomass, solar, wind, waves

Question 6

Define LCA

Answer 6

The measure of the environmental impact of a product throughout it’s lifecycle ‘cradle to grave’

Question 7

LCA uses

Answer 7

Measurement of impact
Comparison
Decision making
Marketing
Strategic management
Public policy making

Question 8

Improvements in LCA

Answer 8

Quality and quantity of data
Using methodology
Interpreting results
Complexity of systems

Question 9

LCA methodology ISO 14040

Answer 9

1. Goal and scope definition
2. Inventory analysis
3. Impact assessment
4. Interpretation

Question 10

Define FU

Answer 10

A quantitative measure of the output of products or services which the system delivers to

Question 11

Define allocation

Answer 11

The system under study produces more than one functional output then the environmental burdens must be allocated among these outputs.

Question 12

System expansion

Answer 12

The emissions from waste incineration are offset by calculating emissions from an alternative heat/power process of the same amount of energy

Question 13

Different ways to allocated products that are recycled

Answer 13

1. Cut-off
2. Value
3. Associate waste with raw material acquisition
4. Associate need to replace waste with raw material
5. Closed loop
6. 50/50

Question 14

LCA impact assessments steps

Answer 14

1. Classification
2. Characterisation
3. Normalisation
4. Valuation

Question 15

Reports and bodies for climate change

Answer 15

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

Question 16

IPPC methodology

Answer 16

1. Define objective
2. Quantify emissions
3. Quantify environmental impact
4. Compare abatement options and rank
5. Evaluate costs of implementing
6. Identify BAT

Question 17

Air pollution control options

Answer 17

1. Process change
2. Abatement
3. Dispersion

Question 18

Air pollution control philosophy

Answer 18

Emission taxes
Cost-benefit standards
Emission standards
Air quality standards

Question 19

MAC and MDC

Answer 19

Marginal abatement cost and marginal damage cost

Question 20

Routes for capture in a combustion plant

Answer 20

Post-combustion capture
Pre-combustion capture
Oxy-fuel combustion
Air sucking

Question 21

CO2 storage techniques

Answer 21

Geological formations
- Depleted oil and gas reservoirs
- Deep saline aquifers
- Unmineable coal seems
Deposition into water on deep ocean floor
Conversion into solid materials

Question 22

Carbon trading phases

Answer 22

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

Question 23

The challenges of waste water management

Answer 23

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

Question 24

Sources of water pollution

Answer 24

Agricultural, industry and households

Question 25

Measurements of water pollution

Answer 25

Biological oxygen demand
Chemical oxygen demand
Total solids
Total suspended solids
Nutrients

Question 26

Waste water treatment stages

Answer 26

Pre treatment (chem or phys)
Primary treatment (phys)
Secondary treatment (bio)
Tertiary treatment (phys or bio)

Check notes for more information

Question 27

What is aerobic treatment (waste water treatment)?

Answer 27

Activated sludge is mixed with waste water in presence of oxygen, the cleaned water is then separated from the sludge

Question 28

What are the options for sludge disposal?

Answer 28

Use as fertiliser, incineration for energy recovery

Question 29

Options for aeration in aerobic digester?

Answer 29

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