Waste management Flashcards
What is waste management?
An activity or action performing collection, transport, recycling and removal/disposal of waste.
What is the purpose of WM?
- recover value (energy, material)
- prevent contamination, protect land
- economic value
- prevent danger/hazards
What is waste?
Waste means any object or substance that the holder discards or intend or is obliged to discard (EU legislation)
- legally, recycling and energy recovery treats waste, not products
When should a substance or object be deemed a by-product rather than waste?
- If it was produced in a manufacturing process where main aim was to produce the substance
- If it can be used directly without any processing other than processing that is normal in industrial practice
- If it will continue to be used in a manner which is acceptable from a health and env. perspective and which does not breach any legislation or other statute.
How does waste differ?
- quantity (how much)
- origin (where from)
- composition
- location (where at)
- Time
- -> very varying material, diff properties, need for many ways to treat waste
Define waste treatments: pre and post use
- Pre consumption waste: measures in extraction and production - reduce losses in production. Production waste could be significantly larger, involving large material losses.
- Post consumption waste: measures in post use - recycle, incineration for energy recovery, composting, treat waste water, landfill and control
How could household’s source separation contribute and be improved?
Contribute:
- divide as residual waste, food/organic waste and recyclables and recycle correctly
Improve:
- user convenience and behaviour
- infrastructure in place
What are the four main waste treatment options?
- recycling
- biological treatment
- incineration
- landfill
Describe Landfill drawbacks and benefits
Drawbacks:
- loss of resources
- land area required
- management of landfill needed to keep safe (leachate. landfill gas methane)
- social impact (odours, scavenging)
Benefits:
- Flexibility: mix of many diff waste types
- Low cost (depending on landfill and taxes)
- Controlled storage of hazardous substances (if dedicated management to landfill)
- Storage of resources for future generations? (metals, plastic)
- Controlled landfills may include landfill gas collected for energy
Describe Waste incineration drawbacks and benefits
Drawbacks:
- air and water emissions
- loss of resources
- ashes and slag disposal (about 1/4 of input)
Benefits:
- Energy recovery (main, heat and electricity)
- volume reduction - scale factor
- Flexibility: mix of many different waste types, but only combustible ones yield energy
- some metal and slag recovery after incineration
Describe Biological treatment drawbacks and benefits
Drawbacks:
- Emissions from processes
- Costly (anaerobic more than composting bc building of infrastructure)
- requires source separated organic waste
- in use, there is risk of contaminating the soil (farmers want to know what is in before spreading it)
- Soil emissions
Benefits:
- volume reduction
- stabilisation
- biogas production (anaerobic digestion)
- yields compost to give back nutrients to ground
- Production/improvement of soil and landscaping
- Nutrient cycle (P scarce and N energy demanding)
Describe Material recycling drawbacks and benefits
Drawbacks:
- often open loops (materials not used within the same requirement as first, degrading, down-loop)
- requires separated waste fractions
- A large variety of recycling chains and processes
- different products have different properties
- with low quantity not economical to have high quality recycling
- Risk of circulating hazardous substances
- Impact from reprocessing/cleaning (water, el, land)
- Cannot meet an increasing material demand without primary materials
Benefits:
- Recovery of material
- can replace primary resources (reduction in primary resources)
- Energy gains compared to primary resources
Why can’t recycled materials alone meet an increasing demand?
ex zink.
- long lifetimes of major uses
- losses through dissipative use and inefficient collection and recycling
What does the waste generation scheme look like?
See lecture WM into
