Recycling (Not coming up) Flashcards
What are the 3 stages of Material Recovery Facilities?
1) Material Preparation
2) Primary Separation
3) Material Recovery
What is MRF?
Material Recovery Facilities
Key aspects of the Preparation Stage?
1) Bag Splitting
2) Removing of Large Objects
3) Feedstock prepared for effective seperation
What is the primary stage?
Crude separation to ensure more effective and efficient recovery stage
What is Clean MRF?
Recyclables are recovered
1) rubbish and mixed recycling collection
2) disc screening
What is Dirty MRF?
Recyclables recovered from municipal solid waste
What is the recovery stage?
Final phase dependant on end recyclate and market requirements.
Segregation can be manual or automated
Sorting equipment includes overband magnets, eddy current separators, optical sorters and air classifiers.
Advantages of Dirty MRF
No presorting
- save labour and space to segregate the waste at soruce
Feedstock incude Mixed Waste
Advantages of clean MRF
1) Better quality materials
2) Less contamination
3) Cleaner - as not mixed with organic waste
4) Feedstock depend on collection
Types of Mechanical Separation?
1) Negative Sorting
- passive
- gravity or air jets
- screens
2) Positive Sorting
- Active Removal
- Manually or Mechanically
- e.g. magnetic seperation
What is a disc screen Separator?
- rotating discs
- larger objects rise to top
- smaller objects settle at the bottom
What is a debris roll screen?
Oval shape rollers or dics create a wave action in the incoming waste
- releases smaller materials through screen opening
What is Optical Separation?
- Distinguish between different types of recyclable materials
- use infra- red, x-ray, pattern recognition
- Materials targeted, PET, HDPE, Heavy paper, Ceramics.
- Through puts slow
What is Baling?
Recyclables are compacted into bales tied with wire or plastic strapping
By products of Recycling?
1) Dry recyclables are reprocessed into new products
2) Organic waste
- composted
- landfil
What is driving separation of more material?
1) Increasing recycling and recovery targets
2) Research and development
3) Improving cost efficiency
- further use of computers
What is autoclaving?
Processing of MSW in a pressurised sealed drum under the action of steam
What are the by products of Autoclaving?
- Autoclave fluff - 50% reduced biodegradability
- Refuse Derived fuel (RDF)
- paper fibre
- Ethanol production
- Biogas Production - Anaerobic digestion
- Clean dry recyclables e.g. glass. metals
- Effluent stream or condensate
- Low calorific residues to landfill
Autoclaving Strengths (+)
1) Proven on MSW application
2) process sterilises waste
3) heat deformation of plastics may enhance efficiency for recycling
i. e. removing of labels and glue
4) Lowers maintenance requirements at combustion facilities
5) Substantial reduction of ash and other products destined for landfills
Autoclaving Weaknesses (-)
1) Perceived as new technology
2) Underdeveloped markets for recovered fibre
3) Products of combustion would result from subsequent use of RDF for energy recovery
