Chapter 4.3
Recycling and waste exchange
TRP Chapter 4.3 1
Recycling
What is recycling?
• The re-use and remanufacture of
waste materials
What is the purpose of recycling?
• To recover useful materials and save
resources
• To prevent pollutants reaching the
waste stream
What are the benefits of recycling?
• More efficient resource use, lower
energy consumption, reduced
pollution
TRP Chapter 4.3 2
On-site recycling
Benefits:
• close to the point of generation
• less contamination
• lower cost raw materials
• reduced waste disposal costs
Costs:
• capital investment in equipment
• staff training
• maintenance and repair
• staff time
• residue disposal
• quality control
TRP Chapter 4.3 3
Off-site recycling
Factors influencing off-site recycling:
•if on-site recycling is not appropriate
•if on-site recycling is not cost-effective
•availability and location of recycling facilities
•availability of advanced technology
•economies of scale
Need:
•storage for materials awaiting collection
•transport to off-site facility
Materials commonly recycled off-site include:
oils, solvents, electroplating sludges, lead-acid batteries
TRP Chapter 4.3 4
Secondary raw materials
• Use of secondary raw materials is common in
some sectors eg metals, paper, oil
• Economics of process may depend on
recycling of by-products
• Large international trade in many such wastes
• Technology for processing requires large
investment, high volumes
• May generate new problematic residue stream
• May provide opportunities for illegal practices
TRP Chapter 4.3 5
Recycling technologies
Recycling Technology
Activated-carbon Absorption
Distillation
Steam Distillation
Electrolytic Recovery
Ion Exchange
Hydrometallurgical Concentration
Membrane Separation
Evaporation
Freeze-Crystallisation
Pyrometallurgy
Waste Type
1 2 3 4 5 6 7 8 9
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1 - Corrosive wastes
6 - Oil-containing wastes
2 - Cyanide containing wastes
7 - Metal containing wastes
3 - Halogenated solvents
8 - Organic containing wastes
4 - Non-halogenated solvents
9 - Reactive wastes
5 - Other organic wastes
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TRP Chapter 4.3 6
Solvent recovery 1
Simple solvent recovery plant, SE Asia 1990
Source: David C Wilson
TRP Chapter 4.3 7
Solvent recovery 2
Source: David C Wilson 1990
TRP Chapter 4.3 8
Case study: Battery recycling
PLACID Process
paste
melting and
casting
leaching
electrowinning
residue
washing
99.99% Pb
ingots
purification
Inert
residues
Bi, Cu, As, Sb ...
TRP Chapter 4.3 9
Case study: Advantages of
process
• No liquid effluent discharges
• Leaching residue is inert gypsum
• Dusts and drosses are recycled
• Leaded slags and soils can be treated
TRP Chapter 4.3 10
Waste exchange
• Puts generators in contact with potential
users
• Example of off-site recycling
• Some free, some charge fees
• List wastes available and wanted
• Some local, some regional, a few
national
• Number increasing thanks to Internet
• Printed catalogue or computerised online systems
TRP Chapter 4.3 11
Types of waste exchange
Information clearinghouse or material broker
Waste
generator
Information on
wastes available
Information on
wastes wanted
Information on
wastes available
Waste
exchange
User
Information on
wastes wanted
TRP Chapter 4.3 12
Which wastes?
• Wastes arising in small quantities
• Wastes needing specialised recycling
• High value materials not usable by
generator
• Low value materials
• Off-specification products
• Contaminated material
• Surplus and outdated materials
TRP Chapter 4.3 13
Waste listings
Often divided into Requests and Offers eg
Requests
Offers
•Ethanol, sodium hydroxide
•Copper sulphate
•Electronic scrap
•Fluorspar
•Fertilisers
•Hydrochloric acid
•Metal containing wastes
•Magnesium hydroxide
•Organic materials
•Filter cakes
•Sludges
•Sodium sulphate
May give detailed description eg
Phenol formaldehyde resin from vat coating of
fibreglass. Solution contains 54% phenolic resin in 23%
ethanol with 1% formaldehyde by net weight. 5 drums
available.
TRP Chapter 4.3 14
Measuring success
•volumes recycled
•raw materials saved
•costs reduced
•awareness raised
Example: US Dept of Defense Defense
Reutilisation Marketing Organisation
TRP Chapter 4.3 15
Influences on expansion of waste
exchanges
· Internet
• Integration of exchanges
· Government support and funding
· Research into opportunities for particular wastes
• Limited liability for users
TRP Chapter 4.3 16
Chapter 4.3 Summary
• Recycling of hazardous waste has a number of
benefits
• It may take place on-site or off-site, depending
on the waste and the technology
• It generates residues
• Many processes use secondary raw materials
as feedstock
• Waste exchange helps promote re-use and
recycling, maximise diversion from disposal
TRP Chapter 4.3 17