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Napier ENVS 3100
Sustainability lecture topic
Waste
Waste definitions
Waste: things we deem as unusable or unwanted
Waste stream: the way our consumption is linked from materials from ‘upstream’
processes to ‘downstream’ processes
Municipal solid waste: the waste that we, as consumers, throw out
Solid waste: other waste within the waste stream
Life cycle assessment: accounts for the environmental impacts of all steps in making
and disposing a product
Where does the waste go?
Open dump
o Unregulated waste disposal
o Produces uncovered and openly accessible piles
o Leachate: rainwater or groundwater mixes with decomposing waste
Carries acids, ammonia, methane etc
Very harmful to humans
o Carbon dioxide produced near the surface via aerobic bacteria
o Methane produced beneath the surface via anaerobic bacteria
Ocean dumping
o Sewage sludge: the waste remaining after sewage is treated
Can cause eutrophication
o Dredge spoils: sediment removed from bodies of water to improve navigation
Contains heavy metals that accumulate in the food chain
Waste management
Incineration
o Controlled burning to reduce the volume of waste
o BENEFITS: waste volume reduction, reduced water pollution risk, less land
required
o COSTS: requires high energy inputs to achieve the high temperatures needed,
produces large amounts of CO2 which contributes to air pollution, harmful
materials carried in the ash
Isolation
o Containing waste in an area away from human and environment contact
Sanitary landfill: isolate and contain waste, whilst managing its content and
treating liquids and gases
Napier ENVS 3100
Sustainability lecture topic
Waste
Waste definitions
Waste: things we deem as unusable or unwanted
Waste stream: the way our consumption is linked from materials from ‘upstream’
processes to ‘downstream’ processes
Municipal solid waste: the waste that we, as consumers, throw out
Solid waste: other waste within the waste stream
Life cycle assessment: accounts for the environmental impacts of all steps in making
and disposing a product
Where does the waste go?
Open dump
o Unregulated waste disposal
o Produces uncovered and openly accessible piles
o Leachate: rainwater or groundwater mixes with decomposing waste
Carries acids, ammonia, methane etc
Very harmful to humans
o Carbon dioxide produced near the surface via aerobic bacteria
o Methane produced beneath the surface via anaerobic bacteria
Ocean dumping
o Sewage sludge: the waste remaining after sewage is treated
Can cause eutrophication
o Dredge spoils: sediment removed from bodies of water to improve navigation
Contains heavy metals that accumulate in the food chain
Waste management
Incineration
o Controlled burning to reduce the volume of waste
o BENEFITS: waste volume reduction, reduced water pollution risk, less land
required
o COSTS: requires high energy inputs to achieve the high temperatures needed,
produces large amounts of CO2 which contributes to air pollution, harmful
materials carried in the ash
Isolation
o Containing waste in an area away from human and environment contact
Sanitary landfill: isolate and contain waste, whilst managing its content and
treating liquids and gases
