Lecture 22: Waste Management Flashcards
What size are microplastics?
5mm
Where do microplastics come from?
- directly or indirectly released into the environment
- microplastics in exfoliators, etc. and from larger pieces of plastic that break down from UV radiation, etc.
what is the largest source of plastic waste?
- fishing gear
Why is waste a human concept?
- in nature waste from one is repurposed as food for another, and resources that are not used typically remain buried underground
Which two principles do humans violate?
- matter cycles: prevent decomposition in landfills
- toxins: release them into the environment
how does a circular system of production compare to natural matter cycles?
- waste as raw material, nothing is wasted
- in nature, nothing wasted only changes forms
What is waste?
- any unwanted material or substance that results from a human activity or process
Why does waste management matter?
- loss of land
- protects human and environmental health
- conserves resources
- reduces toxin and methane release
What is solid municipal waste?
- non liquid, every day waste from individuals, insertions, small businesses
What is industrial solid waste?
Waste from production of consumer goods: mining, agriculture, petroleum extraction/mining
What is hazardous waste ?
- solid or liquid waste that is toxic, chemically reactive, flammable, corrosive
Where does most municipal waste come from?
- comes from packaging and non durable goods (short life time)
What is E waste?
unwanted computers and other electronic devices
What does biodegradable mean?
- materials that can be broken down by aerobic processes
- once broken down it can be reused by other organisms
What does degradable mean? non-degradable?
- degradable: can be broken down by chemical/physical reactions
- non-degradable: made of stable molecules that never break down
What are open dumps?
- waste generation: developing countries get supplies shipped in
- open dump has physical and health hazards
- leachate runs off dump and enters grounwater
- dump not well contained: blows off and enters waterways
what are sanitary landfills?
- sanitary landfills: waste buried in the ground or piled in large engineered mounds
- leachate + methane gas
- engineers to reduce leakage of contaminants
what is landfill gas?
- landfills produce gas that can be used for energy
-mix of gases that contains ~1/2 methane - can be collected, processed, use like natural gas
- when not commercially used gas is flared off to reduce odours
how does a sanitary landfill differ from a waste incinerator?
- sanitary landfill: buries underground
- waste incinerator: burns waste
what does it mean to ‘divert waste’
- reduce waste ending up in landfill
What makes Nova Scotia a leader in MSW management?
2022: average per capita waste 50% lower than the national average
What is composting? How much of Canada’s waste is made up of compostable materials?
conversion of organic waste into mulch or humus through natural biological processes of decomposition
- 28% of Canada’s waste stream is made up of compounds than can undergo composting
Does composting produce methane? Why or why not?
no, it is an aerobic process!
Describe the roles of aerobic bacteria in composting
- aerobic bacteria assist in decomposition
- release heat which kills pathogens
- product is humus: used as fertilizer in garden, reducing need for synthetic fertilisers
- diversion of material from landfill reduces methane and extends life
- can degrade SOME toxic chemicals
What are the 4 R’s of waste management?
refuse, reduce, reuse, recycle
- recycle is the last one because it is the least efficient, costly
