16: Waste Management Flashcards
Major waste streams of most countries
Manufacturing/industry
Municipal waste
Construction
Agriculture/forestry big in Japan
What is the link between waste and wealth?
Countries with higher national income levels generate more waste per capita
Most of the waste of lower GDP countries is organic material
Major ways municipal solid waste is dealt with
- landfill
- incineration
- recycling
What is the waste pyramid/waste hierarchy
From largest to smallest (currently):
disposal-> energy recovery-> recycling-> reuse-> minimalization-> prevention
Hope to invert the pyramid in the future
Slide 7
What is municipal waste? municipal wastewater?
Waste: waste produced by consumers, public facilities and small businesses
Wastewater: water that has been used by people in some way, including sewage, water from showers, sinks, washing machines, etc
Countries with high municipal waste n 2020
Denmark, United States, Luxembourg, New Zealand
What is source reduction? Waste reduction? Waste disposal?
Source reduction: minimizing packaging, purchasing ‘green’ products, efficient industry]
Waste reduction: recover items for recycling/composting
Waste disposal: incinerate, dispose of waste in landfill
Hierarchy of waste management practice
Bury (67%)
Recycle/compost (23%)
Incinerate (9%)
Reuse (0.2%)
Reduce (<0.1%)
Want to bury, incinerate least
Then recycle/compost
Want to reduce most or reuse
SLide 10
What types of solid waste are most commonly diverted from landfill
Paper, organic materials
From residential and non-residential sources
Slide 12, 13
Slides 14-18
Landfills
Two problems with landfills
- you’re stuck with a pile of trash
- wealthy communities often export their garbage to landfills in less-wealthy areas
What was the Basel Convention? Goals
1992 Treaty on Control of Transboundary Movements of Hazardous Wastes and their Disposal
- reduce hazardous waste generation, promote sound management of HW
- restrict transboundary movement of HW
- regulatory system for cases where transboundary movements are allowed
What is e-waste?
Electronic waste: monitors, TVs, computers, phones, DVD players, radios
AND
Electric waste: refrigerators, washing machines, dryers, AC units, vacuums, toasters
Slides 22-26
E-waste
What are waste incinerators?
The combustion of waste at very high temps, reducing it’s volume by as much as 90% (and weight by as much as 75%)
Metals (which can be recycled) are removed before incineration
What is a problem with incinerators
Produce air pollution and secondary pollutants
SO2 can be scrubbed out of emissions, along with some PM to reduce pollution
Slides 28,29
The Edmonton waste management center manages what waste streams?
Recycling, compost, biofuel production, landfill
Currently recycle or compost 50% of waste, goal 90% by 2018
Describe recycling at the EWMC
Processes 50,000 tonnes/year of metals, glass, paper
Material collected from: blue bag program, blue bin program, recycling depots
Also manage an e-waste recycling facility
Describe composting at the EWMC
Divert ~50% of residential waste from landfill to compost or recycling
Process 160,000 tonnes per year
Sold as ‘second nature’ compost and topsoil
What new facility is now at the EWMC? What does it do/what is its goal?
Anaerobic Digestion Facility (ADF)
Bacteria, fungi digest organic material. Collect biogenic natural gas emissions and use it as a fuel source
Goal is to divert 90% of waste from landfill
Slide 33
What is the EWMC landfill? What does it do
Clover Bar Landfill
Landfill gas recovery
- collects CH4, CO2
- used to power generators
How much plastic enters the ocean each year? What % of plastic if recycled?
8 million tones each year
14%
Slides 39, 40
Plastic
Important items to rethink using/waste you might not think of
- disposable diapers
- disposable razors
- disposable bags
- plastic straws
- chewing gum
- condiment packets
What is planned obsolescence?
Designing a product with an artificially limited useful life to force consumers to purchase new products in shorter intervals
Usually by making product difficult to repair, trendy, or programming them to shut off
Pretreatment of municipal wastewater
- aerated grit tank: removes large, heavy materials e.g. rocks
- bar screens: remove large, light materials e.g. plastics, wood
Primary treatment of municipal wastewater
Settling tanks: allows heavier solids/sludge to settle at bottom of tank, removes 60% of suspended solids
Sludge is then fermented, digested or used as fertilizer
Secondary treatment of municipal wastewater
Aeration
- encourages growth of microbes which degrade organic pollutants
- removes biological nutrients (P and N)
- sometimes called “bioreactors”
- does not kill disease causing bacteria, toxins
Steps of tertiary municipal wastewater treatment
- Clarification: second set of settling tanks allows microbes to floc (heavier and sink)
- UV disinfection: treat effluent with UV light to kill remaining microbes
- membrane filtration: similar effects as UV, use micropore filters to remove microbes
What is quaternary treatment? What are some problems?
Removal of pharmaceutical pollutants, and other persistent compounds
Problems:
- we don’t know how to do it efficiently yet
- it will be very expensive
- testing methods involved carbon and ozone
Four things that can go wrong with wastewater treatment
- Equipment malfunction
- Overburdened system (e.g. flood)
- Too expensive to do properly
- Non-compliance or lack of regulations
How can climate change overburden wastewater treatment plants
Less predictable climate = more storms = more stormwater = more wastewater
What can go wrong with improperly treated wastewater?
- Pathogens: in effluent or solid waste used as fertilizer
- Excess nutrients: phosphorus (eutrophication) and nitrogen
What is disruption of biological treatment of wastewater?
Occurs when hazardous waste, toxins get into wastewater
Can disrupt or kill the microbes involved in secondary treatment
Municipal systems not designed to treat this waste
Four things that can go wrong with wastewater treatment
- Untreated wastewater (malfunction, overburden)
- Improper treatment
- Disruptions to biological treatment
- Fatbergs
What are fatbergs?
- Conglomerates of products that can’t degrade in sewage systems
- Mix of fats, oils, diapers, condoms, wet wipes, menstrual products, etc
Why should we try to reduce municipal wastewater?
- Treating wastewater takes energy, resources, and time
- Some sludge is disposed of in landfills
- Some systems produce energy but are rarely energy neutral
What are low flow fixtures?
Method of reducing wastewater by reducing the amount of water needed for a toilet to flush (high efficiency toilets)
