Solid & Liquid Waste: final Flashcards
What is solid waste?
Trash or Garbage
Is the concept of waste management old or new?
The concept of waste management is relatively new.
Until the 20th century, the individual was responsible for discharging waste.
What law is responsible for the handling of municipal wastes? (MSW)
In the U.S., the Resource Conservation & Recovery Act.
Goals;
1) Ensuring that disposal facilities are adequate.
2) Encouraging source reduction, recycling, & recovering energy from waste.
Problems caused by growing volume of waste
In 2008, US residents, businesses, & institutions produced before recycling ~250 million tons of MSW.
Difficulties in disposal
Dump sites being filled
Increases in pollution of aquatic environments.
How many tons of waste was generated by 2014?
By 2014, 258 million tons of MSW was generated in the U.S. (4.44 lbs. per person/day). This is double what it was in 1970.
What has been increasing disposal fees?
The shutting down of landfills has been increasing disposal fees.
*Increase of MSW is also present in developing countries.
Components of Municipal Solid Waste
The most common materials in MSW are paper & paperboard. Together they make up ~one-third by weight of what is thrown away.
Other materials;
-Furniture
-Clothing
-Bottles
-Food waste
-Batteries
-Organic materials
**It does not include construction material, sewage sludge, & hazardous industrial waste.
Total MSW Generated
(by percentage)
26.6% Paper
14.9% Food
13.3% Yard trimmings
12.9% Plastics
9.5% Rubber, leather & textiles
9% Metals
6.2% Wood
4.4% Glass
3.2% Other
EPA’s Hierarchy for Management of MSW
Most to least favored:
(1) Source reduction
(2) Recycling
(3) Disposal
(4) Combustion
When solid waste decomposes in land fills or is combusted, a by product can be production of a useful energy.
Source Reduction refers to;
Source Reduction refers to reducing the amount of waste created, reusing whenever possible & then, recycling what is left.
The volume of solid waste that must be deposited in landfills is limited.
Source Reduction has 2 important components;
1) Waste Reduction, aims to reduce the amount of waste produced at the source.
2) Waste Recycling, refers to the reuse of materials in the waste.
The EPA encourages practices to encourage waste reduction
-Double-side copying
-Use of washable plates & silverware
-Towels instead of disposal ones.
Recycling definition
Minimizing waste generation by recovering & reprocessing usable products that might otherwise become waste.
-In 2014, 89 million metric tons were recycled.
Advantages of Recycling
(6 listed)
1) reduction of greenhouse gas emissions
2) prevents pollution generated using new materials
3) decreases the number of materials shipped to landfills
4) preserves natural resources
5) opens new manufacturing employment opportunities
6) saves energy
Composting definition
Composting is the aerobic biological decomposition of organic materials to produce a stable humus-like product.
What does composting do?
Resembles soil, can be used in the garden.
Reduces the number of materials to go to the landfills.
Is composting considered waste prevention or recycling?
Backyard composting is considered waste prevention rather than recycling.
(Because it prevents waste from entering the municipal stream).
What state has one of the most successful composting programs in the U.S.?
The state of Massachusetts has one of the most successful composting programs in the U.S.
How much does composting do / save?
Yard & food waste are composed, preventing 37,500 tons of waste from entering the disposal process, saving $2 million/each year.
Solid Waste Management: Landfill History
Until the 1970s, most of the MSW in the US was put in a town dump, attracting animals, rats, & insects.
Environmental impact, contamination of groundwater.
Groundwater contamination, air pollution & Leachates are dangers associated with older landfills.
TRUE or FALSE
TRUE
Leachates may include:
Toxic heavy metals (lead, cadmium, arsenic, mercury, & nickel).
Solvents & cleaning agents mat contaminate ground water.
Air Pollutants include
Gaseous emissions from landfills; methane, volatile organic compounds (VOCs), & other gases.
Is methane a greenhouse gas?
Methane vented from landfills pose as a fire hazard & is a greenhouse gas.
VOC emission characteristics
VOCs are;
Potentially carcinogenic
May cause odors & symptoms of respiratory irritation.
*Near landfills, residents complain about odors and frequent respiratory irritations.
What was done to increase the safety of landfills?
In 1988, the EPA adopted federal standard for their construction.
New model of landfill construction reduces the leaching of toxic substances from landfill areas.
-Minimize pollution
-Size expanded (megafills)
-Limit access of rodents/flies & diseases
Well-Designed Landfills
Well-designed
Efficiently operated
A sanitary landfill can be a perfectly adequate means of urban refuse disposal; free from odors, vermin, pollution problems.
Why did landfills become the waste disposal method?
Because they are the most economical of the legal options.
Modern Landfills are/contain;
(Four Major Parts)
Four Major Parts:
1) Bottom liner
2) System for collecting leachates
3) Cover
4) Appropriate location that minimizes contamination of groundwater by materials released from the site.
How do Modern Landfills Work?
Begins as a depression dug into the earth’s surface.
The bottom is lined with a dense layer of clay & sealed with thick plastic sheeting to contain leaks of hazardous materials.
The flexible membrane liner holds in toxic chemicals that might contaminate groundwater.
Modern Landfill (Leachate)
A leachate sump collects leachates, which is pumped to the surface then is subjected to further treatment.
How is garbage processed in Modern Landfills?
Garbage is put into rows.
Bulldozers & rollers compact the garbage.
After the garbage is covered, anaerobic bacteria aid in the decomposition of organic materials & produce methane gas, which is collected & used as an energy source.
The finished landfill is capped with clay to prevent rainwater from entering.
It’s surface area can be used for purpose that does not involve construction (house development) such as a recreational area.
Incineration
-Trash is used to generate energy while at the same time reducing its volume & weight.
-No attempt is made to separate the trash & its components.
Time is taken to separate trash & its components when in the process of incineration.
TRUE or FALSE?
FALSE
No attempt is made to separate the trash & its components.
Incineration
What occurs?
High temperatures of incinerating plants make glass & aluminum melt;
Metals from the residues of combustion can be recycled into scrap metal.
*Remaining ash is deposited into landfills.
How much is typically burnt in an incineration plant?
Some have the capacity to burn ~2,250 tons of solid waste/day at temperatures of 2,500 degrees F.
In 2014, 33 million metric tons were burned for energy generation.
Disadvantages of Incinerating;
1) Emissions may be potentially hazardous to human health & the environment.
2) Toxic materials emitted may cause air pollution or be deposited on the land.
3) Substances contained in the incineration plant emissions are hazardous to human health & the environment (lead, cadmium, mercury, polychlorinated biphenyls).
How is hazardous wastes disposed of legally in the U.S.?
-Discarding on the surface of the land.
-Storing in slurry ponds
-Dumping into landfills or into the ocean
-Incineration
Some waste disposal sites used before 1970 were poorly designed. `
Sources of Hazardous Materials:
Home use:
-Pesticides
-Cleaning products
-Automotive products
-Painting supplies & other flammable materials
-Nonflammable products
Medical use:
-Chemicals
-Medications
-Infectious agents & radioactive materials.
Industrial waste:
-Heavy metals from planting operations.
-Toxic chemicals, solvents
-Residues from the manufacturing of pesticides.
Radioactive waste:
-Spent nuclear fuel & tailings from uranium processing.
Mining & extraction wastes:
-Toxic chemicals (acids, heavy metals)
How many tons of hazardous waste is produced each year worldwide?
~400 million tons of hazardous wastes (HW) are produced/year worldwide.
In some countries, industrial & hazardous wastes are being deposited on the open land causing an increasing level of pollution.
Developed countries produce most of the toxic waste.
TRUE or FALSE?
TRUE
Developed countries produce the most of the toxic waste.
*HW from industrialized countries get shipped to developing countries who then get cash payments for accepting those materials.
When did the U.N. Environmental Program ‘Basel Convention on the Control of Transboundary Movement of Hazardous Wastes & their Disposal’ treaty come into effect?
1989
2021 amendment: export of plastic waste.
What is the purpose of the ‘Basel Convention on the Control of Transboundary Movement of Hazardous Wastes & their Disposal’ of 1989?
To regulate international transport of hazardous wastes & to promote the disposal of the wastes in a safe manner.
Asbestos Abatement
1) Encapsulation: Coated with a polymer sealant.
2) Enclosure: Building non-permeable barrier between exposure & surrounding.
3) Removal: Asbestos containing material removed from structure.
Uncontrolled Hazardous Waste Sites in the U.S.
-The main concern of the U.S. is the presence of toxic materials in uncontrolled hazardous waste sites.
-An estimated 40,000 of these sites have been reported to federal agencies.
-1,300 sites are on the National Priorities List (NPL).
-Superfund legislation mandates the cleanup of the hazardous waste sites.
Impact of Uncontrolled Sites
These materials may be released into the environment from uncontrolled hazardous waste sites with the potential to cause adverse human effects.
-Detrimental human health effects.
-High costs of cleanup
-Reductions in property values
-Potential ecological damage
Medical Waste:
Medical waste is any solid that is generated in the; Diagnosis, treatment, or immunization of human beings or animals.
In the research pertaining thereto.
In the production or testing of biologicals.
U.S. produces ~3.5 million tons of medical waste annually.
Before its disposal in landfills, medical waste is decontaminated.
