1. WASTE DISPOSAL METHODS

2. SOURCES OF WASTE
1) Agriculture – largest producer of non-point air and water pollution and includes:
manure
branches and slash
by-products of food processing
animal wastes
pesticides and pesticide residues
2) Mining and metal processing – includes mine tailings, overburden
from strip mines, and smelter slag
Road and Construction wastes
4) Industrial wastes – most is recycled, converted, destroyed, or
disposed of in private landfills or in deep
injection wells
Municipal wastes – household and commercial refuge
6) Hazardous wastes – wastes that are dangerous to living things or
the environment
All of these are components of the WASTE STREAM = steady flow of the varied wastes we produce.

3. METHODS OF WASTE DISPOSAL #1
OPEN DUMPS
Waste collected, compacted and dumped on the ground in a suitable site. Organic matter rots or is consumed by a variety of organisms. Burning in evening hours is often employed.
It is the predominate method of waste disposal in developing nations.
It is illegal in most developed countries, especially in urban areas.

4. OPEN DUMPS: ADVANTAGES AND DISADVANTAGES
is cheap
DISADVANTAGES:
waste is often burned intentionally, accidentally, or by spontaneous
combustion thus causing air pollution
pollutes water by runoff into nearby streams or seepage into ground water
toxins accumulate
attracts pests which can spread disease
is a breeding ground for disease
litter leaving dump site
is ugly
smells

5. DEVELOPING NATION OPEN DUMP
What are the bulldozers doing?
What are the people doing?

6. What does the top picture
show?

7. Examples of illegal roadside dumps in the U.S.

8. 4. Why would this be an illegal dump?

9. METHODS OF WASTE DISPOSAL #2
OCEAN DUMPING
Barges carry wastes out to sea and dump in into natural trenches, canyons, or onto the deep ocean floor (abyssal plain).
Is prohibited by federal regulations, but still occurs in developing nations or
illegally in developed nations.

10. OCEAN DUMPING: ADVANTAGES AND DISADVANTAGES
is cheap
DISADVANTAGES
destroys ocean ecosystems
washes ashore
kills various aquatic animals
accumulates in floating “masses”, especially the non-degradable plastics

11. What problem with ocean dumping is shown here?

12. An example of the consequences of ocean dumping

13. OCEAN AREAS WHERE THE CURRENTS CAUSE FLOATING MATS OF GARBAGE (ESPECIALLY PLASTICS) TO ACCUMULATE

14. A FLOATING MAT OF GARBAGE IN THE OCEAN

15. A FLOATING MAT OF PLASTICS IN THE OCEAN

16. HARM TO SEA LIFE DUE TO PLASTICS DUMPED IN THE OCEAN
EXAMPLE #1

17. HARM TO SEA LIFE DUE TO PLASTICS DUMPED IN THE OCEAN
EXAMPLE #2

18. HARM TO SEA LIFE DUE TO PLASTICS DUMPED IN THE OCEAN
EXAMPLE #3

19. ANOTHER FLOATING MAT OF PLASTICS IN THE OCEAN

20. METHODS OF WASTE DISPOSAL #3
SANITARY LANDFILLS
Deep pit dug, lined with plastic lining or impervious clay to prevent hazardous substances/contaminated rainwater from seeping into surrounding environment. Trash is compacted daily and covered with 6 inches of soil.
Placement of the landfill must be carefully considered. They are usually placed away from lakes, rivers, floodplains, fault lines, and aquifer (=groundwater) recharge zones.

21. SANITARY LANDFILL: ADVANTAGES AND DISADVANTAGES
not a source of disease
not ugly
doesn’t pollute if properly engineered
may reclaim “useless” land
doesn’t smell
doesn’t attract insects or rodent populations
litter is not a problem
may be designed for methane recovery
DISADVANTAGES
becoming expensive due to rising transportation and land costs,
stricter EPA regulations, construction and maintenance costs, lad
scarcity, LULU’s and NIMBY’s.
land conversion to a landfill not always desirable
depletion of resources (many recyclable or useable materials lost forever)

22. CONSTRUCTION OF A LINED SANITARY LANDFILL

23. COMPACTING A LAYER OF TRASH IN A SANITARY LANDFILL

24. CROSS-SECTION OF AN ACTIVE LANDFILL – NOTE DAILY SOIL COVER

25. SCHEMATIC OF AN ENERGY RECOVERY SANITARY LANDFILL COUPLED TO AN ELECTRICITY GENERATING PLANT

26. METHODS OF WASTE DISPOSAL #4
EXPORTING WASTES (aka TOXIC COLONIALISM)
Shipping wastes, especially hazardous wastes, to less developed nations. (This is a form of toxic colonialism or “garbage imperialism”. May also be a form of environmental racism.)

28. TOXIC WASTES EXPORTEDTO A DEVELOPING NATION

29. METHODS OF WASTE DISPOSAL #5
INCINERATION (aka: ENERGY RECOVERY):
Waste is burned.
Two types:
1) Simple incinerators burn the wastes.
2) Those that use heat from the burning wastes to produce steam and/or
electricity.
Some incinerators are run on REFUSE-DERIVED FUELS (unburnable and recyclable materials removed before burning) while others are MASS BURN Incinerators (everything except extremely large appliances is dumped and burned).

30. INCINERATION: ADVANTAGES AND DISADVANTAGES
reduces the waste stream
saves landfill space
can recover natural resources if use refuse-derived fuels
can be linked to generation of electricity
waste stream increasing in paper and cardboard content
DISADVANTAGES
initially expensive to build
not everything can be burned
ash (especially bottom ash) and unburnable wastes must be disposed of, usually in a landfill
can be toxins (furans, lead, cadmium, mercury, dioxins, PCB’s) in
smoke which can cause air pollution; these can also be in fly ash (fine particles that leave with the smoke) which can also cause air/water pollution
tipping fees generally higher than landfill disposal fees
burning of certain wastes produces acidic gases (PVC materials)

31. EXAMPLES OF INCINERATORS

32. TRASH BEING BURNED INSIDE AN INCINERATOR

33. QUESTIONS
What do you think the advantages and disadvantages of exporting wastes to other countries are:
for the exporting country, and
for the receiving country?