1. Solid Waste Management and Disposal
Chapter 17
Solid Waste Management and Disposal

2. Solid Waste Management and Disposal

3. Outline Kinds of Solid Waste Municipal Solid Waste
Methods of Waste Disposal

4. Kinds of Solid Waste
There are several kinds of waste, some are release into air & water (purposely/accidental), many of purposely released wastes are treated before their release.
Solid waste is generally made of objects or particles that accumulate on the site where they are produced.
They are typically categorized by the sector of the economy responsible for producing them.
We have good info about wastes that are tightly regulated (hazardous wastes, medical wastes) but only general estimates for other kinds such as mining & agricultural ones.

5. Kinds of Solid Waste Mining wastes are generated in three ways:
Waste material is left on the surface when soil & rocks are removed to get to valuable ore
Milling tailings: techniques such as grinding & sorting as well as chemical processes are used to extract valuable materials.
Once valuable materials are removed, waste (tailing) must be disposed. Solid materials might be dumped on the land, liquid might be stored in ponds.
No vegetation grows on top and waste might contain hazardous materials or high amnt of acid.

6. Waste or tailings drainage often contains hazardous materials
Waste or tailings drainage often contains hazardous materials. large quantities of water is used in many mining operations which has low quality and not good for drinking, irrigation, or recreation.
Agricultural Waste
Includes waste from raising animals as well as crop and tree harvesting.
This has lots of organic materials &
90% is used as fertilizer or other forms of soil enhancement.
Some is buried as a source of E, so little is deposited in landfill.
If too much waste, there is not enough farmland to accept them w/o causing water pollution.

7. Kinds of Solid Waste
Industrial solid waste consists of solid waste other than mining.
Estimated to be between million metric tons annually.
Demolition waste
Sludge
Combustion ash
Foundry sand
All materials will be tested if hazardous need to be deposited in special hazardous waste landfills.
Municipal solid waste consists of all the materials people in a region no longer want.
210 million metric tons annually.

8. Municipal Solid Waste
In modern society, many products are discarded when they are broken or worn out, while others only have a temporary use.
Those that have only temporary uses make up the majority of solid waste.
Unites States produces about 210 million metric tons of municipal solid waste annually.
This equates to 2 kg (4.4 lbs) of trash per person per day.
Per capita waste has increased 70% since 1960.

9. Municipal Solid Waste
Generation of municipal solid waste has inc but bec of inc recycling, net production has actually fallen since 1990, and per capita rate has stabilized.
Municipal solid waste generation rates

10. Municipal Solid Waste
Nations with a higher standard of living tend to produce more municipal solid waste per person than less-developed countries.
Large metropolitan areas have the greatest difficulty dealing with solid waste.

11. Waste generation and lifestyle Nations with a higher standard of living tend to produce more municipal solid waste per person than less-developed countries. Large metropolitan areas have the greatest difficulty dealing with solid waste.

12. Methods of Waste Disposal
In the past, the favored means of waste disposal was to dump solid wastes outside of city or village limits.
To minimize the volume of waste, the dump was often burned.
This practice is still employed in remote or sparsely populated areas in the world.
2001, N.Y city closed its Fresh Kills Landfill on Staten Island (was largest in world).

13. Methods of Waste Disposal
Five techniques are now used in waste disposal:
Landfills
Incineration
Source reduction
Composting
Recycling

14. Methods of Waste Disposal
Landfills
A municipal solid waste landfill is typically constructed above an impermeable clay layer, lined with an impermeable membrane .
It includes mechanisms for dealing with liquid and gas materials generated by the contents of the landfill.
Each day’s deposit of fresh garbage is covered with a layer of soil to prevent it from blowing around and to discourage animal scavengers.
Traditionally this has been the primary method of waste disposal.
Cheap and convenient but water contamination was not recognized

15. Although the amount of waste has increased, composting and recycling have removed significant amnt of material from the waste stream and the amnt of material entering landfills has declined.
Selection of landfills site is based on local geological conditions & local concerns

16. Methods of Waste Disposal
Problems associated with poorly designed landfills have been recognized, and substantial efforts are made to reduce the amount of waste entering landfills.
New landfills have complex bottom layers to trap contaminant-laden leachate.
Monitoring systems are necessary to detect methane gas production and groundwater contamination.
In some cases, methane is collected and used to generate electricity or heat.
New landfills currently cost up to $1 million per hectare to prepare.

17. Methods of Waste Disposal
A well-designed modern landfill is self-contained, separated by impermeable membrane & sealed when filled. Water & ground water is monitored continuously.
A well-designed modern landfill

18. Methods of Waste Disposal
The number of landfills is declining.
Many small landfills that were not meeting regulations have been closed.
Capacity has been reached.
Selecting sites in Toronto, N.Y, L.A is difficult bec: (a) difficulty finding a geologically suitable site & (b) local opposition referred to a NIMBY (not-in-my-backyard) syndrome.
In Japan & Western European recycling & incineration are primary methods.
New landfills often resisted due to public concerns over groundwater contamination, odors, rodents, and truck traffic.
Politicians are often unwilling to take strong positions that might alienate constituents.

19. Methods of Waste Disposal

20. Methods of Waste Disposal
Incineration
Incineration is the process of burning refuse in a controlled manner.
Currently, about 15% of U.S. municipal solid waste is incinerated.
Most incinerators are designed to capture heat, which is then used to make steam to produce electricity.
The production of electricity partially offsets disposal costs.
Most incinerators burn unprocessed municipal solid waste. This process is referred to as mass burn technology.

21. Methods of Waste Disposal
¼ incinerators are refuse-derived fuel-collected refuse that has been process into pellet prior to combustion, especially useful w certain kinds of materials, such as tires.
Incinerators drastically reduce the amount of municipal solid waste.
Up to 90% by volume and 75% by weight.
Primary risks of incineration involve air quality problems and toxicity and disposal of ash.
Toxic substances are more concentrated in ash.

22. Methods of Waste Disposal
Modern incinerators have many pollution control devices
Even with modern pollution controls, small amounts of pollutants are still released into environment. including certain metals, acid gases, dioxins & furans (implicated in birth defect & cancer).
Ash has small amnt of heavy metals & is tested if need to be designated as hazardous materials.
The cost of land and construction for new incinerators are also major concerns facing many communities.
Construction costs in North America in 2000 ranged from $45 - $350 million.

23. Methods of Waste Disposal
U.S. EPA has not looked favorably on construction of new waste-to-energy facilities.
It has encouraged recycling and source reduction as more effective solutions to deal with solid waste.
Proponent of incinerators oppose source reduction bec incinerators need large amnt of municipal solid waste to operate & dec waste make incinerators impractical.

24. Methods of Waste Disposal
Disposal methods used in various countries

25. Methods of Waste Disposal
Mulch is organic material used to protect areas where the soil is disturbed, or to control growth of unwanted vegetation.
Organic materials such as large branches and bark are chopped or shredded into smaller pieces.

26. Methods of Waste Disposal
Composting is using natural decomposition to transform organic material into compost, a humus-like product with many environmental benefits.
With proper management of air and water, composting can transform large quantities of organic material into compost over a short period of time.
Small-scale composting can be accomplished in the backyard, mixing green materials (grass clippings, vegetable scraps, etc.) and brown materials (dry leaves, twigs, soiled paper towels).

27. Methods of Waste Disposal
Many state passed law prohibiting deposition of yard waste in landfills (green color), many have composting programs to dill w yard wastes. Even states w/o law can inc life of landfill by inc composting programs
Diverting waste through composting

28. Methods of Waste Disposal
In composting facilities materials such as yard trimmings, food scraps, biosolids from sewage treatment plants, wood shavings, & unrecyclable paper undergo processing & turned into compost in 8-24 weeks.
About 3,800 composting facilities are currently in use in the United States.
Most municipal programs involve one of three composting methods:
Windrow systems
Aerated piles
Enclosed vessels

29. Windrow Systems: placing materials into long piles (windrows), tractors will turn them periodically to mix & aerate them.
Aerated Piles: large piles of material w air pumped through them & is covered w a layer of mature compost to keep it at optional temperature.
Enclosed Vessels: compost materials very rapidly. More complex, materials fed into structures that enval conditions are closely controlled.
Composting improve soil by increasing porosity & water holding capacity, & ads nutrients: N, K, Fe, P, S, Ca

30. Methods of Waste Disposal
The simplest way to reduce waste is to prevent it from ever becoming waste in the first place.
Source reduction is the practice of designing, manufacturing, purchasing, using and reusing materials so that the amount of waste or its toxicity is reduced.
Design changes
Since 2-liter soft drink bottle was introduced in 1977, weight has been reduced by 25%.
As a result, 250 million pounds of plastic have been kept out of the waste stream.
Manufacturing processes reduce waste and increase efficiency.
Purchasing decisions
Choose reduced packaging and plan quantities accordingly.
Purchase products in larger sizes to dec the waste & careful purchasing plans can prevent unused surplus materials becoming part of waste.

31. Methods of Waste Disposal
Using materials to avoid waste generation
Reduce use of hazardous materials.
use less hazardous alternatives (cleaning & pesticide products)
sharing hazardous containing materials instead of throwing out leftovers,
Follow label directions carefully and use the smallest amount necessary.
Reusing items
Delay or prevent entry of items into waste collection stream.
Waste exchanges allow waste of one industry be used as row material in another.

32. Methods of Waste Disposal
Most businesses and manufacturers have a strong economic incentive to ensure they get the most from all materials they use.
Any activities that reduce the amount of waste produced, reduce the:
Cost of waste disposal.
Amount of raw materials needed.
Amount of pollution generated.
“pay-as-you-throw” pay for each can/bag of trash set out for disposal instead of pay through taxes or flat fee.

33. Methods of Waste Disposal
Recycling is one of the best environmental success stories of the late 20th century.
In the United States, recycling (including composting) diverted about 30% of solid waste stream from landfills and incinerators in 2001.
Benefits:
Resource conservation
Pollution reduction
Energy savings
Job creation
Less need for landfills and incinerators

34. Methods of Waste Disposal

35. Methods of Waste Disposal
Recycling percentage for selected materials (2005) and recycling rates from

36. Methods of Waste Disposal
Several programs exist to encourage recycling:
Container laws provide an economic incentive to recycle.
Requires a deposit on all reusable beverage containers.
A national “bottle bill” would reduce litter, save energy and money, create jobs, and help conserve natural resources.
Mandatory recycling laws provide a statutory incentive to recycle.
Provide statutory incentive to recycle.
Many states have it, residents separate their recyclables from other trash.
Some aimed at businesses for certain kinds of material, some forbid disposal of certain materials in landfills.

37. Methods of Waste Disposal
Curbside recycling provides a convenient way for people to recycle.
In 1990, 1,000 U.S. cities had curbside recycling programs.
In 2005, 10,000 cities had curbside recycling programs.
Cities with curbside recycling tend to have higher recycling rates than cities that lack such programs.

38. Methods of Waste Disposal
In the U.S., curbside pick-up of recyclables is increasingly the norm, but rates remain low.
Recycle Bank was founded in 2004.
Families on a garbage route are issued a container with a computer chip. Recyclables are weighed and the family earns points redeemable at merchants like CVS pharmacy.
Recycle Bank launched in Philadelphia in 2006.
Recycle rates rose from 7% to 90%.
In 2008 Recycle Bank started a pilot program in N.Y at Columbia University.
Students recycle and claim their points.

39. Methods of Waste Disposal
There are many technical and economic problems associated with recycling.
Plastics are recyclable, but technology differs from plastic to plastic.
Milk containers tend to be high-density polyethylene (HDPE), while egg containers are polystyrene (PS), and soft-drink bottles are polyethylene terephthalate (PET).
Egg Container
Polystyrene (PS)
Soft-Drink Bottle
Poly-Ethylene Terephthalate (PET)

40. Methods of Waste Disposal
Plastics are a growing components of municipal solid waste in N America, increasing recycling can reverse this trend. Many plastic bottles are not recyclable or properly disposed of.
Increasing amounts of plastic in trash

41. Methods of Waste Disposal
The plastics industry is researching new technologies that promise to inc quality of plastic from recycle.
Economics of recycling are of concern.
Unless demand for products keeps pace with growing supply, recycling programs will face an uncertain future.

42. Methods of Waste Disposal
The long-term success of recycling programs is tied to other economic incentives such as taxing issues, and the development of and demand for products manufactured from recycled materials.
Government subsidies artificially lower cost of virgin forest materials compared to recycled materials.
Demand for recycled products must grow if recycling is to succeed on a large scale.
Individuals can have an impact by purchasing products made from recycled materials.

43. Methods of Waste Disposal
Prices can vary widely from year to year depending on demand.
Recycling composite prices

44. Methods of Waste Disposal
What You Can Do to Reduce Waste and Save Money:
Buy things that last, keep them as long as possible, and have them repaired, if possible.
Buy things that are reusable or recyclable, and be sure to reuse or recycle them.
Buy beverages in refillable glass containers instead of cans or throwaway bottles.
Use plastic or metal lunch boxes and metal or plastic garbage containers without throwaway plastic liners.
Use rechargeable batteries.

45. Methods of Waste Disposal
What You Can Do to Reduce Waste and Save Money:
Skip the bag when you buy anything you can carry with your hands.
Buy recycled goods, and recycle them.
Recycle all newspaper, glass, and aluminum, and any other items accepted for recycling in your community.
Reduce the amount of junk mail you get.
Push for mandatory trash separation and recycling programs in your community and schools.

46. Methods of Waste Disposal
What You Can Do to Reduce Waste and Save Money:
Choose items that have the least packaging or no packaging at all.
Compost your yard and food wastes, and pressure local officials to set up a community composting program.

47. Summary
Municipal solid waste is managed by landfills, incineration, composting, waste reduction, and recycling.
The most fundamental way to reduce waste is to prevent it from ever becoming waste in the first place.
About 30% of the waste generated in North America is handled through recycling.

48. Summary
Future management of municipal solid waste will be an integrated approach involving landfills, incineration, composting, source reduction, and recycling.
The degree to which any option will be used depends on economics, changes in technology, and citizen awareness and involvement.