1. Chapter 7 Solid waste pollution

2. Solid waste is anything discarded or unwanted in solid or semisolid form. In some cases, the waste material may contain a high percentage of water, as in food wastes and sludge.

3. 1 sources and classification of solid waste
Garbage: Refers to food wastes.
Rubbish: Refers to either combustible or non-combustible solid waste constituents. Combustible wastes would include paper, wood, scrap, rubber, leather, etc. Non-combustible wastes are metals, glass, ceramics etc.

4. 1 sources and classification of solid waste
Pathological wastes: dead animals, human waste, and hospital waste constitute pathological wastes .
Industrial wastes: Chemicals, paints, metal ore processing, fly ash, sewage treatment sludge, etc. are the examples of industrial wastes.
Agriculture wastes: Farm animal manure, crop residues, etc.

5. 2 Methods of waste disposal
Until recently, the disposal of municipal solid waste did not attract much public attention. From prehistory through the present day, the favored means of disposal was simply to dump solid wastes outside of the city or village limits or in the “back 40”.

6. 2 Methods of waste disposal
Frequently, these dumps were in wetlands adjacent to a river or lake. To minimize the volume of the waste, the dump was often burned. Unfortunately, this method is still being used in remote or sparsely populated areas in the world.

7. 2 Methods of waste disposal

8. 2 Methods of waste disposal
As better waste-disposal technologies were developed and as values changed, more emphasis was placed on the environment and quality of life. Simply dumping and burning our wastes is no longer an acceptable practice from an environmental or health perspective.

9. 2 Methods of waste disposal
Essentially, five techniques are used:
(1) landfills,
(2) incineration,
(3) composting,
(4) source reduction,
(5) recycling.

10. 2 Methods of waste disposal
2.1 Landfills

11. 2 Methods of waste disposal
2.1 Landfills
A modern municipal solid waste landfill is typically constructed above an impermeable clay layer that is lined with an impermeable membrane and includes mechanisms for dealing with liquid and gas materials generated by the contents of the landfill.

12. 2 Methods of waste disposal
Selection of landfill sites is based on an understanding of local geologic conditions such as the presence of a suitable clay base, groundwater geology, and soil type.
It is important to address local citizens’ concerns.
New landfills have complex bottom layers to trap contaminant-laden water, called leachate, leaking through the buried trash.

13. 2 Methods of waste disposal
Monitoring systems are necessary to detect methane gas production and groundwater contamination.
In some cases, methane produced by decomposing waste is collected and used to produce heat or generate electricity.
The water that leaches through the site must be collected and treated.

14. 2 Methods of waste disposal
Selecting sites for new landfills in locations like Toronto, New York and Los Angeles is extremely difficult because of :
(1) the difficulty in finding a geologically suitable site and
(2) local opposition, which is commonly referred to as the NIMBY, or “not-in-my-backyard” syndrome.

15. Landfill

16. Xingfeng municipal landfill, Guangzhou

17. Xingfeng municipal landfill, Guangzhou

18. Xingfeng municipal landfill, Guangzhou

19. Xingfeng municipal landfill, Guangzhou

20. Xingfeng municipal landfill, Guangzhou

21. Xingfeng municipal landfill, Guangzhou

22. 2 Methods of waste disposal
2.2 Incineration
Incineration is the process of burning refuse in a controlled manner.
Incinerators drastically reduce the amount of municipal solid waste—up to 90% by volume and 75% by weight.
Primary risks of incineration, however, involve air-quality problems and the toxicity and disposal of the ash.

23. 2 Methods of waste disposal
Small concentrations of heavy metals are present both in the air emissions (fly ash) and residue (bottom ash) from these facilities.
Because the ash contains lead, cadmium, mercury, and arsenic in varying concentrations from such items as batteries, lighting fixtures, and pigments, this ash may need to be treated as hazardous waste.

24. 2 Methods of waste disposal
The toxic substances are more concentrated in the ash than in the original garbage and can seep into groundwater from poorly sealed landfills.
Many cities have had difficulty disposing of incinerator ash, and there is still considerable debate about what is the best method of disposal.

25. 2 Methods of waste disposal
The cost of the land and construction for new incinerators are also major concerns facing many local governments.
Incineration is also more costly than landfills in most situations. As long as landfills are available, they will have a cost advantage. When cities are unable to dispose of their trash locally in a landfill and must begin to transport the trash to distant sites, incinerators become more cost effective.

26. 2 Methods of waste disposal
Incinerators produce air pollution, so control equipment is required.
In areas where air pollution is already a severe problem, incineration may not be an acceptable means of solid waste disposal.
Some people are concerned that there might be toxic and possible carcinogenic products resulted from the combustion of plastics.

27. 2 Methods of waste disposal
With the advent of the energy crisis, we have taken a renewed interest in obtaining heat from refuse:
Incinerators can be designed for heat recovery.
Where the incinerator is near other buildings, the steam from the incinerator can be piped to heat the buildings.

28. 2 Methods of waste disposal
2.3 Composting
Composting is the process of harnessing the natural process of decomposition to transform organic materials----anything from manure and corncobs to grass and soiled paper----into compost, a humus-like material with many environmental benefits.

29. 2 Methods of waste disposal
2.3 Composting
In nature, leaves and branches that fall to the forest floor form a rich, moist layer of mulch that protects the roots of plants and provides a home for nature’s most fundamental recyclers: worms, insects, and a host of bacteria, fungi, and other microorganisms.

30. 2 Methods of waste disposal
2.3 Composting
Properly managing air and moisture provides ideal conditions for these organisms to transform large quantities of organic material into compost in a few weeks.

31. 2 Methods of waste disposal
2.3 Composting
A good small-scale example is a backyard compost pile. Green materials (grass, kitchen vegetable scraps, and flower clippings) mixed with brown materials (twigs, dry leaves, and soiled paper towels) at a ratio of 1:3 provide a balance of nitrogen and carbon that helps microbes efficiently decompose these materials.

32. 2 Methods of waste disposal
2.3 Composting-- Benefits
The addition of compost to soil will improve it by making clay soils more porous or increasing the water-holding capacity of sandy soils;
Nitrogen, potassium, iron, phosphorus, sulfur, and calcium are all common in compost and are beneficial to plant growth.

33. 2 Methods of waste disposal
Microorganisms are an important component of compost and play a valuable role in organic matter decomposition, which, in turn, leads to humus formation and nutrient availability.

34. 2 Methods of waste disposal
2.4 Source reduction
The simplest way to reduce waste is to prevent it from ever becoming waste in the first place.
Waste prevention, also known as source reduction, is the practice of designing, manufacturing, purchasing, or using materials (such as products and packaging) in ways that reduce the amount or toxicity of trash created.

35. 2 Methods of waste disposal
2.4 Source reduction
Source reduction, including reuse, can help reduce waste disposal and handling costs, because it avoids the cost associated with recycling, municipal composting, landfilling, and combustion.

36. 2 Methods of waste disposal
2.4 Source reduction
Source reduction and reuse have many benefits, including saving natural resources, reducing the toxicity of wastes, and reducing costs.
Waste is not just created when consumers throw items away. Throughout the life cycle of a product ---- from extraction of raw materials, to transportation, to processing and manufacturing facilities, to manufacture and use ---- waste is generated.

37. 2 Methods of waste disposal
2.4 Source reduction
Reusing items or making them with less material decreases waste significantly. Ultimately, fewer materials will need to be recycled or sent to landfills or waste combustion facilities.
Selecting nonhazardous or less hazardous items is another important component of source reduction.

38. 2 Methods of waste disposal
2.4 Source reduction
Using less hazardous alternatives for certain items (e.g., cleaning products and pesticides), sharing products that contain hazardous chemicals instead of throwing out left overs, following label directions carefully, and using the smallest amount necessary are ways to reduce waste toxicity.

39. 2 Methods of waste disposal
2.5 Recycling
Recycling is one of the best environmental success stories of the late twentieth century. In the United States, recycling, including composting, diverted about 30% of the solid waste stream from landfills and incinerators in 2000, up from about 16% in 1990.

40. 2 Methods of waste disposal
2.5 Recycling
Benefits:
One Sunday edition of the New York Times consumes 62,000 trees. Currently, about 40% of all paper that enters the waste stream in North America is recycled.
The United States imports nearly all of its aluminum and recycled over 60% of its aluminum beverage cans.

41. 2 Methods of waste disposal
2.5 Recycling
Benefits:
There are no sources tin within the United States, however, about 2 kilograms of tin can be reclaimed from each 1000 kilograms of metal food cans.

42. 2 Methods of waste disposal
2.5 Recycling
Benefits:
Crushed glass (cullet) reduces the energy required to manufacture new glass by 50%. Cullet lowers the temperature requirements of the glassmaking process, thus conserving energy and reducing air pollution. In 2000, 23% of the glass in the solid waste stream was recycled.

43. 2 Methods of waste disposal
2.5 Recycling
Recycling concerns:
Problems associated with recycling tend to be either technical or economic.
Technical questions are of particular concern when recycling plastics.

44. 2 Methods of waste disposal
2.5 Recycling
Recycling concerns:
Plastic recycling is still a relatively new field. Industry is researching new technologies that promise to increase the quality of plastics produced from recycled materials and that will allow mixing of different plastics. Until such technology is developed, separation of different plastics before recycling will by necessary.

45. 2 Methods of waste disposal
2.5 Recycling
Recycling concerns:
The economics of recycling are also a primary area of concern. The gradually increased commitment to recycling in many developed nations has produced a glut of certain materials on the market. Markets for collected materials fill up just like landfills. Unless the demand for recycled products keeps pace with the growing supply, recycling programs will face an uncertain future.

46. 2 Methods of waste disposal
2.5 Recycling
Recycling concerns:
The long-term success of recycling programs is also tied to other economic incentives, such as taxing issues and the development of and demand for products manufactured from recycled material.

47. 2 Methods of waste disposal
2.5 Recycling
Recycling concerns:
Government tax policy needs to be readjusted to encourage recycling efforts. Currently in the United Stated, it is still cheaper to transport virgin material, such as fresh-cut pulp wood, than to transport collected paper for recycling.

48. 2 Methods of waste disposal
2.5 Recycling
Recycling concerns:
In addition, on an individual level, we can have an impact by purchasing products made from recycled materials. The demand for recycled products must grow if recycling is to succeed on a large scale.

49. 3 Summary
Beginning with the post-world war II era, increased consumption of consumer goods became a way of life. Products were designed to be used once and then thrown away. By the 1980s, a disposal lifestyle began to cause problems. There simply were no places to dispose of waste.

50. 3 Summary
Municipal solid waste is managed by landfills, incineration, composting, waste reduction, and recycling. Landfills are the primary means of disposal; however, a contemporary landfill is significantly more complex and expensive than the simple holes in the ground of the past. The availability of suitable landfill land is also a problem in large metropolitan areas.

51. 3 Summary
While incineration does reduce the volume of municipal solid waste, the problems of ash disposal and air quality continue to be major concerns. There are several forms of composting that can keep organic wastes from entering a landfill.

52. 3 Summary
The most fundamental way to reduce waste is to prevent it from ever becoming waste in the first place. Using less material in packaging, producing consumer products in concentrated form, and composting yard waste are all examples of source reduction. On an individual level, we can all attempt to reduce the amount of waste we generate.

53. 3 Summary
Recycling initiatives have grown rapidly in North America during the past several years. As a result, the markets for municipal solid waste will be successful only if markets exist for the recycled materials. Another problem in recycling is the current inability to mix various plastics.

54. 3 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 will depend on economics, changes in technology, and citizen awareness and involvement.

55. Corporate response to environmental concerns
In the 1990s, McDonald’s Corporation announced it would switch from polystyrene to paper for packaging its food products. In making this announcement, McDonald’s stated that it was responding to consumer pressure to become more environmentally conscientious. Is using paper to wrap fast-food better for the environment than using polystyrene?

56. Corporate response to environmental concerns
Advocates for the switch say that polystyrene takes up space in landfills and does not decompose. They also argue that the burning of polystyrene foam in incinerators might release harmful air pollutants.

57. Corporate response to environmental concerns
Opponents of the switch argue that polystyrene can be recycled into useful products, such as insulation board or playground equipment. They further argue that using paper means cutting forests and that since the paper used to wrap the food is coated with wax, it cannot be recycled.

58. Corporate response to environmental concerns
Which alternative do you prefer? Why?

59. What you can do to reduce waste and save money?
Here are a few ideas that are easy to follow, will save you money, and will help reduce waste:
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 and recycle them.
Buy beverages in refillable glass containers instead of cans or throwaway bottles.

60. What you can do to reduce waste and save money?
Use plastic or metal lunch boxes and metal or plastic garbage containers without throwaway plastic liners.
Use rechargeable batteries.
Skip the bag when you buy anything you can carry with your hands.
Buy recycled goods, especially those made by primary recycling, and then recycle them.

61. What you can do to reduce waste and save money?
Recycle all newspaper, glass, and aluminum, and any other items accepted for recycling in your community.
Choose items that have the least packaging or, better yet, no packaging (nude products).
Composting your yard and food wastes, and pressure local officials to set up a community composting program.