Copyright © McGraw-Hill Education. Permission required for reproduction or display. Solid Waste Management and Disposal Chapter th Edition A Study of Interrelationships ENVIRONMENTAL SCIENCE 14 th Edition 1

Copyright © McGraw-Hill Education. Permission required for reproduction or display. Outline 18.1 Kinds of Solid Waste 18.2 Municipal Solid Waste 18.3 Methods of Waste Disposal 2

Copyright © McGraw-Hill Education. Permission required for reproduction or display Kinds of Solid Waste 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. 3

Copyright © McGraw-Hill Education. Permission required for reproduction or display Kinds of Solid Waste Mining wastes are generated in three ways: Waste material is left on the surface Milling tailings are dumped on the land or stored in ponds. Waste or tailings drainage often contains hazardous materials. Agricultural waste Includes waste from raising animals as well as crop and tree harvesting. 90% is used as fertilizer or other forms of soil enhancement. 4

Copyright © McGraw-Hill Education. Permission required for reproduction or display 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 Municipal solid waste consists of all the materials people in a region no longer want. 210 million metric tons annually. 5

Copyright © McGraw-Hill Education. Permission required for reproduction or display Municipal Solid Waste Some items are discarded when they are broken or worn out. Other products like magazines, catalogs, newspapers, packaging, bottles, and cans are temporarily useful and then are discarded. Those that have only temporary uses make up the majority of the solid waste stream. 6

Copyright © McGraw-Hill Education. Permission required for reproduction or display Municipal Solid Waste The Unites States produces nearly 230 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

Copyright © McGraw-Hill Education. Permission required for reproduction or display. Municipal Solid Waste Generation Rates 8

Copyright © McGraw-Hill Education. Permission required for reproduction or display 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. 9

Copyright © McGraw-Hill Education. Permission required for reproduction or display. Waste Generation and Lifestyle 10

Copyright © McGraw-Hill Education. Permission required for reproduction or display. The Changing Nature of Trash 11

Copyright © McGraw-Hill Education. Permission required for reproduction or display. Composition of Trash in the United States

Copyright © McGraw-Hill Education. Permission required for reproduction or display 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. 13

Copyright © McGraw-Hill Education. Permission required for reproduction or display. Burning Landfills 14

Copyright © McGraw-Hill Education. Permission required for reproduction or display Methods of Waste Disposal Five techniques are now used in waste disposal: Landfills Incineration Source reduction Composting Recycling 15

Copyright © McGraw-Hill Education. Permission required for reproduction or display. Changes in Waste Disposal Methods 16

Copyright © McGraw-Hill Education. Permission required for reproduction or display. 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. Traditionally this has been the primary method of waste disposal. Cheap and convenient Problems associated with poorly designed landfills have been recognized, and substantial efforts are made to reduce the amount of waste entering landfills. 17

Copyright © McGraw-Hill Education. Permission required for reproduction or display. Landfills New landfills have an impermeable liner and 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. New landfills currently cost up to $1 million per hectare ($400,000 per acre) to prepare. 18

Copyright © McGraw-Hill Education. Permission required for reproduction or display. A Well-Designed Modern Landfill 19

Copyright © McGraw-Hill Education. Permission required for reproduction or display 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. New landfills often resisted due to public concerns over groundwater contamination, odors, rodents, and truck traffic. 20

Copyright © McGraw-Hill Education. Permission required for reproduction or display. Reducing the Number of Landfills 21

Copyright © McGraw-Hill Education. Permission required for reproduction or display. Incineration Incineration is the process of burning refuse in a controlled manner. Currently, about 12% 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. 22

Copyright © McGraw-Hill Education. Permission required for reproduction or display. Incineration 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. 23

Copyright © McGraw-Hill Education. Permission required for reproduction or display. Incineration Even with modern pollution controls, small amounts of pollutants are still released into environment. The cost of land and construction for new incinerators are also major concerns facing many communities. Construction costs in North America in 2010 ranged from $50-$400 million. 24

Copyright © McGraw-Hill Education. Permission required for reproduction or display. Incineration 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. 25

Copyright © McGraw-Hill Education. Permission required for reproduction or display. Disposal Methods Used in Various Countries 26

Copyright © McGraw-Hill Education. Permission required for reproduction or display. Composting Composting uses natural processes of decomposition to transform discarded organic materials—grass clippings, leaves, food waste, or soiled paper—into compost, a humus-like material. 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

Copyright © McGraw-Hill Education. Permission required for reproduction or display. Diverting Yard Waste Through Composting 28

Copyright © McGraw-Hill Education. Permission required for reproduction or display. Composting 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

Copyright © McGraw-Hill Education. Permission required for reproduction or display. Source Reduction 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. 30

Copyright © McGraw-Hill Education. Permission required for reproduction or display. Source Reduction Design changes Since the 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. 31

Copyright © McGraw-Hill Education. Permission required for reproduction or display. Source Reduction Using materials to avoid waste generation Reduce use of hazardous materials. Follow label directions carefully and use the smallest amount necessary. Reusing items Delay or prevent entry of items into waste collection stream. 32

Copyright © McGraw-Hill Education. Permission required for reproduction or display. Source Reduction 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 33

Copyright © McGraw-Hill Education. Permission required for reproduction or display. Recycling Recycling is one of the best environmental success stories of the late 20 th century. In the United States, recycling (including composting) diverted about 35% of solid waste stream from landfills and incinerators in

Copyright © McGraw-Hill Education. Permission required for reproduction or display. Recycling Beverage Container Deposit-Refund programs provide an economic incentive to recycle. Disposable containers are an increasing problem. In 1990 the average US citizen disposed of 550 drink containers. In 2010 this had risen to 784, about a 43 percent increase. Beverage containers currently constitute 25 percent of household trash. In a deposit-refund program a cash value in the form of a deposit is placed on the glass, aluminum, or plastic beverage container. Thus, consumers have an incentive to return their containers for the redemption value. 35

Copyright © McGraw-Hill Education. Permission required for reproduction or display. Recycling All provinces and most territories in Canada and at least 12 countries in Europe have bottle bills. In the United States, 10 states currently have beverage container deposit laws. They have recycling rates of 70 percent or more on containers covered by their laws. The average for the United States is about 35 percent. 36

Copyright © McGraw-Hill Education. Permission required for reproduction or display. Recycling Mandatory recycling laws provide a statutory incentive to recycle. Many states and cities have passed mandatory recycling laws. Some of these laws simply require that residents separate their recyclables from other trash. Some are aimed at businesses and require them to recycle certain kinds of materials such as cardboard or batteries. Some forbid the disposal of certain kinds of materials in landfills. Those states and cities with mandatory recycling laws understandably have high recycling rates. 37

Copyright © McGraw-Hill Education. Permission required for reproduction or display. Recycling Rates 38

Copyright © McGraw-Hill Education. Permission required for reproduction or display. Recycling Curbside recycling provides a convenient way for people to recycle. In 1990, 1,000 U.S. cities had curbside recycling programs. In 2011, 9,800 programs served 70 percent of the U.S. population.. Cities with curbside recycling tend to have much higher recycling rates than cities that lack such programs. 39

Copyright © McGraw-Hill Education. Permission required for reproduction or display. Recycling In the U.S., curbside pick-up of recyclables is increasingly the norm, but rates remain low. Recycle Bank was founded in 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 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. 40

Copyright © McGraw-Hill Education. Permission required for reproduction or display. Recycling Challenges 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). 41

Copyright © McGraw-Hill Education. Permission required for reproduction or display. Increasing Amounts of Plastics in Trash 42

Copyright © McGraw-Hill Education. Permission required for reproduction or display. Recycling Challenges Plastic bags are a convenience, a nuisance, and an environmental hazard. They are handy to carry items from the store. Many marine organisms such as turtles, whales, birds, or seals eat or become entangled in plastic bags. Sea turtles feed on jellyfish and often mistakenly eat plastic bags. 43

Copyright © McGraw-Hill Education. Permission required for reproduction or display. 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 35% of the waste generated in North America is handled through recycling. 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. 44