Chapter 16 Waste Generation and Waste Disposal
Humans generate waste that otherHumans generate waste that other organisms cannot use • In 1900 in the U.S. virtually all metal, wood, and glass materials were recycled. • After World War II, industrialization brought wealth to many Americans, which made it possible for people to purchase household conveniences that could be used and thrown away. • Municipal Solid Waste (MSW)- refuse collected by municipalities from households, small businesses, and institutions such as schools, prisons, municipal buildings, and hospitals.
Approaches to Waste Management • Waste – any unwanted material or substances that results from a human activity or process. • Municipal Solid Waste – non-liguid waste that comes from homes, institutions, and small businesses. • Industrial Solid waste – includes waste from production of consumer goods, mining, agriculture, and petroleum extraction and refining. • Hazardous Waste – refers to solid or liquid waste that is toxic, chemically reactive, flammable, or corrosive. (paint, household cleaners, medical waste, industrial solvents)
Aims for Managing Waste • Waste can degrade • Water • Soil • Human health • Environment • Waste Stream – the flow of waste as it moves from its sources toward disposal destinations. Can be recycled, incinerated, placed in a solid waste landfill or disposed of in another way.
A large dump in Manila, Philippines. Throughout the world, impoverished people scavenge dumps.
E-Waste • Electronic waste or e-waste, is one component of MSW that is small by weight but very important and rapidly increasing. • E-waste includes televisions, computers, portable music players, and cell phones. • E-waste often has heavy metals such as lead, mercury and cadmium.
Lots of e-waste is being recycled and in doing so, the people who are taking them apart are at risk of working with hazardous substances • Much of our e-waste gets shipped over-seas and the disassembly is done by poor workers with minimal safety regulations. • “Environmental Justice Concern” • The cathode ray tubes in TV’s and computers represent the second largest source of lead in landfills.
E-waste being recycled in China. Much of the recycling is done without protective gear and respirators that would typically be used in the U.S.
Three Components of Waste Management • Minimizing the amount of waste we generate • Recovering waste materials and finding ways to recycle them • Disposing of waste safely
The three Rs Reduce, Reuse, Recycle • Reduce- waste minimization or prevention • Reuse- reusing something like a disposable cup more than once • Recycle- materials are collected and converted into raw materials and then used to produce new objects
The three Rs Reduce, Reuse, Recycle • Closed-loop recycling is the recycling of product into the same product. An example is an aluminum can. This process is called closed loop because in theory, it is possible to keep making aluminum cans from only old aluminum cans. • Open –loop recycling is the recycling of one product such as plastic soda bottles into another product, such as a polar fleece jacket.
Minimizing • Source reduction • Manufactures could use materials more efficiently • Consumers can buy fewer goods, less packaging and use goods longer • Reuse goods, buy used and donate used
Reducing Waste is a Better Option • Reducing is the best way to avoid cost of disposal and all the environmental issues that go along with disposal. • Source Reduction – preventing waste generation • Much of waste comes from package • Buy unwrapped fruit and vegetables • Buy in bulk • Use recycled goods • Use re-usable bags to shop with instead of plastic
Recovering Waste Materials • Recovery – recycling and composting is viewed as the next best strategy in management. • Recycling – sending goods to facilities that extract and reprocess raw materials to manufacture new goods. (newspapers, white paper, cardboard, glass, metal cans, appliances and some plastic containers. • Today about 30% of waste is recycled • New technologies have been developed for recycling.
Recycling Consists of Three Steps • Recycling – consists of collecting materials that can be broken down and reprocessed to manufacture new items. • Step 1 – collecting and processing the materials. Materials are taken to a Materials Recovery Facility (MRF’s) • Step 2 – Sorting, cleaning and preparing for reprocessing • Step 3 – Manufacturing new goods and purchasing by the public
Recycling has grown rapidly and can expand further • Thousands of curbside recycling programs exist today • More then 500 MRF’s are in operation. • In the United Sates recycling has risen from 6.4% to 23.8%.
Reuse is the major strategy for waste reduction • Substitute disposal goods for durable goods • Bring your own coffee mug • Bring your own shopping bags • Buy used clothes • Buy used cars
Canadian City Showcases Reduction and Recycling • Edmonton, Alberta has created one of the worlds most advanced waste management programs • 85% of the city’s waste was being landfilled and space was running out. • Today, 35% goes to landfills, 50% is composted and 15% is recycled. • 81% of the cities citizens participate in curbside recycling.
Composting • Biological decomposition – the recovery of organic waste. Organic material that has decomposed under controlled conditions to produce an organic-rich material
Composting • Composting is the conversion of organic waste into mulch or humus through natural biological process of decomposition. • Compost can be used to enrich soil. • Compost can be in underground pits, pile or constructed containers • Things that can be composted – non meat foods, coffee grounds, grass clippings, leaves and many other items.
Composting • Municipal composting facility. A typical facility collects almost 100,000 metric tons of food scraps and paper per year and turns it into usable compost.
Financial incentives can help address waste • Economic incentives to reduce such as “pay-as-you-throw” approach to garbage collection, uses financial incentive to change consumer behavior. • “Bottle bills” 11 states have these laws to allow return for cash of bottles. • Bottle bills – designed to cut down on litter. • Challenges - (1) amendments to the bottle laws needs to include newer type of containers. Such as colored bottles (2) adjust refunds on bottles for inflation
Waste Disposal Methods • Burying waste in landfills • Burning waste in incinerators
Sanitary landfills- engineered ground facilities designed to hold MSW with as little contamination of the surrounding environment as possible. • Leachate- the water that leaches through the solid waste and removes various chemical compounds with which it comes into contact.
Municipal Solid Waste • Municipal waste varies from place to place. • In the United States, paper, yard debris food scraps and plastics are components of municipal solid waste (71%). • Most solid waste comes from packaging and nondurable goods. • U.S leads the world in solid waste followed by – Canada and the Netherlands.
Waste generations is rising in all nations • Waste generations has been increasing since 1960. • Per capita waste has risen 69%. • More and more developing nations are increasing their solid waste. • Over the past 3 decades, per capita waste generation rates have more than doubled.
Open dumping of the past has given way to improved disposal methods • There use to be open dumping and burning of waste. This still exists in some areas of the world. • Some people scavenge on dumps and then sell trash to make money.
Many nations have improved their methods of waste disposal. • Most industrial nations now bury waste in a lined and covered landfill. • Dump – is unlined • Sanitary Landfill – are capped after they have reached there permitted level.
Modern Sanitary Landfill • Landfill constructed today has many features to keep components of the solid waste from entering soil, water table or nearby streams.
Sanitary landfills are regulated by health and environmental guidelines • Designed to prevent waste from contaminating the environment and threatening public health. • Landfills in the United States are regulated locally and by the State but also must meet national standards set by the U.S. Environmental Protection Agency (EPA)
Modern Sanitary Landfill • A municipality or private enterprise constructs a landfill at a tremendous cost. These costs are recovered by charging a fee, called a tipping fee. • Tipping fees at solid waste landfills average $35 per ton in the U.S., although in certain regions, such as the Northeast, fees can be twice as much. • These fees create an economic incentive to reduce the amount of waste that goes to the landfill.
The EPA regulates landfills under the Resource Conservation and Recovery Act (RCRA). • RCRA enacted in 1976 and amended in 1984. How Landfills Work • Waste is partially decomposed by bacteria and compresses under its own weight. • Waste is layered along with soil, this limits odor • Limiting infiltrations allows for biodegradation by aerobic and anaerobic bacteria.
How Landfills Work “Continued” • Landfills are required to be located away from wetlands and earth-quake-prone faults and 6 feet above the water table. • Bottoms and sides must be lined with heavy plastic and up to 4 ft of impermeable clay to help prevent contaminants from seeping into aquifers. • A system of pipes are used to gather leachate – liquid that results when substances from the trash dissolves in water as rainwater percolates down.
Landfill Closure • After a landfill is closed, it is capped with an engineered cover that must be maintained. • The cap is a hydraulic barrier of plastic that prevents water from seeping down and from gas seeping up. • Methane gas is produced by the decompositions that takes place in the landfill. • This gas can be extracted and used as a source of energy when burned.