Transcript Ch 12 Waste PowerPoint

Chapter 12:
Waste
“Nothing can be forgotten, only left behind.”
Jon Harjo, Native American Poet
12.1 Solid Waste: The Throwaway Society
• You have lunch, throw away the garbage…but
what happens to it after you ‘toss it away’?
• It is picked up by a collection service and taken
to a landfill where it will be dumped with
thousands of tons of other trash and then
covered with a thin layer of dirt at the end of the
day
• What happens when it is full, or water runs down
into the landfill, dissolving harmful chemicals
(paint thinner, nail polish remover) and that
seeps into the groundwater?
The Generation of Waste
• Imagine multiplying the waste disposal problems
associated with your trash plus all the trash
everyone else throws away in a day; most is
used once and then thrown away
• US generates more than 10 billion metric tons of
solid waste (any discarded solid material) in a
year; this includes junk mail to coffee grounds to
cars
• Waste generated by Americans has doubled
since the 1960’s
Space and Waste
• Many towns are running out of space to
dispose of the amounts of trash people are
producing
• Ex: In 1987, a huge barge full of trash
sailed up and down the East Coast for
more than 5 months in search of a place to
dump the garbage; it contained 3200 tons
of garbage; eventually, it returned to Islip,
New York, burned the garbage and finally
buried 430 tons of ash
Population and Waste
• Thousands of years ago, hunter-gatherers had a
smaller population and most of the waste
created was animal and vegetable matter
(biodegradable material); larger amounts of land
per person and disposal of waste was easier
• Earth’s population and the waste we produce is
getting larger; amount of land available per
person is becoming smaller; therefore, it is
getting harder to find space to dispose of all the
waste we are creating
Not All Wastes are Equal
• The amount of waste is a concern; however, the
kinds of waste are just as important
• Two basic kinds: biodegradable (can be broken
down by living things) and non-biodegradable
(cannot be broken down)
• Examples of biodegradable products: plant and
animal matter, newspaper, paper bags, cotton
fibers, leather; examples of non-biodegradable
waste are materials created by combining
chemicals to form compounds – polyester, nylon
Plastic Problems
• Plastics illustrate how non-biodegradable materials can
cause problems.
• Made from petroleum or natural gas; these consists mostly
of carbon and hydrogen (same elements which make up
most molecules in living things); however, in plastics, when
put together in molecular chains, are not found in nature.
• Microorganisms have evolved the ability to break down
nearly all biological molecules, but have yet to develop a
way to break down the molecular structure of most plastics
• Some plastics we throw away may accumulate and last for
hundreds of years.
Types of Solid Waste
• Most of what we throw away on a day-today basis is called municipal solid waste
• However, 70% of the other solid waste
comes from manufacturing and mining;
6% is considered hazardous
Municipal Solid Waste
• About 2% of the total solid waste in the US
is made up of municipal solid waste
(produced by households and businesses
• 210 million metric tons of municipal waste
produced per yr. in US; enough waste to
fill a convoy of garbage trucks that would
stretch around the Earth 6 times!
• growing faster than manufacturing and
mining waste
Solid Waste from Manufacturing, Mining and Agriculture
• Waste from manufacturing, mining and agriculture make up the rest of
the total solid waste produced in the US, about 56% of the total
• Includes items like: scrap metal, plastics, paper, sludge and ash
• Consumers do not directly produce manufacturing waste but the
indirectly contribute to it by buying products that have been
manufactured
• Mining waste consists of rock and minerals that are left over from
excavation and processing; left exposed in large heaps, dumped in
oceans or rivers, or disposed of by refilling and landscaping abandoned
mines
• Agricultural waste makes up 9% of the total solid waste; includes crop
waste and manure
• Agricultural waste is biodegradable, can be broken down and then
returned to the soil; however, with the increase use of fertilizers and
pesticides, agricultural waste is becoming more difficult to dispose of
(harmful to the soil)
Section 12.2: Landfills
Solid Waste Management
• Most trash goes to the landfill but some is
incinerated and 25% is recycled
• In 1970, we recycled only 6.6%
Landfills
• More than 50% of our waste ends up in a landfill;
modern day landfills are much safer than the
open dumps of the past (obnoxious smells and
breeding grounds for rats and insects)
• Landfills are permanent waste disposal facilities;
wastes are put in the ground and covered each
day with a layer of soil, plastic or both.
• Function of a landfill: to contain waste that is
buried inside, to keep waste from causing
environmental problems, and most importantly, to
prevent the waste inside the landfill to come in
contact with the soil and groundwater that
surrounds it.
Landfill
Problems with Landfills
• Leachate (water containing toxic chemicals; formed when water
seeps down through the garbage picking up the poisonous
chemicals along the way) continues to be a problem area for
landfills; forms when water seeps down through a landfill and
combines with the dissolved chemicals from decomposing garbage
(ex: paints, pesticides, cleaners, cans, batteries, appliances)
• Landfills typically have monitoring wells and storage tanks to
measure and store leachate, which can then be treated as
wastewater. However, if not monitored well, leachate can flow into
groundwater supplies making area water unsafe to drink
• Methane is another problem. Organic waste decomposes (without
oxygen) producing methane, a highly flammable gas
• Methane is usually pumped out of landfills and used as fuel.
However, if it is not monitored safely, it can seep through the ground
and into basements of homes up to 300 meters from a landfill,
causing dangerous explosions if ignited by a spark
Safeguarding Landfills
• The Resource Conservation and Recovery Act (passed
in 1976, updated in 1984) requires that new landfills
have to be built with safeguards to reduce pollution
problems; must be lined, have systems to treat leachate
and vent pipes to carry methane out of the landfill
(released into air or captured and burned to produce
electricity)
• Adding these safeguards increases the cost of building
them and finding acceptable places to build them is
difficult; must be close to the city producing the waste
but far enough away from the residents
• Any solution is likely to be expensive: legal fees to fight
local residents’ objections or cost of transporting
garbage to distant sites
Building More Landfills
• We can build safer landfills, but we are currently running
out of space we are willing to develop for the new
landfills
• Materials are not decomposing as fast as we can fill
landfills; biodegradable materials (ex: newspaper) takes
several years to decompose
• Total number of active landfills in US in 1988 was 8000;
by 1999, the total number decreased by 2300 because
they had been filled to capacity
• Most existing landfills are scheduled to fill up and close
within the next 10 years; EPA estimates 20 states will be
out of space for additional landfills
12.3 Reducing Solid Waste
Incinerators
• One option for reducing the amount of solid waste sent to
landfills is to burn it.
• In 1999, the US had 102 operational incinerators that were
capable of burning up to 94,000 metric tons of municipal solid
waster per day; solid waste does not disappear, it’s just
reduced by 75%, taking up less space in landfills
• Incinerators cannot separate the hazardous from the non
hazardous waste: therefore, incinerating the solid waste
usually results in dangerous toxic ash; air is polluted from the
gases produced by incineration
• Places with incinerators tend to recycle less because it
requires a certain amount of solid waste to keep them
operating
Reducing Solid Waste
• If incinerators and landfills are expensive and polluting, what
are some other options?
• Producing less waste, Recycling, Changing the materials used
in products
• These methods of reducing solid is known as source reduction
• By producing less waste, we will reduce the expense and
difficulty of collecting and disposing of it. Ex: use both sides of
paper; don’t use unneeded bags, napkins or utensils at
restaurants and stores; don’t buy products with unnecessary
packaging; using washable diapers instead of disposable ones;
use refillable bottles; redesigning products to use less material;
return to using sturdy products that last longer and can be
repaired rather than disposed of
Buying less
• You can influence manufacturers to reduce solid waste by
buying products that have less packaging, products that last
longer or products that can be used more than once
• Manufacturers will be more likely to make more of these
products because the demand for them is greater ex:
dishtowels instead of paper towels, rechargeable batteries
instead of regular batteries
• Until 1965, nearly all bottled drinks were in containers designed
to be returned to stores when they were empty; they were
collected, washed and refilled at bottling companies.
• Today, the demand is for disposable rather than refillable
bottles
• If people were to use more refillable bottles, manufacturers
would start producing them again
Lasting Longer
• Manufacturers could also reduce waste
and conserve resources by redesigning
products to use less material; thus, saving
resources and reduce waste disposal
problems.
Recycling
• Recycle as much as possible
• Besides reducing waste, we need to find ways to make
the best possible use of all the materials we discard
• Making products from recycled materials usually saves
energy, water and other resources
• Ex: Takes 95% less energy to produce aluminum from
recycled aluminum than from ore; 75% less energy to
make steel from scrap ore; 70% less energy to make
paper from recycled paper than from trees
• Most people think only to recycle bottles, cans and
newspaper
Recycling: A Series of Steps
• Most people think about recycling as taking their bottles, cans and
newspapers to a recycling center or putting these things at the curb
in specially marked containers; however, recycling involves a series
of steps in order for recycling to work.
• First: discarded materials must be collected and sorted by type
• Second: each type is taken to a facility where it is cleaned and
made ready for use again ex: glass – sorted by color and then
crushed; paper – sorted by type and made into pulp with water
• Finally: materials are used to manufacture new products to be sold
to consumers
• If more people would buy recycled, demand would increase for
these products causing manufacturers to build more facilities to
make recycled products. Thus, making it easier for communities to
sell the materials they collect from residents for recycling
Composting
• Yard waste makes up more than 15% of a communities municipal solid
waste; doesn’t really need to go to a landfill because it is
biodegradable
• Can be put in a compost pile and it will break down naturally
• Adding fruit and vegetable trimmings and table scraps will encourage
bacteria to grow and break down the waste rapidly (warm, moist and
dark conditions)
• Creates compost which can be used in gardens because of the rich
nutrients
• Some cities provided facilities to take yard waste and compost it at a
large, central facility
• Composting can also be an effective way of handling waste from food
processing plants and restaurants, manure from animal feedlots and
municipal sewage sludge.
• If all biodegradable wastes were composted, the amount of solid waste
going to landfills could be reduced.
Changing the Materials we Use
• Much waste could be eliminated by changing the materials used to
package products
• Ex: drink boxes are make of a combination of foil, cardboard and
plastic and are hard to recycle because there is no good way to
separate the three different components: could be recycled if they
were eliminated and all drinks came in recyclable glass or
aluminum containers
• Recycling other common household products can help eliminate
solid waste, for example, newspapers can be made into cardboard,
egg cartons, and building materials; used aluminum cans can be
recycled to make new cans, lawn chairs, aluminum siding for
homes and cookware; glass bottles and jars can be made into new
glass bottles and jars; plastic beverage containers to be made into
nonfood containers, insulation, carpet yarn, textiles, fiberfill,
scouring pads, toys, plastic lumber and crates.
Degradable Plastics
• Most plastics are not biodegradable, some companies have
developed new kinds of plastics that they say are degradable
• One type is called photodegradable plastic: when left in the sun
for many weeks, it becomes weak and brittle and eventually
breaks into pieces
• Another type is called green plastic: made by blending the
sugars in plants with a special chemical agent to make plastic;
labeled as green because they are made from living things;
requires 20-50% less fossil fuel to produce, engineered to
degrade within 45 days of being thrown away
• When green plastic is buried, bacteria in the soil eat the sugars
and leave the plastic weakened and full of microscopic holes;
chemical agents in the plastic break the longer molecules into
shorter ones until it eventually falls apart into small pieces
Problems with Degradable Plastics
• The biggest problem with the degradable
plastic is that the organic parts degrade
and the plastic parts are only reduced to
smaller pieces; helps the animals in the
environment because they cannot choke
on the plastic pieces, but those pieces do
not completely disappear
12.4 Hazardous Waste
• Many products we use today (laundry soap to
computers) are produced in factories using
thousands of chemicals; some in the processing,
some as cleansers, some used to generate
electricity for the factories
• Large quantities are oftentimes leftover as
waste; many are classified as hazardous waste
which may cause health risks to humans or
other living things
Types of Hazardous Waste
• Can be a solid, liquid or gas; oftentimes contain toxic,
corrosive or explosive materials, ex: cleansers to
disinfect surfaces, lubricants to help machines run
• Methods of disposing these materials are not always
carefully planned out, ex: Love Canal, in Niagara Falls,
NY. Homes and a school were built on land that a
chemical company used as a site to dump toxic waste;
problems started when toxic waste began to leak from
the site.
• Love Canal prompted people to pay more attention to
how hazardous wastes were being stored and disposed
of; federal laws were passed to clean up old waste sites
and regulate future waste disposal.
Resource Conservation and Recovery Act
• RCRA (Resource Conservation and Recovery
Act) requires producers of hazardous waste to
keep records of how their waste were handled
from the time they were made to the time they
are disposed of
• They are legally responsible even if a problem
arises in the future; all sites must be built and
operated according to standards designed to
prevent environmental pollution
The Superfund Act
• Safe disposal of hazardous waste is expensive so illegal
dumping of hazardous waste is tempting
• In 1980, the Comprehensive Environmental Response,
Compensation and Liability Act, aka Superfund Act was passed;
gave the EPA the right to sue owners of hazardous waste sites
and force owners to pay for cleanup
• Also, created a fund of money to pay for cleaning up abandoned
sites; difficult and extremely expensive
• Love Canal alone cost $275 million (put a clay cap on the site,
installed a drainage system and treatment plant to handle the
leaking waste, relocated the residents); 20 years later, the site
was evacuated
• Many Superfund sites will need to be cleaned; 75 of the 1200
approved sites have been completed
Hazardous Waste Management
• Every year, US produces about 252 million
metric tons of hazardous waste; growing
every year
• No guarantee that the methods used today
to dispose of hazardous waste will be safe
for the environment in the future
Preventing Hazardous Waste
• One way to prevent hazardous waste is to produce less of
it; some manufactures have discovered ways to produce
less or no hazardous waste. Ex: instead of cleaning metal
parts with chemicals, some companies found they can use
tiny plastic beads (act like a sandblaster) which can
reused several times and are not hazardous when
disposed of
• Another way it to find a way to reuse it; in US more than
50 programs have been set up for companies to give what
they would normally throw away to another company, who
can use it, ex: cleaning solvents, after one use, can be
sold to another company whose produce would not be
harmed by using the small amount of contaminant in the
solvent
Conversion into Nonhazardous Substances
• Some wastes can be treated with chemicals to
make the waste less hazardous, ex: lime, which
is a base, can be added to acids to neutralize
them; a base compound can react with acids to
convert acids into salts; cyanides, can be
combined with oxygen to form carbon dioxide
and nitrogen
• Wastes can be treated biologically. ex: sludge
from petroleum refineries may be converted by
soil bacteria into less harmful substances.
Land Disposal
• Most hazardous waste produced in US is disposed of on land
• Deep well injection pumps waste deep into the ground where
they are absorbed into a dry layer of rock below the
groundwater level; wastes are covered with cement to
prevent contamination
• Surface impoundment is another common land disposal
facility. It is basically a pond with a sealed bottom; wastes
accumulate and settle to the bottom, water evaporated and
leaves room to add more waste
• Hazardous waste in concentrated or solid form are put in
barrels and buried in landfills; hazardous landfills are similar
to regular landfills only have extra safety precautions to
prevent leakage
Biologically Treating Hazardous Waste
• Biological and chemical agents can
oftentimes absorb, break down or reduce
toxicity of hazardous waste; bacteria grown
in labs can be used to clean up
contaminated areas, ex: mercury, arsenic
and cyanide
• Some plants and trees that absorb heavy
metals can be planted; chemicals to
neutralize and absorb hazardous can be
applied
Incinerating Hazardous Waste
• Burning
hazardous waste in specially designed
incinerators is another method of disposal
• They can be safe but also have several
problems; generally the most expensive form
because they require a lot of energy; must
have pollution control devices; need to be
monitored carefully so hazardous gases and
particles are not released into the air; leftover
ash needs to be buried
Exporting Hazardous Waste
• Until recently, local laws regulated the waste
disposal; many companies would try to get rid of
their hazardous waste by sending them to landfills
in other states, usually less populated southern
states.
• In 1980’s, southern populations grew, and these
states started to refuse taking the waste
• Hazardous waste are also exported to other
countries because there might be a facility there
that specializes in the treating, disposing of or
recycling of particular substances.
•
Hazardous Waste At Home
• Hazardous waste disposal is not only a big
industry problem, it is also an issue in the
home
• Everyday household products can be
hazardous (ex: paint, pesticides, batteries,
computers, fertilizers, cleaners, antifreeze, cell
phones)
• Many household products are poured down
the drain or put in the trash to go to landfills
Disposing of Household Hazardous Waste
• To make sure more hazardous materials are be
disposed of properly, many cities are creating
collection sites for hazardous waste; some cities
collect only once or twice a year; others have
permanent facilities
• Trained workers sort hazardous materials and
send some materials for recycling and pack other
material into barrels for disposal
• Used batteries and motor oil are recycled, paint
may be blended and used for city park
maintenance or used to clean up graffiti
Motor Oil
• When you change your oil at home, do you ever
wonder what to do with the old, dirty oil?
• Many people illegally pour it on the ground or throw
it in the trash; about 700 million liters/185 million
gallons are thrown away by people every year (not
including the oil from service stations and auto
repair shops!)
• What can you do with your oil? Take it to an
automobile service station where it is turned in for
recycling, take it to an oil collection receptacle if
your city has one or call the local city government
to find out where it can be taken