Transcript Document

Chapter 21
Solid wastes are only raw materials
that we’re too stupid to use.
Arthur C. Clarke
What Are Solid Wastes?
 Solid waste is any unwanted or discarded material that
is not liquid or gas
 The U.S., with less than 5% of the worlds population
produces about 1/3rd of the world’s waste
 Guess where most of solid waste comes from?
 Almost 98.5% comes from mining, oil and gas
production, agriculture and industry
 The remaining 1.5 % is Municipal Solid Waste (MSW) =
GARBAGE!!! (from households and businesses)
We live in a high waste or throw-away
society….here’s some food for thought Enough aluminum to rebuild the country’s entire
commercial airline fleet every 3 months
 About 18 billion disposable diapers per year (reach to
the moon and back 7X!!!)
 About 2 billion disposable razors, 30 million cell
phones, 18 million computers and 8 million TV’s
 Used carpet that would cover the entire state of
Delaware
 About 670,000 tons of edible food per year
 Enough office paper to build an 11 foot high wall from
NYC to San Fran
 8.6 million metric tons (17 billion pounds) of packing
peanuts to protect shipped items
Case Study: Trash Production, Recycling
in NYC: Past, Present, and Future
 1920–1940: Highest trash due to coal ash
 1962 and 1963: Lowest trash, coal burning phased out
 1964 and 1974: Rise in trash due to throwaway
containers
 1999: Mandatory recycling
 2001: Fresh Kills landfill closed, trash hauling
How Should We Deal with
Solid Waste?
 A sustainable approach to solid waste is first to
reduce it, then to reuse or recycle it, and finally to
safely dispose of what is left.
We Can Burn or Bury Solid Waste
or Produce Less of It…2 WAYS!
 Waste Management – “high-waste approach” –
unavoidable consequence of economic growth
(burying waste, burning it or shipping to another
state or country)
 Waste Reduction – “low-waste approach” – there is
no “away” – view waste as potential resource or
should not be produced in the first place
Integrated Waste Management:
Priorities for Dealing with Solid
Waste
Science Focus: Garbology
 William Rathje: analyzes garbage in landfills
 Landfills and trash decomposition
We Can Cut Solid Wastes by
Reducing, Reusing, and Recycling  Waste reduction is based on
 Reduce (consume less)
 Reuse (repeatedly use items)
 Recycle
Reusing items decreases the use of
matter and energy resources and
reduces pollution and natural capital
degradation; recycling does so to a
lesser degree.
 3 R's song
SEVEN STRATEGIES(1) Redesign manufacturing processes and
products to use less material and energy
(2) Redesign manufacturing processes to produce
less waste and pollution
(3) Develop products that are easy to repair, reuse,
remanufacture, compost, or recycle
(4) Eliminate or reduce unnecessary packaging
(5) Use fee-per-bag waste collection systems
(6) Establish cradle-to -grave responsibility
(7) Restructure urban transportation systems
What Can You Do?
There Are Two Types of Recycling  Primary, closed-loop recycling – wastes discarded
are recycled to produce the SAME type of
product(newspaper and aluminum cans)
 Secondary recycling - wastes are turned into
DIFFERENT (& usually lesser quality) materials
 About 30% of MSW in U.S. is recycled or
composted
We Can Mix or Separate Household
Solid Wastes for Recycling
 Materials-recovery facilities (MRFs) – large scale
recycling by collecting mixed urban waste ,
transporting it to MRF and then separating it
 Downside –
 expensive to build and operate
 Can emit toxic air pollutants
 Must have a large input of garbage to be
successful
OR
 Source separation  Pay-as-you-throw
 Fee-per-bag
TRADE-OFFS
Recycling
Advantages
Reduces air and
water pollution
Saves energy
Reduces mineral
demand
Reduces greenhouse
gas emissions
Reduces solid waste
production and disposal
Helps protect
biodiversity
Can save landfill
space
Important part of
economy
Disadvantages
Can cost more than
burying in areas with
ample landfill space
May lose money for
items such as glass
and some plastics
Reduces profits for
landfill and
incinerator owners
Source separation is
inconvenient for
some people
Fig. 21-12, p. 573
We Can Encourage Reuse and
Recycling
 What hinders reuse and recycling?
 Lack of large steady markets for recycled materials
 Failure to include harmful environmental and health
costs of raw materials
 More government tax breaks for resource-extracting
industries than for recycling and reuse industries
 Encourage reuse and recycling
 Government


Increase subsidies and tax breaks for using such products
Decrease subsidies and tax breaks for making items from
virgin resources
Bury or Burn???
 Technologies for burning and burying solid wastes are
well developed, but burning contributes to pollution
and greenhouse gas emissions, and buried wastes
eventually contribute to pollution and land
degradation.
WTE’s
 Waste-to-energy
incinerators –
burns solid waste
to produce
electricity
 About 16% of
MSW in U.S. is
combusted!
Trade-Offs: Incineration, Advantages
and Disadvantages
Burying Solid Waste Open dumps – essentially holes in the ground
versus
 Sanitary landfills - about 54% of garbage in US solid wastes are spread out in thin layers and
compacted and covered daily with fresh layer of
clay or plastic foam
When landfill is full, layers of
soil and clay seal in trash
Topsoil
Sand
Clay
Garbage
Probes to detect
methane leaks
Electricity generator
building
Methane gas
recovery well
Compacted
solid waste
Garbage
Sand
Synthetic
liner
Sand
Clay
Subsoil
Leachate
treatment system
Methane storage
and compressor
building
Pipes collect explosive
methane for use as fuel
to generate electricity
Leachate
storage
tank
Leachate
pipes
Leachate pumped
up to storage tank
for safe disposal
Groundwater
Clay and plastic lining to
prevent leaks; pipes collect
leachate from bottom of
landfill
Groundwater
monitoring
well
Leachate
monitoring
well
TRADE-OFFS
Sanitary Landfills
Advantages
Disadvantages
No open burning
Noise and traffic
Little odor
Dust
Air pollution from toxic
gases and trucks
Releases greenhouse
gases (methane and CO2)
unless they are collected
Low groundwater
pollution if sited
properly
Can be built quickly
Low operating costs
Can handle large
amounts of waste
Filled land can be used
for other purposes
No shortage of landfill
space in many areas
Slow decomposition
of wastes
Output approach that
encourages waste
production
Eventually leaks and can
contaminate groundwater
Fig. 21-16, p. 576
What is hazardous waste?
 Legally defined as:
 a. toxic (includes pesticides, solvents, etc)
 b. flammable (catches fire easily – gasoline, solvents)
 c. reactive (acids, bases, ammonia)
 d. corrosive (industrial cleaning agents, drain cleaners)
 Does NOT include: radioactive wastes, mining wastes,
hazardous and toxic materials discarded by households,
oil & gas drilling waste, wastes from small businesses
(<220 lbs/month), liquid waste containing organic
hydro-carbon compounds!!!
How Should We Deal with
Hazardous Waste?
 A sustainable approach to hazardous waste is first to
produce less of it, then to reuse or recycle it, then to
convert it to less hazardous materials, and finally, to
safely store what is left.
Produce Less
Hazardous Waste
Change industrial
processes to reduce or
eliminate hazardous
waste production
Recycle and reuse
hazardous waste
Convert to Less Hazardous or
Nonhazardous Substances
Natural decomposition
Incineration
Thermal treatment
Chemical, physical, and
biological treatment
Dilution in air or water
Put in Perpetual
Storage
Landfill
Underground
injection wells
Surface
impoundments
Underground salt
formations
Fig. 21-17, p. 577
We Can Detoxify Hazardous Wastes
 Collect and then detoxify
 Physical methods
 Chemical methods
 Use nanomagnets
 Bioremediation
 Phytoremediation
 Incineration
 Using a plasma arc torch
TRADE-OFFS
Phytoremediation
Advantages
Disadvantages
Easy to establish
Slow (can take
several growing
seasons)
Inexpensive
Can reduce
material dumped
into landfills
Produces little
air pollution
compared to
incineration
Low energy use
Effective only at
depth plant roots
can reach
Some toxic organic
chemicals may
evaporate from
plant leaves
Some plants can
become toxic to
animals
Fig. 21-19, p. 579
We Can Store Some Forms of
Hazardous Waste
 Burial on land or long-term storage
 Deep-well disposal
 Surface impoundments
 Secure hazardous landfills
Deep-Well Disposal
Surface Impoundment in Niagara
Falls, New York, U.S.
Surface Impoundments
Solutions: Secure Hazardous
Waste Landfill
Hazardous Waste Regulation in the
United States – Need to know!
 1976: Resource Conservation and Recovery Act (RCRA) –
requires EPA to identify hazardous wastes and set
standards for their management (cradle-to-grave)
 1980: Comprehensive Environmental, Compensation, and
Liability Act (CERCLA), or Superfund - trust fund identify and clean-up sites – Polluter pays!!
 Pace of cleanup has slowed
 Superfund is broke
 Laws encouraging the cleanup of brownfields – abandoned
industrial and commercial sites that are contaminated!
(junkyards, gas stations, older landfills)
Leaking Barrels of Toxic Waste at a
Superfund Site in the United States