hazardous waste hazardous waste: is any discarded solid or liquid material that is toxic,...
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HAZARDOUS WASTEHAZARDOUS WASTE
Hazardous wasteHazardous waste: is any discarded solid or : is any discarded solid or liquid material that is toxic, ignitable, liquid material that is toxic, ignitable, corrosive, or reactive enough to explode or corrosive, or reactive enough to explode or release toxic fumes.release toxic fumes. The two largest classes of hazardous wastes are The two largest classes of hazardous wastes are
organic compounds (e.g. pesticides, PCBs, organic compounds (e.g. pesticides, PCBs, dioxins) and toxic heavy metals (e.g. lead, dioxins) and toxic heavy metals (e.g. lead, mercury, arsenic).mercury, arsenic).
What Harmful Chemicals Are in Your Home?
• Glues and cements
• Dry-cell batteries (mercury and cadmium)
• Rust inhibitor and rust remover
• Brake and transmission fluid
General
Cleaning
• Battery acid
• Wood preservatives
• Stains, varnishes, and lacquers
Automotive
• Gasoline• Used motor oil
Paint
• Latex and oil-based paints• Paint thinners, solvents, and strippers
Gardening
• Pesticides• Weed killers• Ant and rodent
killers
• Antifreeze
• Flea powders
• Disinfectants
• Septic tank cleaners• Spot removers
• Drain, toilet, and window cleaners
• Artist paints and inks
• Solvents
Hazardous Waste Regulations in the Hazardous Waste Regulations in the United StatesUnited States
Two major federal laws regulate the Two major federal laws regulate the management and disposal of hazardous management and disposal of hazardous waste in the U.S.:waste in the U.S.: Resource Conservation and Recovery Act Resource Conservation and Recovery Act
(RCRA) …(RCRA) …pronouncedpronounced RICK-ra RICK-ra
• Cradle-to-the-grave system to keep track waste.Cradle-to-the-grave system to keep track waste. Comprehensive Environmental Response, Comprehensive Environmental Response,
Compensation, and Liability Act (CERCLA)Compensation, and Liability Act (CERCLA)• Commonly known as Commonly known as SuperfundSuperfund program. program.
Hazardous Waste Regulations in the Hazardous Waste Regulations in the United StatesUnited States
The Superfund law was designed to have polluters The Superfund law was designed to have polluters pay for cleaning up abandoned hazardous waste pay for cleaning up abandoned hazardous waste sites.sites. Only 70% of the cleanup costs have come from the Only 70% of the cleanup costs have come from the
polluters, the rest comes from a trust fund financed until polluters, the rest comes from a trust fund financed until 1995 by taxes on chemical raw materials and oil.1995 by taxes on chemical raw materials and oil.
**Note: Congress did not renew this this tax, the Superfund **Note: Congress did not renew this this tax, the Superfund is now broke, taxpayers (not the polluters!) are paying the is now broke, taxpayers (not the polluters!) are paying the bill and the pace of cleanup has slowed.bill and the pace of cleanup has slowed.
National Priorities List (NPL) The worst sites that National Priorities List (NPL) The worst sites that represent an immediate and severe threat to human represent an immediate and severe threat to human healthhealth
DEALING WITH HAZARDOUS DEALING WITH HAZARDOUS WASTEWASTE
We can produce less hazardous waste and We can produce less hazardous waste and recycle, reuse, detoxify, burn, and bury what recycle, reuse, detoxify, burn, and bury what we continue to produce.we continue to produce.
Conversion to Less Hazardous Conversion to Less Hazardous SubstancesSubstances
Physical MethodsPhysical Methods: using charcoal or resins : using charcoal or resins to separate out harmful chemicals.to separate out harmful chemicals.
Chemical MethodsChemical Methods: using chemical : using chemical reactions that can convert hazardous reactions that can convert hazardous chemicals to less harmful or harmless chemicals to less harmful or harmless chemicals.chemicals.
Conversion to Less Hazardous Conversion to Less Hazardous SubstancesSubstances
Biological MethodsBiological Methods: : BioremediationBioremediation: bacteria or enzymes help : bacteria or enzymes help
destroy toxic and hazardous waste or convert destroy toxic and hazardous waste or convert them to more benign substances.them to more benign substances.
PhytoremediationPhytoremediation: involves using natural or : involves using natural or genetically engineered plants to absorb, filter and genetically engineered plants to absorb, filter and remove contaminants from polluted soil and remove contaminants from polluted soil and water.water.
PhytostabilizationPlants such as willow trees and poplars can absorb chemicals and keep them from reaching groundwater or nearby surface water.
RhizofiltrationRoots of plants such as sunflowers with dangling roots on ponds or in green-houses can absorb pollutants such as radioactive strontium-90 and cesium-137 and various organic chemicals.
PhytoextractionRoots of plants such as Indian mustard and brake ferns can absorb toxic metals such as lead, arsenic, and others and store them in their leaves. Plants can then be recycled or harvested and incinerated.
PhytodegradationPlants such as poplarscan absorb toxic organic chemicals and break them down into less harmful compounds which they store or release slowly into the air.
Inorganicmetal contaminants
Organiccontaminants
Radioactivecontaminants
Brake fernPoplar treeIndian mustardWillow treeSunflower
Oilspill
Landfill
GroundwaterSoil
PollutedleachateDecontaminated
water out
Pollutedgroundwater in
GroundwaterSoil
Inexpensive
Low energy use
Easy to establish
Trade-Offs
Phytoremediation
Advantages Disadvantages
Some plants can become toxic to animals
Some toxic organic chemicals may evaporate from plant leaves
Produces little air pollution compared to incineration
Can reduce material dumped into landfills
Slow (can take several growing seasons)
Effective only at depth plant roots can reach
Conversion to Less Hazardous Conversion to Less Hazardous SubstancesSubstances
IncinerationIncineration: heating many types of : heating many types of hazardous waste to high temperatures – up hazardous waste to high temperatures – up to 2000 to 2000 °C°C – in an incinerator can break them – in an incinerator can break them down and convert them to less harmful or down and convert them to less harmful or harmless chemicals.harmless chemicals.
Conversion to Less Hazardous Conversion to Less Hazardous SubstancesSubstances
Plasma TorchPlasma Torch: passing electrical current : passing electrical current through gas to generate an electric arc and through gas to generate an electric arc and very high temperatures can create plasma.very high temperatures can create plasma. The plasma process can be carried out in a torch The plasma process can be carried out in a torch
which can decompose liquid or solid hazardous which can decompose liquid or solid hazardous organic material.organic material.
Advantages
Trade-Offs
Plasma Arc
Small High cost
Produces no toxic ash
Can vaporize and release toxic metals and radioactive elements
Can release particulates and chlorine gas
Mobile. Easy to move to different sites
Produces CO2 and CO
Disadvantages
Long-Term Storage of Hazardous Long-Term Storage of Hazardous WasteWaste
Hazardous waste can be disposed of on or Hazardous waste can be disposed of on or underneath the earth’s surface, but without underneath the earth’s surface, but without proper design and care this can pollute the proper design and care this can pollute the air and water.air and water. Deep-well disposalDeep-well disposal: liquid hazardous wastes : liquid hazardous wastes
are pumped under pressure into dry porous rock are pumped under pressure into dry porous rock far beneath aquifers.far beneath aquifers.
Surface impoundmentsSurface impoundments: excavated depressions : excavated depressions such as ponds, pits, or lagoons into which liners such as ponds, pits, or lagoons into which liners are placed and liquid hazardous wastes are are placed and liquid hazardous wastes are stored.stored.
Fig. 22-20, p. 539
Safe method ifsites are chosencarefully
Trade-Offs
Deep Underground Wells
Advantages Disadvantages
Encourageswaste production
Existing fracturesor earthquakescan allow wastesto escape intogroundwater
Leaks fromcorrosion of wellcasing
Leaks or spills atsurface
Low cost
Easy to do
Wastes can beretrieved ifproblemsdevelop
Low construction costs
Can store wastes indefinitely with secure double liners
Groundwatercontaminationfrom leaking liners(or no lining)
Trade-Offs
Surface Impoundments
Advantages
Promotes wasteproduction
Disruption andleakage fromearthquakes
Overflow fromflooding
Air pollution fromvolatile organiccompounds
Wastes can be retrieved if necessary
Can be built quickly
Low operating costs
Disadvantages
Long-Term Storage of Hazardous Long-Term Storage of Hazardous WasteWaste
Long-Term Retrievable StorageLong-Term Retrievable Storage: Some : Some highly toxic materials cannot be detoxified or highly toxic materials cannot be detoxified or destroyed. Metal drums are used to stored destroyed. Metal drums are used to stored them in areas that can be inspected and them in areas that can be inspected and retrieved.retrieved.
Secure LandfillsSecure Landfills: Sometimes hazardous : Sometimes hazardous waste are put into drums and buried in waste are put into drums and buried in carefully designed and monitored sites.carefully designed and monitored sites.
Secure Hazardous Waste LandfillSecure Hazardous Waste Landfill
In the U.S. there In the U.S. there are only 23 are only 23 commercial commercial hazardous waste hazardous waste landfills.landfills.
What Can You Do?
• Use pesticides in the smallest amount possible.
• Use less harmful substances instead of commercial chemicals for most household cleaners. For
example use liquid ammonia to clean appliances and windows; vinegar to polish metals, clean surfaces, and remove stains and mildew; baking soda to clean household utensils, deodorize, and remove stains; borax to
remove stains and mildew.• Do not dispose of pesticides, paints, solvents, oil,
antifreeze, or other products containing hazardous chemicals by flushing them down the toilet, pouring them down the drain, burying them, throwing them into the garbage, or dumping them down storm drains.
Hazardous Waste
Case Study: LeadCase Study: Lead
Lead is especially Lead is especially harmful to children harmful to children and is still used in and is still used in leaded gasoline and leaded gasoline and household paints in household paints in about 100 countries.about 100 countries.
Case Study: Case Study: MercuryMercury
Mercury is released Mercury is released into the into the environment mostly environment mostly by burning coal and by burning coal and incinerating wastes incinerating wastes and can build to and can build to high levels in some high levels in some types of fish.types of fish.
BIOMAGNIFICATION IN FOOD CHAIN
SEDIMENT
PRECIPITATIONPRECIPITATION WINDSWINDS
AIR
WATER
Inorganic mercury and acids
(Hg2+)
Inorganic mercury and acids (Hg2+)
Organicmercury (CH3Hg+)
Inorganicmercury (Hg2+)
Hg2+ and acids
Runoff of Hg2+ and acids
Large fish
Small fish
ZooplanktonPhytoplankton
Hg and SO2Hg2+ and acids
Human sources
Incinerator
Coal-burning plant
Elemental mercury
vapor (Hg)
Photo-chemical
OxidationElemental
mercury liquid (Hg)
Deposition
De
po
sit
ion
Bacteria
Bacteria and acids
Settles out
Settles out Settles
outV
ap
oriza
tion
De
po
sit
ion
De
po
sitio
n
ACHIEVING A LOW-WASTE ACHIEVING A LOW-WASTE SOCIETYSOCIETY
In the U.S., citizens have kept large numbers In the U.S., citizens have kept large numbers of incinerators, landfills, and hazardous of incinerators, landfills, and hazardous waste treatment plants from being built in waste treatment plants from being built in their local areas.their local areas.
Environmental justice means that everyone is Environmental justice means that everyone is entitled to protection from environmental entitled to protection from environmental hazards without discrimination.hazards without discrimination.
Making the Transition to a Low-Waste Making the Transition to a Low-Waste Society: A New VisionSociety: A New Vision
Everything is connected.Everything is connected. There is no “away” for the wastes we There is no “away” for the wastes we
produce.produce. Dilution is not always the solution to pollution.Dilution is not always the solution to pollution. The best and cheapest way to deal with The best and cheapest way to deal with
wastes are reduction and pollution wastes are reduction and pollution prevention.prevention.