HAZARDOUS WASTE Hazardous waste: is any discarded solid or liquid material that is toxic, ignitable, corrosive, or reactive enough to explode or release

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.


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


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.


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.

Documents

HAZARDOUS WASTE Hazardous waste: is any discarded solid or liquid material that is toxic, ignitable, corrosive, or reactive enough to explode or release