Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Hazardous Waste

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings I. Basics of Hazardous Waste A. Hazardous waste is defined as: 1. Ignitable = substances that easily catch fire (natural gas, alcohol) 2. Corrosive = substances that corrode metals in storage tanks or equipment 3. Reactive = substances that are chemically unstable and readily react with other compounds, often explosively or by producing noxious fumes 4. Toxic = substances that harm human health when they are inhaled, are ingested, or contact human skin

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings I. Basics of Hazardous Waste B. Hazardous wastes have diverse sources: 1. Industry = produces the largest amount of hazardous waste -But waste generation and disposal is highly regulated 2. Mining 3. Households = now the largest producer of UNREGULATED hazardous wastes -Paints, batteries, oils, solvents, cleaning agents, pesticides 4. Agriculture 5. Utilities 6. Building demolition

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings I. Basics of Hazardous Waste C. The cornerstones of integrated waste management also apply to hazardous waste management as well: 1.Produce less of it 2.Convert as much as possible to less hazardous waste 3.Put the rest in long term, safe storage * Denmark pretty much the only country that follows these priorities on a national level

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings I. Basics of Hazardous Waste D. Organic compounds are particularly hazardous because their toxicity persists over time E. Synthetic organic compounds = resist decomposition 1. Keep buildings from decaying, kill pests, and keep stored goods intact 2. Their resistance to decay causes them to be persistent pollutants (POP stands for Persistent Organic Pollutant) 3. They are toxic because they are readily absorbed through the skin 4. They can act as mutagens, carcinogens, teratogens, and endocrine disruptors

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings I. Basics of Hazardous Waste F. Hazardous definitions 1.Mutagens – substance that induces or increases the frequency of DNA mutation 2.Carcinogens – substance that tends to produce a cancer 3.Teratogens – substance that interferes with fetal development, usually leading to birth defects 4.Endocrine disruptors - defined as a substance that alters function(s) of the endocrine system, consequently harming an individual life form or its offspringendocrine system 5.Neurotoxin – Assault the nervous system

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings G. Heavy metals can be hazardous 1. Big 8: Lead, chromium, mercury, cadmium, tin, nickel, zinc, and copper 2. Used widely in industry for wiring, electronics, metal plating, pigments, and dyes 3. They enter the environment when they are disposed of improperly 4. Heavy metals that are fat soluble and break down slowly can bioaccumulate and biomagnify

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings II. Hazardous Waste Clean- Up A. For many years, hazardous waste was discarded without special treatment 1. Public did not know it was harmful to human health 2. Assumed the substances would disappear or be diluted in the environment 3. Since the 1980s, cities designate sites or special collection days to gather household hazardous waste

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings II. Hazardous Waste Clean- Up B. Resource Conservation and Recovery Act (RCRA) – 1976, 1984 = states are required to manage hazardous waste 1. Large generators of hazardous waste must obtain permits and must be tracked “from cradle to grave” 2. Intended to prevent illegal dumping 3. Only about 5% of hazardous waste is regulated by RCRA

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings II. Hazardous Waste Clean- Up C. Contaminated sites are being slowly cleaned up 1. Globally, thousands of former military and industrial sites are contaminated with hazardous waste -For most nations, dealing with these messes is too difficult, time consuming and expensive D. Comprehensive Environmental Response Compensation and Liability Act (CERCLA) (1980) (Superfund) 1. Established a federal program to clean up U.S. sites polluted with hazardous waste 2. Experts identify polluted sites, take action to protect groundwater near these sites, and clean up the pollution

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings E. Superfund 1. Later laws charged the EPA with cleaning up brownfields = lands whose reuse or development are complicated by the presence of hazardous materials 2. Two events spurred creation of Superfund legislation -In Love Canal, Niagara Falls, New York, families were evacuated after buried toxic chemicals rose to the surface, contaminating homes and an elementary school -In Times Beach, Missouri, the entire town was evacuated after being contaminated with dioxin from waste oil sprayed on roads

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings II. Hazardous Waste Clean- Up F. Once a Superfund site is identified, EPA scientists evaluate: 1. How close the site is to human habitation 2. Whether wastes are currently confined or likely to spread 3. Whether the site threatens drinking water supplies

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings II. Hazardous Waste Clean- Up G. Superfund Harmful sites are: 1. Placed on the EPA’s National Priority List 2. Ranked according to the level of risk to human health that they pose 3. Cleaned up on a site-by-site basis as funds are available H. The EPA is required to hold public hearings and inform area residents of its findings and to receive feedback

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings II. Hazardous Waste Clean- Up I. CERCLA operates under the polluter pays principle = polluting parties were to be charged for cleanup 1. However, the responsible parties often can’t be found (or businesses go bankrupt) 2. A trust fund was established by a federal tax on petroleum and chemical industries 3. The fund is bankrupt, so taxpayers now pay all costs of cleanup 4. Fewer cleanups are being completed 5. An average cleanup costs $25 million and takes years

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings III. Disposal methods for hazardous waste A.The first step to dealing with hazardous wastes is to collect them properly. B.From there, four main things can happen – physical methods, chemical methods, biological methods, and storage. C.Physical methods for detoxifying hazardous wastes include using charcoal or resins to filter out harmful solids and distilling liquid mixtures to filter out harmful chemicals. 1. Especially deadly wastes can be physically encapsulated in glass, cement, or ceramics and put in a secure storage site.

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings D. Chemical methods are used to convert hazardous chemicals to harmless or less harmful chemicals through chemical reactions. E. Some scientists and engineers consider biological methods for treating hazardous wastes to be the wave of the future. Biological methods include bioremediation and phytoremediation. 1.Bioremediation – bacteria and enzymes help destroy toxic or hazardous substances or convert them to less harmful compounds. 2.So far, more than 1,000 different types of bacteria and fungi have been used to detoxify hazardous wastes. Bioremediation takes longer to work than most physical or chemical methods, but costs much less.

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings F. Phytoremediation – involves using natural or genetically engineered plants to absorb, filter, and remove contaminants from polluted soil and water. Phytoremediation Trade Offs AdvantagesDisadvantages Easy to establishSlow (can take several growing seasons) InexpensiveEffective only at depth plant roots can reach Can reduce material dumped into landfills Some toxic organic chemicals may evaporate from plant leaves Produces little air pollution compared to incineration Some plants can become toxic to animals. Low energy use

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings G. Incineration can break down some hazardous wastes, and convert them to less toxic materials. Incineration of hazardous wastes has the same air pollution issues as incineration of solid wastes. H. A process similar to incineration is plasma arc torch, which is similar to a welding torch to create plasma (ionized gas – mostly CO 2 and H 2 ) of hazardous wastes. Plasma Arc Trade-Offs AdvantagesDisadvantages SmallHigh cost Mobile, easy to move to different sites Produces CO 2 and CO Produces no toxic ashCan release particulates and chlorine gas Can vaporize and release toxic metals and radioactive elements

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Surface impoundments I. Surface impoundments = store liquid hazardous waste 1. Shallow depressions are lined with plastic and clay 2. Water containing waste evaporates, the residue of solid hazardous waste is then transported elsewhere 3. The underlying clay layer can crack and leak waste, and rainstorms cause overflow, contaminating nearby areas

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Trade-Offs for Surface Impoundments AdvantagesDisadvantages Low construction costsGroundwater contamination from leaking liners Low operating costsAir pollution from volatile organic compounds Can be build quicklyOverflow from flooding Wastes can often be retrieved if necessaryDisruption and leakage from earthquakes Can store wastes indefinitely with secure double liners Output approach that encourages waste production

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Deep-well injection J. Deep-well injection = a well is drilled deep beneath the water table and waste is injected into it 1. A long-term disposal method 2. The well is intended to be isolated from groundwater and human contact 3. However, the wells become corroded and leak waste into soil

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Trade-offs For Deep Well Disposal AdvantagesDisadvantages Safe method if sites chosen carefullyLeaks or spills at surface Wastes can often be retrieved if problems develop Leaks from corrosion of well casing Easy to doExisting fractures or earthquakes can allow wastes to escape into groundwater Low CostOutput approach that encourages waste production