For example, a paper mill that changes its pulping chemicals might reduce the amount of toxic liquid left
FIGURE 4.1
Waste management hierarchy
over after the paper is produced. If that is not possible, perhaps the pulping liquid could be recycled and reused in the process. If not, perhaps the liquid can be burned for fuel to recover energy. If not, and the liquid requires disposal, it should be treated as necessary to reduce its toxicity before being released into the environment.
Industrial waste is categorized based on its relative harm to the environment, chiefly to human health. Most wastes produced by industry are nonhazardous. However, the potential danger from hazardous wastes is so severe that the disposal of such wastes is heavily regulated.
Hazardous Industrial Wastes
Hazardous waste is the inevitable by-product of industrialization. Manufacturers use many chemicals to create their products. Hazardous waste is generated by big industries like automobile and computer manufacturers and by small businesses like neighborhood photo shops and cleaners. Although people can reduce quantities of hazardous waste through careful management, it is not possible to eliminate hazardous residues entirely because of the continual demand for goods.
Industrial wastes are usually a combination of compounds, one or more of which may be hazardous; for example, used pickling solution from a metal processor can also contain residual acids and metal salts. A mixture of waste produced regularly as a result of the industrial process is called a waste stream, and it generally consists of diluted rather than full-strength compounds. Often, the hazardous components are diluted in a mixture of dirt, oil, or water.
Officially, hazardous waste is defined as a waste that is either listed as such in EPA regulations or exhibits one or more of the following characteristics: ignitability, corrosivity, reactivity, or toxicity (containing constituents in excess of federal standards). In 2004 the EPA had a list of more than 500 hazardous wastes. Hazardous wastes are regulated under subtitle C of the RCRA. The EPA has the primary responsibility for permitting facilities that treat, store, and dispose of hazardous waste. States can adopt more stringent regulations if they wish. Because of their potential dangers, hazardous wastes require special care when being stored, transported, or discarded.
Contamination of the air, water, and soil with hazardous wastes can frequently lead to serious health problems. The EPA estimates that roughly 1,000 cases of cancer annually, as well as degenerative diseases, mental retardation, birth defects, and chromosomal changes, can be linked to public exposure to hazardous waste. While most scientists agree that exposure to high levels of hazardous waste is dangerous, there is less agreement on the danger of exposure to low levels.
Every two years the EPA, in partnership with the states, publishes The National Biennial RCRA Hazardous Waste Report. The latest report available was published in 2003 and includes data from 2001. The report only includes wastewaters that are disposed via deep well/underground injection. All other wastewaters that are managed in wastewater treatment systems are not included.
The EPA distinguishes between large-quantity and small-quantity generators of hazardous waste. A large-quantity generator is one that
- generates at least 1,000 kilograms (2,200 pounds) of RCRA hazardous waste in any single month,
- generates in any single month or accumulates at any time at least 1 kilogram (2.2 pounds) of RCRA acute hazardous waste, or
- generates or accumulates at any time at least 100 kilograms (220 pounds) of spill cleanup material contaminated with RCRA acute hazardous waste.
Ninety percent of all hazardous waste in the United States is produced by large-quantity generators. The chemical industry is by far the largest producer, followed by petroleum refiners and the metal-processing industry.
In 2001 there were 19,024 large-quantity generators that reported the generation of 40.8 million tons of RCRA hazardous waste. The five states with the largest generation of hazardous waste were Texas (7.5 million tons), Louisiana (3.9 million tons), New York (3.5 million tons), Kentucky (2.7 million tons), and Mississippi (2.2 million tons). Together, these states accounted for 49 percent of the total quantity generated.
The remaining 10 percent of hazardous waste comes from more than 100,000 small-quantity generators—businesses that produce less than 1,000 kilograms of hazardous waste per month. Table 4.1 shows a list of typical small-quantity generators and the types of hazardous waste they produce. Hazardous wastes from small-quantity generators and households are regulated under subtitle D of the RCRA.
Household hazardous wastes include solvents, paints, cleaners, stains, varnishes, pesticides, motor oil, and car batteries. The EPA reports that Americans generate 1.6 million tons of household hazardous waste every year. The average home can have as much as 100 pounds of these wastes in basements, garages, and storage buildings. Many communities hold special collection days for household hazardous waste to ensure that it is disposed of properly.
Methods of Dealing with Hazardous Waste
A variety of techniques exist for safely managing hazardous wastes:
- Reduction—This approach reduces the waste stream at the outset. Waste generators change their manufacturing and materials in order to produce less waste. For example, a food packaging plant might replace solvent-based adhesives used to seal packages with water-based adhesives.
- Recycling—Some waste materials become raw material for another process or can be recovered, reused, or sold.
- Treatment—A variety of chemical, biological, and thermal processes can be applied to neutralize or destroy toxic compounds. For example, microorganisms or chemicals can remove hydrocarbons from contaminated water.
- Incineration—Hazardous waste can also be burned. Unfortunately incineration has a flaw—as waste is burned, hot gases spew into the atmosphere, carrying toxic materials not consumed by the flames. In 1999 the Clinton administration imposed a ban on new hazardous waste incinerators.
- Land disposal—Some hazardous wastes are buried in landfills. State and federal regulations require the pre-treatment of most hazardous wastes before they can be disposed of in landfills. These treated materials can only be placed in specially designed land disposal facilities.
In 2001 there were 2,479 treatment, storage, and disposal facilities that treated and/or disposed of 46 million tons of RCRA hazardous waste. Table 4.2 shows the management
TABLE 4.1
Typical hazardous waste generated by small businesses
| Type of business | How generated | Typical wastes | |
| Drycleaning and laundry plants | Commercial drycleaning processes | Still residues from solvent distillation, spent filter cartridges, cooked powder residue, spent solvents, unused perchloroethylene | |
| Furniture/wood manufacturing and refinishing | Wood cleaning and wax removal, refinishing/stripping, staining, painting, finishing, brush cleaning and spray brush cleaning | Ignitable wastes, toxic wastes, solvent wastes, paint wastes | |
| Construction | Paint preparation and painting, carpentry and floor work, other specialty contracting activities, heavy construction, wrecking and demolition, vehicle and equipment maintenance for construction activities | Ignitable wastes, toxic wastes, solvent wastes, paint wastes, usedoil, acids/bases | |
| Laboratories | Diagnostic and other laboratory testing | Spent solvents, unused reagents, reaction products, testing samples, contaminated materials | |
| Vehicle maintenance | Degreasing, rust removal, paint preparation, spray booth, spray guns, brush cleaning, paint removal, tank cleanout, installing lead-acid batteries, oil and fluid replacement | Acids/bases, solvents, ignitable wastes, toxic wastes, paint wastes, batteries, used oil, unused cleaning chemicals | |
| Printing and allied industries | Plate preparation, stencil preparation for screen printing, photoprocessing, printing, cleanup | Acids/bases, heavy metal wastes, solvents, toxic wastes, ink, unused chemicals | |
| Equipment repair | Degreasing, equipment, cleaning rust removal, paint preparation, painting, paint removal, spray solvents booth, spray guns, and brush cleaning | Acids/bases, toxic wastes, ignitable wastes, paint wastes | |
| Pesticide end-users/application services | Pesticide application and cleanup | Used/unused pesticides, solvent wastes, ignitable wastes, contaminated soil (from spills), contaminated rinsewater, empty containers | |
| Educational and vocational shops | Automobile engine and body repair, metalworking, graphic arts-plate preparation, woodworking | Ignitable wastes, solvent wastes, acids/bases, paint wastes | |
| Photo processing | Processing and developing negatives/prints, stabilization system cleaning | Acid regenerants, cleaners, ignitable wastes, silver | |
| Leather manufacturing | Hair removal, bating, soaking, tanning, buffing, and dyeing | Acids/bases, ignitables wastes, toxic wastes, solvent wastes, unused chemicals | |
| SOURCE: Adapted from "Typical Hazardous Waste Generated by Small Businesses," in Managing Your Hazardous Waste: A Guide for Small Businesses, U.S. Environmental Protection Agency, Office of Solid Waste, Washington, DC, December 2001 | |||
methods used by these facilities. More than 17 million tons of hazardous wastewater were injected into deep underground wells. Figure 4.2 shows a typical Class I (deep) well. There are 163 of these wells located around the country; most are in Texas (78) and Louisiana (18). Eleven of the wells are for commercial hazardous waste injection. They are the only facilities allowed to accept hazardous waste generated off-site. Ten of these wells are
TABLE 4.2
Management method, by quantity of RCRA (Resource Conservation and Recovery Act) hazardous waste managed, 2001
| Management method | Tons managed | Percentage of quantity | Number of facilities* | Percentage of facilities* |
| Deepwell or underground injection | 17,681,650 | 38.3 | 48 | 1.9 |
| Other disposal | 6,429,341 | 13.9 | 206 | 8.3 |
| Aqueous organic treatment | 4,501,963 | 9.8 | 97 | 3.9 |
| Aqueous inorganic treatment | 3,672,052 | 8.0 | 322 | 13.0 |
| Other treatment | 2,355,272 | 5.1 | 562 | 22.7 |
| Landfill/surface impoundment | 2,089,701 | 4.5 | 69 | 2.8 |
| Energy recovery | 1,700,078 | 3.7 | 105 | 4.2 |
| Incineration | 1,646,217 | 3.6 | 174 | 7.0 |
| Metals recovery | 1,461,606 | 3.2 | 191 | 7.7 |
| Stabilization | 1,269,609 | 2.8 | 243 | 9.8 |
| Other recovery | 1,026,255 | 2.2 | 97 | 3.9 |
| Fuel blending | 923,332 | 2.0 | 117 | 4.7 |
| Storage and/or transfer | 717,785 | 1.6 | 639 | 25.8 |
| Solvents recovery | 425,459 | 0.9 | 564 | 22.8 |
| Sludge treatment | 178,975 | 0.4 | 99 | 4.0 |
| Land treatment/application/farming | 65,508 | 0.1 | 14 | 0.6 |
| Total | 46,144,802 | 100.0 | 2479 | |
| *Columns may not sum because facilities may have multiple handling methods. | ||||
| SOURCE: "Exhibit 2.6. Management Method, by Quantity of RCRA Hazardous Waste Managed, 2001," in The National Biennial RCRA Hazardous Waste Report (Based on 2001 Data), U.S. Environmental Protection Agency, Office of Solid Waste and Emergency Response, Washington, DC, 2003 | ||||
located in Gulf Coast states. The other well is in the Great Lakes region. Various types of land disposal and combustion were used to dispose of most of the remaining hazardous wastes from large-quantity generators.
LAND DISPOSAL AND CONTAMINATION.
Groundwater is a major source of drinking water for many parts of the United States. If not properly constructed, land disposal facilities for hazardous waste may leak contaminants into the underlying groundwater. The RCRA imposed control over such disposal facilities to minimize their adverse environmental impacts. The EPA, in order to implement the act, requires that owners/operators of hazardous waste sites install wells to monitor the groundwater under their facilities.
SHIPPING ELSEWHERE.
Many states have refused to accept toxic trash from states that have not developed their own disposal programs. Their position has been undermined, however, by the U.S. Supreme Court's determination that waste is a commodity in interstate commerce and is subject to federal, not state, regulation.
Because of the problems in finding disposal sites, the United States is sending larger and larger amounts of toxic waste out of the country. Mexico and Central and South America have become preferred spots for disposing of sludge and incinerator ash. However, toxic waste is sometimes mislabeled nontoxic by the time it arrives in South American countries. Until 1988 Africa had been a favorite location for dumping toxic waste. At that time, however, most African countries signed agreements that restricted importation of dangerous materials.
Toxic Chemicals in Industrial Waste
The Toxics Release Inventory (TRI) was established under the Emergency Planning and Community Right-to-Know Act of 1986 (PL 99-499). Under the program, certain industrial facilities using specific toxic chemicals must report annually on their waste management activities and toxic chemical releases. More than 650 toxic chemicals are on the TRI list.
Manufacturing facilities (called "original" industries) have had to report under the TRI program since 1987. In 1998 the TRI requirements were extended to a second group of industries called the "new" industries. These include metal and coal mining, electric utilities burning coal or oil, chemical wholesale distributors, petroleum terminals, bulk storage facilities, RCRA subtitle C hazardous water treatment and disposal facilities, solvent recovery services, and federal facilities. However, only facilities with 10 or more full-time employees that use certain thresholds of toxic chemicals are included.
The 2001 Toxics Release Inventory (TRI) Public Data Release Report was published in July 2003. The report states that 26.7 billion pounds (13.4 million tons) of TRI chemicals in production-related waste were managed during 2001. The chemical manufacturing industry accounted for 40 percent of the waste, followed by the primary metals industry with 12 percent and metal mining with 11 percent. The largest amounts of production-related waste were managed by facilities in Texas, Louisiana, and Illinois.
Approximately 36 percent of the waste was recycled, while 13 percent was burned for energy recovery, and 28 percent was treated. The remainder (23 percent) was released to the environment in some way. Figure 5.18 in chapter 5 shows the distribution of TRI releases in 2001. More than half of the releases were to land disposal.
FIGURE 4.2
A typical Class I injection well
Nonhazardous Industrial Waste
Nonhazardous industrial wastes are neither hazardous wastes nor municipal wastes. Figure 4.3 shows a general breakdown of nonhazardous industrial waste by material, as reported by the Office of Industrial Technology.
Manufacturing produces huge amounts of nonhazardous waste. The paper industry, which uses many chemicals to produce paper, accounts for a very large proportion of manufacturing waste. The metal and chemical industries are also large waste producers. Many big manufacturing plants have sites on their own property where they dispose of waste or treat it so it will not become dangerous. Still others ship it to private disposal sites for dumping or for treatment. Smaller manufacturers might use private waste disposal companies or even the city garbage company.
FIGURE 4.3
Non-hazardous waste
Mining also produces much waste, most of it rock and tailings. Normally, miners have to move rock to retrieve the ore or minerals. Tailings are left over after miners have sifted through the rocks and dirt for the ore or minerals. Chemicals used to remove minerals from ore become waste after they have done their job. Sometimes these chemical wastes are liquid, and sometimes solid. Either way, they must be disposed of appropriately so as not to pollute the environment.
Almost all (96 to 98 percent) of the waste from gas and oil drilling is water. Water is either pumped out of the ground before the oil is found, or it is found mixed with oil. This water is often salt water and it must be separated from the oil and gas before these natural products can be turned into refined products for use in automobiles or home heating. Other waste comes from mud and rock extracted by the drilling process. Most oil and gas companies dispose of their own waste.
One method is called "surface impoundment," which consists of a large pond in which liquid wastes can be stored and then treated so they can be disposed of safely. Almost all wastes from oil and gas production, mining, and agriculture end up in surface impoundments.
When an electric company burns coal to heat water to make electricity, about 90 percent of the coal is burned up, but it leaves about 10 percent in the form of ash. This waste must then be discarded somewhere.
State and local governments have regulatory responsibility for the management of most nonhazardous wastes. Different states have different regulatory schemes. For example, Texas categorizes nonhazardous industrial wastes into three classes based on their potential harm to the environment and human health. Class 1 wastes include asbestos, ash, and various solids, sludges, and liquids contaminated with nonhazardous chemicals. Every four years the state evaluates its disposal capacity for Class 1 wastes. The last report available was published in 2000 and includes data for 1997. According to Needs Assessment for Industrial Class 1 Nonhazardous Waste Commercial Disposal Capacity in Texas (2000 Update) nearly 83 million tons of Class 1 waste were generated in Texas that year. The vast majority of the waste (96 percent) was liquid.
Class 2 wastes include containers that held Class 1 wastes, depleted aerosol cans, some medical wastes, paper, food wastes, glass, aluminum foil, plastics, Styrofoam, and food packaging resulting from industrial processes. Class 3 wastes include all other chemically inert and insoluble substances such as rocks, brick, glass, dirt, and some rubbers and plastics.
Industries do not have to report how much Class 2 or Class 3 wastes they generate or how they dispose of it. However, municipal solid waste landfills are required to report the receipt of all industrial waste.
User Comments Add a comment…