Environmental Encyclopedia

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Environmental Encyclopedia 3

Solid waste landfilling

many believe, requires an integrated approach that includes

reduction,

recycling

composting

, and landfilling, along

with incineration.

[Linda Rehkopf]

ESOURCES

OOKS

Clarke, M. Improving Environmental Performance of MSW Incinerators. New

York: INFORM, 1988.

THER

Denison, R. A., and J. Ruston, eds. Recycling and Incineration: Evaluating

the Choices. New York: Environmental Defense Fund, 1990.

Solid waste landfilling

The

Resource Conservation and Recovery Act

(RCRA)

defines

solid waste

garbage

, refuse,

sludge

from

sew-

age treatment

plants, ash from incinerators, mining waste,

construction and demolition materials. It also includes some

small quantities of

hazardous waste

. There are several

acceptable methods for disposing of these wastes. These

include

incineration

composting

recycling

, industrial

surface impoundments, and landfills. In terms of personal

inconvenience, disposing of waste in landfills is easier than

the other methods. Waste can have any shape or condition

prior to being placed into a

landfill

. This is different from

composting and incineration. Waste to be composted must

biodegradable

and have maximal surface area to hasten

the process of composting. Waste to be incinerated must be

combustible and be reduced into small pieces to maximize

surface area and promote burning. Waste to be disposed of

in a landfill is usually broken down with heavy machinery,

then compacted and placed into specially prepared sites.

Formerly, waste was dumped into unused sand or gravel

pits. In 2002, most waste is placed into sanitary landfills.

These are specially prepared sites into which drains and

special linings have been installed prior to the placement of

waste. In sanitary landfills, waste is compacted each day and

covered with a layer of dirt to decrease odor and discourage

flies and other organisms such as rats, mice and birds that

can transmit disease.

In 1960, each American generated 2.7 lb (1.2 kg) of

solid waste. This grew to 4.3 lb (1.9 kg) per person by 1990.

Americans continue to generate more solid waste each day

but the rate of growth has decreased. In 2000, each person

generated 4.5 lb (2.0 kg) each day. The population also

continues to increase. The net effect is to create increased

amounts of municipal waste. The supply of available landfill

space is rapidly decreasing. The attitude of

not in my back-

yard

(NIMBY) further slows the development and con-

struction of new landfills. With fewer landfills, the cost

1327

of sanitary waste disposal has dramatically increased. The

composition of waste dumped into landfills is also important

in terms of capacity and useful life. For instance,

plastics

account for 8% of

municipal solid waste

by weight, but

more than 21% by volume. In an attempt to conserve land

space and reduce other, long term problems, some munici-

palities have banned the deposition of certain materials such

as car batteries, used tires, motor oil,

yard waste

, and

appliances.

In 1980, 81% of solid waste was buried in landfills;

in 1990 the amount had decreased to 67%. In 2000, the

amount of solid waste put into landfills again increased to

approximately 75%. This decrease through 1990 was the

result of a concentrated effort by federal and local organiza-

tions to address problems associated with landfills. Experts

differ as to the reasons for the increase. Many attribute it

to decreased participation in recycling programs. In addition,

contamination of surface and ground waters near landfills

has been reported for the past two decades. Because of these

and other health-related problems associated with landfill

use, the

Environmental Protection Agency

(EPA) contin-

ues to recommend source reduction, recycling, and incinera-

tion as the preferred

waste management

solutions. Placing

solid waste in landfills is the least desirable method for

disposing of solid waste. However, it is an acceptable alterna-

tive that is far superior to unrestricted dumping.

[L. Fleming Fallon Jr., M.D., Dr.P.H. ]

ESOURCES

OOKS

Kreith, F. Handbook of Solid Waste Management. New York: McGraw

Hill, 2002.

McDougall, F. R. Integrated Solid Waste Management: A Life Cycle Inven-

tory. 2nd ed. Oxford, U.K.: Blackwell, 2001.

Thomas-Hope, E. Solid Waste Management. Kingston, Jamaica: University

Press of the West Indies, 2000.

ERIODICALS

Fabbricino, M. “An Integrated Programme for Municipal Solid Waste

Management.” Waste Management Research 19, no. 5 (2001): 368–379.

Wilson, E. J. “Life Cycle Inventory for Municipal Solid Waste Manage-

ment.” Waste Management Research 20, no. 1 (2002): 16–22.

Youcai Z., C. Zhugen, S. Qingwen, and H. Renhua. “Monitoring and

Long-term Prediction of Refuse Compositions and Settlement in Large-

scale Landfill.” Waste Management Research 19, no. 2 (2001): 160–168.

THER

“The Basics of Landfills.” Environmental Justice Advocates. April 9, 2001

[cited July 2002]. <http://www.ejnet.org/landfills>.

Paddock, Todd. “Looking into Landfills.” Academy of Natural Sciences. June

1989 [cited July 2002]. <http://www.acnatsci.org/research/kye/land-

fills.html>.

“Solid Waste.” Annenberg Foundation. 1997–2002 [cited July 2002]. <http://

www.learner.org/exhibits/garbage/solidwaste.html>.

Environmental Encyclopedia 3

Solid waste recycling and recovery

U.S. Environmental Protection Agency. “Landfills.” Industrial Water Pollu-

tion Controls. May 14, 2002 [cited July 2002]. <http://www.epa.gov/ost/

guide/landfills>.

U.S. Environmental Protection Agency. “MSW Disposal.” Municipal Solid

Waste. July 10, 2002 [cited July 2002]. <http://www.epa.gov/epaoswer/non-

hw/muncpl/disposal.htm>.

Solid waste management

see

Waste management

Solid waste recycling and recovery

Recycling

is the recovery and

reuse

of materials from

wastes.

Solid waste

recycling refers to the reuse of manu-

factured goods from which resources such as steel,

copper

plastics

can be recovered and reused. Recycling and

recovery is only one phase of an integrated approach to

solid

waste management

that also includes reducing the

amount of waste produced,

composting

, incinerating, and

landfilling.

Municipal solid waste

(MSW) comes from house-

hold, commercial, institutional, and light industrial sources,

and from some hospital and laboratory sources. In 2000

the United States produces nearly 232 million tons (210.5

million metric tons) of MSW per year, almost 4.5 lb (2 kg)

per resident per day. The percentages of MSW generated

in this country include paper and paperboard, 38.1%; yard

wastes, 12.1%; metals, 7.8%; glass, 5.5%;

rubber

, textiles,

leather and wood, 11.9%; food wastes, 10.9%; plastics,

10.5%; and other, 3.2%.

Recycling is a significant way to keep large amounts

of solid waste out of landfills, conserve resources, and save

energy. As of 2000, Americans recovered, recycled, or com-

posted 30.1% of MSW, incinerated 14.5%, and landfilled

55.3%.

The technology of recycling involves collection, sepa-

ration, preparing the material to buyer’s specifications, sale

to markets, processing, and the eventual reuse of materials.

Separation and collection is only the first step; if the material

is not also processed and returned to commerce, then it is

not being recycled. In many parts of the country, markets

are not yet sufficiently developed to handle the growing

supply of collected material.

Intermediate markets for recyclable materials include

scrap dealers or brokers, who wait for favorable market con-

ditions in which to sell their inventory. Final markets are

facilities where recycled materials are converted to new prod-

ucts, the last phase in the recycling circle.

1328

The materials recycled today include

aluminum

, pa-

per, glass, plastics, iron and steel, scrap tires, and used oil.

Aluminum, particularly cans, is a valuable commodity. By

the late 1980s, over 50% of all aluminum cans were recycled.

Recycling aluminum saves a tremendous amount of energy:

it takes 95% less energy to produce an aluminum can from

an existing one rather than from ore. Other aluminum prod-

ucts that are recycled include siding, gutters, door and win-

dow frames, and lawn furniture.

Over 40% of the paper and paperboard used in the

U.S. is collected and utilized as either raw material to make

recycled paper, or as an export to overseas markets. Recycled

paper shows up in newsprint, roofing shingles, tar paper,

and insulation. Other recyclable paper products include old

corrugated containers, mixed office waste, and high-grade

waste paper. Contaminants must be removed from paper

products before the remanufacture process can begin, how-

ever, such as food wastes, metal, glass, rubber, and other

extraneous materials.

The market for crushed glass, or cullet, has increased.

Recycled glass is used to make fiberglass and new glass

containers. About 1.25 million tons (1.14 million metric

tons) of glass is recycled annually in the United States.

Three types of plastic are successfully being recycled,

the most common being PET (polyethylene terephthalate),

or soft drink containers. Recycled PET is used for fiberfill

in sleeping bags and ski jackets, carpet backing,

automobile

bumpers, bathtubs, floor tiles, and paintbrushes. HDPE

plastic (high density polyethylene) is used for milk jugs and

the bottoms of soft drink bottles. It can be recycled into

trash cans and flower pots, among other items.

Polystyrene

foam is crushed into pellets and turned into plastic lumber

for benches and walkways. Commingled plastics are recycled

into fence posts and park benches.

Iron and steel are the most recycled materials used

today. In 1987, 51 million tons (46 million metric tons)

were recycled, more than twice the amount of all other

materials combined. The material is remelted and shaped

into new products.

More than one billion discarded tires are stockpiled

in the United States, but scrap tires can be shredded and

used for asphalt-rubber or retreading; are incinerated for

fuel; or used to construct artificial marine reefs.

Used oil is a valuable resource, and of the 1.2

billion gal (4.5 billion L) generated annually, two-thirds

is recycled. The rest, about 400 million gal (1.5 billion

L), is disposed of or dumped. About 57% of used oil is

reprocessed for fuel, 26% is refined and turned into base

stock for use as lubricating oil, and about 17% is recycled

for other uses.

Composting is the

aerobic

biological

decomposition

organic waste

materials, usually lawn clippings. Com-

Environmental Encyclopedia 3

Solid waste volume reduction

posting is not an option for a major portion of the solid

waste stream

, but is an important component of the

re-

source recovery

program.

Recycling collection methods vary, but curbside collec-

tion is the most popular and has the highest participation

rates. It is also the most expensive way for municipalities to

collect

recyclables

in their communities. Collection centers

do not yield as many recyclables because residents must do

the sorting themselves, but centers offer the most affordable

method of collection.

Precycling

is an option that is gaining widespread

recognition in this country. Basically, precycling refers to

the consumer making environmentally sound choices at the

point of purchase. It includes avoiding products with extra

packaging, or products made to satisfy only short-term

needs, such as disposable razors.

Resource recovery or materials recovery is the recycling

of waste in an industrial setting. It does not involve recycling

consumer waste or municipal solid waste, but includes re-

processed industrial material that, for whatever reason, is

not able to be used as it was initially intended. Some con-

sumer groups are pressing for government guidelines on

labeling packaging or products “reprocessed” as opposed to

“recycled.”

While the

Environmental Protection Agency

(EPA)

insists that no single alternative to the municipal solid waste

problem should be relied upon, its generally accepted hierar-

chy of waste management alternatives is 1) source reduction

and 2) reusing products. Waste that is not generated never

enters the waste stream.

If recycling is to be used as a genuine MSW manage-

ment alternative rather than a “feel good” way to conserve

resources, then materials must be recovered and made into

new products in large quantities. For some materials, how-

ever, an insufficient market exists, so communities must pay

to have some recyclable materials taken away until a market

is developed. Recycling programs depend on the will of the

community to follow through, and in many areas, response is

weak and enforcement lacking. However, dwindling

landfill

space in the 1990s may force communities to mandate recycl-

ing programs.

Recent EPA regulations seriously affected the num-

ber of operable landfills. The requirements include install-

ing liners, collecting and treating liquids that leach, moni-

toring

groundwater

and surface water for harmful

chemicals

, and monitoring the escape of

methane

gas.

These regulations will increase the number of corporate-

run landfills, but the cost of building and maintaining a

landfill that adheres to the regulations will top $125

million. The end cost to consumers to have trash hauled

1329

away may also force many

garbage

makers to become

reducers, reusers, and recyclers.

[Linda Rehkopf]

ESOURCES

OOKS

Kharbanda, O. P., and E. A. Stallworthy. Waste Management: Towards a

Sustainable Society. Westport, CT: Auburn House/Greenwood, 1990.

Robinson, W. D., ed. The Solid Waste Handbook. New York: Wiley, 1986.

ERIODICALS

Franklin, W. E., and M. A. Franklin. “Recycling.” The EPA Journal (July-

August 1992): 7.

THER

Solid Waste Recycling: The Complete Resource Guide. Washington, DC: Bu-

reau of National Affairs, 1990.

Solid waste volume reduction

Solid waste

volume reduction can take place at several

points in the

waste management

process. Solid waste

volume reduction can take the form of

precycling

reuse

behavior on the part of consumers. This behavior reduces

solid waste at the source and prevents materials from ever

entering the

waste stream

. Precycling on the part of con-

sumers is the best initial activity to reduce the volume of

solid waste. Reuse is also a measure that prevents or delays

the

migration

of materials to the

landfill

. Once the decision

is made that a product is no longer useful and needs to be

discarded, there are several management techniques that can

be used.

Recycling

diverts large volumes of materials from the

waste stream to a manufacturing process. Glass, plastic, pa-

per, cardboard, and other clean, source-separated materials

are well-suited for use in the manufacture of new products.

As markets become more readily available, the volume of

materials that end up in landfills will be reduced even more.

Such troublesome wastes as tires, appliances and construc-

tion debris are targets of serious recycling efforts because

they are large-volume items, take up a lot of space in landfills,

and do not provide good fuel for waste-to-energy facilities in

their discarded state. Once

recyclables

have been separated

from the waste stream, solid waste can be further reduced

in volume through several methods.

Compaction

of waste materials after

source separa-

tion

is useful for two reasons. Compaction prepares waste

for efficient transport by truck, boat or rail car to landfills

or other waste disposal facilities. Compacted waste takes up

less space in a landfill, thereby extending the life of the

landfill. In some cases, compacted waste can be stored for

later disposal. It must be understood that the compaction

Environmental Encyclopedia 3

Solidification of hazardous materials

of waste should only be done after all recyclables have been

removed since this process contaminates post-consumer ma-

terials and makes it almost impossible to recover them for

a manufacturing process.

Incineration

has long been accepted as a waste volume

reduction technique. The burning of solid waste can reduce

the volume by 95%. In the early 1920s, incineration was

used to reduce waste materials to what was thought of as a

harmless ash. We now know that contaminants can become

concentrated in the ash, qualifying it as a

hazardous waste

It wasn’t until the mid-1970s that waste-to-energy facilities

using incineration were considered a viable option, as a con-

sequence of the added benefit of energy supply. Most states

now require that the residual ash from burning

municipal

solid waste

be landfilled in a monofill. A monofill is a

landfill compartment that can only be used for incinerator

ash.

Composting

is another volume reduction technique

that can divert large volumes of waste material from the

waste stream. Leaves, grass clippings and tree prunings can

be reduced in volume through an active composting process

both in the backyard and in municipal composting yards.

Individual homeowners can compost in their back yards by

using simple rounds of wire fencing placed in a shady, cool

corner. The composting materials need to be managed

through the addition of moisture, temperature monitoring,

and frequent turning, until they become a rich

soil

for the

garden. Municipal yards perform the same process on a

much larger scale and then use the resulting soil in city parks

or give it back to the homeowners for personal use. These

solid waste volume reduction techniques for organics in the

waste stream are simple and low cost and can be very ef-

fective.

Methods for encouraging solid waste volume reduction

at the individual household level consist of various incentive

programs. The most common technique is a system of vol-

ume-based user fees. With this method, homeowners are

given free bags into which they can put anything that is

designated by the city as a recyclable material. Distinctly

different bags are sold at the local grocery store or city hall.

These bags usually sell for somewhere between $2 and $5

a package and must be used for all materials destined for

disposal. Homeowners who want to reduce their

garbage

disposal costs would try to reduce the number of purchased

bags they need to use. They can do this through a concerted

effort of solid waste volume reduction. Careful decisions at

the supermarket to reduce packaging and single-use items,

reuse of packaging and containers, careful source separation

of recyclables, and composting of all organically based mate-

rials can reduce the volume of solid waste considerably and

reduce the cost of garbage service. An even greater effort

can be launched by dedicated individuals by taking used

1330

clothing to consignment shops or donating it to organiza-

tions for distribution to needy populations, taking clothes

hangers back to cleaning establishments, and requesting that

junk mail no longer be sent to their households. Of course,

there is also the ongoing debate on using

disposable dia-

pers

, which greatly add to the volume of the waste stream.

Businesses that contribute to the reduction of solid

waste are those that have been set up to take back, repair,

and reuse products and materials that would otherwise end

up in the waste stream. Small appliance repair shops can

recondition appliances and resell them. Businesses that repair

wood pallets make a relatively new contribution to the effort

to reduce the waste volume. Tires are being chipped for fuel

in waste-to-energy incinerators, and are also being pulverized

for use in soils for playing fields. All of these volume reduc-

tion techniques have a significant effect on how we live and

how we do business. The goal of solid waste volume reduc-

tion is to view the waste stream as a resource to be “mined,”

leaving only those items behind that have truly outlived their

usefulness. See also Solid waste incineration; Yard waste

[Cynthia Fridgen]

ESOURCES

OOKS

Blumberg, L., and R. Gottlieb. War on Waste: Can America Win Its Battle

With Garbage? Covelo, CA: Island Press, 1989.

Kharbanda, O. P., and E. A. Stallworthy. Waste Management: Toward a

Sustainable Society. Westport, CT: Auburn House/Greenwood, 1990.

Noyes, R., ed. Pollution Prevention Technology Handbook. Park Ridge, NJ:

Noyes Press, 1993.

ERIODICALS

Porter, J. W., and J. Z. Cannon. “Waste Minimization: Challenge for

American Industry.” Business Horizons 35 (March-April 1992): 46–9.

Solidification of hazardous materials

Solidification refers to a process in which waste materials

are bound in a solid mass, often a monolithic block. The

waste may or may not react chemically with the agents used

to create the solid. Solidification is generally discussed in

conjunction with stabilization as a means of reducing the

mobility of a pollutant. Actually, stabilization is a broad

term which includes solidification, as well as other chemical

processes that result in the transformation of a

toxic sub-

stance

to a less or non-toxic form.

Experts often speak of the technologies collectively

as solidification and stabilization (S/S) methods. Chemical

fixation, where chemical bonding transforms the toxicant to

non-toxic form, and encapsulation, in which toxic materials

are coated with an additive are processes referred to in discus-

sions of S/S methods. There are currently about 40 different

Environmental Encyclopedia 3

Solidification of hazardous materials

vendors of S/S services in the United States, and though the

details of some processes are privileged, many fundamental

aspects are widely known and practiced by the companies.

S/S technologies try to decrease the solubility, the

exposed surface area, and/or the toxicity of a

hazardous

material

. While the methods also make wastes easier to

handle, there are some disadvantages. Certain wastes are not

good candidates for S/S. For example, a number of inorganic

and organic substances interfere with the way that S/S addi-

tives will perform, resulting in weaker, less durable, more

permeable

solids or blocks. Another disadvantage is that

S/S often double the volume and weight of a waste material,

which may greatly affect

transportation

and final disposal

costs (not considering potential costs associated with un-

treated materials contaminating the

environment

). S/S ad-

ditives, such as encapsulators, are available that will not

increase the weight and volume of the wastes so dramatically,

but these additives tend to be more expensive and difficult

to use.

Methods for S/S are characterized by binders, reaction

types, and processing schemes. Binders may be inorganic or

organic substances. Examples of inorganic binders which are

often used in various combinations include cements, lime,

pozzolans, which react with lime and moisture to form a

cement such as

fly ash

, and silicates. Among the organic

types generally used are epoxies, polyesters, asphalt, and

polyolefins (e.g. polyethylene). Organic binders have also

been mixed with inorganic types, e.g., polyurethane and

cement. The performance of a binder system for a given

waste is evaluated on a case-by-case basis; however, much

has been learned in recent years about the compatibility and

performance of binders with certain wastes, which allows

for some intelligent initial decisions related to binder selec-

tion and processing requirements.

Among the types of reactions used to characterize S/

S are

sorption

, pozzolan, pozzolan-portland cement, and

thermoplastic microencapsulation. Sorption refers to the ad-

dition of a solid to sorb free liquid in a waste. Activated

carbon

, gypsum, and clays have been used in this capacity.

Pozzolan reactions typically involve adding fly ash, lime, and

perhaps water to a waste. The mixture of fly ash, lime,

and water form a low-strength cement that physically traps

contaminants. This system is very alkaline and therefore may

not be compatible with certain wastes. For example, a waste

containing high amounts of ammonium ions would pose a

problem because, under highly alkaline conditions, the toxic

gas ammonia would be released. Also, sodium borate, carbo-

hydrates, oil, and grease are known to interfere with the

process.

The pozzolan-portland cement process consists of

adding a pozzolan, often fly ash, and a portland cement to

a waste. It may be necessary to add water if enough is not

1331

present in the waste. The resulting product is a high-strength

matrix that primarily entraps contaminants. The perform-

ance of the system can be enhanced through the use of

silicates to prevent interference by metals, clays to absorb

excessive liquids and certain ions, surfactants to incorporate

organic solvents, and a variety of sorbents that will hold on

to toxicants as the solid matrix forms. Care is needed in

selecting a sorbent because, for example, an acidic sorbent

might dissolve a metal hydroxide, thereby increasing the

mobility of the metal, or result in the release of toxic gases

such as

hydrogen

sulfide or hydrogen cyanide. Borates, oil,

and grease can also interfere with this process.

Thermoplastic encapsulation is accomplished by

blending a waste with materials such as melted asphalt,

polyethylene, or wax. The technique is more difficult and

costly than the other methods introduced above because

specialized equipment and higher temperatures are required.

At these higher temperatures it is possible that certain haz-

ardous materials will violently react. Additionally, it is known

that high salt levels, certain organic solvents, and grease will

interfere with the process.

There are basically four categories of processing

schemes for S/S. For in-drum processing, S/S additives and

waste are mixed and allowed to solidify in a drum. The drum

and its contents are then disposed. In-plant processing is

a second category which refers simply to performing S/S

procedures at an established facility. The facility might have

been designed by a company for their own wastes or as a

S/S plant which serves a number of industries.

A third category is mobile-plant processing, in which

S/S operations are moved from site to site. The fourth cate-

gory is in-situ processing which involves adding S/S additives

directly to a

lagoon

contaminated soil

As may be inferred from the above discussion, the

goals of S/S operations are to remove free liquids from

a waste, generate a solid matrix that will reliably contain

hazardous materials, and/or create a waste that is no longer

hazardous. The first goal is important because current regu-

lations in the

Resource Conservation and Recovery Act

(RCRA) stipulate that free liquids are not to be disposed of

in a

landfill

. The third goal is obviously important because

disposing of a

hazardous waste

, called delisting, is much

more costly and time-consuming than disposing of a regular

waste.

Wastes are deemed to be hazardous on the basis of

four characteristic tests and a series of listings. The tests

are related to the ignitability, reactivity, corrosiveness, and

extraction procedure (EP) toxicity of the waste. It is possible

that S/S procedures delist a waste in any of the four test

characteristics. The processes may also chemically transform

a substance listed as hazardous waste by the

Environmental

Protection Agency

(EPA) into a non-hazardous chemical.

Environmental Encyclopedia 3

Sonic boom

However, S/S techniques generally delist a waste through

effecting a change in the results of the EP toxicity test,

related to the goal of proper containment. If a waste can be

contained well, it may pass the extraction test.

The extraction procedure has changed somewhat in

recent years. Originally, the

solid waste

to be tested was

stirred in a weakly acidic solution overnight, and then the

supernatant was tested for certain inorganic and organic

agents. Recently, the test has been replaced by what is known

as the Toxicity Characteristic Leaching Procedure (TCLP).

Shortcomings of the original extraction procedure were rec-

ognized some years ago, as Congress directed the EPA to

develop a more reliable, second generation test through the

Hazardous and Solid Waste Amendments of 1984. Work

on the TCLP test actually began in 1981. In the TCLP, a

solid waste is again suspended in an acidic solution, but the

method of contacting the liquid with the solid has been

changed. The suspension is now placed in a container that

revolves about a horizontal axis, tumbling solids amidst the

extracting solution. The extraction is allowed to proceed for

18 hours, after which time the solution is filtered and tested

for a variety of organic and inorganic substances. The number

of compounds tested under the TCLP is greater than the

number measured for the original EP test. Failing the TCLP

test dictates that a waste is hazardous and must be managed

as such. See also Hazardous Materials Transportation Act

(1975); Storage and transport of hazardous materials

[Gregory D. Boardman]

ESOURCES

OOKS

Freeman, H. M. Standard Handbook of Hazardous Waste Treatment and

Disposal. New York: McGraw-Hill, 1989.

Martin, E. J., and J. H. Johnson. Hazardous Waste Management Engineering.

New York: Van Nostrand Reinhold, 1987.

Wentz, C. A. Hazardous Waste Management. New York: McGraw-Hill,

1989.

THER

U.S. Environmental Protection Agency. “Background Document: Toxicity

Characteristic Leaching Procedure.” Report No. PB87-154886, Washing-

ton, DC: 1986.

U.S. Environmental Protection Agency. “Guide to the Disposal of Chemi-

cally Stabilized and Solidified Waste.” Report No. SW-872, Washington,

DC: 1980.

Sonic boom

When an object moves through a fluid, it displaces that fluid

in the form of a shock wave. The path left by a speedboat

in water is an example of a shock wave. A sonic boom is a

special kind of shock wave produced when an object travels

though air at a speed greater than the speed of sound (1,100

1332

ft/sec [335 m/sec] at sea level). Supersonic aircraft, such as

the Concorde, produce a sonic boom when they fly faster

than the speed of sound. A number of adverse environmental

effects have been attributed to sonic booms from supersonic

airplanes. These include the breaking of windows and the

frightening of animals and people.

Sorption

Term generally referring to either

adsorption

absorp-

tion

. Adsorption is the process by which one material atta-

ches itself to the surface of a second material. Some air

pollutants settle out and coat the outer surface of a building,

for example. Absorption is the process by which one material

soaks into a second material. Liquid air pollutants may actu-

ally soak into the surface of a building. The term sorption

is most commonly used when the exact process involved,

adsorption or absorption, is unknown. Various sorption

methods are employed to reduce pollutants from contami-

nated air and water. See also Pollution control

Source reduction

see

Solid waste

Source separation

Source separation is the segregation of different types of

solid waste

at the location where they are generated (a

household or business). The number and types of categories

into which wastes are divided usually depends on the collec-

tion system used and the final destination of the wastes.

The most common reason for separating wastes at the source

is for

recycling

Recyclables

that are segregated from other

trash are usually cleaner and easier to process. Yard wastes

are often separated so they may be composted or used as

mulch

. Some experimental municipal recycling projects also

require homeowners to separate household compostibles

such as food scraps, coffee grounds, bones, and

disposable

diapers

. Some studies suggest that as much as 30% of

household waste

may be compostible; another 40% may

be recyclable.

Separate collection of household trash, recyclables, and

yard waste

is gaining popularity in the United States. In

some communities source separation is mandated, while in

others it is voluntary. Many cities provide residents with

recycling bins to be filled with recyclables and placed next

garbage

cans on collection day. Source-separated yard

waste is usually placed in plastic bags or bundled if it is

bulky, like tree trimmings. In areas where curbside collection

of recyclables and yard waste is not available, residents often

Environmental Encyclopedia 3

South

take these source-separated wastes to drop-off centers, or

sell recyclables to buy-back facilities. For source-separated

recycling programs to be successful, citizen participation is

essential. Incentives to increase participation, such as reduced

trash collection charges for recyclers, are sometimes imple-

mented.

Household recyclables that are source separated from

trash can either be commingled (all recyclables mixed to-

gether in one container) or segregated into individual con-

tainers for each material (i.e., glass, newspaper,

aluminum

Commingled recyclables are eventually separated manually,

mechanically, or by some combination of both at transfer

stations or materials recovery facilities. In some cases, com-

mingled recyclables are manually separated at the curbside by

the collection crew. Recyclables that residents have separated

into individual containers are usually collected in trucks with

compartments for each material. The collected materials are

then processed further at materials-recovery facilities or other

types of recycling plants.

Many businesses also separate their solid wastes. This

can be as simple as placing recycling bins next to soda-

vending machines in employee cafeterias or more complex

separation systems on assembly lines. One of the most preva-

lent wastes from the commercial sector is corrugated card-

board (13% of

municipal solid waste

generated). Once it

becomes contaminated by other wastes, it may not be suitable

for recycling. Some businesses find it easier and more eco-

nomical to separate and bale corrugated cardboard for recycl-

ing because this can reduce their waste-disposal costs.

Source-separation programs can reduce the undesir-

able effects of landfills or incinerators. For instance, batteries

and household

chemicals

can increase the toxicity of

landfill

leachate, air emissions from incinerators, and incinerator

ash. In addition, some potentially noncombustible wastes,

such as glass, can reduce the efficiency of incinerators. Re-

ducing the volume of residual ash is another incentive for

diverting wastes from

incineration

Recyclables and special wastes can be retrieved from

the

waste stream

without source separation programs.

Many communities find it more convenient or economical

to separate wastes after collection. In these programs, recy-

clables and special wastes are manually or mechanically sepa-

rated at transfer stations or materials-recovery facilities. Sep-

arating recyclables in this way may require more labor and

higher energy costs, but it’s more convenient for residents

since it requires no extra effort beyond regular trash disposal

procedures.

Source separation may be only one part of an overall

community recycling program. These, in turn, are compo-

nents of more comprehensive waste-management strategies.

To reduce the environmental impact of waste disposal, the

Environmental Protection Agency

(EPA) encourages

1333

communities to develop strategies to decrease landfill use

and lower the risks and inefficiencies of incineration.

Waste

reduction

and recycling are considered to be the most envi-

ronmentally beneficial methods to manage waste.

[Teresa C. Donkin]

ESOURCES

THER

U.S. Congress, Office of Technology Assessment. Facing America’s Trash:

What Next for Municipal Solid Waste. Washington, DC: U.S. Government

Printing Office, October 1989.

U.S. Environmental Protection Agency, Solid Waste and Emergency Re-

sponse. Characterization of Municipal Solid Waste in the United States: 1990

Update. Washington, DC: U.S. Government Printing Office, June 1990.

U.S. Environmental Protection Agency, Solid Waste and Emergency Re-

sponse. Decision-Makers Guide to Solid Waste Management. Washington,

DC: U.S. Government Printing Office, November 1989.

South

The

United Nations Earth Summit

, held in Rio de Janeiro

in June of 1992, illuminated some major differences among

the nations of the world, differences that are summarized

in the terms North and South. The latter term refers to

nations of the Southern Hemisphere—nations that have

significantly different environmental concerns from those of

their northern neighbors. These concerns arise primarily

from rapid

population growth

; low levels of technological

and industrial development; and generally difficult living

conditions.

The distinction between North and South did not

originate with the Rio conference. It was popularized by a

report delivered in 1980 to the Secretary-General of the

United Nations by a commission headed by Willy Brandt

(1913-1992), the former Chancellor of West Germany. The

report, which was entitled To Ensure Survival— Common

Interests of the Industrial and Developing Countries, is some-

times referred to as the Brandt Report. It recommended a

marked rise in development assistance from the developed

countries to the countries of the South. The rich countries

were to increase their official development assistance (ODA)

to 0.7% of their gross national product (GNP) by 1985, and

to 1% by 2000. The Brandt Report was followed by a second

study in 1983, Common Crisis North–South: Cooperation for

World Recovery. This report predicted conflict and catastro-

phe if the imbalance between North and South were not

corrected.

An important conclusion that was drawn from the Rio

conference is that the marked differences between North

and South must somehow be reduced if global problems are

ever to be solved. Twenty years after the Brandt Report,

however, the results are discouraging. Instead of an increase

Environmental Encyclopedia 3

Spaceship Earth

in ODA, there has been a marked decrease, in terms of both

absolute dollar amounts and GNP percentages. As of 2002,

financing for the development of the South is in serious

crisis. ODA contributions by all OECD countries fell from

a high of $59.6 billion (in US dollars) in 1994 to an estimated

$56.0 billion in 1999. ODAs share of the North’s GNP fell

accordingly from 0.30–0.24%. Policy recommendations that

were made in 2001 included a proposal to finance the costs

of development by an international tax on energy consump-

tion and

carbon dioxide

emissions.

[Rebecca J. Frey Ph.D.]

ESOURCES

OOKS

Kaul, Inge, Isabelle Grunberg, and Marc A. Stern. Global Public Goods:

International Cooperation in the Twenty-First Century. New York: Oxford

University Press, 1999.

Reid, David. Sustainable Development: An Introductory Guide. London, UK:

Earthscan, 1995.

THER

Martens, Jens. Overcoming the Crisis of ODA—The Case for a Global Develop-

ment Partnership Agreement. Presentation to the Civil Society Hearings at

the United Nations, November 7, 2000.

RGANIZATIONS

Dante B. Fascell North–South Center, University of Miami., 1500 Monza

Avenue, Coral Gables, FL USA 33146 (305) 284-6868, Fax: (305) 284-

6370, Email: nscenter@miami.edu, www.miami.edu/nsc

Spaceship Earth

Spaceship Earth is a metaphor which suggests that the earth

is a small, vulnerable craft in space.

Adlai Stevenson used the metaphor in his presidential

campaign speeches during the 1950s, but it is not clear

who originated it. Perhaps R. Buckminster Fuller was most

responsible for popularizing it; he wrote a book entitled

Operating Manual for Spaceship Earth and was described by

one biographer as the ship’s “pilot.” Fuller was impressed

by how negligible the craft was in the infinity of the universe,

how fast it was flying, and how well it had been “designed”

to support life.

Fuller took the metaphor further, noting that what

interested him about the earth was “that it is a mechanical

vehicle, just as is an automobile.” He noted that people are

quick to service their automobiles and keep them in running

condition but that “we have not been seeing our Spaceship

Earth as an integrally-designed machine which to be persis-

tently successful must be comprehended and serviced in

total.” He did observe one difference between the spaceship

and a car: there is no owner’s manual for the earth. The lack

of operating instructions was significant to Fuller because it

1334

has forced humans to use their intellect; but he also main-

tained that “designed into this Spaceship Earth’s total wealth

was a big safety factor” which allowed the support system to

survive human ignorance until that intellect was sufficiently

developed. It was Fuller’s lifelong quest to persuade humans

to use their intellect and become good pilots and mechanics

for Spaceship Earth. He was an optimist, and believed that

humans are all astronauts—“always have been, and so long

as we exist, always will be”—and as such can learn the

mechanics of the system well enough to operate the vehicle

satisfactorily.

Political scientist Barbara Ward borrowed the phrase

from Fuller to claim that “planet earth, on its journey through

infinity, has acquired the intimacy, the fellowship, and the

vulnerability of a spaceship.” She claimed this image to be

“the most rational way of considering the whole human race

today.” Humans must begin to see humanity “as the ship’s

crew of a single spaceship on which all of us, with a remark-

able combination of security and vulnerability, are making

our pilgrimage through infinity.” Ward used the metaphor

to argue for the reality of global community: “This is how

we have to think of ourselves. We are a ship’s company on

a small ship. Rational behavior is the condition of survival.”

The rational behavior she advocated was building the institu-

tions, the laws, the habits, and the traditions needed to get

along together in the world.

Nigel Calder appreciated the value of the spaceship

metaphor and described it in more specific terms: “Whether

its watchkeepers were

microbes

or dinosaurs, the Earth

system of rocks, air, water and life worked like the life-

support system of a manned spacecraft.” He went on to

suggest that “the gas and water tanks of Spaceship Earth

are the air and the oceans” and that “the sun is the spaceship’s

main power supply.” Calder used the metaphor as an intro-

duction to a detailed consideration of what he describes

as a new “Earth-system science,” moving from there to a

depiction of the globe as a total system.

Kenneth Boulding

, an economist, has made essen-

tially the same point, describing an inevitable transition from

a “cowboy economy” where support systems are open with

no linkage between inputs and outputs, to a “spaceman”

economy where “the earth has become a single spaceship,

without unlimited reservoirs of anything, either for extrac-

tion or for

pollution

, and in which, therefore, man must

find his place in a cyclical ecological system which is capable

of continuous reproduction of material form even though it

cannot escape having inputs of energy.”

The purpose of the spaceship metaphor is to persuade

people that the earth has limits and that humans must respect

those limits. It provides a modern, new-age image of a small,

comprehensible system, which many people can understand.

In that sense, the metaphor helps people understand their

Environmental Encyclopedia 3

Spawning aggregations

relationship to the

environment

by depicting a system, as

Ward notes, that is small enough to be vulnerable and needs

to be cared for if it is to sustain life.

But the image can also be delusive, even specious, with

negative implications not generally recognized. A spaceship

is an artifact, a structure of human creation. Some have

argued that depicting the earth as such is seductive, but

borders on the arrogant by implying, as Fuller seems to, that

humans can completely “control” the operations of the earth.

Furthermore, spaceships are commonly thought of as small

and crowded, with a life-support system devoted exclusively

to human inhabitants. Since humans are using more and

more of the planet’s resources for their own benefit, and the

pressure of an increasing human population is extinguishing

other life-forms, some environmentalists argue that the

spaceship metaphor should be used with caution. See also

Environmental ethics; Green politics

[Gerald L. Young Ph.D.]

ESOURCES

OOKS

Boulding, K. “The Economics of the Coming Spaceship Earth” and “Space-

ship Earth Revisited.” In Valuing the Earth: Economics, Ecology and Ethics.

Cambridge, MA: The MIT Press, 1993.

Calder, N. Spaceship Earth. New York: Viking Penguin, 1991.

Fuller, R. B. Operating Manual for Spaceship Earth. New York: Simon and

Schuster, 1969.

Ward, B. Spaceship Earth. New York: Columbia University Press, 1966.

Spanish flu

see

Flu pandemic

Spawning aggregations

Spawning aggregation is defined as a group of fish of the

same

species

that are gathered together for the purpose

of spawning—releasing sperm or eggs for the purpose of

reproduction. The fish population that is together at this

time is significantly greater than during periods the fish are

not reproducing. For fish whose

habitat

is stable, drawing

aggregations revolves around a relatively small area. In tran-

sient populations the individuals might travel for days or

weeks in order to reach the aggregation site.

The U.S.

Fish and Wildlife Service

(FWS) oversees

the recovery of species listed under the

Endangered Species

Act

. For fish, that goal is tended through the National Fish

Hatchery System—coordinating efforts between hatcheries

and fisheries management. As a result, national fish restora-

tion programs have returned abundance to the populations

of various species, including the

Great Lakes

lake trout, the

1335

Atlantic coast striped bass, Atlantic

salmon

, and Pacific

salmon. Much of the success has come through the agency’s

captive propagation programs. And, according to the FWS,

“The success of captive propagation for recovery depends

upon a number things, including careful genetics planning

and management, concurrent habitat restoration, thorough

evaluation studies—and funding. Propagation of imperiled

fish species is often more than twice as costly as rearing

non-native game fish due to genetic analyses, special diet

requirements, and rearing conditions that enhance survival

in the wild, along with rigorous monitoring and evaluation

studies.” A critical factor in the reproduction of

endangered

species

is the understanding of spawning aggregations.

In various coastal systems in the United States and

throughout the world, fisheries management relies on the

knowledge of spawning aggregation locations. It is crucial

to understanding how to protect the populations, as well as

key to maintaining the ecological balance of marine life.

Reef fish are more vulnerable to disruption of spawn-

ing aggregations because many species only aggregate for

brief time periods. If reef fish spawning aggregations are

fished during the activity, then their populations are depleted

due to unsuccessful reproduction. There are many reef fish

species that reproduce in unprotected federal waters of the

U.S. Caribbean, the Gulf of Mexico, and the South Atlantic.

These species include the black grouper, cubera snapper, gag

grouper, gray snapper, jewfish, Nassau grouper, red hind,

scamp, and yellowfin grouper.

Two examples of decline in particular fish populations,

according to Mark W. Sprague of the Department of Physics

at East Carolina University in Greenville, North Carolina,

in (2000) are the weakfish (Cynoscion regalis), and the red

drum (Sciaenops ocellatus). It was his theory that using fish

sounds could assist researchers in identifying their spawning

activity. In the abstract presented for his presentation at the

conference Sprague presented this preview of his presenta-

tion. “Weakfish and red drum, both members of family

Sciaenidae, use their swim bladders to produce species-spe-

cific sounds associated with spawning activity. Large spawn-

ing aggregations of these fish can produce sound levels as

high as 145 decibels (re: 1[mu]Pa), and these sounds will

be presented for each species. Water depth, bottom type

and contour, sound-speed gradient, and water current all

affect the propagation of the fish sounds through the water.

Measurements of these factors and the sound level of the

fish calls are used to obtain an approximate range to the

spawning aggregation.” Sprague’s work was supported by

the North Carolina Division of Marine Fisheries and the

U.S. Fish & Wildlife Service.

Some debate exists among those who fish commer-

cially regarding whether the federal and state regulations for

spawning aggregations are overly conservative. An example

Environmental Encyclopedia 3

Special use permit

of one such debate appeared in Fishermen’s Voice Monthly

Newspaper a periodical of the fishing industry in Maine. The

article recounted an aspect of the spawning issues in August

2000. The new plan unveiled there, “calls for a series of

three rolling closures of one month duration. Flexible start-

ing dates and options for extending the closures are designed

to protect the fish only when they are spawning. Less astrin-

gent tolerance levels in the amended plan allow fishing

within the closed areas provided the fish landed are less than

20 percent Stage V or Stage VI spawners.” The purpose of

regulation over spawning areas is intended to protect the

spawning populations and therefore protect future popula-

tions so that

overfishing

does not become a problem.

The

conservation

of fish and the protection of marine

wildlife species, such as

sharks

and

whales

, depends on

the management of spawning aggregations. The debate over

how that is best done will continue well into the twenty-

first century.

[Jane E. Spear]

ESOURCES

ERIODICALS

Zeller, Dirk. “Spawning Aggregations: Patterns of Movement of the Coral

Trout Plectropomus leopardus (Serranidae) as Determined by Ultrasonic Te-

lemetry.” Marine Ecology (February 12, 1998).

THER

Darwin Initiative. Conversation of Whale Sharks & Fish Spawning Aggrega-

tions in Belize. [cited March 25, 2002]. <http://www.ayork.ac.uk>.

Fish Base. Global Information System on Fishes. [cited June 2002]. <http://

www.fishbase.org>.

“Herring.” Fishermen’s Voice August 2000 [cited July 2002]. <http://

www.fishermensvoice.com>.

Johannes. R. E. “MPA Perspective: Indo-Pacific Should Protect More

Reef Fish Spawning Aggregation Sites.” MPA News. March 2000 [cited

July 2002]. <http://www.depts.washington.edu/mpanews>.

U.S. Fish and Wildlife Service. “National Fish Hatchery System.” [June

2002]. <http://www.fisheries.fws.gov>.

RGANIZATIONS

U. S. Fish and Wildlife Service, Washington, D.C. , <http://www.fws.gov>

Special use permit

An authorization from the appropriate governmental agency

to another agency or to a private operator to use publicly

owned land for certain purposes. The Secretary of Agricul-

ture and the

Forest Service

issue permits for special uses

not explicitly covered by timber, mining, or grazing laws or

regulations on lands in the

national forest

system. Uses

must be carefully controlled and be compatible with forest

policy as well as with other uses. Commercial users pay a

fair market fee to mine stone and gravel, operate ski areas,

conduct sporting and planned

recreation

events, and con-

1336

struct rights-of-way, pipelines, power lines, and microwave

stations. Other special uses include archeological explora-

tions and leases for public buildings and summer homes.

Species

A species is a group of closely related, physically similar

beings that can interbreed freely. In practice, the dividing

lines between species or between species and subspecies are

sometimes unclear.

In sorting out species, biologists search for easily recog-

nized diagnostic characteristics. For example, it is easier to

recognize a giraffe by its long neck than by its blood proteins.

However, species differ from one another not just by conspic-

uous features. Members of a species share a common

gene

pool

and have a common geographic range,

habitat

, and

similar characteristics ranging from the biochemical and

morphological to the behavioral.

In taxonomy, the hierarchy of biological classification,

species is the category just below genus. The major groups

in the classification hierarchy are kingdom, phylum (for

animals) or division (plants), class, order, family, genus, and

species. Taxonomically, a species is designated in italics by

the genus name followed by its specific name, as in Felis

domesticus, or domestic cat. New species are named and

existing species names are altered according to the Interna-

tional Rules of Botanical Nomenclature, the International

Rules of Zoological Nomenclature, and the International

Bacteriological Code of Nomenclature.

Isolating mechanisms prevent closely related species

living in the same geographic area from mating with each

other. These are called sympatric species, as opposed to

allopatric species, which are closely related species living

in different geographical areas. Sympatric species are very

common. Bullfrogs, green

frogs

, wood frogs, and pickerel

frogs, all members of the genus Rana, may be found in or

near the same pond. They are prevented from mating by

reproductive isolating mechanisms.

Allopatric speciation allows new species to arise from

one or more preexisting species, which is a long, slow process.

Most allopatric species evolve when a small population be-

comes physically isolated from the main part of the species,

and gene flow between them stops. Genetic differences

spread and accumulate in the small, isolated group. This

process is most likely to occur at the border of a species, where

environmental conditions exceed the range of tolerance of

members of the species and there is a barrier to the species’

spread. The barrier could be a mountain range, a

desert

forest, large body of water and so on.

Organisms that are part of a region’s natural

flora

and

fauna

are called native or indigenous species. Those