WASTEWATER MANAGEMENT CONSIDERATIONS
food preparation, washing, waste transport, lawn
a. Technological considerations. Programs for-
uses. industrial uses include process water, cool-
mulated to manage the discharge of wastewaters
ing water and transportation of waste materials.
generated by domestic use and industrial opera-
The main agricultural water use is irrigation;
tions require a broad understanding of the rela-
others are livestock watering and waste disposal.
tionship between water sources, waste generation,
(2) Indirect water reuse. The indirect method
and the environmental consequences of waste
of water reuse is commonly practiced when
disposal. With very few exceptions, all problems
wastewater from one community is discharged to
associated with wastewater discharges have envi-
a receiving water and subsequently used as a
ronmentally acceptable solutions. The technology
water supply by another community. Due to the
for achieving any desired level of effluent quality
treatment provided by modern water treatment
is already developed and in most cases, well
facilities and the natural assimilation of wastes
proven. The task of the environmental engineer
by the receiving water, this type of water reuse
dealing with wastewaters is to identify the prob-
has become acceptable. The main pollution con-
lem and to apply the most appropriate technology
trol need for waters used for public supplies is to
in order to achieve the desired goal.
remove constituents that may pass through the
b. Wastewater disposal. Liquid wastes from
water treatment facility or result in excessive
domestic and industrial sources are ultimately
disposed of into receiving water bodies or onto
(3) Wildlife habitat. Wildlife, such as water-
land. Portions of the waste products may be vola-
fowl, waterbased animals, fish, shellfish, plankton
tilized and discharged to the atmosphere, while
and other aquatic life, require water that is free
part or all the water may be recycled for repeated
of oil, excess solids and other toxics and that
use. When an environmentally acceptable solution
meets their needs for dissolved oxygen, tempera-
to a problem is being sought, equal emphasis
ture, etc. The successive buildup of chemicals in
should be placed on all three components of the
the flesh of predator animals has been extensively
environment, i.e., land, air, and water.
documented. Similarly, the buildup of toxic mate-
rials and flavor tainting substances have been
2-2. Water resources and usages
observed in fish and shellfish.
a. The hydrologic cycle. The cycle of water in
(4) Recreation. The pollution control require-
nature allows water to be used repeatedly. Water
ments to maintain recreational uses are related to
vapor is condensed from the atmosphere in the
those of wildlife habitation through hunting, fish-
ing and other activities that utilize wildlife.
and either flows as runoff to surface waters
Primary (complete) body contact activities such
(streams, rivers, lakes and eventually oceans) or
as swimming have strict water quality require-
ments regarding bacteria, pH and turbidity.
fers. Plants draw water from surface water or
(5) Aesthetics. Waste treatment requirements
for aesthetic reasons have become increasingly
important with the emphasis on environmental
the atmosphere through evapo-transpiration.
concerns and protection of the complete human
environment. Control of odor, color and turbidity;
majority of the water returned to the atmosphere.
removal of objectionable and unsightly floating
b. Water uses. Water quality criteria in the
materials; and elimination of secondary effects on
U.S. are normally established to protect the water
aquatic or stream bordering plants will usually
users. In foreign locations where no pertinent
satisfy aesthetic requirements.
water quality regulations exist, downstream wa-
ter uses must be recognized and pollution control
2-3. Effects of discharge on the envi-
(1) Water supply. Water supplies are required
Water usage generally results in production of
for domestic, industrial and agricultural uses.
wastewaters requiring disposal. These wastes are
Domestic uses include water for drinking and