tion is more difficult in cold climates also. Ex-
combined and treated with normal sanitary waste.
treme warm weather areas have few unusual
In these instances, laboratory studies are quite
often conducted to determine treatability by the
are aided by higher ambient temperatures.
system. If it is treatable, then pilot scale studies
(1) Cold region treatment systems. The U.S.
may be initiated to yield data required for full
Army Cold Regions Research and Engineering
scale design. Among commonly employed bench
Laboratory, P. O. Box 282, Hanover, NH 03755,
and/or pilot scale studies on industrial or com-
should always be contacted when exploring waste
bined domestic-industrial wastes are unit pro-
treatment alternatives for facilities located in
cesses such as activated sludge, carbon adsorpo-
regions where the ambient temperature is below
tion, and dissolved air flotation.
32 degrees F for significant periods of the year.
(2) Application to domestic waste. In situa-
(2) Treatment processes for other areas. In-
tions where wastewater requiring treatment origi-
stallations located in arid and water-short areas
nates from sanitary or domestic sources, the need
often require the direct and indirect reuse of
for bench or pilot scale facilities is normally
water due to limited supply. A high degree of
unnecessary. However, it may be desirable or
treatment is often required for wastewaters prior
even necessary to conduct such studies to assess
to discharge due to the very low dilution provided
the impact of severe climates on some processes;
by small stream flows in these areas. In wildlife
to confirm design criteria; or to determine the
refuges, fish spawning waters, and wetland areas,
most cost-effective process selection.
wastewater discharges must have low pollutant
b. Alternative treatment choices.
concentrations to preserve the delicate environ-
(1) Connection to municipal systems. When
mental balance. This is particularly true with
upgrading existing facilities to meet a higher
regard to toxics, oxygen demanding material,
level of treatment or selecting a wastewater
treatment facility for a new installation, consider-
nutrients, and temperature.
d. Treatment reliability. Components of the
partially treated wastewater to a municipal sys-
treatment process must be selected to ensure a
tem if such a facility is within a practical and
economical distance. When the municipality can
always be provided for high maintenance units,
provide the necessary increment of treatment
treatment processes requiring frequent cleaning,
capacity, such practice eliminates facility duplica-
and units which are essential for proper opera-
tion and removes the operational and staffing
tional efficiency. Some examples of these are
problems from the military installation. It can
pumps, screens, filters, and chlorination equip-
also reduce costs. Combined or joint treatment is
the preferred method outlined in the 1972 Amend-
(1) Toxic waste. When treating toxic sub-
stances such as strong solutions of heavy metal
salts and cyanides, sufficient testing after treat-
(2) Expanding existing treatment facilities.
ment is required to ensure acceptable quality
When an existing facility is expanded to handle
before release. Redundant or duplicate processing
more waste or upgraded to provide a higher level
steps may also be warranted. Automatic controls
of treatment, consideration must be given to
should be arranged for fail-safe operation.
(2) Domestic waste. For treatment plants
Studies must be made to determine the types of
primarily handling sanitary wastes, treatment
processes to be added, timing to avoid service
interruption, and provisions for any future facility
lished water quality standards.
(3) Establishing reliability requirements. In
c. Geographic and climatologic. In the selection
areas where effluent or stream standards are
of a cost-effective treatment scheme, geographic
and climatologic conditions must be carefully
established, coordination with the Regional U.S.
EPA Federal Facilities Coordinator should be
analyzed. In cold climates, the rate of biological
employed to determine treatment requirements
degradation of waste materials decreases with
and reliability y necessary to meet all conditions.
decreasing temperature to a point where it may
The U.S. EPA has set forth certain design
virtually cease during the winter months. Other
treatment schemes, such as physical-chemical
guidelines to be used to ensure reliability of
treatment processes dependent upon the type of
treatment, need to be explored in such situations.
receiving watercourse. Equipment and facilities to
Extreme cold may cause operating problems due
meet these requirements shall be incorporated
to freezing of mechanical components. Construc-