TM 5-852-5/AFR 88-19, Volume 5
CHAPTER 7
WASTEWATER COLLECTION
7-1. General.
7-2. Design considerations.
The basic criteria for design of sewarage systems for
As described in chapter 2, the location of the pipe,
military facilities are in TM 5-814-1/AFM 88-11,
above or below ground, is critical to satisfactory
Vol.1, and TM 5-814-2/AFM 88-11, Vol.2. The
performance. An above-ground location with the
unique aspects of design and construction of these
piping installed on piles may be necessary because
systems in the cold regions are in this section. In
of soil conditions. However, the grades necessary
addition some further detail is included on the use of
for gravity flow are difficult to maintain with above-
pressure and vacuum sewers since the flat terrain
ground sewers. Above-ground sewers also hinder
and permafrost make it difficult to design a conven-
transportation, block surface drainage and snow
tional gravity sewer system in the Arctic. Combined
removal, have high heat losses, and are more
utility systems called utilidors are covered in chapter
susceptible to vandalism. The operation and main-
8. Table 7-1 compares the characteristics of gravity,
tenance costs for above-ground systems are about
vacuum and pressure systems for use in cold
three times higher than those for similar systems
regions. Vehicle hauling of water and wastewater is
buried undergound. Above-ground construction
still used at some remote sites, but for the general
costs for a single pipe depend on the foundations
case, military facilities will be serviced by piped
required. If the pipe can be laid directly on the
collection systems. Normally, a conventional gravity
surface, construction costs will be 20 to 40 percent
sewer system will have the lowest life-cycle cost and
of that required for the same pipe installed on piling.
a. Sewage temperatures. Domestic wastewater
must be used whenever practicable. Gravity systems
have an additional advantage over pressure systems
from barracks, mess halls and family housing on
in that they seldom flow full. As a result gravity
military installations in the cold regions will range
pipes are less likely to break if freezing occurs.
from 50 to 60 degrees F at the source. Wastewater
from facilities not having hot water heaters can be as
7-1
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