Figure 5-51.Sand trap.
Figure 5-50.Root removal by steel rod and auger, manual
fit the sewer pipe, may be used, as shown in figure 5-
51, to collect the sand. Commercial traps are available
with adjustable slots to lower the water level below the
top of the trap. Sand is removed by scoops or buckets.
For heavy sand deposits, a cable-drawn bucket is
used, especially for storm sewers and larger sanitary
sewers. The cable may be pulled by a hand winch, by a
power winch, or by a truck with the cable through an
anchored sheave. The sewer can be damaged if the
bucket catches on misaligned joints, improper house
connections, or other fixed obstructions, especially
with power-driven buckets.
Turbine-driven tools (fig. 5-52) clean sewers with
difficult obstructions and grease coatings. These tools
are powered by water under pressure from a fire hose.
The tool and hose are pulled through the sewer by a
Various types of power-driven sewer-cleaning
machines are available. These machines normally
have a 3/4-horsepower electrically reversible motor
and weigh about 90 pounds. They are especially
designed for clearing sewer pipelines, ranging from 1
l/2 inches to 10 inches in diameter and up to 200 feet in
length. Some have a cable counter indicator, so the
operator knows the distance the tool is in the line.
Others have a headlight to aid you in working the dark
A major difficulty with sewer systems buried in
the ground is tree ROOTS. These are hard to detect just
by looking in the manholes. With trees growing rather
close to a sewer line, you can expect roots to cause a
break in the line. Such trees as poplars, willows, and
elms are the most troublesome when it comes to root
growth. When these trees are growing within 100 feet
of a line, you can look for trouble from roots sooner or
later. Take a close look at figure 5-53 which shows tree
roots penetrating a line.
One method for removing roots in a sewer is to
apply copper sulfate (blue vitriol). Another method is
to use cable drawn scrappers; these may be homemade
or equipment as shown in figure 5-50. Try copper
sulfate first since this is the most economical.
When a sewer is completely stopped up, it is
useless to apply copper sulfate. A partially blocked
line that is flowing from 5 to 10 gallons per minute only