In sewage disposal, clogging of the disposal field is the most common
trouble. This may be caused (1) by a tank too small for the volume of
sewage, (2) by failure to clean the tank regularly, (3) by interior
arrangement that does not provide slow flow through the tank or that
allows scum or sludge to pass out with the effluent, or (4) by a
disposal field that is too small or is incorrectly built.
The remedy for a clogged disposal field is to dig up and clean the
tiles and re-lay them 3 or 4 feet to one side or the other of their
former position. Sometimes a tile line can be cleaned by opening up
the line at each end and flushing it thoroughly with a hose. With this
method provision must be made to drain off and safely dispose of the
water used for flushing.
Tile lines laid with improper slope allow the effluent to collect in a
limited area and saturate the soil, causing odors. Bacteria cannot work
in such areas, where the soil becomes sour, or "sewage-sick." These
lines must be relaid on the correct slope. Odors or a water-logged soil
may also indicate that the disposal field is too small.
House sewers frequently clog. This is due, in most cases, to roots
and less frequently to trash, garbage, or other foreign materials
discharged with the sewage. Greases in the sewer may cause trouble,
especially when the slope is insufficient to give the sewage a
cleansing velocity. Drain solvents will sometimes remove the
obstruction, but more often it is necessary to clean the sewer by
rodding. In some cases it may be necessary to dig up the line to reach
the obstruction or, at least, to open the line so that it can be rodded
from two directions. When it has been cleaned, a manhole could be built
for use in case of future trouble. If stoppage is due to roots it may
be necessary to re-lay the sewer with root-tight joints, or to move
either the sewer or the vegetation so that roots cannot reach the line.