View report page

41
The results cannot be deemed satisfactory. Out of the 1,725
inspected, in 291 there was either an escape of sewer gas into the
house drains, or there was an accumulation of sewage in the inspection
chamber. In addition, there were others in which the trap although
not obstructed, yet was in such a state as to be a nuisance.
In view of these facts it is no wonder that some authorities
have advocated the total abolition of the intercepting traps. Undoubtedly,
this would simplify the problem of sewer ventilation,
and the unventilated condition of town sewers is universally recognised
to be unsatisfac'ory, but in view of Major Horrocks' experiments,
one should hesitate to advocate the abolition of the trap.
Moreover, it is the experience of many householders that the presence
of the trap is one of the best means against rats. One could name
many premises in Acton which formerly were overrun by rats. The
drainage system was overhauled ; the house drains were intercepted
from the sewer, and the premises have since been immune from
the plague of rats. Under present conditions, it would not be
advisable or safe to abolish the trap, but further powers should be
given to local authorities in the bye-laws.
The systematic inspection made between May and November
was obviously limited to intercepting traps in which the housedrains
terminated in a manhole, but as a large majority of the intercepting
traps in the district have inspection chambers in connection
therewith, this limitation is not of consequence.
Strictly speaking, the trap is simply the method by which the
sewer air is kept out of the house drains, and as this is brought about
by the interposition of water between the inlet and outlet of the
trap, the only essential part is the " water seal." The cleansing
arm and the inspection chamber are accessories to the trap, and are
placed there for purposes other than those by means of which the
house drains are intercepted from the sewer. Theoretically, all
that is necessary is a simple siphon placed at the point of the
house drain nearest to the sewer, but owners of property
as well as sanitary authorities have found it advisable to have also