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7
Report of the Committee appointed to consider the
question of Sewer Ventilation.
The Committee is of opinion that the question of sewer
ventilation cannot be considered apart from the much wider
subject of the prevention of nuisance arising from sewers.
The Committee recognises the fact that the Metropolitan
Board of Works conducted an enquiry extending over many
years, with the object of discovering some agent or appliance
that should be effective in so altering the constituent elements of
sewer gas as to remove the danger to health resulting from its
presence in streets and houses. Chemicals for the decomposition,
neutralization or absorption of gases had been placed on trays at
the inlet, the outlet, and in the channel of sewers. Chlorine
generators had been hung in the mains. Draft producers and
foul air consumers by an ingenious contrivance had been
connected with street lamps. Although the methods tried were
numerous, and the experiments exhaustive, the Metropolitan
Board of Works had been unable to recommend the adoption of
of any of them as of practical value.
The Committee considers it useless to pursue an enquiry into
methods which already have been the subjects of experiment
conducted by able experts employed by the Board of Works, and
with results so unsatisfactory ; and it considers that attention
should be directed rather to the removal of the cause than to the
treatment of the nuisance when it has already arisen.
In examining into the nature of the cause, the following facts
were under notice :
(1) Fermentative changes, leading to decomposition, and
the disengagement of gases are the causes of
nuisances in connexion with sewers.
(2) Decomposition is not usually observable in sewage as it
enters the sewer, consequently this change may be
regarded as taking place in the sewer.
(3) Fermentative changes in fresh sewage are hastened by
its admixture with stale sewage—by stagnation, and
by the presence of foul and heati d air. They, on