The subject of sewer ventilation has made little or no progress during
the year, and, as usual, numerous complaints have been received of
noxious smells emanating from the gullies and ventilators. Each case has
been dealt with as far as possible; and in many of the cases charcoal
filters have been introduced, with the result of putting a stop to
complaints. I am, nevertheless, somewhat sceptical as to the value of
this plan, as I cannot divest my own mind of the suspicion that they
impede ventilation, and may prove effectual only by preventing the escape
of foul air. The subject was brought very prominently before your Vestry
during the current year, in consequence of numerous complaints by
inhabitants of Elsham-road of bad smells, not only in the roadway, but
also in the houses. I made an exhaustive report on the locality, and
advised measures for diminishing pressure in the sewers, by opening up
blind ends, and so allowing the gas to circulate, or, at least, to escape
innocuously into the open air, rather than into the houses. I described
the sanitary defects which existed in the houses, and recommended
ventilation of the house drains by independent pipes carried from the
highest point of the drain to some distance above the parapets of the
houses, and I pointed out that this remedy alone would go far to remove
the cause of complaint. To what extent the plans have been carried out I
have not yet ascertained, but it is certain that a long period had since
elapsed without any communication on the subject having been received in
my department.
With respect to the question of circulation of air in sewers, _plus_
ventilation, I may mention that a striking illustration of the value of
this plan was afforded in the locality of Notting Hill Square. At one of
the houses at the southern, or loftiest side of the square, there had
been numerous cases of fever, and there was clear evidence of the escape
of sewer gas into the house in question. Upon careful enquiry into the
drainage of the locality, 1 ascertained that the sewer which received the
house drainage originated in a dead or blind end, and that the
ventilation was insufficient. Your Vestry directed a communication to be
made between the blind end in question and another very near to it, thus
setting up a free circulation in the system; and at the same time freely
ventilated the sewer near the junction. The effect was everything that
could be desired: for certain improvements in respect of the trapping and
ventilation of the house drains having been carried out, the evil
complained of was effectually removed, and no farther illness has been
reported.
It is much to be wished that some effectual plan may be soon discovered
for ventilating sewers; and, although I do not profess myself competent
to decide what direction such a discovery is likely to take, the most
promising idea I have yet heard proposes the extraction of foul air by
the action of fans placed in suitable localities, the present ventilators
being retained in the capacity of inlets for pure air, instead of outlets
for foul air; acting, in fact, like the down draught in a mine. We all
know, by reading, what great lengths of galleries in mines deep below the
surface of the earth are ventilated, and very efficiently, in this
manner, and it seems not unreasonable to hope that the system may be
found applicable to the purpose under consideration. Certainly, there
seems no reason to doubt the almost illimitable power of steam fans to
induce currents in any direction; and leaving the question to be worked
out by those who are making a practical study of it, I can but wish them
every success, believing an effectual system of sewer ventilation to be
one of the chief sanitary _desiderata_ of the present day.