SEWER VENTILATION.
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.