SEWER VENTILATION.

New Zealand Times, Volume LVIII, Issue 2747, 19 February 1896, Page 3

SEWER VENTILATION.

TO 'i’ll E EDITOR. .Sir, — Would you favour mo with apace lo review somo unsatisfactory evidence recently given by the drainage engineers on . behalf of the Corporation in tho Magiaf tratu’s Court, us reported in the New Zealand Times and elsewhere ? About twenty years ago Buchan, of Glasgow, introduced an improved system of trapping and ventilating drains. After long delay the Wellington City Council adopted the plan, and it was embodied in by-law 1891, sections 16, 28 and 29, and practically continued in by-law 1893, sections 32 and 43. By these specifications, when faithfully carried out, the sewer gas is completely intercepted, and tho house drain thoroughly ventilated between tho disconnector trap, open at top, and the up cast shaft at tho soil pipe. But this salutary arrangement has been interfered with by an obnoxious clause section 33. Armed with this enactment

our engineers now invade private property, cause the disconnector trap to bo planted lit the houso wall (instead of its original and proper place close to tho boundary fence,) and compel tho unfortunate landlord, at his own expense, to provide and lix a metal pipe there, carried up above the roof, for tho solo purpose of ventilating the main or street sower. This is easily proved. The disconnector trap, wherever situated, always indicates tho terminus of tho house-drain, consequently tho intervening length from the trap to tho street sower is virtually a branch of tho latter, and it is sheer nonsense to call it “ tho house drain." And as the venti-

lator in question rises from the sower side of tho trap, it has no possible connection with the real house drain. Moreover, as mentioned, tho house drain isalready amply ventilated according to by-law. Therefore

each householder has to provide at least two ventilators, ono being for the house drain and the other for the street sewer. So if the engineers' evidence was contrary

to this, it was not in accordance with the facts. As for gas being generated in the house drain, or forced back through the trap, they must have forgotten that in such cases it would either ascend through tho open shaft of the trap, or be aspirated out by tho soil-pipe ventilator ; it could not pass into the house. Again, about drains choking, surely the Corporation inspectors can be trusted to see that tho by-law ns to pipe-laying is strictly enforced. Besides, our sanitary experts must know that unless these sower ventilation pipes are perfectly alike in height and other respects they will net act with regularity; therefore, some householders may get more than their share of tainted air: not very pleasant to think of during epidemics. Further, I would ask, how long will these flimsy pipes resist the wind and weather, even when guyed up with fencing wire ? Yet our drainage engineers declare that this mongrel stylo of sewer ventilation is recommended in approved text books. Let ua see. In Latham's Sanitary Engineering, new edition, page 35G, we read : —“ Tho ventilation of sowers by moans of shafts communicating with tho crown of |tho sower, and terminating about tho centre of tho roadway, has boon carried out In London and many other places. In the opinion of tho author this system of venti- ; luting public sewers, when ventilators are provided insufUcieutnurnber,and furnished with materials for absorbing and destroying tho escaping gases, is decidedly the best system that can bo adopted." (Wood charcoal he recommends as tho cheapest and most efficient purifying agent.) Again, at page 357: —“All shafts or chimneys of every description, when used for tho ventilation of sewers, must bo looked upon as having little or no power in themselves to produce ventilation, but must bo considered as a simple extension of the sewer for facilitating the discharge of noxious matter at some convenient spot where it will be harmless." The same author in Chambers’ Cyclopedia, edition 1892, under “ Sewage," favours the use of ventilating pipes carried up houses, but on condition that they bo free from all obstructions and interference, and independent of other pipes and connections with the sowers. Professor Ewing, under “ Sewerage," Ency. Brit., 1886, says: “To disconnect the pipes of each individual house from the atmosphere of the common sower is the first principle of sound domestic sanitation." Bawlinson, in Minutes Inst. C.E., 1880, vol. Cl, said:—“Ho wished to urge that tho health of a district depended, in the first place, upon the proper arrangement of tho sowers; in tho second place, upon their proper ventilation ; and, in the third place, upon the effectual cutting off of house drains from all direct connection with the sewers." Other reliable information points to tho street ventilator system as the simplest and most practical, with openings about 100 yards aparts; and when narrow roadways or crowded localities make that plan objectionable, capacious substantia! pipes are carried up the highest available buildings, here and there as required. The ratepayers of Wellington have had enough of unsavoury surroundings in the past, and must now take a stand against any attempt to vitiate tho atmosphere of their dwellings. Already litigation is looming up at Melrose and Watts' Peninsula against tho coming nuisance at the drainage outfall, and will probably add still more to tho city taxation. So far as I know, sanitary law in Great Britain compels municipal corporations to ventilate the public sewers without violating private rights, and, as Mr A. Wilson contends that such is the duty of tho Wellington authorities, it is to be hoped that ho will receive tho support of all householders in his resolution to appeal against the decision of the Magistrate’s Court. —I am, &c. John Wilson, Frankville terrace, ,17 th February,