N.Z. MAIL PUBLISHED WEEKLY. FRIDAY, DECEMBER 10, 1886.

New Zealand Mail, Issue 771, 10 December 1886, Page 16

N.Z. MAIL PUBLISHED WEEKLY. FRIDAY, DECEMBER 10, 1886.

Thebe is another point of great importance* —beside the paramount consideration, ways and means —which needs to be authoritatively determined before any defiuite steps can be taken with reference to a complete scheme of drainage for this city. What is to be the ultimate disposal of the sewage? This, indeed, is a question which at the present time is perplexing the whole civilised world. Unfortunately science has hitherto failed to discover any thoroughly satisfactory method of disposing of sewage. All agree that if it can be got quickly and cheaply into the deep sea, that is by far the best and most economical mode of dealing with this troublesome thing. Some theorists warmly advocate the sewage-farm system, and severely denounce the “ wicked 'waste” of vast quantities of fertilising material. Many sewage farms, indeed, are now in operation in England, and some are said to be yielding fairly satisfactory results. But it is undeniable that in the majority of cases the experience has been quite the other way. It does not follow, because sewage contains a certain proportion of fertilising elements, that therefore the fluid in which these elements are found so copiously diluted will in practice possess much economic value. The case is somewhat similar to that of common clay, which contains vast quantities ( of the very useful met-il aluminium. Could chemists devise any cheap and practicable mode of extracting the metal from the refuse, the worthless clay would become more valuable than iron ore. But there is, as yet, no known method of extracting aluminium from clay profitably, and thus the clay continues to be mere re- < fuse. So it is generally with sewage. Is holds in suspension many fertilising elements,, but these are so largely diluted as to be of little use, as a rule, in farming. Sewage is most copiously diluted in winter when the land is already too wet, and this is one of the t most serious obstacles to its utilisation. The results of the dry-earth system are equally disappointing. It was supposed that with a systematic use of earth closets the resulting substance would be a most valuable manure. But experience proved the absorbent and disintegrating power of dry earth to be such that when the same material had been used twice or tbrice over it was only equivalent to commou garden mould as a fertiliser. Thus the water-carriage system is generally accepted as an ’economic necessity, and the only question is how to apply it in detail. Where is the sewage to be finally deposited ? At present, in defiance of all the canons of sanitary science, we daily and hourly pour iuto oUr 1 beautiful land-locked bay the refuse of nearly 30,000 people. This has been i goingon foryearsandyears,anditisbut too certain that we must sooner or later pay the penalty for this persistent defilement of our harbour. The practice is alike filthy, barbarous, and dangerous. It may be that

there are tidal currents* in the bay which, if accurately determined and systematically utilised, would constantly sweep away the outpoured filth to a distance sufficiently great to preclude all fear of its return upon our foreshore. But at present all is haphazard and glorious uncertainty. It can only be asserted a priorvvriih. little fear of contradiction that persistence in so deleterious a practice as that of turning the harbour into a cesspool must sooner or later carry its natural penalty and render the city very unhealthy, if indeed the prevalence of zymotic disease at particular seasons of the year be not already largely attributable to this source. Accepting it as an indisputable axiom that the harbour must not be the receptacle of Wellington’s sewage, the question is—What are we to d:o with it? The only answer appears to be: Conduct it to deep water in Cook Strait by. the shortest route available ; and that is the destination which all the engineers who have advised the Wellington Corporation on the subject agree in adopting. But next comes the preblem how to get the sewage thitherIn the rival schemes of Messrs Clark and Climie the sewage was to be conveyed by gravitation to a low-level point south of the city. It was then to be raised to a high level and suffered to flow by gravitation into Cook Strait. So far the two schemes agreed, but in their mode of effecting this discharge they differed as widely as/ possible. Mr Climie proposed to raise the sewage vertically by a chain-pump and to discharge it at once into the sea. Mr Clark’s plan was to force it up a rising main a mile long, and then before allowing it to run into the sea to compel it to flow over a large area of sand-dunes, which were to be gradually fertilised by this means, the sewage ultimately escaping to the sea as almost pure water after parting with its foreign matter as fertilising agents to the sterile sand-dunes, which were to be planted by degrees with suitable vegetation such as would steadily form mould, so that in the end the barren sand would become cultivable agricultural soil. Whatever may be the probabilities or improbabilities of this outcome, they do not affect the merits of the scheme as a mode of sending away our sewage, and in this respect its merits have never been competently challenged. The trouble that lies in the way — after the primary obstacle of expense—is that vested interests have grown upon the seashore itself, and although one of these has been reckoned with there remain others which may yet prove very troublesome in the demands for comnensation on account of possible future injury through the sewage washing ashore. This brings into prominence an old suggestion by the Wellington Harbour Master, Captain Holliday, that the sewage should be discharged into huge pontoons built for the purpose, to be towed out to sea when full and emptied in deep water. This, if practicable, would be the most direct and thorough method of getting rid finally of our sewage, but there may be difficulties in detail which do not appear on the surface. At all events the plan is worth considering when the whole question of Wellington sanitary reform comes before the City; Council. We trust it soon will be boldly grappled with, and that the Mayor-elect will make this course the salient feature of his approaching Mayoralty.