Page:Transactions NZ Institute Volume 9 Supplement.djvu/18

626 Mr. W. R. E. Brown felt very strongly on the subject of draining into the harbour. He hoped to get statistics from Sydney on the subject, and would submit them to the meeting. He was much afraid that the sewage would return with the tides.

Mr. Campbell, on being called on by the President to reply, said that it had been remarked by several speakers that slop-water contained a great part of the decomposable matter, and that pails removed only a small portion. This was quite true, but, as Dr. Newman observed, the pails were removed at the same time as the ashes, which had always to be carted away. The pail system removed the most objectionable part of the sewage. In the River Commissioners' Reports some midden towns are stated to have a discharge from the drains containing a greater amount of impurity than that of many water-closet towns. This, however, was due to old and defective drains, and was not a fair comparison. With regard to the separate system, he believed Mr. Carruthers to have stated that the sizes of sewers would not be smaller than those of a combined system. Now supposing an area of 2,500 acres, say, was reserved to carry off three and a half cubic feet from each person daily, did Mr. Carruthers mean to say that the sewers would not have to be larger to carry off the fourteen million gallons that Mr. O'Neill said would have accumulated in twenty-four hours, with a quarter-inch rainfall only? When pumping is necessary, the advantage of having a regular flow is most apparent. A great number of English towns are adopting the system, as they find they cannot manage the variable discharge from the combined system. The rain-water drains are not provided with either man-holes or lamp-holes, and are laid only four and a half feet deep. Storm overflows are necessary in the combined system, the discharge from, which very often has more impurities than the ordinary sewage, on account of the sand and sewage mud deposits accumulated for a month or more being then removed. Mr. O'Neill was mistaken in supposing that intermittent filtration was not successful. Mr. Bailey Denton, who introduced it at Merthyr Tydvil, has since treated the sewage of many other towns very successfully, the affluent water proving remarkably pure. Another speaker (Mr. Frankland) described the Zurich mode of scavenging. In Florence an improvement on that was used. The town is drained into cesspools, which are emptied periodically by an exhaust pump attached to an air-tight vat, and into which the contents are sucked. Mr. Higginson had described the pail system as abominable, and useful only when there was no water supply. The objections to the pails were only imaginary, for a person could not detect the slightest smell from the collecting carts when they passed along the streets of Rochdale. The pail system is not the only means where there is no regular water supply, for at Walton-on-Thames the house-slops form an efficient vehicle for the contents of the closets; many of the street pipes being only six-inch the rainfall is excluded. The subject of currents in the bay had been alluded to. There appear to be none. Those alluded to by Mr. George, in his account of the Patent Slip, appear to be merely an undertow, caused by the heaping up of the water against the shore by a strong wind. The evil effect of drainage into harbours had been experienced at Scarborough, and many other English towns. Margate, Hastings, and Brighton, had outfalls into the sea, near to or opposite the towns, and had to take steps to take them further away. The Brighton sewage is now taken by a tunnel in the chalk cliff eight miles to the outfall. The evil practice spoken of by Mr. Higginson, of carrying the waste water-pipe from cisterns into the soil-pipe of a closet was very general, and was of course most objectionable.

The President said the object under discussion was one of vast importance to the whole community, and he was glad that the Society could offer a medium for ventilating the views and opinions of those who had studied this question of town drainage. He