NEW RISING MAIN.

Evening Star, Issue 14001, 6 March 1909, Page 5

NEW RISING MAIN.

TENDER ACCEPTED. The Dunedin Drainage Board have accepted the tender of John Dutliie, Ltd., of Wellington, for the supply of 1,636 ft of 3it 6in drain cast-iron pipes for the rising main. The price is £4,942 15s 6d. duty paid, in the whip's slings at Dunedin wharf. The figure the successful tenderers quoted in bond was £4,367 15s 6d, with £575 added for duty. There will be 465 tons of material in the consignments, and they offered to deliver the pipes (which will be in 9ft lengths) on the ground at Alusselburgh for an additional £348 15s, being 5s per ton for wharfage, and 10s per ton for cartage. By accepting delivery in the ship’s slings the Board evidently intend to make their own arrangements for transport at this end. The new main, as explained a few days ago, is to replace one of the two structures leading from the pumping station to the beginning of the gravitation outfall. These are built of wooden staves, hooped together and caulked, and covered with concrete, and have proved by no means satisfactory. Probably when the storm water channels into the harbor are completed. and the bulk of sewage is turned into the main intercepting sewer, the need of adopting Air J. B. Cardews recommendation to relay the other rising main in cast iron also will begin to be felt. Each of the present mains is connected to but one pump. The new rising main will connect to both pumps by means of a fork or “turn out” just outside the station. Thus the bulk of the work will not fall on only one pumping ’engine. The engines can be spelled in turn or used together. It is probable that at the time the new main is being laid the Board will ako put in an additional small sump alongside and deeper than the well or sump from which the main pumps lead. A connection will be put in from this to the new main, to provide for continuous pumping, with the Waipori electrical power as the motive force. A condenser will also be. placed at the junction through which the water supply for the water jackets of the pumping engines will circulate, the cooling being'done by the flow of water along the main. Tho question lias been raised as to whether the cast iron pipes, will be corroded and eaten through by tho sewage, but Air S linger, the Board’s engineer, states that this will be prevented by coating the inside of the pipes with a composition.