THE WATER SUPPLY

Auckland Star, Volume XXXIII, Issue 150, 26 June 1902, Page 4

THE WATER SUPPLY

ME. POND'S ANALYSIS

utr t 'i he - meeti ? gof the City Council last evening a lengthy Report was recensed from Mr. J. /. F LI, Government Analyst, on the analysis of the FBttt supply from the Nihotupu and Western Springs- sources. Mr. Pond stated that he took samples frcm, various portions of the Nihotupu sufiply from the Western Springs and tfa* city reservoirs. He found traces of Phosphoric acid in the six samples obtained at Titirangi and Nihotupu, but/ faint traces and traces of it in .the samples obtained from the city re- , servoirs, a faint- trace, at the Niho* tupu m let at the Western Springs and traces and faint traces- in the other v\ estern Springs samples. The number of *, grains per gallon of chlorine in chlorides in the Nihotupu samples was 1.65, in the reservoir samples 1.59, in the Western Spring mam spring sample 1.85. The nitrogen in nitrates was from .005 to .0125 m the Nihotupu samples, to .288 in the main spring sample and the Pon- • sonby reservoir sample. Eree ammonia ranged from .0011 to .0036 in the '' Nihotupu samples, and from .0010 to .0025 in the other samples. The oxygen absorbed in four hours in the Nihotupu samples was from .078 grains per gallon to .127 grains. In the Nihotupu samples the total solid' matter (dried at 220deg. Fahr.) was from 5.6 to 8.18 grains per gallon, and in the other samples from 7.0 to 10.64 per gallon, a small precipitate of *' vegetable debris was found in all the samples except two, where the precipitate was large. In the course of his report Mr Pond I stated that with respect to* the water f flowing from the main spring he finds | hardly any difference in its purity I for many years past. It was exceed-j gratifying to find that the main] spring yielded so pure a water, and? he could oniy repeat the remarks of. himself and Mr. McLaurini of May/ 1900, "that the natural filter beds ar| in excellent condition, and the watep flowing normally from them an excef tionally pure article." Unfortunately* the contamination which this watJr ~* suffered from being allowed to fI;W into the collecting pond was a natter for serious consideration. jß_e-'■■■: had again and again urged the Cconcil to securely pipe the water fpm the main spring to the pump well,ind thus escape the danger of thefexposure in the large surface oflthe pond, which the analysis showel to be still more impure. He hal no doubt that the Nihotupu water/was capable of improvement, and' the necessity for it was shown, in the .'■* large precipitate chiefly of vegetable debris brought down after aeavy rains. The presence of this fatter nullified any benefit from aeraion in the long journey through thepipes, as there was always a large excess of organic matter present.! This should be .removed by filtratjm. In conclusion, to secure the ptfity.of- . the water supplied by the Cotiicil Mr. Pond recommended: (1) Tae re-* / moval of the cause of the disolonjation and ftnpurity of the fthotupu stream at its source; (2) theerection of sand filters for the Nihoupu supp!y; (3) the protection, whre neces- - sary, from the direct lieat tf thesun, of the convej'ing pipes bet\feen Nihotupu dam and Titirangi; i) conveying tbe water from the ma/i spring at the Western Springs tc/the pump r jwell, clear of the collecliigpond, to avoid contamination fromthis source. The report was refeyed to .the. Waterworks Commiftee,/ ;._.__.-7.;'