THE CITY WATER SUPPLY.

New Zealand Herald, Volume XXIV, Issue 7903, 23 March 1887, Page 6

THE CITY WATER SUPPLY.

(REPORTS OP ANALYSES BY MR, POND.

In compliance with the instructions of the City Council, the Town Clerk forwards to us for publication the following reports of analyses of the city water supply, furnished by Mr. J. A. Pond, Public Analyst

Auckland, March 19, 1887.

Sir,—ln accordance with the instructions contained in your letter of the 4th inst., I herewith forward you my report upon the purity of the city water supply, the direction of the Council requiring that the water for analysis should "bo taken from the pumping station, reservoirs, and from standpipes at tho high and low levels of the city." On the 7th inst. I obtained samples from the pump well at the pumping station, the collecting pond, and from the reservoirs at Ponionby and Kyber Pas*. On the 12th iost; I obtained a check sample from the pump well, and on the 17th inst. samples from the standpipe at the corner of Queen and Customs Streets, and from Pollen-street, Surrey Hills. In the latter instance I departed from my instructions, and obtained the sample from a private tap, in consequence of a letter appearing in one of the papers, speaking of the impure state of the water in this street. This sample was obtained from a tap in Mr. Clayton's photographic studio, and as he stated he had been Using a large quantity of water, it may be taken as a fair average then being supplied in the neighbourhood.

On obtaining the sample from the pump well on the 7th inst., and finding it turbid, I examined the inlet to the pipes at the main sprfng, and found the turbidity caused by an influx of water from the collecting pond, which at this time was very discoloured, locally, by a further addition to the filter bed.

With the analyses of all the samples, I have also attached a copy of analysis made under the same conditions, the samples being drawn March 19, 1884, from the pump well and a city standpipe. From these results it will be soon that there is an inorease of organic matter and of nitrates, while the chlorine and ammonia are about the same. The cause of this is undoubtedly owing to a large influx of water from the collecting ponds; as in the analysis of the sample taken from the pond near the pump well, it will be seen that the amount of oxygen absorbed in four hours is exceptionally high. It is also shown by the presence of a larger quantity of algie and moving organisms than before. There can be no question that it is to this cause may be attributed the many complaints made lately of the large amount of insect life in the water.

The remedy for this objectionable addition to our otherwise excellent water supply, is either to discard the water from the collecting ponds, or a more perfect mode of filtration. At present further addition* of fine gravel are being made which, though an improvement, will not suffice to exclude the finest particles of organic matter. The ad' dition of a filter-bed, of the magnetic ironsand from the West Coast, easily obtainable at Onehunga, will be more effectual than any other medium for this purpose, and can be so arranged that the exit from the springs when the pumps are not at work will always keep the filter-bed clean. The jeration of the water while in transit from the pumps to the reservoirs would also prove of great value under the present circumstances.

I cannot close this report without again calling the attention of the Council to a matter which, to my mind, threatens the purity of our water supply more than any other cause. I allude to the cemetery at Mount Albert, and would refer yon to my report to the Special Water Committee, dated April 21, 1884. Since that report was written, the opening of the cemetery at Waikomiti has rendered less necessary the one at Mount Albert.—l have, &c., J. A. Pond, Colonial Analyst. P. A. Philips, Esq., Town Clerk, Auckland.

Results expressed in grains per gallon. March 31, 1884. Gentlemen, —In accordance with your instructions I have examined the city waters ab supplied to consumers, taking one sample from the Western Springs and the other from the stand-pipe, corner of Wellesley and Symonda Streets, and herewith beg to forward the report:— Analysis. Water from Water from Western Springs. Stand-pipe. Date when drawn March 19. March 19. Temperature .. .. 63* Fah 06' Fah. Appearance in 2ft tube Clear greenish white Clear blueish white Smell when heated to 100" Fah. .. .. .. None. None. Chlorine in Chlorides .. 1-0 I*9 Phosphoric acid in phosphates.. ... .. Slight trace Very slight truce Nitrogen in nitrates .. '196 "195 Ammonia—free .. .. "0037 *0008 Ammonia— Albuminoid .. *0042 '001!) Oxygen absorbed in 15 minutes to 80* Fah. .. '001 None. Oxygen absorbed in 4 hours '0025 None. Hardness before boiling— < Clark's scale .. ..3' 3" Hardness after boilingClark's scale .. ..3* 3' Total solid matter ..9' 7' Microscopic examination Of deposit .. .. Diatom*, sand, alg» No deposit. Results expressed in grains per gallon. This water is of excellent purity for drinking purposes. —I have the honour to be, gentlemen, your obedient servant, J. A. Pond, Colonial Analyst. To His Worship the Mayor and Councillors.

7 Collecting Analysis.— well ills Custom and Queen 12 7 7 I 64" la ! yellowish bid, cloudy, slightly .Jii® g yellow lingo yellow wmto white tinge Smell, 1 3 Chorine trace! . _. phosphate! "352 *857 '323 in '0009 Ammonia'. 0019 Albuminoid SO' at Oxygen '184 *165 3- 8* before 8" Hardness boiling 62 10 22 solid sllf»' 1 ..-J ale moving organisms organisms