THE SEWERAGE WORKS.

Colonist, Volume LII, Issue 12765, 5 February 1910, Page 2

THE SEWERAGE WORKS.

MR HAY'S REPORT,

SEVERAL LEAKING SEWERS

HEALTH DEPARTMENT'S REPORT BORNE OUT.

At the. meeting of the City Council last evening the report of Mr Robert Hay, M.lnst C.E., of Dunedin, who was called in by the Council to report upon the city sewerage works in consequence of the Health Department s strictures, was read. In a covering letter Mr Hay stated that he had arranged with the City Engineer to put a weir mi at the outlet from the septic tank, in order that accurate guagings could be taken at any time of day or night, so that the actual discharge, from the whole sewerage scheme could be ascertained m a' few minutes at any time. Mr Hay's report was as follows: — In accordance with your instructions I have made a close inspection of he drainage system of Nelson, together with its various accessories ; also the septic tank and main outfall. X have perused the report of the Government Health. Department, and your Engineer's reply thereto; also Mr Mestayer's report of February, 1909 and the correspondence that has passed between the Inspector appointed by the Health Department and yourself. I have now the honour to report on the result of my investigaReticulation.— l will take first the sewer reticulation^ of jour streets, which consist of 9, 8, and 6 inch earthenware pipes (jointed with cement mortar) which junction, ft street intersection with properly constructed manholes, and where, , Mie streets are long and the intersections far apart, intermediate manholes -re constructed so that the sewers can Le inspected in short sections and where necessary flushed. The, gradients as laid out are generally speaking very good, the flattest being 1 in 400, ani there are not many lengths of sewers on these grades, and whore they haye been adopted, it was impossible +o obtain anything better owing to tne contour o/the land.. Of course m the matter of setting out sewer grades engineers differ, but I think an ,m---provement might have been made ,n Cambria street, which instead of bein 2 traded to fall entirely to LoilingWKJd street, might have been arranged so that about one, half of the Cambria street sewer would have discharged at Collingwood street and uhe other half to Tasman street. law would have lessened the depth at which the sower is laid and kept the pipes above saturation level. coilinewood and Weka streets would also have benefited in a similar manner. With these exceptions I am of opinion that the reticulation has been well laid out. , Leakage.— There is, however, a considerable leakage in parts of Cambria street, Wainui street, Trafalgar road and probably in lower Collingwood street," and a large, body of water is being carried to the ejectors at the foot of Collingwood street (Wood area No. 3 and a fair average of tne quantity from several observations may be taken at 216,000 gallons for tho 24 hours. This of course, places a heavy amount of work on the engines at the power house, and it will be necessary that the leaking sowers be lifted and carefully relaid as qiiickly. as possible. I think tho principal part of tho leakage emanates from the lower half of Cambria street. In ' xamining the sewers I have in a number of cases measured the depth or the flowing liquid and I find that tho. depths varied from 1 inch to f of an inch (except the leaking sewers), and in some cases the flow was extremely slow, and in others almost stagnant. This is easily accounted for. and is caused by the intermittent supply of sewage to the drains owing to the small number of house, connections that have been made — in some instances only one or two to a line of sewer. The effect of this is to cause unpleasant odours to arise from the manholes owing to the sewage matter nullifying in the drains instead of being carried away rapidly to the septic tank as would bo the case if suflicient connections had been made whereby a constant current of sewage would be running in the sewers. 1 suggest that householders be induced to make sewer connections as rapidly as possible, and the sewers will soon assume their natural functions. Flushing. — In the meantime I iecommend that the drains that are carrying insufficient sewage to enable them to be self cleansing, be periodically and intelligently flushed, and I may say that I consider this operation absolutely necessary for the sanitary condition of the town. Manholes.— l would also recommend that the trays that are in many cases placed under the manhole covers be removed and the iron dirt catchers substituted, as the former cover up the air inlets and prevent the ingress of fresh air to the sewers. The manholes at the Collingwood street ejector should be built up and raised to such a height as would prevent the sea water entering through the ventilated covers when the tides are specially high. Road Grit.— Every care must I c taken in excluding road grit from the sewers, as material of this kind wll form a big factor in causing the-, toppage of the sewers. Ejectors.— There are three sets of ejectors serving the Nos.l,2,and 3 areas. No. 1 area, Russell street, electors, two of 100 gallons capacity eaon. No 2 area, Vanguard street, two ejectors of 150 gallons capacity. No 3 area (Wood) Collingwood street, two ejectors of 150 gallons each. Th© ejectors generally appear to be working well. The ejectors at No 1 station, Russell street, had little work to do owing to there being so few_ connections on, 53 in all, and it occupied more than i-alf an hour to discharge the. two ejectors that contained 200 gallons. No 2 station, Vanguard street: The ejectors here were not being subjected to any hard work, as the total discharge only amounted to 30 gallons a minute. House connections in this district number 283. No 3 station (Collingwood street) discharges the sewage from the Wood area and is at present heavily taxed, and the two ejectors are discharging about 150 gallons pet minute. This would mean over the. 24 four hours a quantity of- 216,000 gallons. Of course this discharge will decrease as the leaks in the Cambria and other sewers are located and stopped. Septic Tank. — This tank is not in the meantime getting fair play owing to the large quantity of subsoil water, which from the analysis of Dr Freng■ly contains cloride of sodium or salt, that passes through the tank, which no doubt will prevent complete septic action, and some portion of the sewage though disintegrated, will pass out into the harbour in its natural condition of crude .sewage. Ho wever,l anticipate that when the leaks are stopped, and the sewage resumes its normal flow, that there will her no further trouble of this kind. I understand that • i«s septic tank as first designed wae double the size of the one now in position, but the smaller one was substituted as a matter of cconom7 with a proposal to duplicate in the future when necessity arose, and I would recommend that the suggestion be adopted, as I think when the leakage is stopped that the present tank will suffice! for some time. It would a'?o J be advisable to arrange as soon r-s j possible with those whose houses ye j connected with the old sewer to make fresh connection with the new system • as quickly as possible. Soma complaints have been raised by the Health Officer in connection with using the by-wash instead of passing | the sewage through the septic tank. I understand that., special circumstances induced tho city" officials to utilise the by-wash, but I see no objection or benefit in the by-wasb being used out- j side of such circumsu\nces, and I t.m sure the officers of the Council can be trusted to use the by-wash when only absolutely necessary, without sealing the valve as suggested, which would

be useless as the sewage could be bj--washed at each and all of the ejector stations quite independently of ,ho tank by-wash. The officials can have no special object in preventing the sewage from passing through the septic tank. If, however, they persisted in this course for some unknown reason, then the remedy is quite apparent, and lies in the hands of the Council.

Foreshore. — Some question has been raised that the overflow from the tank has caused offensive smells on the foreshore. If such a nuisance exists it can easily be accounted for as proceeding from tho sewage passing out from the old sewer which has upwards of 700 house connections and discharges immediately on the foreshore, while the discharge from the soptic tank is delivered over threequarters of a mile seaward into a channel, and as the sewage now is in the first place highly diluted with tho Bubsoil water and again incorporated with vast quantities of sea water at the mouth of the outfall, there would not be the least chance in the meantime of the effluent from the tank 'causing or contributing to the alleged nuisance on the foreshore. The total number of house connections on the new system is 545. Inspection. — The work of testing the sewers was undertaken by the Government Health Department, ami on May Bth, 1908,. this Department agreed, to undertake the testing of all the sewers- then laid and to be laid, and an inspector was appointed with specific instructions from Dr Mason that, everything was to be done to ensure that good w,ork was nut in. This inspection, then proceeded and from the reports of the inspector, in which every, leak is. detailed, there is no reason to doubt that such inspection was carried out in accordance with the instructions issued by Dr Mason, who was at that time occupying the position of Chief Health Officer. On the 6th December last, the Inspector-Gen-eral, Dr Valintine, writes, in submitting the report of the District Health Officer, that the drainage of the city has been "marred by inefficient construction and supervision,'' although the work was under the immediate supervision of an inspector appointed by his own Department. The combined . report of Dr Frengley and Mr Middleton does nofc bear out the general condemnation of Dr Valintine, as their answer to the question of "whether the system of drainage that had been inaugurated in this city will prove effective for the proper sanitation of the city," is that there is "evidence of bad construction and indifferent supervision in parts." No doubt parts of the sewers already mentioned, viz., Cambria street, Trafalgar road, Wainui street, and lower Collingwood street,' are taking in considerable quantities of subsoil water which is being discharged into the septic tank. Whether these defects have been caused by careless work in jointing or breaking pipes, etc, in tho refilling, or whether subsidence nas opened up the sewer, I cannot say, but. as the work was carried out by day labour there was no inducement to slum the work. It may be interesting to note that on the 18th June, 1909, the Town Clerk wired the Chief Health Officer asking the Department to retain the inspector's services Jor a fortnight at the Council's expense in order that he might finish the testing of the sewers which were practically completed, and Dr Valintine wired agreeing to the Council's proposal. It ''is very evident that the Council throughout the work hayo evinced every desire that the sewers should be properly inspected, and if there has been any dereliction of duty in this respect, which I don't suggest, the responsibility rests on the Health Department and not on the Council or their officers. After an extensive examination of the Nelson" drainage ystem, and all the correspondence anj documents relating thereto, I am of opinion that the scheme, with the necessary supervision to details, is workable one, and generally designed and laid out on proper lines excepting the sewers already mentioned in the Wood area. I. may. here, point out that it i" no use spending - a large amount of money on. a scheme and then when completed leave it to look after itself. - All drainage systems require constant supervision and attention, especially when first placed in operation^ owing as I have ■ already pointed out, to their nofc receiving, for some time, sufficient sewage to induce the flow necessary for self cleansing for which the gradients and size or the sewers were designed, and I again, impress on your Council the absolute necessity for periodically flushing certain portions of the sewers to which I have already drawn the attention of your foreman. It may not be. out of place here to call the attention of your Council to the extraordinary , consumption of water . in your town, amounting to about 100 gallons p.er. head for 24 hours. From 10 p.m. to 6 a.m., when the draw, off should be slight, about 26,000 gallons per hour is recorded, or a draw off' of 208,000 gallons over 8 eight hours of least requirements. lam convinced that a very large proportion of this is waste caused either, by _ defective, water fittings or leaky pipes,, or both. .As a considerable quantity of the city sewage has to bo raised by the ejectors it will become in the future an item to be reckoned with in extra cost of power, and it is for this reason that I bring tho matter under your notice. I have to thank yourself and the City Engineer for the assistance given me in making my investigation..

Cr Grace moved that tho discussion of the report be deferred to the next meeting, when, tne City Engineer would be present. Or Neale thought it unwise to defer the matter for so Jong. Work was proceeding in Wainui street and it might bei money wasted, as Mr Hay recommended lifting the pipes and relaying them. # Cr Grace agreed to include in his motion a proviso that work in Cambria street be stopped until the report had been considered.

The Mayor said the report was just what he had expected. The leakage was in Cambria street, and possibly a little in Wainui - and Collingwood streets. Cr Turner opposed deferring the matter. There was a large leak in Gloucester street which had not been reported. The cost of pumping was endrmous. . Cr Adams said it might be found necessary to alter the grade in the Wood, and if that were decided upon, the work now going oh would be of no use whatever. .All work should be suspended pending the Council's final decision.

Cr Field said he wanted to stop work in tha Wood when it was decided to obtain a. report, and to ask for the result of the Health Department's observations of the results of the repairs in the Wood, but he was not allowed to move. They could not go properly into the report than, bufc there was no reason why it should not be discussed.

Cr Pettit moved that the report be discussed at the conclusion of ordinary business. Cr Turner seconded the amendment, which was lost.

The resolution was carried. Cr Neale moved that all repair work in Cambria street be for the present suspended. The Mayor said hei would oppose the motion. There were only three men employed in Cambria street, and they could not do more mischief than had been done. (Laughter.) Cr Grace seconded the iiotion. Cr Pettit supported the motion. There was nothing new in the report. The Council had aU the information before it eighteen months ago, and might have put the matter right at a small expenditure if it had risen to the occasion. The Mayor said it would be a tremendous work to relay the sewer ..He had no fear of the other sewers, which were well laid and mostly in .dry ground. He was opposed to luting any sewers, and to stopping work in Cambria street. " _ The jS&yor then put the jnotionj ana

declared it lost, but on a division being demanded the voting was shown to be : Ayes, 7 ; Noes, 3. Cr Field moved that the Health Department be asked to send an experi to Nelson .to ascertain tho effect ci tho repairs in Cambria street, and to confer with the Council as to . the carrying out of Mr Hay's recommendations in tho most effective and the least expensive manner. ■ r Tho Mayor ruled the motion out. oJ order at that stage of the meetuig. Mr Hay's fee, 35 guineas, and expenses, £4 18s, were passed for payment. . . ' At a later stage of, the meeting Oi Field obtained permission to introduce his resolution. He ' said there were *wo courses open, to the Council.— First to make ,thifl a matter of friction between the Council and the Department, or to put any feeling of irritation, however natural, on one side, and unite with the Department in placing the drainage of thei city above reproach, and remove the slur cast upon the city by the Department's report. They should do all they possibly could to put matters right. From what he knew of Dr Valintine he was sure that if he thought his report had boon unduly severe, he would be one of the first to say so, and he would do all he could to help the Council in putting matters right. They could improve the sanitary condition of the foreshore very easily. Cr Pettit seconded the motion. He '•titasted thc< Council would realise the importance of working with tne Department to repair the defects in the scheme. Cr Grace opposed tho resolution, it amounted to requesting the, Department to assist in carrying out works which they had not yet decided to carry out. How could the Department help them? It had no expert civil engineer in its employ. What d:d the Department know about engineering? It knew nothing. The Departr ment had condemned its own inspection, and he contended that the Department had failed utterly to earn tho money it had taken from the Council. He hoped they would have nothing further to do with the Health Department. The Department's report had damaged the city to the pxteait of thousands of pounds during the holiday season. . The Mayor opposed the motion. He had never said anything against the Health Department, but such a motion should not be carried before Mr Hay's report was considered. Cr Nealo said he could not support the motion at the present stage. They should not, however, work against wa Department. Cr Turner said tho Department had been asked to report, and it had reported absolutely correctly, yet it was being attacked for doing so. It seemed to him that the Council would have been delighted if the report '-ad been a favourable one, though the Department by so reporting would have put itself in the wrong. ' Cr Field replied, after which the Mayor ruled tho portion of tho resolution relating to Mr Hay's recommendations out of order. Cr Field amended the resolution Ly substituting the words "consideration of" for the words "carrying out of" Mr Hay's recommendations, and the Health Department's requirements. The motion in this form was lost on the Mayor's casting vote.