THE SEWERACE SCHEME.

Colonist, Volume LII, Issue 12726, 18 December 1909, Page 2

THE SEWERACE SCHEME.

H-EALxii -JT^ ARTMENT-S REPORT.

CITY ENGINEER'S REPLY.

THE DISCUSSION ADJOURNED

A special' meeting of the City Council was held last night for the purpose of considering- the report of tho l)istrict Health Officer, Dr Frengley, and Mr Middleton, a Health Department inspector, on the city sewerage scheme. There were- present the Mayor and Counci'.lors Adams. Field, Pettit, Bisley, Neale, McCouchie, Li^htband, Grace and Turner. The City Engineer presented tan following reply to tho criticisms contained in the Health Department s re- j port:^---"In response 'to -a, resolution passed by you at your meeting .of the lotu instant that I should submit to you at this meeting my reply to the report furnished by. Dr trengley on the new system of sewerage for the city.-l beg to state that I have given it my very careful consideration, and find it to contain severe strictures and serious allegations against myself and staff, and also against the; Department's own inspector. it would iiot be unfitting at this stage, I'entlemen, to inform you that m dealing with Dr Frengley- s report 1 i will do so in -a fair and impartial 1 spirit. Where I consider his remarks aire correct I will have no hesitation in supporting them, and where I consider tlrem to bo inaccurate. 1 shall 'deal with them in a mauner befitting such inaccuracies. Ac the re.port is the product, of tiro men (Dr Frengley and Sanitary Inspector Middlefcm) it may. in some cases in my reply be necessary to maKe the singular include the plural. In ' the opening section of the report it is stated that a manhole in front of the Foundry (Wakefield Quay) was visited and opened, and it is; asserted that it-is suitable-forits intended purpose so far as' cleaning out the drains with rods is concerned. Surely they must know that these manholes serve a dual purpose, mas:- : much that' hot only do they provide means for getting down t-6 the sewers for cleaning purposes, but they also provide an inlet for fresh. air to the sowers through the elongated openings iii the cover, the presence of which the report seems to take exception- to, and which, are alluded to as cavities.. In the same paragraph the report goes on to_ state that the liquid in the manhole invert was about two inches in-, depth. 1" This is a matter I would not dispute, as it is a very, difficult matter for anyone standing on the surface looking down a na.rrow dark shaft ten feet in depth to guess with any degree of accuracy the depth or composition of any liquid flowing .at the bottom, but I do know that I have measured it under "practically "similar conditions and found the depth of sewage to be • J-inches. — "In section- 2 it is pointed out that at -the "manhole at Itussell street the ilow from; Wakefield- Quay still continued in the same volume (presum-ably-as that noticed in front of the Anchor -Company's- Foundry). Now, this must mean either one of two things, either that there was not 2in of sewage in front- of the Anchor Company's, or there must have been more at Bussell street, becaxvse the pipe that Mr Middleton has evidently mistaken for the. Wakefield Quay and Haveii road west sewer- is the inlet from the collecting -chamber, which (-pith the exception of three houses in 'Russell street) receives the whole of the sewage from that area bounded by Britannia Heights, on the south, Maori road on the east,; and Mary "Ann street on the west, a goodly sized area with- a fairly large number of connections.

"11l commenting on the ejector station you are informed that it contains am ejector of 100 gallon capacity, and that tho walls were not altogether free from moisture. In regard "to the moisture on the walls, it must be fully recognised that the: walls, of- any. subterranean chamber, •will always' sweaty which must^apply in this case *as the only portions of the walls that could be seen from the surface "are iivu feet above saturation level, and lam quito sure Mr Middleton', never descended- into the chamber or he would have found 'that there were- two 100 gallon ejectors installed, and not only one as he asserts. ~^- "In regard to section 3 — in order to make my reply as coherent as possibie 1 /will allucle to it in conjuiictiodi with section 10.

"In section 4 tho veport states that Collingwood street ejector No. 3 was receiving and discharging at a. rapid rate. This statement is quite correct. I will allude to the^caiise of it at a later stage. I would here point out that' this station is also htted with two ejectors, and not only one, as Mr Middleton.' s remarks would convey, and . the manhole cover 'is ■ a plain hinged cast iron cover without any"opeiiings in it whatever, as Mr Middleton asserts it has. The Sea water gains access to the chamber round the edges of the cover, which are not tight fitting. ""It. is not really, necessary for these chambers ,to be ventilated, as they are fitted with air •scour pipes connected with the prcs^ sure main and continued to "the bottom of the chamber in order that before any one enters the chamber he may turn on the air pressure and M the chamber with pure air. "Section 5 will be dealt with in conjunction with .Collingwood street and "Cambria street.

"Section 6, ejector station No. 2, Vanguard and Hardy streets.— This chamber contains two 150 gallon ejectors. The water in 'the bottom noticed by Mr Middleton was in the collecting sump.. situated immediately ■under the manhole cover, and not all over the floor as the report would imply. Jt : is quite correct that the. Vanguard street- south section was delivering a. good ,; flow of sewage, which is -later on in the report alluded to :as reasonable.- As a" matter of fact this /manhole receives sewage "from a fairly large: area, one of the best drained in ijhe citjv "Sections "7 and 8 will, be dealt with in conjunction . with Dr ~ Frengley's comments: • ■:'■■■ "The first paragraph-of section " 9 wjill be. dealt-with in conjunction with .; section/14.^- % V---' 1 " -!■'":■ C-i- . ■.'..'"' '-'lii -the : second: paragraph of section 9, to the 1 receiving chamber: in 'Gollingwood street, it is stated that the /sewer -was discharging a volume equal to about fourfifths the area of the pipe, although the .same pip© was full a few chains higher up the street. Surely Mr Middleton- would not have you believe that because a pipe was full at its inlet.that it should also flow full at the outlet, . especially when there, is provision made : for an increased velocity: at that outlet. ••' I. should not have, "remarked on, that point had it not been for the inference that there 'was something in the sewer impeding the flow to that extent. It is also stated that the .!Weka street sewer was discharging about three inches in-depth into the same manhole, i A small study of the position would jhave convinced him of the cause. Am lie has evidently overlooked: it, I. will make mention of it for your information.: It is well known that tho ejec^tors .tforfe alternately with certain periods", or rest between each discharge. "When the liquid to be dealt with comes in to the manhole in fairly | large quantities as it -does in this case, ; there is always an accumulation in' "the manhole between^ the:discharges, and as there is : very little differeJic«" in the 1 : levels of V Collingwood .street- arid Wainui ; street inlefcs, the :'se\v>£ge '■■ will .jjatufally back" up.- iiito Wainui street for a good distance, iowitig/to the flat. fall in that' street. Consequently, when either of , theejec. tors was Teceiying its next charge and, the manhole' emptied again to myerf level the backed up setvage would,rei i/uvn again- -through the manhole to ' the ejector,- : ' ": - '•;".• ■": '".."'- ..■•;'

"In regard to sections 3, 10, and | 11, Cambria street, I quite concur nith the zeport that the condition of things from Collingwood street to about a. chain eastward of Tasman street is undoubtedly defective, permitting subsoil water to enter the sewer. This matter has-been receiving attention for some little time. Several defects have been found and remedied, mainly broken pipes. These pipes must have been broken by careless filling in, as the sewer was -tcstted with a live feet head water pressure under the supervision of" Inspector Dorizac.

"Section 12.— In regard fto -the manhole at tho junction of Milton and Cambria streets, the only reason of flushing from tin's is for the purpose of. cleansing that 'flat portion of the sewer between Milton and Tasman street. Nothing accumulates jn that manhole that would necessitate flushing- on its own account. "Section 13.— 1t is stated in this section that at the junction of Miltan and Bridge streets, also Milton and Hardy streets, the 8-inch sewers did not contribute sewage of a greater depth than one inch. I might" point out that the measured flow at thtse points lias never been founi. to* exceed the depth stated, but the pipes are.six~inoh.es in diameter and not eight inches as stated ih tho report, whicii moans a very different thing when the comparative wetted perimeter of the pipe has to be considered. "Sections 9 and 14. — Ejectors. When dealing wiiih section 4, I intimated that I would again refer to it in connection with section 14. In reference to the rapid discharge of the ejectors in the Collingwbod street station, this may be the result of three causes. When Mr Mestayer was here _ in January" last he laid down certain methods of testing for leaks which were .to be conducted over a given section. These' tests- were to be carried out at. certain intervals, aaid necessitated-stopping out the section to be tested:' Consequently the sewage- at the back of such, section backed" up-' for a. considerable distance during the period of carrying out the test, so that when this backed up sewage was released it would natural-

ly give the ejectors much additional work for the time being. The same thing applies to flushing tho sewers. This work is not done as "many no doubt think, i.e.j by simply putting the -hose in a manhole and turning on the water till the flushed think it

has Had enough. The modus operandi is this. The inlet to the manhole above the section is plugged, and the men. then, fill this section from the main, afterwards withdrawing tife ,plug, allowing the accumulated water to suddenly rush, through the section to be flushed. This would again give the ejectors extra work for the time being, and I think I am safe in saying that the amount of water -used in this way is in excess of what the sewage will b f &- when the whole of the connections are completed, inasmuch that it does not take a very .great amount of water to keep the solids travelling, but^once they stop and accumulate, it takes 'a fair body of water to start them again.' These causes together with .the leakage in Cambria street will account for the speed of the Collingwood street ejectors. Taking the number of houses in the Wood area connected with the sewer the estimated flow of sewage should not exceed 86,000 gallons per day. Wliem the report states tfiaV 196,000 gallon pass through the No. 3 ejectors this is no doubt an exaggeration. Mr. Middleton admits that he has based his figures on a 21 minutes' observation. From my knowledge of the efficiency -of the ejectors and repeated timing, together with gaugings of the discharges checked separately from the other stations, the discharge during tho whiter floods did not exceed 132,000 gallons per -day, which points oui that 46,000 -gallons per day of subsoil water was finding its way into the Cambria street sewer between

Tasmau street and Collingwood street. On. blocking out this section- and letting the' sewage riso in the maJihole and flow through Tasmaii street" and Weka street, ■ the- flow fell to what may bo estimated to : be practically normal. Dr Frengley remarks that 50 gallons per head per day may for Nelson, be regarded as the maximum uso of the sewers. I might point out that during the- winter months when there is no street or garden watering the average consumption per head is 93 gallons, so on that basis I think about 60 gallons per head may find its way into the sewers.

"Septic tank^ — Dr Frengley states in his comments that on visiting the septio tank he found the by-pass open and the sewage passing direct to the harbour. This was'sa; diluted sewage was: passing into the main outfall arid, delivered into the waters of the bay at a point over three-quarters of a mile from the septic tank.. I was unaware that the valve had been openedj'but I afterwards ascertained the reason for it. Duiing the winter months when repeated floods and heavy tides prevailed, which completely submerged several of the sewer manholes, much water found its way into the sewers' Tho ejectors, especially -Nos. 2 and '3, were, .very. heavily taxed, and were requir-, ed to deliver large Volumes of wator£ Being as well aware" as Dr Frengley that 22£ square yards of straining niedium consisting of material varying from 4in and 6in in size to small pea. gravel was not designed for and could not possibly pass the requisite amount of water, it was found necessary at times to open the by-pass to permit of those flood waters being delivered, otherwise than through the tank. On two occasions the tank did overflow, washing away a portion of the unprotected bank before we

could get down to relieve it. Another reason for by-passing is that while effecting repairs to Cambria street ifc still becomes necessary to carry on flushing operations, and if at such atime the surface pump on the repairing works goes wrong, them we have to resort to pumping out the trench witlr the ejectors rather than let the water rise and damage tita work. _ This is what had happened when"Dr Frengley visited the tank Another reason for by-passing at intervals, is that as the valve is about two feet back from the face of tho chamber, this length gets filled with .solid matter, which if not relieved before it sets hard becomes very difficult to shift; therefore the valve is opened: for a few minutes on different occasions to relieve this before it has the opportunity to set. The reoson the sewage in tho Bcroeuinc chamber was 2% inches below the crest of the aerating weir (not four niches as Dr Frengley states) was. due to the fact that it becomes necessary to work the sluice valve at intervals in order to prevent it sticking. Tliis operation is carried .. out during ebb tide, and to it no" doubt is due the fact _ that, the ;tank effluent was below the crest, as this was done when the bypass was opened the day before Dr i rengley's inspection. -

' 'Continuing, Dr Frengley stafces that the sewer in Cambria street is defective. I was perfectly aware of this. Before his visit this defect had been discovered by me, and the worfc of effecting the necessary repairs put in hand. In regard to the ". other manholes ;. and streets mentibned by him .as being "flow reasonable," "reasonably good," "condifcione within the normal," etc., these remarks are undoubtedly ambiguous. With all respect to'Dr Frengley, I would like to -know ibw he- has arrived at this decision,, for there is not the

slightest doubt;in, my mind. that he.is totally unaAvare of the number of houses connected -with the various

sections or whether the sewers are -laid in wet or-dry ground. "In commenting on. the old sewers, it is remarked that there is just as-much sewage coming down by the old system as the new. Here again the- doctor is correct, as _ there are more services connected with the old ' than with' the new system. The doc-

tor in liis concluding rtemarks states that it is imjxtssible to have any effective system with such evidence of extremely bad construction and indifferent supervision in parts thereof. I will deal with this in connection with section 5 of his remarks. "Section 2. — In this connection tho matter of by-passing the sewage into the waters of the bay over threequarters of a mile from the tank is again dwelt upon, etc. would be interesting to know wliafc further demonstrates the probability that this has been going on for some time. I have already stated that it has been, done when occasion demanded it. On, the question of analysis, I am quite prepared to accept the doctor's superior knowledge on those points, as it would be absolute arrogance on mv part to question them. ."Continuing, it is stated that "inview of these results it is not surprising tome to We heard it said iix Nelson- that near 'the foreshore offen. Biro smells are frequent." Surely the" intermittent by-passing of diluted sewage to a distant point which becomes further .diluted (it is safe to say; to the extent of 100.000 to one is not going to be blamed for that I also notice that danger is apprehended trom this source in connection, with the -oyster beds inside the Boulder Jhnk at Lighthouse Point, . and the doctor supposes the facetious contenI turn is advanced that the sewage is being treated before ifc enters tho harbour. The. matter of oysters has nothing to do with this Council, and I should not have alluded to it had it not been sandwiched in with tho septic tank and by-passing the sewage and holding the latter out as » further mmos to the public health, lhe facts arenas I happen to know" tiiat after careful and repeated cur-- - rent observations taken chrrine: vary-- ' ing states of the tide- and winds,backed up by local knowledge afforded by men wio have been boating iff the harbour for years, and having good cause to study the currents ft was discovered -that the water commg into the tho harbour up ' the south channel never crossed the middle bank on the ebb. tide .but set straight out again past the Government wharf. T~hat is why Dr Mason pernntted Merlino's oyster beds in- . side the Boulder Bamk at Lighthouse Point. • .

_ ''In the. first, paragraph of section o I have no doubt_that Dr Frengley is correct, but in the second paragraph ifc js stated that on account of bad construction and insufficient supervision subsoil water has not been, adequately kejrt out in Cambriastreet, and he fears that smaller leakages will be found elsewhere in the Wood. In regard to the alleged bad construction and inefficient supervision, I may state that, l visited the work from time to time myself, and there was also a works . superintendent and a ganger, and in addition the Health Department's own inspector spent a great amount of time on this section, apart from the work of carrying out the. necessary, tests. "In regard to Dr Frengley' s recommendations to his Department, and to the -.Council, I consider those outside the scope of my reply to Tda report.

"Conclusion. — In submitting to you this reply to the criticisms and strictures conveyed in Dr Frengley's report, I have found_ it necessary to correct certain' obviously erroneous remarks made by him, I have no i doubt that the cause of such remarks a'lid the amount of supposition that ha has found it necessary to indulge in has been due to the fact that it was- utterly impossible for him to become better acquainted with all details of the question owing to 'the limited time at his disposal, and on the wihole I don't think his report whom corrected conveys to the public anything that they were not cognisant of before. The doctor complains of the indifferent supervision, a. point that I do not admit, for as a matter of fact it does not matter how good ~ the supervision the workmen will beat the supervisor sometimes. la the- case of sewers this can, "only, be found out by testings, and I would point out that the major- portion, of this work, including Cambria street, v.-as conducted by the Department's own" officbr, and'tho subsidy to the Department for his services together with his assistant's wages, cost" this Council over £300^ per annum. I might aJso point out to you that tiho report is. the production of gentlemen _ wihose knowledge of any engineering construction work must by their calling in life or profession be limited to an extent. It is only consistent with reason that any engineering work ca-ft only- be criticised by anyone, .possessing a thorough engineering knowledge of the subject be-" fore them. This point affects both Mr Mestayer as well as myself, a3 Mr Mestayer in his report of February last expressed himself perfectly satisfied with everything - that had been done, with the exception of th« deep sewers in the Wood, i.e., Cambria street, two sections, and laid down certain tests to be done to ascertain ; the -leaks. ■ Therefore I would respectfully .suggest that either he or some other gentleman . who by virtue of Jiis special; > professional, training, is competent to express an ■opinion, should make an exhaustive examination of the system, and submit to your. Council an exhaustive ■—' and comprehensive report."

Hie Mayor moved that tho report; bo considered on January 7th. By then they would have time to CO thoroughly into it. Cr. Turner seconded "the motion, pro forma. He thought they should go on with the matter at once ; they knew as much about it then as they would in six months' time. Everyone knew the position in regard to iwrts of the \Yood. They would have the Government on them if tbev delayed the matter. .- ,

Or. Fiekl said there were some matters which should be .gone, into without delay. For instance, tho payment mentioned by -the City Engineer to the Health Department for inspecting the work,, which was reported on as satisfactory. He would like to know how many reports they had from the Health Department, and what tho Department did. .

In reply to -Or. Neale the Mayor stated that p^rt of the Cambria streofc work was mer#y inspected by Mr. Dormac on his own account. It was after that the Department was asked t<3 Tindertako tho responsibility of inspecting tho work officially. The .resolution /asking the Department to do' this work was read. Cr. Grace said immediately upon that resolution being submitted to tho Department, Inspector Dorizac who was already in the city, becamo in a sense the paid servant of the Council. Or I< ield said the Council virtually i™ 1 -^ upou da y Iab o"r in November 190/. In the following March the Aledical Association- drew the attention of tho Council to the manner in winch the sowers viy-re being tested. In April, when four miles of sewer had been ' laid, the Health. Department commenced -.the testinc;. Their request jto the Health Department to s.yery definite one, and if tho Department found that nart of the work «ould not he 'tested it'fjiiyhfc havo mfoirmed the. Council to that effect. Anything occurring after thafr time was the Health Department's /responsibility. ■-.-"■ The City Engineer said -the Departmentjiad never done any testing in tlie Wood. ■ -I--' .-.;■

The Town Clerk read the Department's report- on. \the testing, nvhicii did not include the" Wood area. ■ ■"'Or. Petti* said the f DeDarttnent had -promised a report on the Wood area, but it ..was . stated that it was impossible to "test sowers already, laid with-

out opening up the work.. If the matter was' to be doferrVd;the Health De-

partment p.hould " be- -askeii -in the meantime . why no ronorfc had been made previously upon the portion of tho work' now condemned. He was confident that the Department would disclaim responsibility. The only proper course for the Conucil to follow, •was to request Mr. ■ Mesbayer to vitifc

.Nelson and report exhaustively upon the scheme. ...'■.'_■ , , .„ Cr. Turner thought that a silly idea No one could report upon the work unless it was opened^up. , Th© Mayor said they did not want to go in for heroics over.themattor TheylTOl all Known '*V vffiv ti^ 1 iime that there vere.j Wks in, tho Wood. All tho Council had to deal ■whfiwas in connection with Cambria si^c did not want any more ex-

Grace hoped tho ? Question; before the Meeting would be, decided feiriy and S q«ardy., Personally he did wish to disenss either report at^ ■^S & Alm9 .thought it would bo best to get an independent samtary engineer to report on the scheme. The motion, was put and carried. Cr FieCd said that they had done a foolish thing in carrying the motion.They should-^ask the- Health: Department for further information. :On the motion of Cr. Nealo, seconded by Cr. Grace, it was decided to hand the Engineers' report to. the

? In reply to Cr. Grace, the Engmeef said it would be possible to test a -sewer after it had been laid and covered in. „ '- .j '■ The meeting then adjourned.,