Danger from Sewage

Sun (Auckland), Volume I, Issue 303, 14 March 1928, Page 1

Danger from Sewage

HARBOUR BOARD’S REPORT PUBLISHED INQUIRY DESIRABLE That the Harbour Board has been alive in recent years to the possibility of danger arising from the disposal of sewage into the Auckland Harbour is evident from a report prepared by the engineer and harbourmaster between November, 1925, and May, 1927, at the direction of the board. In view of the fact that the question of the nuisance caused by the Auckland and Suburban Drainage Board’s sewer outfall at Orakei is under inquiry by the Departments of Public Health and Public Works, the board decided yesterday to make the report public. The board also agreed to a motion passed by the board in committee in the following terms: “That it be a recommendation to the Minister of Health that the committee to be set up to inquire into the question of the disposal of sewage into the harbours of Auckland and Manukau consist of the district engineer. Public Works Department, and the district officer of health, and that they be asked to call a conference of all local bodies interested and report to the Minister with a view, if they thought desirable, of the Government appointing an expert in sewage disposal to report on the whole question.” The report reviews the sewage systems of six local bodies, namely, the Auckland and Suburban Drainage Board and the Devonport, Birkenhead, Takapuna and Otahuhu Borough Councils. SEWAGE AT ORAKEI Orakei, being the most important, was dealt with at length: “It is customary for the discharge to commence about half an hour after high water and to continue for four to five hours. Continuous daily observations over a very long period, supported by float tests, show that in the early stages and with the wind off shore, the sewage travels in a north-easterly direction and spread's out in a fan-shaped and clearly defined course toward the beacon marking the outer end of the western Bastion reef. “Diffusion with the tidal water appears to be reasonably rapid and complete considering the very large volume of sewage discharged on each tide. As the ebb proceeds there is a greater tendency for the course of the sewage to pass to the west of Bean Hock Lighthouse and into the main channel, but at about four hours ebb the tidal current completely changes and the course of the sewage is then almost due west past the end of the Orakei Wharf. “With the wind from the north and north-east the course of the sewage is diverted further inshore and in the early stages travels more in the direction of the eastern Bastion reef, while after four hours ebb it frequently passes underneath the Orakei Wharf. “It is possible that if the sewer outfall were extended for from 1,000 to 1,200 feet beyond its present position the objectionable conditions from the point of view of residents in the vicinity would be mitigated, though it is doubtful if they would be entirely removed, and it is very questionable whether the great cost of constructing the extension would be justified by the results achieved, nor does the law give this board power to demand such an extension.” SOME RECOMMENDATIONS “We are of opinion that this board should request the Drainage Board to prepare plans and detailed estimates for the necessary works on shore as provided under clause 30, paragraph 8 ot the Act, for chemical precipitation and removal of sludge, or other approved method of treating the sewage so as to provide an inoffensive effluem so that members of this board wo??,' be m a position to decide when it would be reasonable to insist upon the additional expenditure.” It recommends, further, that the Government be asked to set up a commission to investigate the position, with a view to having the outlying boroughs and districts combined into suitable drainage areas with a drainage board for each district; such boards to prepare schemes for the disposal of sewage in their respective areas, position of outfalls and nature of effluents to be approved by the Harnntfsii 80 ® 1 ? 3, J? n<l all applications for outfalls into the Waitemata or Manukau Harbours to be made through such drainage boards.