GREEN ISLAND DRAINAGE

Evening Star, Issue 22618, 9 April 1937, Page 11

GREEN ISLAND DRAINAGE

MAIN SEWER TESTED FROM BOROUGH TO CPRM SEA Yesterday marked a further stage in the progress of the Green Island Borough, as the main sewer from the New'Zealand Drug Company’s premises to the sea was satisfactorily tested, and is now available to convey sewage from any portion of the borough to the sea. With the assistance of the New Zealand Refrigerating Company Limited, sufficient water was obtained to flush out. the sewer thoroughly and to prove its efficiency throughout its length. . , ' The work is of considerable magnitude, many phases requiring special engineering design and provision, and of particular interest is the constructional work at the outfall. The main sewer consists of reinforced spun concrete pipes from 12in to 21in in diameter, with the exception of some 2 ; 000ft of main sewer, which was earned over tho low-lying swamps which are found near the outlet of the Kaikorai. Stream. These pipes consist of concrete-lined steel of the spigot faucet pattern, the jointing being done in cement. The main sewer terminates at the penstock, which is situated above highwater mark on the Green Island Beach. From the penstock the discharge of sewage is made through 15in diameter cast iron pipes to Ift below low water ordinary spring tides. The pipes have been secured to ironbark piles driven approximately 12ft into the sea bed. The work has been difficult and arduous, and after being advanced to low-water mean ordinary spring tides could be carried out only during spring tides—and then only when the sea was calm and the wind suitable. This is the first occasion in New Zealand where sewage discharge has been made into the open sea, and it is indeed satisfactory to find that, whereas the work was slow, it has been successfully accomplished. The engineer (Mr F. J. Williams) speaks very highly of the men who carried out this undertaking, and of tjie excellent work they performed - despite the very trying conditions under which the work was carried out on many occasions. The .works were commenced at tho beginning of April, 1935, so that the major portion of the undertaking has been completed within two years.