The Daily News. THURSDAY, MAY 8, 1902. DISPOSAL OF SEWAGE.

Taranaki Daily News, Volume XXIV, Issue 107, 8 May 1902, Page 2

The Daily News. THURSDAY, MAY 8, 1902. DISPOSAL OF SEWAGE.

As the Borough Council contemplates submitting to the ratepayers a scheme of public works involving ao expenditure of some £BO,OOO, a considerable portion of which is in connection with a drainage system, any information regarding the practice in towns where the conditions are somewhat similar to those existing in New Plymouth woukl doubtless be interesting to the Borough 'Jouncil and to ratepayers. Mr Leslie Reynolds, C.E., whose ability as an engineer is recognised throughout the colony, and who has had exceptional experience in connection with the designing of sewerage schemes, is at | present in Napier, having arrived from Maeterton, where he has been inspecting the water supply and sewerage schemes which were carried out accord ing to principles designed by himself. At the request of the Hawke's Bay Herald he consented to furnish gome

particulars of the method adopted at Mastwton for the disposal or sewage. It, appears that in 1897 he was called in to advise on a scheme suitable for Mastsrton. Although the physical conditions of tbe surroundings of that town are very favourable to the discharge of sewage into the JJuamahunga river, the Municipal Corporations Act of 1886 rendered this course impossible. In his report to tbe borough Mr Bsynolds Bays:—"lt is perhaps not for me to question the wisdom of indiscriminately forbidding the discharge of sewage into rivers of rapid flow and large volume, as compared with the amount of sewage which would be discharged into them, above their tidal compartment whare the water is constantly flowing in the one direction, and at the same time sanction discharge within their tidal reaches where

the conditions affecting sewage purification become more complex as the tidal prism oscillates up and down with each ebb tide and flow of the tide." As, however, the Legislature hid decided the question it was necespary to devise some system of sewage treatment and purification. The system finally adopted was that known as the septic tank, with intermittent downward filtration. The work was begun i two years ago and completed last September, when it was h&Bded over to the borough authorities. As this is the most extensive instance of septic tank I treatment in this colony, and perhaps in all Australasia, it has naturally been the subject ef great interest. Th 6 tank is made of concrete, completely roofed in and air-tight, The dimensions are 100 ft by 30ft by Bft 6in. The sewage, without any preliminary treatment or straining, flows from the sewers, which are kid to meet the re-

quirements of 10,000 p»op]», direct to i tbe tank at one end, and discharge! 'at tbe other end to all appeii-J ance clarified and pure. No folidj substance is perceptible ia the liquid I issuing from the tank. Tho discharge is led in cast-iron pipes to filtbi' hedw approximately 100 feet square, which ara composed of screened Hiiiufjle gtavel and sand, in layors, and which are four cr fiv« feet in depth, l'iiese beds are divided into two compartments, and tho sewage by a simple uutuiuitsc tipping arrangement ia ad justed to flow alternately for fix hours at a time on to each bed. The discharge is regula'o:! by perforated iron traps, S'xty fte6 long, in'o which it run?, and , make.i its w>:y through the perforation on to the beds. Afttr filtration the tewage gets away through the under

lying natural gravel. Any portion which is not so absorbed is led by a pipe to thrt river. In conjunction with ( the filter beds tho sewage works embrace tfn acres of shingle bed, over which the sewage is spread by surface irrigation by m aus of ploughed furrows. By turning the sewage into this I irrigation area '/he filter beds are given for a few (?ays tho rest which is neceswary in any system of filtration. Otherwise the crganit-ms in the beds sickoa and cease to perform the purification, required. This is an important point' in tbe bacteriological treatment of sewage, and has been so arranged at Masterton that there are several different methods of disposal during the periods of rest, The works have been in full swing at Masterton for over sis months, and have given complete satisfaction. AH the machanism of the works is automatic, so that the attendance reduced is [reduced to a nr'nimum. The whole cost of the work, including water supply and sewerage system, was £26,000. Mr Reynolds' recent visit to Masterton was made with a view of meeting tha borough authorities and making a final inspection af'er the system was in full swing. Ho expresses himself as highly satisfied with the success of the scheme.