SEWAGE DISPOSAL

New Zealand Herald, Volume LXXIV, Issue 22700, 12 April 1937, Page 12

SEWAGE DISPOSAL

Sir, —I have read with interest Sir Albert Howard's lecture on "The Manufacture of Humus by the Indore ; Process," as quoted by several of jour correspondents. A careful digest of the .facts shows that, although the process may be quite well suited for use on tea and coffee plantations on loose soils in tropical climates, yet there is no evidence quoted of its adoption for large cities or closely-settled areas. In fact, the lecturer merely infers that it could be utilised for new cities or extensions of existing ones. Its adoption in Auckland with its water-borne sewage system would, however, necessitate radical alterations in our sanitary systems, as Sir Albert Howard clearly states that excess of water is detrimental to i j the manufacture of humus and it has | therefore to be filtered out. Now this j is a point which your correspondents j have overlooked, viz., the disposal of I the 95 per cent of. flu They give no II indication or suggestion as to how this , should be done. Humus manufacture-" i depends for its efficiency on the use of | large amounts of vegetable matter, | wood ashes, peat, and a percentage of I animal waste. To put into operation j such a scheme in Auckland would i necessitate the co-operation of all muni- ! cipalities and the separation of vegej table matter from household Waste throughout Greater Auckland. Need- | less to say, there would be consideri able nuisance produced as fermentation ! readily sets in with household refuse. - Further, a period of 90 to 140 days is required for the humus to mature and, even with the use of compressed air, offensive gases would be dissipated, liencc any plant or factory would require to be located well away from populated areas. As I have previously mentioned, there is anmle area available on Brown's Island for the establishment of sludge conversion plant, whenever it is found advisable! I consider Sir Albert Howard's scheme of humus manufacture to be an admirable one for tea. coffee, sugar plantations and similar enterprises, but fail to see how it can be efficiently and economicr ally adopted for Greater Auckland conditions.

Assoq. -M. Ixst. C.E. (London).