NOTE AND COMMENT.

Taranaki Daily News, Volume XLVI, Issue 297, 20 December 1904, Page 2

NOTE AND COMMENT.

11l many suburban districts, as well us in country towns SEPTIC where complete drainTANKS. age systems do not ex-' ist, the method of sewage disposal known as septic-tank treatment Iras been adopted. This system (writes the N.Z. Times) has been highly recommended by scientists ; yet it has to be remembered that, if it is not applied witli scientific care and accuracy, it may become a source of danger—a tiisseni'inator of disease instead of a preventive. What is the septic-tank system of sewage treatment ? Duclanx, iis greatest exponent, has defined it generally thus :—Whenever and wherever there is a decomposition of organic matter, whether it ho (he', case of a herb or>an oak, of a worm or a whale, the work is exclusively done by infinitely small organisms. They are the important, almost the only agent of | universal 'hygiene ; they clear away more quickly than the dogs of Constantinople, or the wild beasts of the desert, the remains of all that has life." They protect the living against the dead ; more, it is to' them we owe the conI tinued existence of living beings on the face of the earth. These are the | minute organisms set to work in the | septic system, which is in consequence known as the system of

" bacterial treatment; " of sewage. Briefly, the sewage is collected in tanks where it is liquefied and purified, and then passed l over filters until it ia sent forth, an effluent, colourless, odourless water, safe from all evil consequences, but, nevertheless, valuable as a fertiliser to many forms of plant life. The popularity ol the septic-tank system, because of its THEIR cheapness and thorough DANGERS. cleansing efl'eet, may

■ constitute a serious ganger, for people may adopt this method without having the appliances properly constructed and attended to. A discussion has lately been raging in the Sydney press, from which the uninitiated might conclude that the system has been proved a failure. "Insanitary Septic Tanks," "The Septic Tank a Failure,'" "Nuisances Caused by Septic Tanks"— these and other such headings are abounding in the correspondence columns of the newspapers. The system, for all that, is not a failure ; but one is driven to the conclusion that the people who work the system have, in some instances, faiied to make it work successfully. There are in the system two sets of bacteria, as Mr Scarle, C.E., of Sydney, points out. Of these one works in the dark—known as the anaerobic, or workers without air—while the other works in the brightest light that can be found, and the name aerobic is sufficiently designative, The first does the work of clearing away the results of decomposition in the tank ; the other confines his attention to the filter beds. The conditions to success are, then, that 'the tank where the liquefying process is going on must be dark, and the filters must be open to the air and light. Secondly, nothing that is insoluble in water must be allowed into the tank. Thirdly, as time is required by both sots of bacteria to do their work thoroughly, the 'tank and the tillers must be large enough for the work their inmates have to do. and the filter must pass the liquid through not too quickly. Fourthly, and this applies more to the sewage of hospitals, all antiseptics used must be adaqttately diluted, else they will bo disastrous to the well-toeing of the diminutive workers. With these things attended to, there need be no fear of the success of the septic-tank system. With any of them disregarded the tanks had much better not lie used at all. The .proper thing would appear to be to (have the tanks all examined before being brought into use, and to have the effluent periodically analysed to make sure that the liquid is innocuous. This matter ought to' receive the attention of the local authorities and of the Health Department.