LOWER HUTT SEPTIC TANKS

Dominion, Volume 12, Issue 93, 14 January 1919, Page 8

LOWER HUTT SEPTIC TANKS

In tho report submitted tn tho Lower Hutt Borough Council last evening by tho Borough Engineer (Mr. A. K. Gwnblcy) the following comments were made respecting tho eastern and western septic tanks :— "As far as one is ablo to judge by mere visual inspection tho effluents arc not as good as they should be, ale though they are not as bad as one would expect when considering the conditions under which tho tanks are working. Apparently at times of storm the tanks havo to copo.with a considerable amount of storm water (in addition to sewage) which finds it way ...into the sowers. In addition, their action is interrupted to »certain extent by tho fact that air (and therefore oxygen) is admitted to tho tanks by tho fact that they aro not scaled down as they should be, and as tho manhole doors aro lifted at times it is admitted very freely; in addition light is also admitted , . As, both those tanks depend on the action of auaorobic bacteria (that is bacteria which thrive and therefore work most effectively whero there is an absence of lijrht and oxygen) for the liquifying of tho sewage, you will readily seo that they are working under adverse conditions. In addition, tho. tanks are now really too small for the work they have to do. Reckoning that each tank should be capable of dealing with duo and a half days' dry weather flow nisd imkoning forty gallons of sewage per capita per diem, each tank (without fliakin" any. allowance whatever lor "sludge deposited on tho bottom) is capable of dealing with tho sewage from 1060 persons, that is to say that thd eastern and- western tanks are each capable of dealing with tho towago from 2120 persons. In January, 1918, there were close on lOOOconntctions to-the sewers. Reckoning (no persons por connection, the tanks were then treating the sewago from 5000 persons. As you may judge, the result is that the rate of flow through tho tank is considerably in excess of what it should be, and in-consequence-the sewage is not effectively treated.