New Britain herald., 1924-09-04

< there is no air. and the sewage is decomposed by the onarobic bac- teria. and there is some settlement of the heavy sludge. The sewage is drawn from this tank and sprinkled over a coarse filter where the Aro- bic bacteria and air complete the treatment of the sewage.
 Tor the actiyated sludge process small bubbles of air are blown through tank of sewage, causing the Arobic bacteria to grow rapidly and the sludge thus formed has chemical and biological properties of
 value In the treatment of sewage and is known as activated sludge.
 'The activated sludge is then mix
 cd with crude sewage in an aeration
 tank which is agitatec with an air
 blast, the whole mass becoming thor
 oughly treated. This treated sewage
 is then run into a settling tank
 where the sludge settles out quickly,
 and the effluent or liquid which
 runs off is clear water, white and
 odorless and bacteria very low.
 Enough of the activated sludge is
 pumped back and used for treating
 more crude sewage, and the rest run
 onto filters and dried.
 "At the experimental station large
 wooden tanks were used, with con-
 crete covered bottoms and wood
 baffles, and | the air was blown
 through the sewage through filtros
 plates in the bottom.
 I "A turbine blower was used to
 furnish the air under the necessary 4 pressure. The air was also used to i lift the settled sludge to the reaera-
 ton tank, or to the sludge drying
 beds.
 r "A further test was made to try the acid heat Notation process, for de-watering the sludge by the addi-
 ton of acid and application of heat.
 The acid caused the suspended
 sludge to shrink, and the heat caused
 further shrinkage, and the sludge
 became light and floated, and the
 clear water was drawn from the bot
 tom of the tank. This acid heat treat
 ment was to help in the drying and
 disposal of the sludge.
 The third process tried out at the experimental station was the Imhof
 sprinkling filter. This also proved successful in handling the sewage. ] As l said earlier, this process is 8 : double treatment; A septic tank where the sewage is decomposed by
 one kind of bacteria which lives where air is not present, called Anar- abic bacteria, and the treatment on a coarse filter where the treatment is
 completed by the bacteria requiring : air, called Arobic. Wooden tanks were used for the experimental work, and the sewage was pumped to the first of septic / tank, where 1t was partially decom- posed. The effluent was pumped to the filter which formed the second
 part of the process. Here 1t was sprayed at intervals on 8 filter con- , sisting of underdrains, and one foot , of four inch crushed stone, with five . feet of two inch crushed stone on Y top. The intervals of spraying were , one minute spraying, and three min- y utes' resting. -..... f "One advantage of this process is !. the fact that the area of the filters f do not need to be large, because of V the first treatment in the septic tank. 0 These filters will handle two million e gallons DOT day. per acre, whereas, e our present when working properly e will handle only 50,00O gallons per e day per acre. The effluent from the
 1mhoff sprinkling filter plant was as s clear, and odorless, as from the acti. = vated sludge process.
 g The difference in cost Of installa. }, don of these two systems and the = difference in annual operating cost - of these two systems, are matters of e detail for the experts to work out . and study. The point we should all e be interested in, is to insist that the h problem be worked out and present. d ed to the city government, so that r the necessary money can be appro.
 priated, and we can obtain an ade. : quate and sanitary plant, for tho 1T disposal of the sewage of the city,