Candy-Whittaker
Patent Bacterial Sewage Purification Tank
Sectional Elevation
Fig. 44.
Candy-Whittaker Bacterial Tank.—Somewhat similar in form to some of the previously described tanks, the Candy-Whittaker bacterial tank is circular in plan and provided with a deep inner cone, which divides it into two compartments as shown, [Fig. 44]. The sewage enters the outer compartment through a pipe, by means of which it is evenly distributed. The outlet is through submerged effluent troughs situated inside the cone, so that the sewage must flow down to within a short distance of the bottom of the tank in order to pass under the bottom of the cone and reach the outlet troughs. In consequence of this method of construction, the bulk of the solids in suspension are deposited in a circular V-shaped gutter or sump, from which the sludge is removed by the pressure due to the head of water forcing it up a sludge pipe similar to that previously described in connection with the Dortmund type of tank. In the Candy tank, however, the inlet end of the sludge pipe has a returned end with a swivel joint, which is rotated by means of a vertical spindle operated by a crank handle at the side of the tank, working through suitable gearing. It is claimed that any scum which may be formed on the surface by floating solids, or by sludge freed from the bottom of the tank by gases produced by fermentation, is retained in the outer compartment, and thus prevented from passing away at the outlet with the clarified sewage.
Non-septic Cylinder.—The troubles due to foul-smelling gases arising from the over-septicisation of sewage in tanks, are very liable to occur in small installations for country houses, where the daily volume varies periodically, and may drop to a mere dribble when the family is away and only one or two servants are left in the house. To meet the requirements of these cases, an arrangement has been designed by Messrs. Adamsez, Ltd., which consists of a deep glazed fir-eclay cylinder, provided with special inlet and outlet pipes. In consequence of the small diameter of the cylinder, the sewage passes direct through to the outlet in a very short space of time, but leaves the solids in suspension in the cylinder, where they undergo decomposition without affecting to any great extent the character of the fresh sewage on its way to the filter. This tank is shown in connection with a small filter and special distributing apparatus in [Fig. 45], and is known as the “Non-septic” cylinder. The sewage, as it leaves this cylinder, is well suited for further oxidation in properly constructed filters, or on suitable land without any possibility of causing a nuisance from smell.
Fig. 45.—“Non-septic” Cylinder with Small Filter.
“Kessel.”—In addition to those already described, other ingenious devices have been designed with the same end in view, viz. the prevention of nuisance from smell. Two of these, introduced by the Septic Tank Co., are based upon the theory that it is desirable to separate the solids in sewage from the liquid at the earliest possible moment after they enter the sewer. These are illustrated in [Figs. 46] and [47]. The former shows what is known as the “Kessel,” its name in Germany, where it was first used. Briefly described, it consists of a vacuum chamber, in which the sewage rises, by reason of the pressure of the atmosphere, to a height of about 25 feet, and then flows down again through a vertical tube, emerging from the apparatus at a level a few inches below the level of the invert of the incoming sewer. It is claimed that the deposition of the solids in suspension, due to their specific gravity being slightly greater than that of the liquid sewage, is greatly assisted by taking place in vacuum, and that a high percentage of the suspended solids is removed. The bottom of the “Kessel” is in the form of an inverted cone, to the apex of which a sludge pipe is connected, with its outlet end delivering into a separate sludge well. The deposit which takes place in the “Kessel” is drawn off at frequent intervals, before it has had time to become foul, and the capacity of the “Kessel” is so small by comparison with the daily flow of sewage, that the latter passes out very slightly altered in character from the state in which it entered. The apparatus is provided with various arrangements, for ensuring its continuity of action, for producing the necessary vacuum, and for facilitating the removal of the sludge. Other advantages claimed for the system are that it is constructed above the level of the sewer, so that costly construction below ground is avoided, and that only a few inches of fall are lost between the inlet and the outlet.