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Home Sanitation and Hygiene: Extend

Admit the sewage into the first chamber through the 6-inch vitrified inlet pipe (g). Extend this at least 2 feet below the water level fixed by the top of the partition between the two chambers. Extend the two baffle boards (dd) to about two-thirds the depth of the tank. The first is designed to break the force of the inrush of water through the inlet pipe. The second keeps the scum on the surface of the first chamber from flowing over the partition.

As soon as the sewage is brought into the first chamber the anaerobic bacteria attack the sludge at the bottom of the tank. At the same time a scum begins to form on the surface of the sewage. This soon mats into a tough mass a foot or more in thickness. It excludes the light and air and provides the conditions required by the anaerobic bacteria for their work. Under these conditions so much of the sludge at the bottom of the tank will be liquefied and will escape between the second baffle board and the partition into the second chamber that the removal of the sludge by other means will be required only at long intervals of time. The stand pipe (h) of 6-inch vitrified tile with its tee and connecting bend of 4-inch pipe at (k) serves as an overflow, and at (i) and the discharge pipe (j) there is an arrangement which permits the discharge of the whole contents of the second chamber, when intermittent irrigation is desired, by drawing the plug (m) above the opening (i). This can be done by pulling upward the handle (1). The top of the stand pipe at (1) serves as an exit for the gases formed in the second chamber and also as an inlet for air into the sub-soil or irrigation pipes. A series of holes should be bored in the upper part of the two baffle boards above the water level. These afford an inter-communication of gases between the separate chambers of the tank. Also provide an opening into the stand pipe at (o) to serve as a means of escape for the accumulated gas, otherwise an explosion might occur. The whole tank is covered tightly with the plank (p). All the materials required for this tank may be had in any locality. The construction is simple and the expense is chiefly for labor. A better plan, however, is to provide an automatic syphon of which there are several styles on the market, so that the sewage may be discharged at required intervals without constant attention.

Syphon Tanks. -The principle of the automatic syphon is well known.

It consists simply of a section of pipe so curved that one leg is longer than the other. The long leg is erected vertically to a proper height in the second chamber of the tank and covered at the top by a suitable bell. It is connected by means of the short leg with the outlet pipe. When the liquid sewage enters the second chamber it rises under the bell, flows into the long leg of the syphon and seals the trap at the bottom of the bend.

As the depth of sewage increases, it compresses the air in the long leg of the syphon until, at the proper level, the pressure becomes great enough to force the water in the bottom of the trap out through the short leg and the outlet pipe and thereby creates sufficient suction to empty the second chamber. Once the level of the fluid descends below the mouth of the bell, air is admitted, the syphon is broken and no further discharge can occur until the tank is again refilled. - Flush Tank. The two-chamber septic tank above described may be deemed necessary for proper sub-surface irrigation, and is desirable in all cases. But for surface irrigation a simple flush tank having a single chamber and operated by hand by means of a check valve, or by an automatic syphon, may be sufficient. The accompanying illustration shows a simple form of flush tank designed Manhole flouse drain, Cast-Iron Manhole frame a Cover Earth Wire Baskets, TRANSVERSE SECTION, LONGITUDINAL SECTIONS Siphon 4 outlet House FLUSH TANK YPHON AMBO 4 Outlet PLAN.