Septic tanks are nothing but long underground, water-tight cisterns through which the sewage passes very slowly and evenly. Located underground, they are warm and dark—ideal conditions for the development of the bacteria, little germs which eat up the sewage and render it harmless in much the same way as another kind causes cider to ferment. To prevent the bacteria (which live in the frothy sludge) from being disturbed cross-walls, called baffle boards, are placed to break up the current of the inflowing sewage. The purified sewage, merely clear water, may be discharged into the farm drain tile.
Locate the septic tank where it can be placed entirely with the side walls underground and out of danger of flood waters. For a family of 8 to 10, plan a tank with 8-inch walls, 5 feet wide, 5 feet deep and 10 feet long—all dimensions in the clear. Lay out the tank and construct it in exactly the same manner as [ Underground Cisterns], page 68.
Before filling the forms, set in the 6-inch inlet and outlet drains at the same height, 2 feet 6 inches below the ground level. To aid further in breaking up the currents and keeping out too much air, use elbow bends, so that the sewage in the tank will cover the mouths of the tile. In the side forms, at a distance of 2 and 4 feet from the inlet wall, set ¾-inch bolts to which the baffle boards will later be attached. These boards reach entirely across the tank, project above the sewage, and extend to within 1 foot of the bottom. While building the manhole covers, for the needed ventilation, insert in them four short lengths of 1-inch gas pipe.
Remove the forms the same as for [underground cisterns].
Concrete Hydrant Sink
Window Hatches
Window hatches should be protected by a flap cover, to close in times of heavy rain or snow.