Among the problems which his miniature municipality brings to the country house owner is the unromantic but necessary one of sewage disposal. In a suburban area it is merely a matter of connecting the house to the street main and paying higher taxes. With the country house, each owner must cope with the question for himself. He cannot leave it to chance or delude himself that any old system will serve. Some hot August day when his house is filled with guests, the makeshift disposal system will suddenly cease to function and an otherwise tactful guest will ask whether that queer smell is just part of the regular country air or what.
Of course, nobody thinks of disposing of household waste by piping it to a brook or letting it flow down a sandy side hill some distance from the house. Those were the methods of the ignorant and unscientific past. The means of disposal recommended by sanitary experts are those in which the wastes undergo a bacterial fermentation which finally renders the sewage odorless and harmless. It can be accomplished by a septic tank or a tight cesspool. The latter with its two chambers is really a variety of the septic tank itself. The first vault is built of stone or brick laid in mortar and covered with a coat of waterproof cement. With both supply and overflow pipes below the normal level of the liquids, beneficial fermentation takes place in this compartment before the liquids pass over into the second chamber from which they gradually seep into the ground. Such an installation calls for more excavation and construction than a septic tank and, since it accomplishes nothing that cannot be done with the latter, is only used where there is not enough ground area for the disposal fields of a septic tank.
The latter is an air-tight cylindrical or oblong container placed below ground, in which raw sewage purifies itself by the inherent bacteria. The first stage takes place within the tank and the second in the porous pipes that constitute the disposal fields. From the moment household wastes enter the tank, fermentation begins its work of reducing them from noisome sewage to harmless water. Both intake and outlet pipes extend below the level of the contents, with a baffle plate across the center which prevents direct outward flow. The heavy solids sink to the bottom and anaerobic bacteria, which develop only where there is no oxygen, breed rapidly and break these up so that they rise to the top and provide the ever present scum which excludes all air and stimulates fermentation of the entire content. Meanwhile, liquid from the tank is flowing into the disposal fields, which are porous land tile laid in shallow trenches and covered with earth and sod. Here some air is present and aerobic bacteria (those which thrive where there is oxygen) develop and complete the process of transforming the wastes into clear water.