Sewage is defined as a combination of
(a) the liquid wastes conducted away from residences, business buildings, and institution; and
(b) the wastes from industrial establishments; with
(c) such ground, surface, and storm water as may be admitted to or find its way into the sewers.
Sewage a is frequently known as sanitary sewers or domestic sewage. Sewage be is usually called industrial waste. Sewers are classified according to the type of sewage that they are designed to carry. Sanitary sewers carry sanitary sewage and the industrial wastes produced by the community and only such ground, surface, and storm water as may enter through poor joints, around manhole covers, and through other deficiencies. Storm sewers are designed to carry the surface and storm water which runs of the area that they serve. Combined sewers carry all type of sewage in the same conduits.
The following discussion has for its purpose the development of methods of estimating the quantity of sewage that is or would be carried by sanitary sewers, i.e., wastes from residences, business buildings, institutions, industrial plants, and such water as may enter incidentally. The surface water runoff that must be carried b y combined and storm sewers.