§ 51.01 DEFINITIONS.
   (A)    B.O.D. (denoting biochemical oxygen demand). The quantity of oxygen utilized in the biochemical oxidation of organic matter, under standard laboratory procedure in 5 days of 20°C (68°F.) expressed in parts per million by weight.
   (B)    COMBINED SEWER. A sewer receiving both surface runoff and sewage.
   (C)    COOLING WATER. The water discharged from any system of condensation, air conditioning, cooling, refrigeration, or other, but which shall be free from odor and oil. It shall contain no polluting substances which would produce B.O.D. or suspended solids, each in excess of 10 parts per million by weight.
   (D)    DWELLING UNIT. A room or group of rooms occupied or designed to be occupied as living and sleeping quarters for one or more persons and equipped with the usual facilities for the preparation and cooking of food.
   (E)    INDUSTRIAL WASTES. The liquid wastes from industrial processes, as distinct from sanitary sewage.
   (F)    NORMAL SEWAGE. Sewage which, when analyzed, shows by weight a daily average of not more than 2,500 pounds (300 parts per million) of suspended solids; not more than 2,000 pounds (240 parts per million) of B.O.D.; and not more than 417 pounds (50 parts per million) of soluble matter (grease and oil), each per million gallons of daily flow.
   (G)    PERSON, ENTERPRISE, ESTABLISHMENT, or OWNER. Any individual, firm, company, association, society, corporation, or group using the sewage system.
   (H)    pH. The logarithm of the reciprocal of the weight of hydrogen ions, in grams per liter of solution. Is used to indicate the concentration of free acid and alkali.
   (I)    PUBLIC SEWER. A sewer controlled by a public authority.
   (J)    SANITARY SEWAGE. Sewage discharging from the sanitary conveniences of dwellings (including apartment houses), office buildings, factories, or institutions, and free from storm, surface water, and industrial wastes.
   (K)    SANITARY SEWER. A sewer which carries sewage and to which surface and ground waters are not intentionally admitted.
   (L)    SEWAGE. The water-carried wastes from residences, business buildings, institutions, and industrial establishments, singular or in any combination, together with such ground, surface, and storm waters as may be present.
   (M)    SEWERAGE SYSTEM. All facilities for collecting, pumping, and disposing of sewage.
   (N)    SEWER. A pipe or conduit for carrying sewage and other waste liquids.
   (O)    STORM SEWER or STORM DRAIN. A pipe or conduit which carries storm and surface waters and drainage, but excludes sewage and industrial wastes; it may, however, carry cooling waters and unpolluted waters.
   (P)    UNPOLLUTED WATER OR WASTE. Any water or waste containing none of the following: free or emulsified grease or oil; acid or alkali; phenols or other substances imparting taste and odor in receiving waters; toxic or poisonous substances in suspension, colloidal state, or solution; and noxious or odorous gases. It shall contain not more than 10,000 parts per million by weight of dissolved solids, of which not more than 2,500 parts per million shall be as chloride, with permissible volume subject to review by the service director; and not more than 10 parts per million each of suspended solids and B.O.D. The color shall not exceed 50 parts per million.
   (Q)    SUSPENDED SOLIDS. Solids that either float on the surface of, or are in suspension in water, sewage, or other liquids; and which are removable by laboratory filtering.
   (R)    SEWAGE LIFT STATION. A pump or other mechanical device used for lifting sewage from a sewer system on a lower level to one on a higher level, and shall include the housing of such pump and all sewer pipes or conduits leading from a lower sewer system to the pump and from the pump to the higher level sewer system.
('73 Code, § 51.01)