A.   Prohibited Discharges Into Sanitary Sewer: No person shall discharge or cause to be discharged any stormwater, surface water, groundwater, subsurface drainage, uncontaminated cooling water, or unpolluted industrial process waters to any sanitary sewer.
   B.   Use Of Storm Sewers: Stormwater and all other unpolluted drainage shall be discharged to such sewers as are specifically designated as storm sewers, or to a natural outlet approved by the supervisor. Industrial cooling water or unpolluted process waters may be discharged, on approval of the supervisor, to a storm sewer, or natural outlet.
   C.   Specific Prohibited Discharges Into Public Sewers: No person shall discharge or cause to be discharged any of the following described waters or wastes to any public sewers:
      1.   Any gasoline, benzene, naphtha, fuel oil, or other flammable or explosive liquid, solid or gas;
      2.   Any waters or wastes containing toxic or poisonous solids, liquids or gases in sufficient quantity, either singly or by interaction with other wastes, to injure or interfere with any sewage treatment process, constitute a hazard to humans or animals, create a public nuisance, or create any hazard in the receiving waters of the sewage treatment plant, including, but not limited to, cyanides in excess of two milligrams per liter (2 mg/l) as CN in the wastes as discharged to the public sewer;
      3.   Any waters or wastes having a pH lower than 5.5, or having any other corrosive property capable of causing damage or hazard to structures, equipment and personnel of the sewage works;
      4.   Solid or viscous substances in quantities or of such size capable of causing obstruction to the flow in sewers, or other interference with the proper operation of the sewage works such as, but not limited to, ashes, cinders, gravel, grout, concrete wash and construction wastewater, sand, mud, straw, shavings, metal, glass, rags, feathers, tar, plastics, wood, unground garbage, whole blood, paunch manure, hair and fleshings, entrails and paper dishes, cups, milk containers, etc., either whole or ground by garbage grinders.
   D.   Harmful Discharges: No person shall discharge or cause to be discharged the following described substances, materials, waters or wastes if it appears likely in the opinion of the supervisor that such wastes can harm either the sewers, sewage treatment process, or equipment, have an adverse effect on the receiving stream, or can otherwise endanger life, limb, public property, or constitute a nuisance. In forming his or her opinion as to the acceptability of these wastes, the supervisor will give consideration to such factors as the quantities of subject wastes in relation to flows and velocities in the sewers, materials of construction of the sewers, nature of the sewage treatment process, capacity of the sewage treatment plant, and other pertinent factors. The substances prohibited are:
      1.   Any liquid or vapor having a temperature higher than one hundred forty degrees Fahrenheit (140°F).
      2.   Any water or waste containing fats, wax, grease or oils, whether emulsified or not, in excess of one hundred milligrams per liter (100 mg/l) or containing substances which may solidify or become viscous at temperatures between thirty two (32) and one hundred forty degrees Fahrenheit (140°F).
      3.   Any garbage that has not been properly shredded. The installations and operation of any garbage grinder (disposal) equipped with a motor of one horsepower or greater shall be subject to review and approval of the supervisor.
      4.   Any waters or wastes containing strong acid iron pickling wastes, or concentrated plating solutions whether neutralized or not.
      5.   Any waters or wastes containing iron, chromium, copper, zinc, and similar objectionable or toxic substances; or wastes exerting an excessive chlorine requirement, to such degree that any such material received in the composite sewage at the sewage treatment works exceeds the limits established by the supervisor for such materials.
      6.   Any waters or wastes containing phenols or other taste or odor producing substances, in such concentrations exceeding limits which may be established by the supervisor as necessary, after treatment of the composite sewage, to meet the requirements of the composite sewage, to meet the requirements of the state, federal, or other public agencies of jurisdiction for such discharge to the receiving waters.
      7.   Any radioactive wastes or isotopes of such half-life or concentration as may exceed limits established by the supervisor in compliance with applicable state or federal regulations.
      8.   Any waters or wastes having a pH in excess of 9.5.
      9.   Materials which exert or cause:
         a.   Unusual concentrations of inert suspended solids (such as, but not limited to, grout, fuller's earth, lime slurries, and lime residues) or of dissolved solids (such as, but not limited to, sodium chloride and sodium sulfate).
         b.   Excessive discoloration (such as, but not limited to, dye wastes and vegetable tanning solutions).
         c.   Unusual BOD, chemical oxygen demand, or chlorine requirements in such quantities as to constitute a significant load on the sewage treatment works.
         d.   Unusual volume of flow or concentration of wastes constituting "slugs" as defined herein.
   E.   Substances Not Amenable To Treatment: Waters or wastes containing substances which are not amenable to treatment or reduction by the sewage treatment processes employed, or are amenable to treatment only to such degree that the sewage treatment plant effluent cannot meet the requirements of other agencies having jurisdiction over discharge to the receiving waters.
   F.   Authority Of Supervisor: If any waters are discharged, or are proposed to be discharged, to the public sewers, which waters contain the substances or possess the characteristics enumerated in subsection D of this section, and which, in the judgment of the supervisor, may have deleterious effect upon the sewage works, processes, equipment, or receiving waters, or which otherwise create a hazard to life or constitute a public nuisance, the supervisor may:
      1.   Reject the wastes;
      2.   Require pretreatment to an acceptable condition for discharge to the public sewers;
      3.   Require control over the quantities and rates of discharge; and/or
      4.   Require payment to cover the added cost of handling and treating the wastes.
   G.   Pretreatment Plant And Equipment, Review And Approval: If the supervisor permits the pretreatment or equalization of waste flows, the design and installation of the pretreatment plant and equipment shall be subject to the review and approval of the supervisor, and subject to the requirements of all applicable codes, ordinances and laws.
   H.   Grease, Oil And Sand Interceptors: Grease, oil and sand interceptors shall be provided at the expense of the property owner when, in the opinion of the supervisor, they are necessary for the proper handling of liquid wastes containing grease in excessive amounts, or any flammable wastes, sand, or other harmful ingredients, except that such interceptors shall not be required for private living quarters or dwelling units, except where required by the supervisor. All interceptors shall be of a type and capacity approved by the supervisor, and shall be located as to be readily and easily accessible for cleaning and inspection.
   I.   Maintenance Of Treatment Facilities: Where preliminary treatment or flow equalizing facilities are provided for any waters or wastes, they shall be maintained continuously in satisfactory and effective operation by the owner at his or her expense.
   J.   Control Manhole: When required by the supervisor, the owner of any property serviced by a building sewer carrying industrial wastes shall install a suitable control manhole together with such necessary meters and other appurtenances in the building sewer to facilitate observation, sampling and measurement of the wastes. Such manhole, when required, shall be accessibly and safely located, and shall be constructed in accordance with plans approved by the supervisor. The manhole shall be installed by the owner at his or her expense, and shall be maintained by the owner so as to be safe and accessible at all times.
   K.   Measurements, Tests And Analyses: All measurements, tests and analyses of the characteristics of waters and wastes to which references are made in this chapter shall be determined in accordance with Idaho standards for public works construction, with the latest edition of "Standard Methods For The Examination Of Water And Wastewater", published by the American Public Health Association, and shall be determined at the control manhole provided, or upon suitable samples taken at said control manhole. In the event that no special manhole has been required, the control manhole shall be considered to be the nearest downstream manhole in the public sewer to the point at which the building sewer is connected. Sampling shall be carried out by customarily accepted methods to reflect the effect of constituents upon the sewage works and to determine the existence of hazards to life, limb and property. (The particular analysis involved will determine whether a 24 hour composite of all outfalls of a premises is appropriate or whether a grab sample or samples should be taken. Normally, but not always, BOD and suspended solids analysis are obtained from periodic grab samples.)
   L.   Special Agreements: No statement contained in this section shall be construed as preventing any special agreement or arrangement between the city and any industrial concern whereby an industrial waste of unusual strength or character may be accepted by the city for treatment, subject to payment therefor, by the industrial concern. (Ord. 624-08, 8-12-2008)