(A) No person shall discharge or cause to be discharged the following described substances, materials, 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 any hazard in the receiving waters of the sewage treatment plant, or to cause the effluent from the treatment works to violate applicable effluent standards.
(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 structure, equipment, and personnel of the sewage works.
(4) Solids or viscous substances in quantities or of the 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, 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, either whole or ground by garbage grinders.
(B) No person shall discharge or cause to be discharged the following described substances, materials, waters, or wastes to any public sewers if it appears likely in the opinion of the Operator that the wastes can harm either the sewers, sewage treatment process, or equipment, have an adverse effect on the receiving stream, as determined in the NPDES permit received by the city or otherwise endanger life, limb, public property, or constitute a nuisance. In forming his/her opinion as to the acceptability of these waters, the Operator 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, degree of treatability of wastes in the sewage treatment plant, and other pertinent factors. The substances prohibited including all limitations and prohibitions imposed by the NPDES permit of the city are:
(1) Any liquid or vapor having a temperature higher than 150°F or 65°C.
(2) Any water or waste containing fats, wax, grease, or oils, whether emulsified or not, in excess of 100 mg/l or containing substances which may solidify or become viscous at temperatures between 32°F and 150°F and 0°C. and 65°C.
(3) Any garbage that has not been properly shredded. The installation and operation of any garbage grinder equipped with a motor of ¾ horsepower (0.76 horsepower metric) or greater shall be subject to the review and approval of the Operator.
(4) Any waters or wastes containing strong acid iron pickling wastes, or concentrated plating solutions whether neutralized or not.
(5) (a) Any waters or wastes containing iron, chromium, copper, zinc, and similar objectionable or toxic substances beyond the maximum allowable concentrations as determined by the Operator.
(b) The Operator will evaluate each toxic or objectionable substance waste on a concentration dilution basis and will establish maximum allowable discharge concentrations for each individual person to protect against the following:
1. Decreased sewage plant treatment process efficiencies and degraded effluent qualities exceeding the current requirements of the regulatory agencies.
2. Concentrations of any toxic or objectionable substance in the sewage treatment plant effluent exceeding the current maximum limits established by the regulatory agencies for such plant effluent flows.
3. Any concentrations of toxic or objectionable substances in plant effluent flows which will result in concentrations of such substances in the receiving waters which will exceed the regulatory agency's maximum allowable limits for these substances in the receiving waters.
(c) Any waters containing mercury of any of its compounds in excess of 0.0005 mg/l as Hg at any time.
(d) No waste discharged to municipal sewer system shall contain detectable levels of cyanide at any time except as permitted below:
1. Any person desiring to discharge cyanide or cyanogen compounds to the municipal sewer system shall apply for and procure approval from the city. The application shall contain sufficient information on discharge concentrations, flows, and the like to provide adequate data to enable the city and its representatives to evaluate the discharge and secure required state environmental protection agency approval.
2. When permitted, total cyanide shall not exceed 10 mg/l provided any sample tested shall not release more than 2 mg/l of cyanide when tested at a pH of 4.5 and at a temperature of 150° for a period of 30 minutes. The discharges shall be permitted only when the agency has determined that no violation of the effluent criteria of 0.025 mg/l concentration (alone or in combination with other sources) will result from such discharge.
3. Any waters or wastes containing phenols or other taste or odor producing substances, in such concentrations exceeding limits which may be established by the Operator as necessary, after treatment 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.
4. Any radioactive wastes or isotopes of such half-life or concentration as may exceed limits established by the Operator in compliance with applicable state or federal regulations.
(6) Any waters or wastes having a pH in excess of 9.5.
(7) Materials which exert or cause:
(a) Unusual concentrations of inert suspended solids (such as, but not limited to, Fullers 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.
(8) 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 including the NPDES permit of the city.
(9) All exhaust from steam engines and all blow offs from steam boilers shall be first connected with a proper basin, and shall not be allowed to connect directly with the public sewers without special permission from the approving authority.
('72 Code, § 51.047) (Ord. 51-A, passed 10-4-76; Am. Ord. 19-03, passed 5-6-19) Penalty, see § 51.999