No person shall discharge or cause to be discharged the following described substances, materials, waters or wastes to any public sewer if it appears likely in the opinion of the PWD that such 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 or her opinion as to the acceptability of these waters, the PWD 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:
(A) Any liquid or vapor having a temperature higher than 150°F (65°C).
(B) Any water or wastes containing fats, wax, grease or oils, whether emulsified or not, in excess of 100 milligrams per liter or containing substances that may solidify or become viscous at temperatures between 32°F and 150°F (0°C and 65°C).
(C) 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 hp metric) or greater shall be subject to the review and approval of the PWD.
(D) Any waters or wastes containing strong acid, iron pickling wastes or concentrated plating solutions, whether neutralized or not.
(E) Any waters or wastes containing a toxic or poisonous substance in sufficient quantity to injure or interfere with any sewage treatment process to constitute a hazard to animals or create any hazard in the receiving waters of the sewage treatment plant. The following limits on the concentration by weight of various wastes as discharged to the sewer by an industry are hereby established as follows:
(1) The concentration of chromium as discharged to the sewer shall not exceed 3.0 mg/l.
(2) The concentration of zinc as discharged to the sewer shall not exceed 1.0 mg/l.
(3) The concentration of copper as discharged to the sewer shall not exceed 1.0 mg/l.
(4) The concentration of cadmium as discharged to the sewer shall not exceed 3.0 mg/l.
(5) The concentration of lead as discharged to the sewer shall not exceed 1.0 mg/l.
(6) The concentration of nickel as discharged to the sewer shall not exceed 8.0 mg/l.
(7) The concentration of silver as discharged to the sewer shall not exceed 1.0 mg/l.
(8) The concentration of mercury as discharged to the sewer shall not exceed 0.0005 mg/l.
(9) No waste discharged to city sewer system shall contain detectable levels of cyanide at any time except as permitted below:
(a) Any person desiring to discharge cyanide or cyanogens to the city 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 Illinois Environmental Protection Agency approval.
(b) When permitted, total cyanide shall not exceed 10 mg/l, provided any sample tested shall not release more than two mg/1 of cyanide when tested at a pH of 4.5 and at a temperature of 150°F for a period of 30 minutes. Such discharges shall be permitted only when the Agency has determined that no violation of the effluent criteria of 0.025 mg/1 concentration (alone or in combination with other sources) will result from such discharge.
(c) Any waters or wastes containing phenols or other taste or odor-producing substances, in such concentrations exceeding limits which may be established by the PWD 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.
(d) Any radioactive wastes or isotopes of such half-life or concentration as may exceed limits established by the PWD in compliance with applicable state or federal regulations.
(F) Any waters or wastes having a pH in excess of 9.5.
(G) Materials that exert or cause:
(1) Unusual concentrations of inert suspended solids (such as, but not limited to Fullers earth, lime slurries and lime residue) or of dissolved solids (such as, but not limited to sodium chloride and sodium sulfate).
(2) Excessive discoloration (such as, but not limited to dye wastes and vegetable tanning solutions).
(3) Unusual BOD, chemical oxygen demand or chlorine requirements in such quantities as to constitute a significant load on the sewage treatment works.
(4) Unusual volume of flow or concentration of wastes constituting "slugs" as defined herein.
(H) 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.
(I) 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.
(Ord. 1121, passed 12-20-99)