No person shall discharge or cause to be discharged to any public sewer the following described substances, materials, waters or wastes without the expressed written permission from the director.  The director may give his permission if he finds such wastes will not harm the public sewers, sewage treatment process, or equipment, have an adverse effect on the receiving stream, or will not otherwise endanger life, limb, public property or constitute a nuisance.  In forming his opinion as to the acceptability of these wastes, the director 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 are:

    1. Any liquid or vapor having a temperature higher than one hundred fifty degrees Fahrenheit or sixty-five degrees Centigrade;

    2. Any water or waste containing fats, wax, grease or oils, whether emulsified or not, in excess of one hundred mg/1 or containing substances which may solidify or become viscous at temperatures between thirty-two degrees and one hundred fifty degrees Fahrenheit or zero degrees and sixty-five degrees Centigrade;

    3. Any garbage that has not been properly shredded.  The installation and operation of any garbage grinder equipped with a motor of three-fourths horsepower (0.76 hp metric) or greater shall be subject to the review and approval of the director;

    4. Any waters or wastes containing strong acid iron pickling wastes or concentrated plating solutions;

    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 director for such materials;

    6. Any waters or wastes containing penults or other taste or odor producing substances, in such concentrations exceeding limits which may be established by the director 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;

    7. Any radioactive wastes or isotopes of such half-life or concentration as may exceed limits established by the director in compliance with the 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. Excessive discoloration (such as, but not limited to, dye wastes and vegetable tanning solutions),

            b. Unusual chemical oxygen demand, or chlorine requirements in such quantities as to constitute a significant load on the sewage treatment works,

            c. Unusual concentration of wastes constituting slugs;

    10. Any waters or wastes having: (A) a five-day biochemical oxygen demand greater than three hundred parts per million by weight; or (B) containing more than three hundred fifty parts per million by weight of suspended solids, or (C) having an average daily flow greater than two percent of the average sewage flow of the city;

    11. Waters or wastes containing substances which are not amenable to treatment or reduction by the sewage treatment processes employed, or are amendable 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.

    12. Any waters or wastes containing dissolved sulfides in excess of 0.5 mg/L.

    13. Septic tank waste from a truck or tank or bulk holding device by whatever description.  (Ord. 90/T-9329;  88/T-6121; S-39108, 1979).