Sec. 26-134. Same--Types permitted at discretion of city engineer.


No person shall discharge or cause to be discharged to any public sewer the following described substances, materials, waters or wastes, if it appears likely in the opinion of the city engineer that such wastes can harm the public 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 opinion as to the acceptability of these wastes, the city engineer will give consideration to such factors as the quantities of subject wastes in relation to flows and velocities in the sewers, materials or construction of the sewers, nature of 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:


(a)   Any liquid or vapor having a temperature higher than one hundred fifty (150) degrees Fahrenheit (sixty-five (65) degrees Centigrade).


(b)   Any water or waste containing fats, wax, grease or oils, whether emulsified or not, in excess of one hundred (100) mg/l or containing substances which may solidify or become viscous at temperatures between thirty-two (32) and one hundred fifty (150) degrees Fahrenheit (zero (0) degrees Centigrade and sixty-five (65) degrees Centigrade).


(c)   Any garbage that has not been properly shredded. The installation and operation of any garbage grinder equipped with a motor of three-fourths (3/4) horsepower (seventy-six one hundredths (0.76) hp metric) or greater shall be subject to the review and approval of the city engineer.


(d)   Any waters or wastes containing strong acid iron pickling wastes, or concentrated plating solutions.


(e)   Any waters or wastes containing 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 treatment works exceeds the limits established by the city engineer for such materials.


(f)   Any waters or wastes containing phenols or other taste- or odor-producing substances, in such concentrations exceeding limits which may be established by the city engineer 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.


(g)   Any radioactive wastes or isotopes of such half-life or concentration as may exceed limits established by the city engineer in compliance with applicable state or federal regulations.


(h)   Any waters or wastes having a pH in excess of 9.5.


(i)    Materials which exert or cause:


(1) Unusual concentrations of inert suspended solids (such as, but not limited to, Fuller's earth, lime slurries and lime residues), 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.


(j)   Waters or wastes containing substances which are not amendable 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.


Source:  Ord. No. 3014, 16, 10-5-81