Unless allowed by a service contract or industrial discharge permit, it shall be unlawful to permit or cause flow of any of the following substances into the public sewer:
   A.   Any grease, fatty material, offal or garbage;
   B.   Any stone dust, sand, dirt, gravel, sawdust, metal filings, broken glass or any other material which may cause an obstruction in the sewer;
   C.   Gasoline, benzene, fuel oil, phenols or cresols, or any petroleum products or volatile liquids, or any wastes which create a fire explosion hazard;
   D.   Milk, or any liquid milk waste products, in quantities in excess of ten (10) gallons during each twenty four (24) hour period;
   E.   Any cyanide, phenols or other chemical substance which interferes with or prevents the functioning of the sewer system or wastewater treatment facilities;
   F.   Paint or waste products from paint manufacturing;
   G.   Radioactive wastes;
   H.   Any material from cesspools and septic tanks, other than effluent;
   I.   Any other matter, substance or liquid deleterious to the sewer system and wastewater treatment facilities or which shall endanger the employees, operation or treatment processes of wastewater disposal, or which shall cause encrustation or otherwise chemically or physically corrode or erode the sewer system and wastewater treatment facilities. In no case shall wastes with a pH lower than 5.0 be permitted into the public sewer. (1952 Code § 8-11-10.05)