Sec. 21-212. - Substances prohibited in public sewers.
(a) Except as otherwise provided in this section, no person shall discharge or cause to be discharged any of the following waters or wastes into any public sewers:
(1) Any liquid or vapor having a temperature higher than 150 degrees Fahrenheit.
(2) a.
Any water or waste which may contain more than 100 ppm, by weight, of fats, oil or grease, or any water or waste containing oil, grease, or other substance that will solidify or become viscous at temperatures between 32 and 90 degrees Fahrenheit.
b. As set forth in sections 21-154—21-156, minimal pretreatment of wastes containing concentrations of grease (i.e., animal and vegetable fats and oils) in excess of 75 ppm is required.
c. Such minimal pretreatment requires passage through a grease trap meeting the city's engineering standards and providing a minimum retention time of ten minutes between influent and effluent battles with 20 percent of the total volume as allowance for a sludge pocket. This sludge pocket should be kept reasonably free of inorganic solids, and all grease and other floating materials shall be skimmed from the tank at sufficiently frequent intervals to avoid reduction of efficiency of the trap.
d. Upon written notification by the director that a grease trap is required for a given discharge, the user will have a period of 90 days for compliance. Such compliance consists of the complete installation and operability of a grease trap approved by the director. Failure to comply will result in the implementation of the enforcement procedures of division 2 of this article. Grease traps shall be available for inspection by the director or his staff at all reasonable times.
(3) Any gasoline, benzene, naphtha, fuel oil, mineral spirits, commercial solvent, motor oil or other flammable or explosive liquid, or any other petroleum derivative.
(4) Any waters or wastes that contain more than ten ppm by weight of hydrogen sulfide, sulfur dioxide or nitrous oxide.
(5) Any ashes, cinders, sand, mud, straw, shavings, metal, glass, rags, feathers, offal, plastics, wood, whole blood, paunch manure, hair and fleshings, entrails, lime residues, beer or distillery slops, chemical residues, fiberglass, paint or ink residues, cannery waste, bulk solids or any other solid or viscous substance capable of causing obstruction to the flow in sewers, or other interference with the proper operation of the wastewater works without proper pretreatment and written approval of the director.
(6) Any waters or wastes having a pH lower than six or higher than nine at any time, or having any other corrosive property capable of causing damage or hazard to structures, equipment or personnel of the wastewater works, or the treatment process.
(7) a.
Any waters or wastes containing toxic or poisonous substances in such concentration as to constitute a hazard to humans or animals, or to interfere with any wastewater treatment process, or to create any hazard in the receiving waters of the wastewater treatment plant without proper pretreatment and written approval of the director.
b. These limits may be used as a guide in design and plant control, but may be altered by the director as required or authorized by state or federal law in the event of a cumulative overload on a particular drainage basin or wastewater treatment plant.
(8) Any waters containing suspended solids of such character and quantity that unusual provision, attention or expense is required to handle such materials at the wastewater treatment plant.
(9) Any noxious or malodorous gas or substance, capable of creating a public nuisance or hazard to life or preventing entry into sewers for their maintenance, inspection and repair.
(10) Any waters containing quantities of radium, naturally occurring, or artificially produced radioisotopes in excess of presently existing or subsequently accepted limits for drinking water as established by the National Committee on Radiation Protection and Measuring.
(11) Any concentrated dye wastes, spent tanning solutions or other wastes which are highly colored, or wastes which are of unusual volume, concentration of solids or composition that may create obstruction to the flow in sewers or other interference with the proper operation and treatment of influent of the wastewater works without proper pretreatment and written approval of the director.
(12) Any waters or wastes containing substances which are not amenable to treatment or reduction by the wastewater treatment processes employed, or are amenable to treatment to only such degree that the wastewater treatment plant effluent cannot meet the requirements of other agencies having jurisdiction over discharge to the receiving waters.
(13) Any water or waste containing more than 2,000 ppm total solids.
(14) Any wastes at a flow rate and/or pollutant discharge rate which is excessive over a short period of time so that there is a treatment process overload and subsequent loss of treatment efficiency.
(15) Any wastewater containing phenols or other taste-producing substances in such concentrations as to produce odor in the effluent as to affect the taste or odor of the receiving water. Quantities of such substances will be determined by the director on a case-by-case basis.
(b) No person may discharge into grinder pumps or operate grinder pumps in any manner which is not recommended by the equipment manufacturer.
(Code 1982, § 20-202; Ord. No. 87-167, § 1, 5-14-1987)
