§ 36-76. Use of the public sewers.

(a)

Stormwater, runoff, cooling water, etc. No person shall discharge, or cause to be discharged, any stormwater, surface water, groundwater, roof runoff, subsurface drainage, uncontaminated cooling water, or unpolluted industrial process waters to any sanitary sewer.

(b)

Unpolluted discharges. Stormwater and all other unpolluted drainage shall be discharged to such sewers as are specifically designated as combined sewers or storm sewers, or to a natural outlet approved by the public works director. Industrial cooling water or unpolluted process waters may be discharged, on approval of the public works director, to a storm sewer, combined sewer, or natural outlet.

(c)

Prohibited discharges. No person shall discharge or cause to be discharged any of the following described waters or wastes to any public sewers:

(1)

Any gasoline, benzene, naphtha, fuel oil, or other flammable or explosive liquid, solid or gas.

(2)

Any waters or wastes containing toxic or poisonous solids, liquids, or gases in sufficient quantity, either singly or by interaction with other wastes, to injure or interfere with any sewage treatment process, constitute a hazard to humans or animals, create a public nuisance, or create any hazard in the receiving waters of the sewage treatment plant, including, but not limited to, cyanides in excess of 0.2 mg/L as CN in the wastes as discharged to the public sewer.

(3)

Any waters or wastes having a pH lower than 5.5 or having any other corrosive property capable of causing damage or hazard to structure, equipment, and personnel of the sewage works.

(4)

Solid or viscous substances in quantities or of such size capable of causing obstruction to the flow in sewers, or other interference with the proper operation of the sewage works such as, but not limited to, ashes, cinders, sand, mud, straw, shavings, metal, glass, rags, feathers, tar, plastics, wood, unground garbage, whole blood, paunch manure, hair and fleshings, entrails, and paper dishes, cups, milk containers, etc., either whole or ground by garbage grinders.

(5)

No person shall discharge or cause to be discharged the following described substances, materials, waters, or wastes if it appears likely in the opinion of the public works director that such wastes can harm either the 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 public works 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 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 150 degrees Fahrenheit (65 degrees Celsius).

b.

Any water or waste containing fats, wax, grease, or oils, whether emulsified or not, in excess of 100 mg/L or containing substances which may solidify or become viscous at temperatures between 32 and 150 degrees Fahrenheit (0 and 65 degrees Celsius).

c.

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 public works director.

d.

Any waters or wastes containing strong acid iron pickling wastes, or concentrated plating solutions whether neutralized or not.

e.

Any water or wastes containing toxic or poisonous substance that exceed limits established by the public works director, state environmental protection division or the U.S. Environmental Protection Agency.

f.

Any wastes containing 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, including, but not limited to, hydrogen sulfide, sulfur dioxide and nitrous oxide in excess of 1.0 mg/L.

g.

Any radioactive wastes or isotypes of such half-life or concentration as may exceed limits established by the public works director in compliance with 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 amenable to treatment or reduction by the sewage treatment process 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.

k.

Water or wastes having a five-day biochemical oxygen demand in excess of 300 parts per million by weight on a 24-hour composite basis, or for any sample period having a five-day BOD in excess of two times the average influent value for the affected sewage treatment plant during the previous calendar year.

l.

Water or wastes having a suspended solids content in excess of 350 parts per million by weight on a 24-hour composite basis or having a suspended solids content for any sample period greater than two times the average influent value for the affected sewage treatment plant during the previous calendar year.

(d)

Evaluation of substances. If any waters or wastes are discharged, or are proposed to be discharged to the public sewers, which waters contain the substances or possess, the characteristics enumerated in section 36-75, and which, in the judgment of the public works director, may have a deleterious effect upon the sewage works, processes, equipment, or receiving waters, or which otherwise create a hazard to life or constitute a public nuisance, the public works director may:

(1)

Reject the wastes;

(2)

Require pretreatment to an acceptable condition for discharge to the public sewers;

(3)

Require control over the quantities and rates of discharge; and/or

(4)

Require payment to cover the added cost of handling and treating the wastes not covered by existing taxes or sewer charges under the provision of this division.

If the public works director permits the pretreatment or equalization of waste flows, the design and installation of the plants and equipment shall be subject to the review and approval of the public works director, and subject to the requirements of all applicable codes, ordinances and laws.

(e)

Grease, oil, and sand interceptors. Grease, oil, and sand interceptors shall be provided when, in the opinion of the public works director, they are necessary for the proper handling of liquid wastes containing grease in excessive amounts, or any flammable wastes, sand, or other harmful ingredients; except that such interceptors shall not be returned for private living quarters or dwelling units. All interceptors shall be of a type and capacity approved by the public works director, and shall be located so as to be readily handle liquid wastes containing grease in excessive amounts, or any flammable wastes, sand, or other harmful ingredients; except that such interceptors shall be of a type and capacity approved by the public works director, and shall be located as to be readily and easily accessible for cleaning and inspection.

(f)

Preliminary treatment and flow equalizing systems. Where preliminary treatment or flow-equalizing facilities are provided for any waters or wastes, they shall be maintained continuously in satisfactory and effective operation by the owner at his expense.

(g)

Manhole for industries. When required by the public works director, the owner of any property serviced by a building sewer carrying industrial wastes shall install a suitable control manhole together with such necessary meters and other appurtenances in the building sewer to facilitate observation, sampling, and measurement of the wastes. Such manhole, when required, shall be accessibly and safely located and shall be constructed in accordance with plans approved by the public works director. The manhole shall be installed by the owner at his expense, and shall be maintained by him so as to be safe and accessible at all times.

(h)

Examination of water. All measurements, tests, and analyses of the characteristics of waters and wastes to which reference is made in this article shall be determined in accordance with the latest edition of Standard Methods for the Examination of Water and Wastewater, and shall be determined at the control manholes provided, or upon suitable samples taken at said control manhole. In the event that no special manhole has been required, the control manhole shall be considered to be the nearest downstream manhole in the public sewer to the point which the building sewer is connected. Sampling shall be carried out by customarily accepted methods to reflect the effect of constituents upon the sewage works and to determine the existence of hazards, to life, limb, and property. (The particular analyses involved will determine whether a 24-hour composite of all outfalls of a premises is appropriate or whether a grab sample or samples should be taken. Normally, but not always, BOD and suspended solids analyses are obtained from 24-hour composites of all outfalls whereas pHs are determined from periodic grab samples).

(i)

Industrial agreement with city. No statement contained in this section shall be construed as preventing any special agreement or arrangement between the city and any industrial concern whereby an industrial waste of unusual strength or character may be accepted by the city for treatment, subject to payment therefor, by the industrial concern.

(Code 1985, § 7-105)