A. Discharges prohibited. A person shall not 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. Designated storm sewers. Stormwater and all other unpolluted waters shall be discharged to sewers which are specifically designated as storm sewers, or to a natural outlet approved by the City. Industrial cooling water or unpolluted process waters may be discharged, on approval of the City, to a storm sewer or natural outlet, subject to approval and the issuance of a discharge permit by the Minnesota Pollution Control Agency.

C. Discharges specifically prohibited. A person shall not discharge or cause to be discharged any of the following described waters or wastes to any public sewers:

(1) Explosive materials. Any liquids, solids or gases which by reason of their nature or quantity are, or may be, sufficient, either alone or by interaction with other substances, to cause fire or explosion or be injurious in any other way to the wastewater disposal system or to the operation of the system. Prohibited materials include, but are not limited to, gasoline, kerosene, benzene, naphtha, fuel oil, toluene, xylene, ethers, alcohols, ketones, aldehydes, peroxides, chlorates, perchlorates, bromates, carbides, hydrides, and sulfides.

(2) Toxic, poisonous materials. Any waters or wastes containing toxic or poisonous solids, liquids, or gases as defined by Section 307(a) of the Clean Water Act 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 in spite of treatment, 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 federal and state requirements in the wastes as discharged to the public sewer.

(3) Corrosive materials. Any waters or wastes having a pH lower than 5.0 or higher than 9.0, or having any other corrosive property capable of causing damage or hazard to structures, equipment, or personnel or the sewage works.

(4) Materials causing obstructions, interference. 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, sanitary napkins, 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.

D. Specific harmful discharges prohibited. A person shall not discharge or cause to be discharged the following described substances, materials, waters or wastes if it appears likely in the opinion of the Engineer and/or the Public Works Department that the wastes can harm either the sewers, sewage treatment process, or equipment, have an adverse effect on the receiving waters, or can otherwise endanger life, limb, public property, or constitute a nuisance. In forming an opinion concerning the acceptability of these wastes, the Engineer and/or the Public Works Department will give consideration to such factors as the City's NPDES permit, the quantities of subject wastes in relation to the flows and velocities in the sewers, materials and construction of the sewers, nature of the treatment process, capacity of the treatment plant, degree of treatability of the wastes in the sewage treatment plant and other factors deemed pertinent. The substances prohibited are:

(1) Substances in violation of NPDES permit. Any wastewater that would directly or indirectly result in a violation of the City's NPDES permit.

(2) Substances in excess of 150°. Any liquid or vapor having a temperature higher than 150° F. (65° C.).

(3) Substances that solidify. Any water or waste containing fats, wax, grease, 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° F. (0° to 65° C.).

(4) Garbage not shredded. Any garbage that has not been properly shredded. The installation and operation of any garbage grinder equipped with a motor of 3/4 horsepower or greater shall be subject to the review and approval of the Public Works Department or its authorized representative.

(5) Pickling wastes, plating solutions. Any waters or wastes containing strong-acid iron-pickling wastes or concentrated plating solutions, whether neutralized or not.

(6) Toxic, objectionable substances. Any waters or wastes containing iron, chromium, copper, zinc, nickel, lead, cadmium, mercury, cyanide, PCBs, and similar toxic or objectionable substances to the degree that any such material received in the composite sewage at the treatment works exceeds limits established by the Minnesota Pollution Control Agency for such materials.

(7) Taste- or odor-producing substances. Any waters or wastes containing phenols or other taste- or odor-producing substances, in concentrations exceeding limits which may be established by the Public Works Department as necessary, after treatment of the composite sewage, to meet the requirements of the state, federal, or other public agencies of jurisdiction for the discharge to the receiving waters.

(8) Radioactive wastes, isotopes. Any radioactive wastes or isotopes of such half-life or concentration which may exceed limits established by the Public Works Department, in compliance with applicable state and federal regulations.

(9) Materials which exert or cause:

(a) Unusual concentrations of inert suspended solids (such as but not limited to slurries and lime residues) or of dissolved solids (such as but not limited to sodium chloride and sodium sulfate).

(b) Excessive discoloration (such as but not limited to dye wastes and vegetable tanning solution).

(c) Unusual BOD₅, chemical oxygen demand, or disinfection requirements in such quantities which constitute a significant load on the sewage treatment works, except by special permit or agreement.

(d) Unusual volume of flow or concentration of wastes constituting "slugs" as defined in this article.

(10) Substances not treatable. Waters or wastes containing substances which are not amenable to treatment or reduction by the treatment process employed, or are amenable to treatment only to the degree that the treatment plant effluent cannot meet the requirements of the agencies having jurisdiction over discharge to the receiving waters.

E. Disposition alternatives available to Engineer and/or the Public Works Department.

(1) 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 Subsections C and D of this § 215-28 and which in the judgment of the Public Works Department and/or Engineer 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 Engineer and/or the Public Works Department may:

(a) Reject the wastes;

(b) Require pretreatment to an acceptable condition for discharge to public sewers,

(c) Require control over the quantities and rates of discharge, and/or

(d) Require payment to cover the added cost of handling and treating the wastes not covered by existing taxes or sewer service charges under the provisions of Article IV, Sewer Service Charge System.

(2) If the Engineer and/or the Public Works Department permits the pretreatment or equalization of waste flows, the design and installation of the plants and equipment shall be subject to review and approval by the City and subject to the requirements of all applicable federal and state codes, ordinances, and pretreatment standards established pursuant to Section 307(b) of the Clean Water Act.

F. Provision of interceptors. Grease, oil, and sand interceptors shall be provided when, in the opinion of the Public Works Department, they are necessary for the proper handling of liquid wastes containing constituents, as described in Subsections C and D of this § 215-28, in prohibited amounts. All interceptors shall be of a design approved by the City and shall be located conveniently for cleaning and inspection.

G. Maintenance of equalization facilities. Where preliminary treatment or flow equalization facilities are provided for any wastes or water, they shall be maintained continuously in satisfactory and effective operation by the owner at the owner's expense.

H. Diluting discharge prohibited. A user shall not increase the amount of process water or, in any manner; attempt to dilute a discharge as a partial or complete substitute for adequate treatment to achieve compliance with the limitations contained in Subsections C and D of this § 215-28, or contained in the National Categorical Pretreatment Standards or any state requirements.

I. Manholes. When required by the Engineer and/or the Public Works Department, the owner of any property serviced by a building sewer carrying industrial wastes shall install a suitable control manhole or manholes together with the necessary meters, samplers, and other appurtenances in the building sewer to facilitate observation, sampling and measurement of the wastes. The manhole shall be easily accessible and safely located and shall be constructed in accordance with plans approved by the City. The manhole shall be installed by the owner at the owner's expense, and shall be maintained by the owner to be safe for use at all times.

J. Compliance. The owners of any property serviced by a building sewer carrying industrial wastes may, at the discretion of the City, be required to provide laboratory measurements, tests, or analyses of waters or wastes to illustrate compliance with this article and any special condition for discharge established by the City or regulatory agencies having jurisdiction over the discharge. The number, type, and frequency of sampling and laboratory analyses to be performed by the owner shall be as stipulated in writing by the City. The industry must supply a complete analysis of the constituents of the wastewater discharge to assure that compliance with federal, state and local standards are being met. The owner shall report the results of measurements and laboratory analyses to the City at such times and in the manner as prescribed by the City. The owner shall bear the expense of all measurements, analyses, and reporting required by the City. When necessary, the City reserves the right to take its own measurements and samples for analysis by an independent laboratory.

K. Standards for analyses. 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, published by the American Public Health Association. Sampling methods, location, times, duration and frequencies shall be determined on an individual basis, subject to approval by the Public Works Department and Engineer.

L. Special arrangements. Statements contained in this article shall not be construed to prevent 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 for the special arrangement by the industrial concern, providing that National Categorical Pretreatment Standards and the City's NPDES and/or state disposal system permit limitations are not violated, and that payment for the operation, maintenance, and replacement costs of wastewater treatment is in proportion to the industry's contribution of wastewater loadings to the treatment facilities, in accordance with 40 CFR 35.2140 and Article IV, Sewer Service Charge System.