(A) Specific prohibitions. No user shall contribute or cause to be contributed into the POTW the following pollutants, substances or wastewater:
(1) Pollutants that create a fire or explosive hazard in the POTW, including but not limited to, waste streams with closed-cup flashpoints of less than 140°F (60°C), using the test methods specified in 40 C.F.R. 261.21. (This prohibition does not apply to any aqueous solution containing less than 24% alcohol by volume, which would otherwise be a hazardous waste under 40 C.F.R. 261.21 by virtue of having a closed-cup flashpoint of less than 140°F (60°C).) Wastes that may prevent or make hazardous the maintenance or inspection of sewers and associated structures and equipment, such as gasoline, kerosene, fuel oil, used antifreeze, solvents, strong acids and alkalis, cyanides, radioactive wastes, exhaust gases from internal combustion engines and others as may be prescribed by the Director.
(2) Wastes that limit the hydraulic capacity of county sewers and associated equipment and structures, such as grease, garbage with particles greater than one-quarter inch in any dimension, animal guts or tissues, paunch manure, bones, hair, hides or fleshings, whole blood, feathers, ashes, cinders, sand, spent lime, stone or marble dust, metal, glass, straw, shavings, grass clippings, rags, spent grains, spent hops, waste paper, wood, plastics, gas, tar, paint, lacquer, varnish, asphalt residues, residues from refining or processing of fuel or lubricating oil, mud, solid or viscous pollutants, or glass grinding or polishing wastes.
(3) Petroleum oil, non-biodegradable cutting oil, or products of mineral oil origin in amounts that will cause interference or pass-through.
(4) Wastes that have the potential to damage sewers and associated structures and equipment, such as grit, wastes having a pH lower than 5.0 or higher than 10, or other corrosive wastes as may be prescribed by the Director.
(5) Any wastewater containing pollutants, including oxygen-demanding pollutants (BOD and the like), in sufficient quantity (flow or concentration), either singly or by interaction with other pollutants, to cause interference with the POTW.
(6) Any wastewater having a temperature that will inhibit biological activity in the POTW treatment plant resulting in interference, but in no case wastewater that causes the temperature at the introduction into the treatment plant to exceed 104°F (40°C).
(7) Any pollutants that result in the presence of toxic gases, vapors or fumes within the POTW in a quantity that may cause acute worker health and safety problems.
(8) Any trucked or hauled pollutants, except at discharge points designated by the Director in accordance with § 51.58.
(9) Any noxious or malodorous liquids, gases or solids or other wastewater that, either singly or by interaction with other wastes, are sufficient to create a public nuisance or hazard to life, or are sufficient to prevent entry into the sewers for maintenance and repair.
(10) Any substance that may cause the POTW’s effluent or any other product of the POTW, such as residuals or scums, to be unsuitable for reclamation and reuse, or to interfere with the reclamation, process. In no case, shall a substance discharged to the POTW cause the POTW to be in noncompliance with sludge use or disposal regulations or permits issued under Section 405 of the Act, the Solid Waste Disposal Act, the Clean Air Act, the Toxic Substances Control Act, or state criteria applicable to the sludge management method being used.
(11) Waters or wastes containing dyes or other color that cannot be removed by biological processes, and that require special chemical treatment in order for sewage treatment plant effluent to meet standards set by state law, or rules, regulations or orders made pursuant to law.
(12) Any wastewater containing any radioactive wastes or isotopes except as specifically approved by the Director in compliance with applicable state or federal regulations.
(13) Wastes containing waxes, greases or oils that may solidify or become viscous at temperatures between 32°F (0°C) and 140°F (60°C). Fats, oils, greases or waxes that are free floating shall not be discharged into the sewer system. Fats, oils and greases shall not be discharged to the sewer system if their concentration and physical dispersion results in separation and adherence of such materials to such structures. If such materials cause blockage in the sewer system, then they must be removed prior to discharge into the sewer system.
(14) Any medical wastes, except as specifically authorized by the Director.
(15) Any material containing ammonia, ammonia salts or other chelating agents that will produce metallic complexes that interfere with the municipal wastewater system.
(16) Any material that would be identified as hazardous waste according to 40 C.F.R. 261 if not disposed of in a sewer, except as may be specifically authorized by the Director.
(17) Any wastewater causing the treatment plant effluent to violate state water quality standards for toxic substances as described in 15A NCAC 2B.0200.
(18) Wastewater causing, alone or in conjunction with other sources, the treatment plant’s effluent to fail a toxicity test.
(19) Any wastes containing detergents, surface-active agents or other substances that may cause excessive foaming in the municipal wastewater system.
(20) Wastes that form excessive amounts of scum that may interfere with the operation of a sewage treatment plant, or cause undue additional labor or expense in connection with its operation.
(21) Waters or wastes that require excessive quantities of chlorine for stabilization in addition to biological treatment.
(22) Wastes containing any toxic or poisonous substances in sufficient quantity:
(a) To interfere with the biological processes used in a sewage treatment system, singularly or in combination.
(b) That, singularly or in combination with other liquid wastes, upon passing through a sewage treatment plant, will be harmful to persons, livestock or aquatic life utilizing the receiving streams into which water from a sewage treatment plant is discharged.
(23) Wastes that, singularly or in combination, would cause an interference and/or contaminate the resulting residuals, or other wastes as may be prescribed by the Director.
When the Director determines that a user(s) is contributing to the POTW any of the substances enumerated above, in such amounts that may cause or contribute to interference of POTW operation or pass-through, the Director shall advise the user(s) of the potential impact of the contribution on the POTW, and take appropriate actions in accordance with § 51.72 to protect the POTW from interference or pass-through.
(B) Local limits.
(1) No person shall discharge wastewater containing concentrations in excess of the following limitations, without having first obtained an industrial wastewater discharge permit specifying more lenient limits:
BOD 500 mg/1
SS 500 mg/1
Cd 0.005 mg/1
Cr 0.03 mg/1
Cu 0.20 mg/1
Pb 0.05 mg/1
Ni 0.05 mg/1
Zn 0.50 mg/1
Silver 0.002 mg/1
Cyanide 0.005 mg/1
Arsenic 0.005 mg/1
Mercury 0.0002 mg/1
(2) No person shall discharge wastewater containing concentrations in excess of:
Hydrocarbon O/G = 100 mg/1 (must be emulsified)
pH - not less than 5.0 nor more than 10.0 units
(3) Discharge imitations for specific pollutants will be determined by the Director on an individual basis and specified on the wastewater discharge permit. In no case will limitations specified be less stringent than applicable federal or state guidelines. The Director may impose mass limits in addition to, or in place of, the concentration-based limits above.
(4) If a user’s 12-month running average flow will fluctuate 20% or more from the flow allocation specified on the discharge permit, a new wastewater discharge permit must be obtained.
(5) The instantaneous discharge flow rate shall not exceed the following limits:
Average Flow in Gallons per Day | Allowable Ratio of Instantaneous Flow Rate To Average Flow |
50,000 - 100,000 | 3 |
100,000 - 500,000 | 2 |
more than 500,000 | 1.5 |
Users whose average flow is less than 50,000 gallons per day shall not discharge an instantaneous rate of flow in excess of 150,000) gallons per day | |
(6) No person shall discharge any wastes or wastewaters in a “slug” as defined in § 51.02.
(C) Right of revision. The county reserves the right to establish limitations and requirements that are more stringent than those required by either state or federal regulation, if deemed necessary to comply with the objectives presented in § 51.01, or the general and specific prohibitions in §§ 51.47 and 51.48, as is allowed by 40 C.F.R. 403.4.
(D) State requirements. State requirements and limitations on discharges shall apply in any case where they are more stringent than federal requirements and limitations or those in this chapter.
(E) National categorical pretreatment standards. Users subject to categorical pretreatment standards are required to comply with applicable standards as set out in 40 C.F.R. Ch. 1, Subch. N, pts. 405-471 and incorporated herein.
(1) Where a categorical pretreatment standard is expressed only in terms of either the mass or the concentration of a pollutant in wastewater, the Director may impose equivalent concentration or mass limits in accordance with 40 C.F.R. 403.6(c).
(2) When wastewater subject to a categorical pretreatment standard is mixed with wastewater not regulated by the same standard, the Director shall impose an alternate limit using the combined waste stream formula in 40 C.F.R. 403.6(e).
(3) A user may obtain a variance from a categorical pretreatment standard if the user can prove, pursuant to the procedural and substantive provisions in 40 C.F.R. 403.13, that factors relating to its discharge are fundamentally different from the factors considered by EPA when developing the categorical pretreatment standard.
(4) A user may obtain a net gross adjustment to a categorical standard in accordance with 40 C.F.R. 403.15.
(F) Pretreatment of wastewater.
(1) Users shall provide wastewater treatment as necessary to comply with this chapter and wastewater permits issued under § 51.58, and shall achieve compliance with all national categorical pretreatment standards, local limits and the prohibitions set out in §§ 51.47 and 51.48 within the time limitations as specified by EPA, the state, or the Director, whichever is most stringent. Any facilities necessary for compliance shall be provided, operated and maintained at the user’s expense. Detailed plans showing the pretreatment facilities and operating procedures shall be submitted to the county for review and shall be approved by the Director before construction of the facility. The review of such plans and operating procedures shall in no way relieve the user from the responsibility of modifying the facility as necessary to produce an effluent acceptable to the county under the provisions of this chapter. Any subsequent changes in the pretreatment facilities or method of operation shall be reported to and be approved by the Director prior to the user’s initiation of the changes.
(2) Additional pretreatment measures.
(a) Whenever deemed necessary, the Director may require users to restrict their discharge during peak flow periods, designate that certain wastewater be discharged only into specific sewers, relocate and/or consolidate points of discharge, separate sewage waste streams from industrial waste streams, and such other conditions as may be necessary to protect the POTW and determine the user’s compliance with the requirements of this chapter.
(b) The Director may require any person discharging into the POTW to install and maintain, on their property and at their expense, a suitable storage and flow-control facility to ensure equalization of flow. A wastewater discharge permit may be issued solely for flow equalization.
(c) Grease, oil and sand interceptors shall be provided when, in the opinion of the Director, they are necessary for the proper handling of wastewater containing excessive amounts of grease and oil or sand. All interception units shall be of type and capacity approved by the Director and shall be so located to be easily accessible for cleaning and inspection. Such interceptors shall be inspected, cleaned and repaired regularly, as needed, by the user at the user’s expense.
(d) Users with the potential to discharge flammable or toxic substances may be required to install and maintain an approved gas detection meter.
(G) Accidental discharge/slug control plans. At least once every two years, the Director shall evaluate whether each significant industrial user needs an accidental discharge/slug control plan. The Director may require any user to develop, submit for approval and implement such a plan. Alternatively, the Director may develop such a plan for any user. An accidental discharge/slug control plan shall address, at a minimum, the following:
(1) Description of discharge practices, including non-routine batch discharges;
(2) Description of stored chemicals;
(3) Procedures for immediately notifying the Director of any accidental or slug discharge, as required by § 51.59; and
(4) Procedures to prevent adverse impact from any accidental or slug discharge. Such procedures include, but are not limited to, inspection and maintenance of storage areas, handling and transfer of materials, loading and unloading operations, control of plant site runoff, worker training, building of containment structures or equipment, measures for containing toxic organic pollutants, including solvents, and/or measures and equipment for emergency response.
(Ord. passed 9-9-08)