Effluent limitations in issued national pollutant discharge elimination system permits

1. Any permit issued by the department shall specify average and maximum daily quantitative limitations for the level of pollutants in the authorized discharge in terms of weight or some other appropriate measure such as pH, temperature, or radiation. When it is at all appropriate the requirement is that the discharge must be expressed in terms of weight. The department may also impose additional quantitative limitations in terms of average or maximum concentration levels. 2. When applicable, permit conditions in national pollutant discharge elimination system permits shall be calculated in compliance with the requirements of 40 CFR 122.45, which is incorporated into this chapter by reference. 3. The effluent quality for municipal wastes shall be that required by the department and shall be based on the following: a. Municipal wastes shall receive a minimum of secondary treatment or equivalent in compliance with 40 CFR 133, which is incorporated by reference in section 33.1-16-01-30. b. Wastes shall be effectively disinfected before discharge into state waters if such discharges cause violation of the bacteria criteria as set forth in the standards of water quality for the state of North Dakota, chapter 33.1-16-02.1. The effluent shall meet the water quality criteria for bacteria except as provided in subdivision c. c. The effluent limitations specified under secondary treatment and bacteria criteria may be adjusted to reflect site-specific considerations as provided in the following: (1) A five-day biochemical oxygen limit of twenty-five milligrams per liter (consecutive thirty-day average) may be applied in instances in which limits expressed in terms of secondary treatment standards would be impractical or deemed inappropriate to protect receiving waters. (2) In certain instances, external circumstances or specific uses of the receiving waters make either attainment or application of the suspended solids or bacteria limitations an ineffective means of controlling water quality. For this reason, the department reserves the right to evaluate the application of these limitations on a case-by-case basis. (3) The pH of natural ground waters and surface waters in some parts of the state (presently used for water supplies with or without treatment) are basic, and the stabilization process of wastewater treatment in lagoon systems can result in more alkaline (increased pH) water. Discharges from waste treatment facilities may exceed the upper pH limit of 9.0 provided in the secondary treatment standard due to these uncontrollable properties. Approval to discharge may be granted, providing the pH of the receiving water is not violated. d. The department may require treatment in addition to that listed in this section if such waste discharges, made during low streamflows, cause violations of stream water quality standards or have a detrimental effect on the beneficial uses of the receiving waters. 4. Industrial waste effluents shall meet all parameters of quality as set forth in section 33.1-16-01-13 and shall not violate North Dakota water quality standards.