Statutes, codes, and regulations
Mississippi Administrative Code
Title 11 - Mississippi Department of Environmental QualityPart 6 - Wastewater Pollution Control RegulationsChapter 1 - Mississippi Commission on Environmental Quality National Pollutant Discharge Elimination System (NPDES) Permits, Underground Injection Control (UIC) Permits, State Permits, Water Quality Based Effluent Limitations and Water Quality Certification
Subchapter 2 - Water Quality Based Effluent Limitations
Rule 11-6-1.2.4 - Waters Difficult To Model

11 Miss. Code. R. 6-1.2.4

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Current through January 14, 2025
Rule 11-6-1.2.4 - Waters Difficult To Model
A. Losing flow streams.

Many losing flow streams can and should be modeled to determine effluent limitations. Such models are only applicable to the point of zero flow.

B. Lakes.
(1) Computerized and/or ecological type models may be used, if appropriate and available.
(2) For existing discharges, current effluent limits may be appropriate, if ambient water quality data indicate water quality standards are met and no nuisance conditions associated with the discharge exist.
(3) Nutrient budget models may be used to determine if nutrient reductions are needed. Nutrient contribution and abatement from both point and nonpoint sources shall be considered.
(4) Discharges to embayments and coves shall be evaluated on a case-by-case basis. However, effluent limitations more stringent than TBEL may be required.
(5) Diffuser outfalls for discharges to the main body of a lake may be required when needed to eliminate localized water quality impacts.
(6) Permit limitations for toxicants shall be determined based upon State, and/or EPA recognized, procedures and best professional judgment in accordance with applicable law.
C. Natural Wetlands
(1) In the absence of site specific water quality standards, effluent limitations for discharges to swamps, marshes, bogs, wetlands, etc., shall be determined based upon potential or existing physical, chemical, and biological water quality impacts.
(2) Discharges of sanitary or other oxygen demanding wastewater to natural wetland areas must, at a minimum, meet secondary treatment standards.
(3) The permittee may be required to monitor biological health of the wetland and the water quality of the receiving wetland (pre and post - permitting).
(4) No toxic substances shall be discharged in amounts that violate the State's Water Quality Standards.
(5) For industrial discharges, the ultimate oxygen demand of the wastewater shall also be considered when developing permit limitations. Limits equivalent to 30 mg/l BOD5 or less shall be given to industrial discharges of oxygen demanding wastewater to natural wetlands.
D. Nutrient Enriched Waters.

In case of nutrient enriched waters, data from a water quality field assessment and/or appropriate models shall be used to determine impact and set effluent limitations.

11 Miss. Code. R. 6-1.2.4

Miss. Code Ann. §§ 49-2-1, et seq. and 49-17-1, et seq.