Guidance for Municipal and Industrial Discharges
The following list highlights the most frequently requested guidance materials used in the wastewater program. These and other wastewater documents can be found in the EGAD/SWIMS digital library, a searchable database of electronic policy and guidance materials used in the DNR's water quality programs. Certified and finalized guidance from all DNR programs is listed on the Final DNR program guidance page.
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316(b)/Cooling water intake structures
According to section 316(b) of the federal Clean Water Act and s. 283.31(6), Wis. Stats, the department must determine whether the location, design, construction and capacity of cooling water intake structures reflect the best technology available for minimizing adverse environmental impact.
Adaptive management (AM) is a phosphorus compliance option that allows point and nonpoint sources (e.g. agricultural producers, storm water utilities, developers) to work together to improve water quality in those waters not meeting phosphorus water quality standards. The AM page contains guidance for DNR staff and externals interested in exploring the adaptive management option.
Additives come in a variety of chemical formulations including, but not limited to, chemical salts, polymers, acids and bases, and organic chemicals. Many additives have not undergone rigorous toxicological testing required to develop water quality criteria for the protection of aquatic life Instead, secondary acute and chronic values are derived for these substances and used to determine allowable usage rate (i.e., permit limits, application rates).
Phosphorus implementation guidance
To protect human health and welfare, revisions to Wisconsin’s Phosphorus Water Quality Standards for surface waters were adopted in 2010. In addition to setting water quality standards for phosphorus in surface waters, these rules also set procedures to implement these standards in WPDES permits.
Phosphorus multi-discharger variance
The multi-discharger variance (MDV) extends the timeline for complying with low-level phosphorus limits. In exchange, wastewater dischargers commit to reductions within their effluent, as well as helping to address nonpoint sources of phosphorus in other areas of the watershed.
Thermal implementation guidance
Any municipal and industrial surface water discharge with a WPDES permit may be subject to thermal regulations. This “Guidance for Implementation of Wisconsin’s Thermal Water Quality Standards” is intended to help DNR staff and externals understand and implement the thermal rule.
TMDL implementation guidance
A TMDL is developed after consideration of all sources of pollution to an impaired waterbody and is stated as the amount of pollutant that the waterbody can assimilate and not exceed water quality standards. Once a TMDL is developed and approved, regulations require that WLAs delineated in the TMDL be reflected in WPDES permits. Guidance is intended to help DNR staff implement TMDLs in wastewater permits for municipal POTWs and industrial sources.
A variance to a water quality standard may be appropriate when a permittee is unable to meet the effluent limit for a given pollutant and a compliance option is not feasible at the time. Variances must be based on one or more of the factors listed in s. 283.15(4), Wis. Stats, and be approved by the DNR and the EPA.
Water Quality Trading
Water Quality Trading (WQT) may be used by municipal and industrial permittees to demonstrate compliance with water quality-based effluent limitations (WQBELs). Generally, trading involves a point source facing relatively high pollutant reduction costs compensating another party to achieve less costly pollutant reduction with greater water quality benefit. The WQT page contains guidance for DNR staff and externals interested in using trading to meet their WQBELs.
Whole Effluent Toxicity (WET)
Whole Effluent Toxicity (WET) tests are used to measure, predict and control the discharge of materials that may be harmful to aquatic life. All municipal POTW and industrial surface water discharges are evaluated to determine whether WET testing should be required in the WPDES permit. This guidance document contains numerous chapters intended to help DNR staff implement and permittees to conduct WET testing in WPDES permits.