General Eligibility Requirements
To be eligible for authorization under either the batch or continuous General Permit for Domestic Sewage Lagoons, a facility must be:
- A facultative or aerated sewage treatment lagoon; and
- Classified as a minor (i.e. have an average daily design flow of less than 1.0 million gallons per day); and
- Located within the State of Montana, except for within the boundaries of Indian Lands and excluded waterbodies (see below).
Even if a facility meets the above eligibility requirements, they are not eligible for coverage under this General Permit if they:
- Have a pretreatment program (see 40 CFR 403.3);
- Accept discharge from categorical industrial users (CIU) or significant industrial users (SIU);
- Operate within the following excluded waterbodies:
- Outstanding Resource Waters or other waters of unique ecological or recreational significance, based upon considerations of Montana stream classifications, impacts on fishery resources, local conditions at proposed discharge sites, and designations of wilderness areas under 16 USC 1132 or of wild and scenic rivers under 16 USC 1274; or
- National Parks; or
- Waterbodies classified as A-1 or A-Closed waters.
- Are classified as a “new or increased source” that discharges to “high quality water,” as defined in the Nondegradation of Water Quality Subchapter 7.
Furthermore, any facility covered under an individual MPDES permit with site-specific water quality-based effluent limits (i.e. ammonia, nitrate+nitrite, nutrients) cannot request coverage under this GP.
Additional Eligibility Requirements for Batch Dischargers
In addition to the above general eligibility requirements, any facility that wishes to be authorized under the domestic sewage treatment lagoons General Permit for batch dischargers must:
- Discharge effluent as batch or with a periodic discharge strategy; and
- Discharge nine months each year or less.
Facilities authorized under the Domestic Sewage Treatment Lagoons – Batch Dischargers are prohibited from discharging during the applicable nutrient criteria period (typically July 1st – September 30