The EPA issued the final combined National Pollutant Discharge Elimination System (NPDES) general permit (GP) for discharges from potable water treatment facilities (PWTFs) for New Hampshire and Massachusetts. The new GP replaces the 2009 PWTF GP that expired on October 2, 2014, and provides coverage for PWTFs that discharge less than or equal to 1.0 million gallons per day (MGD) of wastewater from one or more of the following treatment processes:
- Media filtration;
- Membrane filtration (not including reverse osmosis); and
The 2017 PWTF GP contains several changes from the previous permit, including:
- Possible permit coverage for facilities previously excluded due to use of aluminum in the water treatment process. These facilities are required to submit additional Notice of Intent (NOI) samples, including 12 effluent samples and 10 upstream ambient water samples. PWTFs in New Hampshire must analyze the samples for total recoverable aluminum with the assumption that the entire fraction of measured total recoverable aluminum is in the acid soluble form.
- Additional aluminum monitoring requirements for facilities that use aluminum-based products as part of their treatment processes. Facilities in New Hampshire and Massachusetts that use aluminum must monitor for total recoverable aluminum on a monthly basis. In New Hampshire, the assumption is that the entire fraction of measured total recoverable aluminum is in the acid soluble form.
- Required monthly iron monitoring for PWTFs using iron based coagulants.
- Required monthly phosphorus monitoring for PWTFs using chemicals containing phosphorus and discharging into an impaired New Hampshire water body.
- A new permit condition requiring applicants to conduct one chronic and one acute Whole Effluent Toxicity (WET) test on an annual basis.
Permittees seeking coverage under the new PWTF GP, including facilities previously covered under the 2009 permit, must submit an NOI to EPA Region 1 and the New Hampshire Department of Environmental Services (DES). The new permit went into effect on March 6, 2017.