Nutrient Impacts of Florida APRICOT Act Discharges: Case Study of Potential Impacts of Florida Nutrient Rule

EPA's Proposed Rule containing nutrient criteria for the state of Florida could lead to more stringent effluent limits for two facilities operated by the Clay County Utility Authority (CCUA). These facilities are covered under the state's APRICOT Act, which promotes water reuse and allows for the permitting of backup discharges to surface waters for reuse systems that provide advanced waste treatment. A series of technical analyses were conducted in support of providing formal comments on the Proposed Rule for CCUA. Results of these analyses show that: 1) neither of the CCUA APRICOT Act discharges is predicted to cause an exceedance of the Instream Protection for Values nitrogen or phosphorus contained in the Proposed Rule; 2) the discharges from these facilities typically occur during high flow and/or cold weather conditions when nutrient impacts are expected to be lowest; and 3) and the large majority of the discharged nitrogen will be transported to the Atlantic Ocean prior to be converted into a biologically available form. The CCUA discharges occur on low flow streams that represent the lower end of the spectrum of assimilative capacity. The absence of adverse nutrient impacts from these APRICOT Act discharges on streams with limited assimilative capacity provides supporting evidence that APRICOT Act discharges under the new criteria should not be subject to more stringent treatment requirements than they are already required to apply.