Illinois Nutrient Pollution Assessment and Reduction Plan efforts continue to bounce forward slowly

As discussed in the following memo to Illinois EPA, IEPA continues work to develop National Pollutant Discharge Elimination System permits for Illinois dischargers. The process has not been quick or smooth.

To: IEPA- Bureau of Water

From: Sierra Club, PRN, ELPC and MRC

April 4, 2025

Background and General Comments

Sierra Club, Prairie Rivers Network, Environmental Law and Policy Center and the Mississippi River Collaborative (“Commenters”) are commenting on each the four IEPA summaries and proposed permit condition papers we were sent on four different nutrient assessment and reduction plans (FRIP. NIP and NARPs). We believe that, in addition, some background applicable to all of the IEPA papers, and a few general comments would be helpful.

BACKGROUND

In very general terms and without footnotes, the Fox River Implementation Plan (FRIP), DuPage River Salt Creek Implementation Plan (NIP) and Kankakee and Kishwaukee nutrient assessment and reduction plans (NARPs) emerged from a series of discussions held over more than a decade as to setting phosphorus limits in Illinois NPDES permits under 40 CFR 122.44(d) and 35 Ill. Adm. Code 309.141 and 309.143  in the absence of technology-based phosphorus effluent limits for wastewater treatment plants (WWTPs) or numeric phosphorus water quality standards. NPDES permit limits, of course, are to be set as the tighter of the technology-based limit (TBEL) and water quality-based effluent limit (WQBEL).

Simplifying these discussions and agreements greatly, it can be written that it was agreed in 2017 by the Agency, the Illinois Association of Wastewater Agencies (IAWA) and the participating environmental groups (ELPC, NRDC/MRC, PRN, and Sierra Club), first, to secure phosphorus load reductions that could be achieved through readily available technology by 2030. It was thought that a 0.5 mg/l annual average limit was generally appropriate under this TBEL-like approach.

Further, it was agreed to determine - as to each water body through studies of that water body or through use of the statewide 0.1 mg/L recommendation of the Nutrient Science Advisory Committee – the level of phosphorus below which there would not be:

-          violations of the water quality standards regarding dissolved oxygen (DO), or the narrative water quality standards regarding “unnatural plant or algal growth,”

-           or the risk of cultural eutrophication.

Using this Target level to which phosphorus levels should be reduced, an implementation plan was to be developed to reduce phosphorus levels to the Target found appropriate for each water body or to 0.1 mg/L TP.

GENERAL COMMENTS

We have reviewed the FRIP, the DRSC NIP and a large number of NARPs that were made public. It is clear from those documents that much good work has been done improving wastewater treatment and important reductions in phosphorus have been achieved.

As stated in the Agency papers, “46 facilities had total phosphorus annual average concentration at or below 0.5 mg/L in 2022.” This makes clear that reduction of effluent concentrations to that level by 2030 is certainly feasible.

However, the FRIP, the NIP and the NARPs do not identify the Target level to which phosphorus level should be reduced to prevent violations of water quality standards. This should be done soon because obviously it is impossible to develop a plan to reach a target using specific NPDES numeric permit limits and narrative conditions if the Target has not been set. In this regard, the recent U.S. Supreme Court decision in San Francisco v. EPA (2025) makes still more clear that permits must be written carefully to contain numeric limits and best management practice to assure compliance with water quality standards.

Further, as to all of the watersheds where it is proposed to allow discharges that may cause or contribute to violations of the DO or “unnatural plant or algal growth” Illinois water quality standards, it is necessary for the dischargers or IEPA to seek a Time Limited Variance under 40 CFR 131.14, 415 ILCS 5/7.5 and 35 Ill. Adm. Code 104.200.

The variance procedures were developed to address exactly the situation where it is infeasible to meet water quality standards at the time of the permit issuance. Such variances are subject to safeguards, including reconsideration of the variance every five years. Given the careful work that was done to create the variance path by U.S. EPA, the General Assembly, IPCB, IEPA, and numerous participants in IPCB R2018-18, there is no excuse for not using that path.  

In this regard, the NIP report and several of the NARPs make claims that it is infeasible to achieve certain low WWTP effluent concentrations but do not provide any economic or engineering data or analysis to support these claims. Part of the showing that must be made to qualify for the Time Limited Variance will be to show that costs of meeting the standards will cause widespread economic damage (unless another of the 40 CFR 131.10(g) factors is applicable).

Still further, it is important to recognize that the Illinois River is also experiencing harmful algal blooms that threaten drinking water source water and recreation. The dischargers involved in the FRIP, NIP and many of the NARPs may also be required to address downstream problems in the Illinois River in the future.

Finally, several of the NARPs state that pollution levels coming from Wisconsin or Indiana are such as to render it impossible or much more difficult for Illinois waters to meet water quality standards. This may be true but IEPA, Illinois dischargers and members of the public are not helpless as to pollution from those upstream sources. In addition to informal efforts to persuade upstream authorities and dischargers to limit pollution, downstream interests may challenge upstream NPDES permits or bring other regulatory challenges. Illinois should not use upstream dischargers as an excuse not to act.