Prairie State Generation coal-fired plant poses water threats as well as creating greenhouse gas.

12/1/21 - As stated in comments to the Illinois Environmental Protection Agency filed last week by me and Andrew Rehn on behalf of Sierra Club and Prairie Rules Network in comments on a draft NPDES permit for this massive facility which discharges into the Kaskaskia River, our initial review of the draft notice and the data currently available to us indicates that the permit and the IEPA consideration of the permit is defective in at least the following respects:


  • The limits imposed fail to take into account that the Kaskaskia River is already impaired for due to lack of dissolved oxygen (DO) and excessive sediment and mercury.

  • The heat allowed by the permit will cause or contribute to the exacerbation of the existing problems with low DO and toxicity, thus the proposed permit violates 35 Ill. Adm. Code 304.105, 35 Ill. Adm. Code 309.141(d)(1), (2), 35 Ill. Adm. Code 309.143(a); 40 C.F.R. § 122.44(d).

  • Ammonia discharges are permitted that contribute to and will exacerbate the existing DO violations through nitrogenous dissolved oxygen demand. Thus, the draft permit cannot be issued under the regulations cited above.

  • The chlorine discharge allowed by the permit is acutely toxic and violates 35 Ill. Adm. Code 304.105, 35 Ill. Adm. Code 309.141(d)(1), (2), 35 Ill. Adm. Code 309.143(a); 40 C.F.R. § 122.44(d).

  • A zone of initial dilution has not been shown to be available or protective (Fact sheet p.8) but some of the proposed discharge limits seem to presuppose availability of a ZID or a mixing zone.

  • There is no limit to protect against chronic chlorine toxicity although the Illinois water quality standard is 0.011 mg/L

  • There is no limit to protect against chronic chloride toxicity. Such a limit would be much lower than the 500 mg/L limit in the permit to protect against acute toxicity.

  • There should be a pathogen limit on the discharge containing domestic waste.

  • Tighter limits are necessary on TSS given the existing impairment.

  • Metals monitoring is inadequate.

  • The allowance for emergency discharges is plainly improper. An equipment breakdown is not an unpreventable act of God.

  • The antidegradation analysis is inadequate because it fails to consider whether continuing to operate this plant on balance accommodates social and economic development.

  • The mussel survey referenced in the antidegradation assessment is over 15 years old (surveys completed 2002-2006). An updated mussel survey should be completed.

  • The EcoCAT consultation claims that no threatened and endangered species in the Kaskaskia River. However, the smooth softshell turtle, an Illinois endangered species, is known to use the Kaskaskia River in St. Clair County near the Prairie State Coal Plant (Ross et. al 2015). The species did not appear in the IDNR EcoCAT consultation. Additional consideration and consultation, and possibly sampling for this species should be done.

  • The EcoCAT consultation for the two proposed sediment ponds identified that “protected resources may be in the vicinity of the proposed action.” More detail on the protected resources should have been included in the antidegradation assessment so that the public can be aware of potential impacts.

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