STATE OF WISCONSIN DEPARTMENT OF NATURAL RESOURCES PUBLIC NOTICE OF INTENT TO MODIFY A WISCONSIN POLLUTANT DISCHARGE ELIMINATION SYSTEM (WPDES) PERMIT No.WI-0022772-10-3 Permittee: CITY OF WAUPUN, 817 South Madison St, Waupun, WI 53963-0431 Facility Where Discharge Occurs: Waupun Wastewater Treatment Facility, 501 N Fond du Lac St, Waupun, WI Receiving Water And Location: South Branch of Rock River (Upper Rock River Watershed, UR12 – Upper Rock River Basin) in Fond du Lac County Brief Facility Description: The facility's preliminary and primary treatment includes influent pumping, fine screening, grit removal, and primary settling. Secondary treatment is provided through a trickling filter and activated sludge, both of which are followed by secondary clarifiers. Phosphorus is removed through the addition of ferric chloride, which is fed prior to the secondary clarifiers. The facility's sand filters were demolished as a part of the recent upgrades. Effluent from the secondary clarifiers is pumped to a tertiary algal treatment process for low-level phosphorus removal followed by a membrane separation unit process to capture the algae. The effluent from the membrane process flows to the existing chlorine contact basin for seasonal disinfection, followed by dechlorination and discharge to the Rock River. Algal sludge captured by the membrane separation unit is centrifuged for thickening, then dried in a double drum dryer. Sludge from primary and secondary clarifiers is digested anaerobically and stored as liquid sludge or dewatered on a belt filter press. Digested sludge is seasonally applied to farm fields as a soil amendment. Permit Drafter's Name, Address, Phone and Email: Sarah Donoughe, DNR, 2984 Shawano Ave, Green Bay, WI 54313-6727, (920) 366-6076, Sarah.Donoughe@wisconsin.gov Basin Engineer's Name, Address, Phone and Email: Jordan Main, DNR, 141 NW Barstow St, Room 180, Waukesha, WI 53188, (608) 535-0368, jordan.main@wisconsin.gov Proposed Modification: The permit modification is proposed to reduce the effluent PFOS/PFOA sampling frequency from 1/ 2 months to annual, after a review of submitted data, pursuant to s. NR 205.066, Wis. Adm. Code. The Department has tentatively decided that the above-specified WPDES permit should be modified. Persons wishing to comment on or object to the proposed permit action, or to request a public hearing, may write to the Department of Natural Resources at the above-named permit drafter's address. All comments or suggestions received no later than 30 days after the publication date of this public notice will be considered along with other information on file in making a final decision regarding the permit. Anyone providing comments in response to this public notice will receive a notification of the Department's final decision when the permit is issued. Where designated as a reviewable surface water discharge permit, the U.S. Environmental Protection Agency is allowed up to 90 days to submit comments or objections regarding this permit determination. If no comments are received on the proposed permit from anyone, including U.S. EPA, the permit will be issued as proposed. The Department may schedule a public informational hearing if requested by any person and shall schedule a public informational hearing if a petition requesting a hearing is received from 5 or more persons or if response to this notice indicates significant public interest pursuant to s. 283.49, Wis. Stats. Requests for a public informational hearing shall state the following: the name and address of the person(s) requesting the hearing; the interest in the proposed permit of the person(s) requesting the hearing; the reasons for the request; and the issues proposed to be considered at the hearing. Information on file for this permit action, including the draft permit, fact sheet and permit application, may be inspected and copied at either the above-named permit drafter's office or the above named basin engineer's office, Monday through Friday (except holidays), between 9:00 a.m. and 3:30 p.m. Please call the permit drafter or basin engineer for directions to their office location, if necessary. Information on this permit action may also be obtained by calling the permit drafter at (920) 366-6076 or by writing to the Department. Reasonable costs (15 cents per page for copies and 7 cents per page for scanning) will be charged for information in the file other than the public notice, permit and fact sheet. Permit information is also available on the internet at: http://dnr.wi.gov/topic/wastewater/PublicNotices.html . Pursuant to the Americans with Disabilities Act, reasonable accommodation, including the provision of informational material in an alternative format, will be made to qualified individuals upon request. WNAXLP April 30 2026 LWIX0506051