STATE OF WISCONSIN DEPARTMENT OF NATURAL RESOURCES PUBLIC NOTICE OF INTENT TO MODIFY A WISCONSIN POLLUTANT DISCHARGE ELIMINATION SYSTEM (WPDES) PERMIT No.WI-0025038-10-1 Permittee: City of Oshkosh, 233 N. Campbell Road, Oshkosh, WI, 54901-1130 Facility Where Discharge Occurs: Oshkosh Wastewater Treatment Plant, 233 N. Campbell Road Receiving Water And Location: Upper Fox River in Fox River of Fox River (upper) in Winnebago county Brief Facility Description : The City of Oshkosh operates an advanced secondary wastewater treatment facility (WWTF) designed for an average daily flow of 20 million gallons per day (MGD), providing regional service to the City of Oshkosh and sanitary districts in the towns of Algoma, Blackwolf and Oshkosh. The sanitary sewer collection system is separate from the storm sewer system in the Oshkosh WWTF's service area. The facility receives domestic, commercial, and industrial wastewater and the permittee administers an industrial pretreatment program that regulates the industrial contributors. The facility accepts domestic holding tank wastes, septic tank wastes, commercial septage, and landfill leachate. Upon reaching the WWTF, wastewater is screened and then pumped to one of two identical trains for treatment. Each train consists of an aerated grit chamber, two primary clarifiers, an aeration basin (secondary biological treatment with an activated sludge system), two secondary clarifiers, and a chlorine contact basin. Dechlorination is accomplished by the addition of liquid sodium bisulfite. Phosphorous removal is accomplished by the chemical addition of ferric chloride to the primary clarifier effluent channel prior to aeration. The facility's primary effluent discharge is to the Fox River, and it has an emergency overflow which discharges to Campbell Creek during conditions of high flow in either the river or the WWTF. The facility also has the capability of diverting flow around the biological treatment process during periods of high flow to the WWTF. By-product solids (biosolids) are anaerobically digested, thickened by centrifuge, then stored off-site until land application to agricultural land or landfilled. BLENDING- The permittee has requested blending approval to continue as part of their permit application. Based on an evaluation of their request and associated documentation, blending is conditionally approved per s. NR 210.12(2), Wis. Adm. Code. Permit Drafter's Name, Address, Phone and Email: Ashley Clark, 2984 Shawano Ave, Green Bay, WI, 54313, (920) 857-0450, Ashleym.Clark@wisconsin.gov Basin Engineer's Name, Address, Phone and Email: Mark Stanek, 625 E County Road Y, Suite 700, Oshkosh, WI 54901, (920) 808-0670, Mark.Stanek@wisconsin.gov Proposed Modification: Permit Modification -1 was completed following the Department becoming aware that the calculations (target value) for the MDV payment to the county were incorrect. This update was determined to be necessary for payments to be calculated correctly. The Department has tentatively decided that the above-specified WPDES permit should be modified. Limitations and conditions which the Department believes adequately protect the receiving water are included in the proposed permit. Land application of waste shall be done in accordance with permit conditions and applicable codes. All land application sites shall be approved prior to their use. To receive a list of approved sites, or to be notified of potential approvals, contact the above-named basin engineer. 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) 857-0450 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. NAME OF PUBLISHING NEWSPAPER: Oshkosh Northwestern ADDRESS OF PUBLISHING NEWSPAPER: 224 State Street, Oshkosh, WI 54904 Date Notice Issued: November 20, 2025 WNAXLP November 20 2025 LWIX0409469