Jack Day

Harold John (Jack) Day died on August 31, 2025, at the age of 96. He was born to Everett and Mary (Godfrey) Day on May 22, 1929 in Milwaukee, Wisconsin. Jack graduated from Washington High School in Milwaukee and enlisted in the Navy at age 17. Following Electronic Material School at Great Lakes Naval Training School, he was assigned to the aircraft carrier USS Philippine Sea CV47 and then on to the Mediterranean as part of the US Sixth Fleet. He served two years in the Navy. Upon release he enrolled at the University of Wisconsin Madison where he graduated with a B.S. degree in Civil Engineering in 1952 and a M.S. in 1953. During his time in Madison, Jack met the love of his life, Janis Carlson. They were married June 20, 1953, and shared 66 years together.

Following graduation Jack worked for Scott Paper as a Pulp Mill Engineer in Oconto Falls, WI and later as a Maintenance Engineer in South Glens Falls, NY and Chester, PA. He returned to the University of Wisconsin Madison to enroll in the PhD program for Civil Engineering in 1959 and received his degree in 1963. The family then moved to Pittsburgh, PA where Jack worked as an Associate Professor of Environmental Engineering at Carnegie Mellon University for seven years. When the University of Wisconsin expanded to include a campus in Green Bay, the family returned to Wisconsin in 1970. Jack was a professor for 25 years at the University of Wisconsin Green Bay, teaching classes in environmental science until his retirement at the age of 65. As part of his professional responsibilities in Green Bay, Jack served as a citizen commissioner of the Green Bay Metropolitan Sewerage District. He was one of six citizens managing the establishment and operation of the wastewater treatment system for a period of 29 years.

Jack continued to work as a consultant after retirement. He worked for the United Nations as part of the Industrial Development Organization in Viet Nam and received three Fulbright awards to conduct studies in Viet Nam and Mexico. He was also a guest professor in Viet Nam, Mexico and Peru and traveled extensively throughout the world. His wife Jan was at his side through most of his travels and they made many friends over the years.

Wisconsin held a special place in Jack's heart as his family and Jan's family lived in the state for multiple generations and part of their homesteads are still in family hands. His interest in clean water, the environment and global warming continued long past his retirement and consulting days were over. His former students and colleagues, with help from Jack's sister Audrey, organized what was called," The Jackfest" in 2022 at Jan's family home in northern Wisconsin. Jack was an eternal optimist who believed in problem solving by motivating others to join him in battling environmental woes. His motto was, "If not Me, then Who? If not Now, then When?". He received numerous honors over the years. An education building at the mouth of the Fox River and the bay was named in his honor.

Jack was preceded in death by his parents, wife Janis (Carlson) Day, and brother William Day. He is survived by his two daughters Katharine Van Rooy and Carolyn (Monte) Radeke, seven grandchildren, John (Chaimae Bakour) Van Rooy, Thomas (Laia Marco Perpina) Van Rooy, Sarah (Justin) Orler, Paul (Abbey Berg) Van Rooy, Mary Van Rooy, Mason (Gia) Radeke, and Marisa (Brent) Martin and three great grandchildren, Amalia Van Rooy, Mila Radeke, and Briggs Martin, one sister Audrey (Bruce) Kemp and one brother in law, Thad (Janet) Carlson.

The family would like to recognize the special friendship Jack had with the people at the mall and all the caring people at the United Methodist Church who supplied him with coffee and cake after the service. They were his social life after Jan's death. The family would also like to thank Unity Hospice, Home Instead and Cornerstone for their care during Jack's illness.

In lieu of flowers, the family ask for donations to be made to the Harold "Jack" Day Memorial Fund. Donations can be sent to the UW-Green Bay Foundation, CL805, 2420 Nicolet Drive, Green Bay, WI 54311-7001. A service will be held at the First United Methodist Church, 501 Howe Street in Green Bay, Wisconsin on October 16 at 11:00 with visitation starting at 9:00. A reception will be held at the Mauthe Center at UWGB from 12:30 until 2:30.