Vessco Inc., a portfolio company of Bloomfield Hills, Mich.-based private equity firm O2 Investment Partners LLC, invested an undisclosed sum in Dorner Products Inc.

Dorner supplies water and wastewater treatment technology, specializing in fluid process equipment and controls. Vessco provides distribution and engineering services for municipal and industrial water and wastewater treatment projects, primarily in the upper Midwest and central U.S.

Vessco hired Dan Axelson, a senior financial leader in family and private equity-owned businesses, as its new CFO, it said in a release.