KKR and XPV Water Partners Form New Platform to Promote Water Quality


Meet our team of experts.

We've developed a cross-disciplinary team of experienced professionals with strong educational backgrounds and related wastewater process knowledge. Over the years, our team has accumulated a wealth of field and lab experience with various technologies and in the different industries we serve.

Leadership Team

Thomas J. Walkosak CEO

Tom joined EOSi in 2018 and has over 22 years of experience in leadership and management of environmental services and water treatment chemical businesses. Prior to joining EOSi, he was General Manager of USP Technologies, a Trojan / Danaher company that provides environmental technology, equipment and chemical service programs for municipal and industrial water and wastewater treatment applications. Mr. Walkosak was also a VP and member of the Trojan Technologies Executive Team. Prior career experience included a series of progressively responsible positions in manufacturing, marketing and business management at FMC Corporation, a leading global producer of hydrogen peroxide and other specialty and industrial chemicals. Mr. Walkosak earned a B.S. degree in Chemical Engineering from the Pennsylvania State University and also completed “The Executive Program” at the Darden Graduate School of Business Administration.

Samuel Ledwell President

Sam joined EOSi at the company’s inception in September 2003. He has over 14 years of experience in biological contaminant removal with a specific focus on developing the MicroC® portfolio of carbon sources.  He previously worked in the Department of Physical Oceanography at the Woods Hole Oceanographic Institution and in the Neurology Department at Massachusetts General Hospital. He holds a B.S. in Biology with a minor in Chemistry from Oregon State University and an MBA from Suffolk University.

Jeffrey Prellberg Vice President, Sales & Marketing

Jeff joined EOSi in May of 2019 and he brings over 30 years of domestic and international experience in the water / wastewater treatment industry.  Prior to joining EOSi, Jeff worked at Trojan Technologies, Inc., a Danaher company.  The company provides water and wastewater treatment technology and service solutions.  He most recently held senior level commercial positions including Director, Global Service and Aftermarket, and Vice President, Municipal Business Development.  In addition, while with Danaher, he worked at their USP Technologies business for 12 years as part of the senior management team in various commercial leadership roles.   Jeff holds a B.S. Degree in Geosciences, with a minor in Chemistry, from the University of Arizona, and has completed 2 years of graduate course work in Environmental Engineering, also from the University of Arizona. 

Rob Keeling Vice President, Operations

Rob brings over 15 years of experience in supplier development, supply chain management, procurement, and operations. In his role, he manages our supplier development, raw material procurement, risk management, rail car fleet, inbound rail and truck logistics, and new manufacturing site development for our nationwide network of production facilities. He is also instrumental in identifying new materials for use within EOSi products. Rob was previously with the largest biodiesel producer in the United States, where his responsibilities included supplier development, raw material procurement, risk management, biodiesel co-product marketing. Mr. Keeling holds a B.A. in Business Management from Simpson College, and is pursuing his CPSM certification.

Ryan Coleman, P.E., LEED AP Director, Process Solutions & Programs

Ryan has eleven years of wastewater operations and process knowledge as well as hands-on experience in the protein industry. Ryan has managed industrial wastewater treatment plants for several companies in Colorado, Idaho, and Pennsylvania. As an Environmental Manager with Cargill, Inc., he led a series of BNR optimization initiatives that successfully reduced effluent total nitrogen concentrations by more than 97 percent. Ryan has managed the construction and operation of facilities creating renewable, clean energy from dairy waste. Ryan has a B.S. in Environmental Systems Engineering from Pennsylvania State University, an M.S. in Engineering from Purdue University with a focus on industrial engineering and engineering economics, and he has an MBA from the University of Indiana's Kelley School of Business. Ryan is also a registered Professional Engineer in the state of Idaho.

Sandra L. Clark Director, Quality Management Systems

Sandy is an ASQ Certified Manager of Quality and Organizational Excellence and an ASQ Certified Quality Engineer. She brings to EOSi over 25 years of Quality Management experience. Sandy is responsible for expanding and developing new quality processes working alongside management to support the manufacturing of EOSi’s products, procurement of raw materials, meeting and exceeding customer expectations and creating value through the company’s quality management system. She has held Quality Management roles in various manufacturing environments including underwater robotic systems, underwater side scan sonar and acoustic systems, printed circuit boards, injection molding and machine shop fabrication. She has implemented and maintained ISO9001 compliant Quality Management Systems and has lead several lean quality enterprise initiatives. Sandy holds a Bachelor of Science degree from Montana State University.