CenterOak Partners has finalized the sale of Shamrock Environmental to Republic Services. This transaction marks the eighth and final portfolio company exit from CenterOak Equity Fund I LP, a 2016 vintage buyout fund.
Shamrock Environmental provides industrial waste and wastewater treatment services, specializing in non-hazardous wastewater treatment, waste collection, and industrial cleaning. The company operates six permitted Centralized Wastewater Treatment (CWT) facilities and several solidification sites.
Shamrock also maintains a fleet of company-owned tankers and vacuum trucks for liquid waste collection and transportation. The company serves commercial and industrial clients across more than 20 states, including businesses in manufacturing, energy, and chemical processing. Founded in 1994, Shamrock is headquartered near Greensboro in Browns Summit, North Carolina, and employs more than 300 people.
CenterOak acquired Shamrock Environmental in January 2020. During its ownership period, the company completed five add-on acquisitions, including three notable deals: Virginia-based Virginia American Industries in December 2020, Virginia-based Environmental Options in June 2023, and Pennsylvania-based JG Environmental in February 2024.
“Alongside management, CenterOak built a scaled provider of wastewater and waste processing services covering growing markets located on the East Coast from Florida to Pennsylvania,” said Jason Sutherland, a managing partner at CenterOak. “Over five years working with the company, revenue and EBITDA grew significantly due to investments that more than quadrupled permitted capacity to provide non-discretionary, mission-critical services.”
Republic Services (NYSE: RSG) is a waste management and environmental services company serving residential, commercial, industrial, and municipal customers across the United States. The company also offers landfill operations, transfer stations, and energy recovery services. Republic Services operates in 41 states and Puerto Rico, with more than 350 collection operations, 200 transfer stations, 190 active landfills, and 90 recycling centers. Founded in 1998 by Wayne Huizenga, the company is headquartered in Phoenix, Arizona.
According to Republic Services CEO Jon Vander Ark, the company spent $358 million on acquisitions in 2024 and plans to invest $1 billion in acquisitions in 2025, with the purchase of Shamrock Environmental as its first transaction of the year.
Headquartered in Dallas, CenterOak makes equity investments ranging from $20 million to $150 million in companies with enterprise values between $50 million and $500 million and EBITDA between $5 million and $35 million. The firm focuses on sectors including business services, industrial services, and consumer services.
In August 2024, CenterOak completed the final close of CenterOak Equity Fund III LP at its $1.1 billion hard cap. The firm’s second fund closed at its $690 million hard cap in April 2021, while its first fund closed in 2016 with $420 million of capital.
Houlihan Lokey acted as the lead financial advisor to Shamrock Environmental on this transaction, with Brown Gibbons Lang serving as co-advisor.
© 2025 Private Equity Professional | February 21, 2025
