Evergreen Industrial Services is buying private equity-backed Gem Mobile Treatment Services for an undisclosed amount.

Gem Mobile, headquartered in Signal Hill, California, provides engineered environmental remediation services, such as vapor control and wastewater treatment, for the petroleum, petrochemical, environmental and energy industries. The company is backed by Sterling Partners, a Chicago private equity firm that has about $5 billion in assets under management. For more on Sterling's activity, see our December cover story Retail Reboot: Investors Snatch Up E-Commerce Services, and watch our video interview with Sterling senior managing director Rick Elfman. 

Evergreen provides industrial cleaning services for oil refineries, petrochemical plants, power generation plants, manufacturing sites and mills. The company is backed by Platform Partners, a Houston private equity firm. Platform invests between $10 million and $75 million per deal. The firm's other investments include Avalon Advisors LLC, Cadence Bancorp LLC and Landmark Aviation.

More deals are expected to take place in the oil and gas services sectors as low oil prices drive the industry into distress. For more, see Investors Flow Into Oil & Gas.