Mendota Heights-based Restaurant ­Technologies Inc. has taken the dirty-to-dangerous job of delivering and disposing of cooking oil and turned it into a technology-driven growth business that employs 750 workers at 41 depots that cover the country's largest metropolitan areas.

And this "green" recycling business, which will sell millions of pounds of used grease to the ­biodiesel industry this year, also is generating green for its owners.

The privately held company, with anticipated sales of about $450 million this year, is growing revenue and profits at a 10 percent-plus clip, said CEO Jeff Kiesel, who joined RTI in 2005.

But the secret to success is not just in the hand-held computers, expensive trucks and efficient handling of product for thousands of restaurant and institutional kitchens daily.

"How we treat front-line employees and their success is reflected in how they treat ­customers," Kiesel said. "The cost of any turnover and new employees is very expensive. We're growing employment by 10 to 15 percent a year. We want a well-trained, satisfied base of employees, two-thirds of whom are hourly. And we want to retain 85 percent of them."

Don MacPherson, president of Modern ­Survey, does employee surveys and in-depth reviews for dozens of client companies annually, including RTI. MacPherson has been talking since the Great Recession of 2008-09 about the record-low state of employee morale. That's partly due to ­stagnant wage rates received by those who ­survived layoffs but who have been working harder during the slow recovery that has sent corporate profits to record levels. And not much recognition from management.

But MacPherson said the employee-engagement scores at RTI, essentially a measure of employee loyalty to the company, is very high. He shared those results with the company's permission.

"RTI has 37 percent of employees fully engaged compared to the U.S. benchmark of 10 percent and they demonstrate the practices that other organizations should have in place," MacPherson said. "That means management has fewer headaches. They are easily in the top 2 percent.''

To be sure, it may be easier to be appreciated by the troops when you're growing, giving raises and handing out year-end bonuses. And nearly 85 percent of RTI's employees have a favorable view of their manager and the company and how they are treated.

RTI starts with competitive pay, benefits, including a 401(k) retirement plan with 50 percent company match, bonuses and training. Line workers, many with just high school degrees, start in jobs that pay $18 to $25 per hour, plus benefits and profit-sharing. But MacPherson said what sets RTI apart is its "transparency" and a set of values from a credible leadership team that people understand.

Every month, Kiesel discloses companywide financial and performance results, right down to the depot level. And everybody is paid out of the same bonus pool, although senior management gets a bigger chunk.

Kiesel and Rick Copeland, human resources vice president, said the company tries to hire the right people, train them, listen to them and give them a career path. Not everybody works out, and the work can be demanding for drivers and technicians making multiple daily stops. There is room for error, timeouts and improvements. And employees have the opportunity to suggest changes at regular depot roundtables.

Kiesel said that disclosing to employees more information about operations, profitability and performance than most other companies allows RTI to focus on moving forward.

He describes the way employees are treated as a "collegial meritocracy."

"This is a pretty good place to work,'' said RTI service technician Matt Bartusek, 28, a five-year employee who once worked construction. "Jeff is a pretty open and honest guy. They give us a quarterly breakdown of the financials and how each depot is doing. Our benefits package is great.

"I have a construction background and I like being out in the field doing things, to train a customer on equipment or doing an installation. And the pay is better. I have no problem with my position, my managers and where we are headed as a company. In construction, the winter months come around … and things get slow."

Rebecca Sansone, 26, is a customer experience specialist with 30 months' experience. She manages national accounts to ensure they are getting the equipment, service and training they need.

"There's an entrepreneurial attitude that everyone carries to roll up sleeves and get the job done and I feel like we all are working toward the same goal," she said. "It's a transparent organization. We have a business-update lunch monthly on a Friday. One of the standing pieces is somebody walks through our financials. How many ­customers, installs, earnings … how we're doing on ­operations.''

Sansone said the regular updates help each employee understand how they fit into the ­organization.

"We can see how we can improve and what we can do. It promotes a team mentality. And we're all in the same bonus pool,'' she said. "The ­executive team pretty much lives up to the RTI values … the five 'C's of customer, character, commitment, courage and community. And people are willing to help each other out around here."