In rural Senegal in West Africa, an enterprising woman named Aissatou Ly is earning an extra few bucks a day selling a tasty, nutritious ground-peanut paste dubbed "peanut butter" at a local market.

That is thanks to a simple grinder that has cut her labor and increased her income markedly in a country where the per capita economic output is only about $2,500 annually.

"The grinder is simple and durable and I don't need help to fix it, or need gas" to run it, said Ly in a written statement from Senegal. "I provide grinding services to other women and I sell peanut butter. I use the money to support my family. I like that, in my community, I've been able to find an opportunity … to become self-sufficient."

This is the recently improved version of the grinder, first developed years ago for small farmers and entrepreneurs in several African and Latin American countries by the retired science and business volunteers at Compatible Technology International (CTI) of St. Paul.

CTI opened a Senegal office two years ago and already several hundred of the $275 grinders have been distributed to small entrepreneurs who cover the acquisition cost within a few months with increased income, benefiting families and communities with better nutrition and improved incomes.

"The farmers and others can more quickly process peanuts or grains in less time and add value to products they sell in the market," said Aliou Ndiaye, CTI's Senegal country director on a recent visit to 35-year-old CTI's St. Paul headquarters and shop. "We are marketing the product, which has been improved. We are training them on the tools, business model and financing. We're changing the way they work, so they can feed their families better and sell more product to get more income.

"Most of them repay over several months with the increased income."

The improved grinder, which can be hand-operated or run with an electric motor, is the latest innovation for CTI. It was designed in consultation with the African people who use them and can be repaired locally.

I last wrote several years ago about the retirees at nonprofit CTI who are helping provide clean water to hundreds of thousands of rural residents in the mountains of Nicaragua, thanks to the CTI 8 Chlorinator. It costs about $125 and can be installed and repaired by local technicians in each village. The devices save lives by markedly reducing disease from waterborne bacteria, particularly among infants and small children.

Don Jacobson, 72, a retired food scientist from General Mills, is the five-year CTI volunteer who oversaw the improved grinder that is going into the hands of small farmers and entrepreneurs in Senegal and Malawi, in southeast Africa.

"This one is lighter, only about 15 pounds and it's less expensive," said Jacobson, who plans to travel to Senegal in October. "I worked on this with a volunteer CTI engineer for two years. Ultimately, it will be manufactured [in Africa]. But these won't wear out in a lifetime. There are only two bearings and it turns easily by hand.

"This is more than just a device. It's for farmers, mostly women who use it, and they set up micro businesses, sometimes with other women, and they can double their farm income making a peanut butter paste, for example, out of ground peanuts. It's really nutritious.

"And it replaces a lot of drudgery. Most of these people previously used a pestle, or bowl and a [hand mortar] with a long shaft that lifts and drops and grinds the peanuts, or the grain. This lets them get a lot more done faster and easily. And it produces higher-quality food."

Bupe Mwakasungula, CTI's Malawi project manager, said the grinder means more women are working, generating more income, and using the money to send kids to school and otherwise upgrading their lives.

These humble American volunteers, working with in-country partners, promote the best of America.

It's not just the Navy that is America's "force for good."

CTI folks help the poor help themselves through training and appropriate tools to a better life.

I've met numerous CTI volunteers over the years, including Pentair engineers and a former Minneapolis waterworks manager. They are motivated to do good with their skills in retirement. They are enriched by the work.

"I've been given a lot in life," said Jacobson. "Family, education, good jobs, good pay, wonderful experiences. And I need to pay back.

"I had a brain aneurysm years ago and it took me three years to walk and fully recover. I rehabbed at Courage Kenny [Rehabilitation] Institute. I volunteer there 10 hours a week, too. I'm just trying to help add value to other people's lives at CTI and Courage Kenny. I'm grateful."

Today, more than 2,000 grinders, including earlier versions, are used by small businesses in the developing world.

The addition of new grinders could double that number within a few years.

Neal St. Anthony has been a Star Tribune business columnist and reporter since 1984. He can be contacted at nstanthony@startribune.com.