Hortencia Solís stood beside a Frankenstein-like conglomeration of tubes, tubs and tanks in the backyard of coffee cooperative Coopedota.
Brushing flakes of red paint from a sun-baked barrel, the agricultural engineer explained how her giant science experiment could turn waste into wealth.
At the peak of the coffee harvest, Coopedota, in the Los Santos region south of San José, produces 3.4 million liters of wastewater from coffee bean processing. The sweet liquid can be processed into almost 190,000 liters of ethanol, Solís estimates.
“The impact this project has is very important,” Solís said.
Like other Costa Rican farmers, coffee growers are getting squeezed by the rising cost of petroleum, fertilizer and herbicide.
Meanwhile, the price of coffee on the international market has stagnated. The combination makes farming a marginal business.
Coopedota’s goal is to reduce its 784 associates’ production costs by finding creative ways to reuse coffee processing byproducts.
Wastewater and plant matter are converted into organic fertilizer for members’ fields.
Plans are also in the works to turn captured methane from fermented wastewater into cooking gas.
But the cooperative’s main focus is on generating ethanol that members can purchase to fuel their farm vehicles. “(Coffee farmers) are going through a crisis,” said Adrian Cordero, Coopedota’s quality control manager. “And it all points in one direction: fuel.”
Solís explained the cooperative can produce a batch of ethanol in several days from processed bean wastewater. Sugary liquid containing bean pulp and soft mucilage lining ferments in giant plastic tubs for up to three days, producing carbon dioxide and alcohol.
The mixture is sent to a boiler, which maintains it a constant temperature between 85 and 90 degrees Celsius. Eventually, the brew turns into a vapor and wafts into a vertical fractional column where water is separated from the alcohol.
In the last step, the alcohol passes to a tank containing copper coiling. Here it condenses and drops in liquid form to a storage tank, and, voilà, ethanol is born.
Cordero and Solís said theirs is the sole cooperative producing ethanol from coffee waste products. A quick survey of the competition proves their word. While other cooperatives are using waste for compost, fertilizer or as fuel to burn in roasting machines, they are not experimenting with ethanol production.
Coopedota plans to start construction of its 2,140-square-meter ethanol plant in September, with a finish date projected for the end of 2008. The cooperative hopes to receive funding for the $250,000 project through loans from partners in Liechtenstein.
Members could purchase ethanol by early 2009, Solís estimated. Prices would reflect the going market rate.
Cordero said the cooperative will not discriminate among farmers according to the size of their fields, which range from half a hectare to 50 hectares.