Grass: The Surprising Solution that Keeps Coffee Pollution Out of Rivers
By Carole Hemmings, Global Coffee Sustainability Director, TechnoServe
When you sip your morning coffee, you probably aren’t thinking about the rivers that flow through farming communities. They are connected, however: the production of coffee can pollute the very waterways that these communities rely on.
Today, on World Water Day, we consider the effects of this hidden problem in the coffee industry — foul-smelling rivers, undrinkable water, unhappy communities — and the surprising solution: vetiver grass.
The environmental cost of good coffee
For farmers in places like rural Ethiopia, coffee production is one of the best opportunities to earn a better living and lift their families out of poverty. But to improve the quality of the final product, and to attract the specialty coffee buyers who offer better prices to farmers, the coffee typically needs to be processed at wet mills — low-tech facilities that strip away the pulp surrounding the coffee bean.
Unfortunately, however, many of the these wet mills (especially those built decades ago) are significant polluters. They require large amounts of water to process the coffee, and the wastewater and coffee pulp they produce often find their way into local rivers. Downstream from these mills, the pollution can be so great that it generates the same biochemical oxygen demand (BOD) as raw sewage. This renders the river water unusable for washing and other domestic tasks, as well as agricultural tasks like watering animals and irrigating crops.
“We had old pulping machines that dumped toxic water from pulping into the river. Further, we suffered because wet mills above us on the river were also polluting, which affected the water we used to process [coffee]… And the wet mills smelled of pollution. It had gotten so bad that it was posing a health risk to both people and animals. There was a problem producing vegetables in the area,” recalled the secretary of one Ethiopian coffee cooperative.
The pollution forces community members — almost always women and girls — to seek out unpolluted water elsewhere, often miles away.
While this problem has long plagued coffee farming communities, there are now impactful and cost-effective solutions that allow them to raise their incomes without sacrificing the health of local waterways.
Vetiver grass and eco-pulpers
As unlikely as it sounds, a simple grass is one of the most important tools in tackling this pollution. Vetiver grass is a deep-rooted plant that originated in Asia, where farmers used it to control rain runoff and fight land erosion. Working together, Ethiopia’s Jimma Agricultural Research Centre and TechnoServe developed and tested the use of vetiver grass wetlands to absorb the polluted water from wet mills.
That technique is now at the center of an approach that owners and operators are implementing at their wet mills. TechnoServe advisors help the staff of the wet mill learn to monitor their water usage and find easy opportunities to reduce it. After the coffee is processed, the wet mill staff separate out the solid coffee pulp, which is turned into compost for farmers. The wastewater flows through the vetiver grass wetland, and any wastewater that is not absorbed by it ends up evaporating in a reinforced pool. When wet mills adopt this low-cost approach, virtually all of the river pollution is eliminated.
Modern engineering has provided another important tool: the eco-pulper. Produced by several companies in South America, these machines are the proverbial “better mousetrap”: they strip away the coffee pulp using just 10–20 percent of the water used by traditional machines. Consequently, TechnoServe supports cooperatives to install eco-pulpers when they build new wet mills.
These innovative technologies have the potential to eliminate the problem of coffee-related river pollution. And in partnership with companies like Mother Parkers and Nespresso and donors like IDH, we have helped hundreds of wet mills to improve their water sustainability. To reach a future in which no community sees its river polluted for the sake of coffee, we need even more cooperation between the private sector, governments, nonprofit organizations, and — most importantly — farmers.
