Reducing Wastewater Contamination Starts with a Conversation

In Accra, Ghana, most homes do not have indoor plumbing or sewage systems. Instead, households dispose of waste into the same ditches and streams that urban farmers use to irrigate the crops they sell at local markets. The use of wastewater on farms presents a significant health risk and has been banned by the government. But because many farmers don’t have access to clean sources of water, they lack other options for irrigating their crops.

In 2005, the International Water Management Institute (IWMI), a non-profit organization working in Asia and Africa to improve water and land management for farmers and the environment, received funding from several groups, including the Consultative Group on International Agricultural Research (CGIAR) initiative Challenge Program for Water and Food, to work with urban farmers in Ghana to develop improved farm wastewater management.

“Ideally we would start at the city level to address wastewater treatment through infrastructure,” says Ben Keraita, an irrigation and water engineer and researcher with IWMI. “But there is no money or support for a big project like that, so we start with the farmers to find affordable, small, and simple ways to reduce the risk of contamination.”

Starting with the farmers is critical for another reason, Keraita explains. “There are too many different kinds of interventions when it comes to reducing the risk of contamination from waste water, and farmers do not react well to having new techniques pushed upon them.” Instead, Keraita and other project coordinators used their existing relationships with local farmers to call a meeting to discuss the problem and hear potential solutions from the farmers themselves. “Farmers know that the waste water is a problem and have lots of their own ideas about how to address it.”

Keraita and his colleagues created a list of innovations suggested by farmers and then introduced a few of their own, exposing the farmers to best practices from around the world. “Nothing we introduced was invented on the spot, and many are simple enough to be adopted immediately, like avoiding stepping into irrigation water and stirring up sediment that might contain contaminants by putting down a plank to walk on instead,” Keraita explains. Farmers are then asked to volunteer to adopt the practices that they think will be most effective, keeping track of their work daily so that an assessment can be made of the innovation at harvest time.

“If farmers don’t like a technique then we suggest doing another trial with a new technique,” Keraita says. “And we invite other farmers to view the harvest and the weighing of the crops so that they can give each other feedback and learn from the experiments of others.”

Based on these group discussions and trials, urban farmers in Accra are now irrigating with water collected in “waste sedimentation ponds”—ponds built specifically to allow sediment to sink to the bottom so farmers can irrigate with the cleaner surface water—and with simple containers of filtered water. Some are now also using drip irrigation from kits produced by International Development Enterprises (IDE), allowing them to use water more precisely and to conserve clean water (see also Slow and Steady Irrigation Wins the Race).