BIO4Africa research has identified the best biochar for water purification – highlighting the intrinsic value of each type of agricultural waste

Clean drinking water is available all year round in the village of Dougba in rural Côte d’Ivoire following the installation of a new water purification tower. Empty coconut shells have gone from worthless waste to a valuable raw material in the process.

BIO4Africa partner Institut National Polytechnique Félix Houphouët-Boigny (INP-HB) designed and developed the system based on research into biochar produced from selected agricultural side streams.

A chance for less disease
As a leading producer of cashew nuts, cocoa and coconut, Côte d’Ivoire has large volumes of relevant feedstock available for biochar production. After studying the characteristics of each biochar produced, INP-HB’s conclusion was clear: coconut shells make the best biochar for water filtration.

Such findings are important in a country where contaminated water is a serious health hazard.  According to the most recent statistics, water-borne diseases are associated with more than 50% of adult deaths and 80% of deaths among children below the age of five[1].

Coconut shell biochar is a local, low-cost opportunity to improve this poor track record.

Upscaled to village needs
During the BIO4Africa project, INP-HB has upscaled its water purifier from a 200-litre prototype to a solar-powered purifying system capable of producing 500 litres of drinking water a day.

Located a short drive from the INP-HB biochar lab, Dougba is the first village to benefit. 

“Between 200 and 300 people live in Dougba, depending on the time of year. With this water purification capacity, it’s possible to fill the gaps in access to the national water supply,” says INP-HB professor Yao Casimir Brou.

“But there is a need for investment and local community involvement before biochar for water purification can be fully commercialised,” he adds.

Biochar with many uses
All the coconut shell biochar for the water purification tower is produced in the Brazilian pyrolysis kiln, one of the BIO4Africa pilot technologies established at the INP-HB test site in 2023.

Biochar engineer Dr Esaïe Appiah Kouassi estimates that around 300 local farmers supply the pyrolysis kiln with feedstock.

“Pyrolysis technology has great potential in rural and semi-rural areas because the biochar produced has many uses. In addition to water purification for human and animal consumption, it can purify mining wastewater, improve agricultural soil and provide sustainable fuel for household cooking.”

The full results of INP-HB’s biochar trials are currently pending publication.

[1] World Bank. 2021. République de Côte d’Ivoire 2021-2030 - Sustaining High, Inclusive, and Resilient Growth Post COVID-19