Turning waste to value in Ivory Coast 

In and around the city of Yamoussoukro in Ivory Coast several lakes are heavily overgrown with an invasive species: water hyacinth. Although it is a plant with beautiful flowers, water hyacinth is an aquatic weed that originated in the Amazon Basin. It has become one of the world’s most difficult waterweeds to control, spreading rapidly across Latin America, the Caribbean, Africa, Southeast Asia, and the Pacific. When not effectively controlled, water hyacinth covers lakes, rivers, and ponds entirely, impacting water flow, blocking sunlight from reaching native aquatic plants, and reducing dissolved oxygen which leads to a significant decline in fish stocks. The plants reappear just as quickly as they vanish. To address this pressing issue, LONO approached PUM to collaborate on developing a plan for managing this water hyacinth issue.  

The project assessed different lakes in terms of their potential for water hyacinth harvesting. Each lake presented unique challenges, such as varying levels of accessibility, different plant compositions, maturity of the plants, and the proportion of free-floating versus rooted plans. Various harvesting methods were considered, including manual hand-pulling, using canoes or boats, and mechanical techniques such as dredging from the shore or using mowing boats and weed harvesters. A decision matrix was created to guide the selection of the most appropriate equipment for each situation.  

The harvested plants will be processed at an existing biomass facility. The plants can be valorised through the production of biochar or biomass. This enhances the fertilisation of soils used for production by farm cooperatives and individuals.