Kubeko turned crop waste into fuel and fertilizer on Ivorian farms

Côte d'Ivoire's cassava, cocoa, palm oil, and mango farms generate roughly 30 million tonnes of agricultural biowaste a year -- two to five times the volume of the crops actually sold -- and the standard fate of that waste is simple disposal, a pure cost with no offsetting value. The same smallholder farms and cooperatives, meanwhile, separately spent money buying cooking gas and fertilizer inputs they needed for their households and their next planting cycle.

Disposal and procurement were treated as two unrelated line items on the same farm's budget, handled by different habits and different suppliers, even though the biowaste being thrown away and the fuel and fertilizer being purchased were chemically close cousins -- one was simply never being converted into the other.

Chemical engineer Noël N'guessan built Kubeko, a set of low-cost biowaste processing equipment -- a biodigester and a companion composter -- that ferments a farm's daily agricultural byproducts directly into the two things the farm was buying separately. The biodigester converts roughly 5 kilograms of daily green waste into about 2 hours of cooking gas plus 50 litres of liquid compost; the composter turns 400 kilograms of biowaste into 150 kilograms of solid compost a month. Rather than treating waste disposal and input procurement as separate problems needing separate solutions, Kubeko collap