Award-winning waste converters are helping farmers in Ivory Coast turn mountains of agricultural by-products into compost for their fields or gas for their cooking stoves. The small green KubeKo box was dreamt up by chemical engineer Noel N'guessan to make use of the 30 million tonnes of waste generated by crop production in the West African country each year and other biowaste like animal dung. Farmers like palm oil producer Michel Ahouri simply throw in organic matter and wait four weeks. One box can create 150kg of compost per month.