Leftover food, animal dung and an invasive water weed - Faranak Amidi talks to two female entrepreneurs in Nigeria and the US who have found profitable uses for stuff that no-one else wants.

Pashon Murray is the founder of Detroit Dirt, a company that collects food waste from businesses and animal dung from the zoo and mixes them together into rich compost, or 'black gold'. Inspired by her grandfather's connection to the land, and determined to reduce landfill and promote sustainability, Pashon wants to re-connect communities with the soil. However she says she is not running a charity, and it is a business model that others could learn from.

Returning to Nigeria after an absence, Achenyo Idachaba saw that the waterways were choked with an invasive weed called water hyacinth; and she had a hunch that maybe this problem plant could be turned into something useful. A few years on and her company MitiMeth is paying local fishermen and artisans to harvest the weed, training them to make high-end handicrafts from it and selling them. Achenyo says it is a win-win for the environment and the economy of her country.

(L) Pashon Murray (credit: Anastasia McKendrick) and (R) Achenyo Idachaba (credit: Christian Morales)