If you have ever had the misfortune to stand next to a pig farm when the wind is blowing in the wrong direction, you could be forgiven for questioning the rumour that besides being highly intelligent, these creatures with the curly pink tails are also "clean." Whether or not they live up to that reputation, the muck they produce can be used to create energy that genuinely is clean. This week on eco@africa, we find out how animal excrement is being used to power homes.

We will also explore how a slowing down of the oil industry is affecting a town in western Germany, and meet a group of European grannies who, armed with knitting needles and pure wool, are doing their bit for the enviroment.

And in Africa, we go to Senegal where a back to basics approach to farming is helping stave off problems of soil erosion, try and find a solution to a human-wildlife conflict in Ethiopia, and look at the correlation between climate change and security.