To harvest electrical energy from farm or field by microbial fuel cell (MFC) together with agricultural area.
To use steel wool that used for washing utensils for making electrodes.
I just poured a shot of coconut water. One day later. It seems voltage increases. Perhaps some nutrients should help.
But still without current. And there is some bubling.
Will it be layer as in Winogradsky column ?
I think that graphite felt or even homemade activated charcoal are expensive (or hard to manufacture) for electrodes. I could use cheaper off-the-shelf steel wool. It possible to use it for electrodes. And I should add micro algae into cathode too. It should increase power. I could buy chlorella or micro algae from e-commerce stores in Thailand (mostly sell to moina breeder).
For proof of concept. I conducted experiment for mud MFC with graphite felt electrods for few weeks. Open circuit voltage is about 0.14 volts. No closed circuit current. Next step is to find new electrode material should be cheaper.