Sodium percarbonate addition as electrolyte and buffer to produce electricity economically using industrial-tempeh-wastewater based microbial fuel cell

Microbial Fuel Cell (MFC) is an energy conversion system used by bacteria to generate electricity from organic wastes. Currently, MFC electricity is still small, so it complemented by electrolytes. Previous research shows the addition of potassium persulfate can increase electric voltage 10-fold, but this is less economical so it is necessary to find alternative electrolyte. Sodium percarbonate is a cheap electrolyte which has buffering ability. Therefore, a performance study of single-chamber-MFC using sodium percarbonate electrolyte and or without buffer was conducted by measuring electricity production and tempe wastewater treatment quality (BOD and COD). This result was compared with the results of MFC with potassium persulfate with and without a buffer in the same procedure. In MFC containing sodium percarbonate, charge reversal occurred, with average power 0.04 mW/m², only 1.25% average power of MFC containing potassium persulfate. These results increased by buffer addition. Other results show that MFC containing sodium percarbonate will degrade more than 40% COD, greater than MFC with potassium persulfate, but still not efficient because Coloumb Efficiency was only in the range of 10^-6 %. Nevertheless, this system can produce 63% BOD₅ reduction when a buffer was not added.