19  EP 2 000 000 A1 20  7. A combined electrode according to claim 6, wherein at the most 90% of the cathode chamber is surround- ed by the anode electrode, such as at the most 80 %, eg. at the most 70%, such as at the most 60 %, eg. at the most 50%, such as at the most 40 %, eg. at the most 30%, such as at the most 20 %, eg. at the most 10%, such as in the range of 10-60%, eg. in the range of 20-80%, such as in the range of 30-70%, eg. in the range of 40-50%. 8. A combined electrode according to claims 5-37, wherein only one side of the cathode chamber is facing the anode electrode. 9. A combined electrode according to claims 5-8, wherein the anaerobic environment actsas an anode electrode chamber and wherein the anode electrode chamber is surrounding the cathode chamber 10. A method for obtaining bio- energy, said method comprises the steps of: GLYPH<3> 11. A method according to any of claim 10, wherein the microbial fuel cell is as defined in any one of claims 1-4. 12. A method according to any of claim10, wherein the combined electrode is as defined in any one of claims 1-4. 13. Use of the microbial fuel cell of claims 1-4 and the combined electrode of claims 5-9 for generation of electrical energy. 14. Use of the microbial fuel cell of claims 1-4 and the combined electrode of claims 5-9 for bioremediation. 15. Use of the microbial fuel cell of claims 1-4 and the combined electrode of claims 5-9 for use as a bio- sensor. (i) submersing one or more anode electrode (s) and one or more cathode chamber (s), said cath- ode chamber comprising an inlet through which influent enters the cathode chamber, an outlet through which the effluent depart the cathode chamber, a cathode electrode and a electrolyte membrane and one or more combined elec- trodes into an anaerobic environment, (ii) permitting microorganisms in the anaerobic environment to oxidize reduced organic or inor- ganic material thereby producing a plurality of electrons and (iii) obtaining a voltage between the one or more anode electrode (s) and the one or more cathode electrode (s) 11