NOVELTY - An ecological microbial fuel cell coupling electrode biofilm system comprises ecological microbial fuel cell (E-MFC) subsystem and biofilm-electrode reactor (BER) subsystem in which E-MFC subsystem comprises E-MFC reaction cell, E-MFC water inlet (1) set on bottom side of E-MFC reaction cell, E-MFC water outlet (2) set on top side of E-MFC reaction cell, non-conductive substrate (5) laid on bottom of E-MFC reaction cell, E-MFC anode electrode (9) placed in non-conductive substrate, and E-MFC cathode electrode (7) placed on top of E-MFC reaction cell.    USE - An ecological microbial fuel cell coupling electrode biofilm system for sewage treatment (claimed).    ADVANTAGE - Ecological microbial fuel cell coupling electrode biofilm system strengthens phosphorus and nitrogen removal, saves energy, promotes microorganism growth, does not require chemical agents, and has small footprint and simple process.    DETAILED DESCRIPTION - An ecological microbial fuel cell coupling electrode biofilm system comprises ecological microbial fuel cell (E-MFC) subsystem and biofilm-electrode reactor (BER) subsystem in which E-MFC subsystem comprises E-MFC reaction cell, E-MFC water inlet (1) set on bottom side of E-MFC reaction cell, E-MFC water outlet (2) set on top side of E-MFC reaction cell, non-conductive substrate (5) laid on bottom of E-MFC reaction cell, E-MFC anode electrode (9) placed in non-conductive substrate, E-MFC cathode electrode (7) placed on top of E-MFC reaction cell, and plants (8) grown on surface of E-MFC cathode electrode, BER subsystem comprises BER reaction cell, BER water inlet (3) set on bottom side of BER reaction cell, BER water outlet (4) set on top side of BER reaction cell, and BER anode electrode (11) and BER cathode electrode (12) set in BER reaction cell, E-MFC water outlet is connected to BER water inlet, E-MFC anode electrode is connected to BER cathode electrode by 1st conductor (10), and E-MFC cathode electrode is connected to BER anode electrode by 2nd conductor (15). An INDEPENDENT CLAIM is included for removing phosphorus and nitrogen in sewage which involves sending sewage through E-MFC water inlet into E-MFC reaction cell, converting organic nitrogen into nitrate and organic phosphorus into phosphate using microorganisms in sewage, generating current using electrons and protons produced during oxidation reaction, performing microelectrolysis to produce hydrogen in BER cathode, diffusing hydrogen through biofilm, denitrifying using autotrophic denitrifying bacteria on cathode surface with hydrogen as electron donor and using heterotrophic denitrifying bacteria with organic material as electron donor, electrolyzing to form iron hydroxide, and separating precipitate to remove phosphorus.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic diagram of ecological microbial fuel cell coupling electrode biofilm system.    E-MFC water inlet (1)    E-MFC water outlet (2)    BER water inlet (3)    BER water outlet (4)    Non-conductive substrate (5)    E-MFC cathode electrode (7)    Plants (8)    E-MFC anode electrode (9)    1st conductor (10)    BER anode electrode (11)    BER cathode electrode (12)    2nd conductor (15)