الملخص الإنجليزي
Recently, microbial fuel cells (MFCs) considered as a promising technology for direct
conversion of biochemical energy into electrical energy. The new technology is
environment friendly and efficient for recovering bio-electricity and removing organic
wastes. That's why, it is attracting the great attention to the scientific community. Different
substrates had been used in MFCs as food for bacteria. Landfill leachate showed a
promising feedstock for MFCs system.
In this study, two identical single chamber air-cathode MFCs (Volume, 1250 ml) with
carbon brushes as anode electrode and Platinum (Pt) coated carbon cloth as cathode
electrode was used to investigate the bio-electrical performance for two different
concentrations of diluted landfill leachate. The system operated with 8 hours hydraulic
retention time (HRT). The MFCs were operated in continuous mode after inoculation of
microbial community using raw domestic wastewater for 30 days. The COD content of the
raw wastewater used for inoculation was 376-593 mg/L. The MFC produced 161.9 mW/m2
of power density with an internal resistance of Rint = 36 12 during inoculation period, when
domestic wastewater was the sole substrate for bacteria. Then the systems were operated
with two mixtures of leachate and wastewater as 1:10 (leachate: wastewater) and 1:5
(leachate: wastewater). The mixtures, 1:10 and 1:5 (leachate: wastewater) contained COD
as 2,588-4,008 mg/L and 4,286- 6,068 mg/L, respectively. Each mixtures were used as substrates for 5 days during power optimization period. With the ratio of 1:5 mixture, the
maximum power density and columbic efficiency (CE) of the MFCs were observed as 1,031
mW/m2 and 11.1%, respectively, for an observed Rint = 6 12. For the ratio of mixture 1:10
(leachate/wastewater), the power density and Ce reached to 775 mW/m2 (Rint = 62) and
11.7% respectively. Increasing the fraction of leachate into the influent substrates of the
MFCs showed remarkable improvement of recovering power and coulombic efficiency.
The performances of COD and ammonium removal by the MFC systems were observed as
28.2% and 8.2% (for 1:10 mixture) and 23.2% and 4.7% (for 1:5 mixture), respectively. The higher removal of COD and ammonia were observed in case of low concentration of leachate in wastewater, whereas, the higher production of power and columbic efficiency were observed in case of high concentration of leachate in wastewater. The bio electrochemical performances of the MFCs revealed that the system had a great potential for recovering electrical power and removing contaminants from wastewater and leachate. As a new promising technology, the MFC system needs lot of improvement in terms of
reactor design, electrode materials, and operating parameters as pH, temperature, electrolytic conductivity and substrate loading.
