Process Biochemistry, Vol.101, 89-98, 2021
Demonstration of energy and nutrient recovery from urine by field-scale microbial fuel cell system
Scaling-up of Microbial fuel cells (MFC) involves optimizing parameters like the number of units, electrodes and unit size. This study demonstrates the working of a 10 L scale MFC stack for nutrients recovery (struvite as slow phosphorous release fertilizer) and energy recovery from urine over a three-month analysis period. The MFCs employed, a part of three staged systems (pH development, precipitation and treatment), were membrane divided double-chambered, operating in multiple-fed batch mode with a hydraulic retention time of 48 h. The average removal of chemical oxygen demand (COD) achieved was 75.55 +/- 2.8 %, with removal rates of 4.252 kg/m(3) day. The recovery of Ortho-Phosphates and ammoniacal nitrogen as struvite was 90 +/- 1.5 % and 46 +/- 2.16 %. The stacked MFC showed an average open-circuit voltage of 3.29 +/- 0.68 V with power density of 14.5 mW/m(2). Our findings suggest that the proposed three-stage process employing MFC stack achieved acceptable performance concerning nutrient recovery and organics removal.
Keywords:Microbial fuel cells;Biofilm;Cyclic voltammetry;Electrochemical impedance spectroscopy;Struvite precipitation