Safwat Mahmoud, PhD, PMP

This study shows the effects of various conditions on performance of microbial fuel cells (MFCs) used to treat synthetic wastewater that contained glucose. The conditions included the following: three different configurations (dual-chamber MFC with proton exchange membrane (PEM), single-chamber MFC with PEM, and single-chamber MFC without PEM); bacterial adhesion; and increasing the anode surface area by using activated alumina, extruded activated carbon, and granular activated carbon. The maximum voltage production, power density, and COD removal values were 28 mV, 0.46 mW/m2, and 68.8 %, respectively, in case of dual-chamber MFC with PEM; 3 mV, 0.0053 mW/m2, and 54.5 %, respectively, in case of single-chamber MFC with PEM; and 78 mV, 10.77 mW/m2, and 83 %, respectively, in case of single-chamber MFC without PEM. The voltage generation, power density, and COD removal increased to 351 mV, 218 mW/m2, and 98.7 %, respectively, when using an anode electrode that was immersed in the microbial solution for 1 week beforehand in the single-chamber MFC without PEM. The voltage generation and power density improved to 420 mV and 312 mW/m2, respectively, after increasing the anode area through with 170 g activated alumina, but no improvement was observed when using extruded activated carbon or granular activated carbon under the same conditions.

The biological treatment process using effective microorganisms (EM) in an anaerobic sequencing batch reactor (ASBR) for primary settled wastewater treatment was investigated. Activated EM was formed from raw EM to increase its efficiency by ensuring that the microorganisms were in an exponential phase of growth. A benchscale ASBR (volume 2.6 l) was seeded with activated EM and the characteristics of the influent and effluent wastewater were investigated under different temperatures and reaction times. This system achieved good removal efficiency for all the analyzed parameters. The removal efficiency of the chemical oxygen demand (COD), soluble COD, biochemical oxygen demand, total suspended solids, ammonia, and total phosphorus increased with increasing reaction time and temperature, and reached 72.1%, 61.5%, 75.7%, 80.9%, 50.4%, and 62.5% respectively, at a reaction time of 24 h and at 35 °C. The system showed good removal of total coliform and salmonella and a reduction in ammonia and sulfate-reducing bacteria. Biogas can also be obtained using this system.