Application of Air Cathode Microbial Fuel Cells for Energy Efficient Treatment of Dairy Wastewater

Abstract

Microbial Fuel Cells (MFCs) offer a promising new solution for wastewater treatment due to their advantageous characteristics: lower energy demand and less excess sludge compared to the conventional activated sludge wastewater treatment technology. In this study, two systems of single chamber air cathode MFCs with a working volume of 14 L were investigated for the energy efficient treatment of dairy wastewater. Biomass-originated carbon cathode and noble-metal free cathode catalyst were applied to meet the demand for a lower investment cost. Influent chemical oxygen demand (COD) was in the range of 900 to 3830 mg L–1, while hydraulic retention time was ~ 2.4 days. Systems provided 156 mW m–3 and 170 mW m–3 maximum power densities and coulombic efficiencies of 11.5 % and 12.8 % in average. Organic removal efficiency of 71.1 ± 8.0 % was observed when influent COD was between 900 and 1500 mg L–1, however effluent quality and removal efficiency (67.9 ± 12.6 %) deteriorated as influent COD was increased (1500 – 3830 mg L–1). At high influent CODs (over 3000 mg L–1), an organic elimination rate of 0.82 ± 0.11 kg COD m–3 d–1 was calculated, that can be considered as the upper limit of organic removal in the systems. Based on the results, MFCs may offer a potential solution for small-scale dairy factories for the pretreatment of their effluent to meet the criteria for wastewater discharge to sewer systems. The modular MFC design also facilitates to tailor the system to actual capacity requirements.

Precipitation Method for Determination of Carbon and Oxygen Isotopes to Detect Groundwater Contamination Near a Municipal Landfill

“…As discussed previously, sometimes this method is not appropriate [10]. Assuming that the landfill leachate contains high concentrations of dissolved organic matter (as a result of organic matter biodegradation), which might contaminate the groundwater, BOD/COD ratio can be used to assess the spread of the leachate plume in the aquifer [21,22]. As the biodegradable organic compounds may also be of natural origin (peatlands), this method can be unreliable [21].…”

“…Assuming that the landfill leachate contains high concentrations of dissolved organic matter (as a result of organic matter biodegradation), which might contaminate the groundwater, BOD/COD ratio can be used to assess the spread of the leachate plume in the aquifer [21,22]. As the biodegradable organic compounds may also be of natural origin (peatlands), this method can be unreliable [21]. It is commonly known, that BTEX, PAHs, pesticides, microplastics, and other components not formed in the natural environment are clearly indicative of contamination [22][23][24][25][26].…”

Dairy Wastewater as a Potential Feedstock for Valuable Production with Concurrent Wastewater Treatment through Microbial Electrochemical Technologies

“…During another investigation, TiO 2 nanofillers were added to SPEEK to synthesize the TiO 2 -SPEEK membrane for application in an MFC. Different weight percentages of TiO 2 that varied from 2.5 to 10% were studied to understand the membrane performance; a 5% TiO 2 -SPEEK membrane generated a peak power density of 1.22 W/m 2 and a voltage of 0.635 V, which were higher than those of the Nafion [150].…”

Efficiency Increase of Biological Methanation based Power-to-Methane Technology Using Waste Heat Recovery with Organic Rankine Cycle

“…In the presence of H 2 , microbes can convert the CO 2 in the biogas into CH 4 through their metabolism. When the CH 4 concentration of the resulting gas reaches 95-98%, the product gas is biomethane ( bio CH 4 ) [26][27][28].…”