Analysis of the Potential of an Increase in Yeast Output Resulting from the Application of Additional Process Wastewater in the Evaporator Station

The Role of Fungal Fuel Cells in Energy Production and the Removal of Pollutants from Wastewater

Pure water, i.e., a sign of life, continuously circulates and is contaminated by different discharges. This emerging environmental problem has been attracting the attention of scientists searching for methods for the treatment of wastewater contaminated by multiple recalcitrant compounds. Various physical and chemical methods are used to degrade contaminants from water bodies. Traditional methods have certain limitations and complexities for bioenergy production, which motivates the search for new ways of sustainable bioenergy production and wastewater treatment. Biological strategies have opened new avenues to the treatment of wastewater using oxidoreductase enzymes for the degradation of pollutants. Fungal-based fuel cells (FFCs), with their catalysts, have gained considerable attention among scientists worldwide. They are a new, ecofriendly, and alternative approach to nonchemical methods due to easy handling. FFCs are efficiently used in wastewater treatment and the production of electricity for power generation. This article also highlights the construction of fungal catalytic cells and the enzymatic performance of different fungal species in energy production and the treatment of wastewater.

The Membrane-Less Microbial Fuel Cell (ML-MFC) with Ni-Co and Cu-B Cathode Powered by the Process Wastewater from Yeast Production

Research related to measurements of electricity production was combined with parallel wastewater parameter reduction in a membrane-less microbial fuel cell (ML-MFC) fed with industry process wastewater (from a yeast factory). Electrodes with Ni–Co and Cu–B catalysts were used as cathodes. A carbon electrode (carbon cloth) was used as a reference due to its widespread use. It was demonstrated that all analyzed electrodes could be employed as cathodes in ML-MFC fed with process wastewater from yeast production. Electricity measurements during ML-MFC operations indicated that power (6.19 mW) and current density (0.38 mA·cm−2) were the highest for Ni–Co electrodes. In addition, during the exploitation of ML-MFC, it was recorded that the chemical oxygen demand (COD) removal per time for all types of electrodes was similar to the duration of COD decrease in the conditions for wastewater aeration. However, the COD reduction curve for aeration took the most favorable course. The concentration of NH4+ in ML-MFC remained virtually constant throughout the measurement period, whereas NO3− levels indicated almost complete removal (with a minimum increase in the last days of cell exploitation).

Renewable Energy and EU 2020 Target for Energy Efficiency in the Czech Republic and Slovakia

Our paper focuses on the renewable energy and EU 2020 target for energy efficiency in the Czech Republic and Slovakia. We study the reduction of greenhouse gas (GHG) emissions in these two EU Member States through the prism of the Europe 2020 strategy and the 3 × 20 climate and energy package and economic growth (represented by the Gross Domestic Product (GDP) that allows to measure the national dynamics and provide cross-country comparisons) without attributing specific attention to issues such as the electrification of transport or heating, and thence leaving them outside the scope of this paper. Both Czech Republic and Slovakia are two post-Communist countries that still face the consequences of economic transformation and struggle with the optimal management of natural resources. Both countries encountered profound system transformation after 1989 that are apparent in all three measures of sustainable development used in our study. We show that it is unlikely that the planned increase in renewable energy in the Czech Republic and Slovakia will reach its targets, but they might succeed in reducing their energy consumption and greenhouse gas emissions. Our findings show that the energy intensity of Czech and Slovak economies increased in the early 2000s and then stabilized at a level about twice of the EU average. It appears that this value is likely to remain the same in the forthcoming years. However, implementation of GHG emissions in the Czech Republic and Slovakia may be at risk in case the proper energy policy is not maintained. Moreover, our results show how the increase in the share of renewable energy and improvement in energy efficiency go hand-in-hand with mining and exploiting the energy sources that is notorious for the transition economies. We also demonstrate that a proper energy policy is required for effectively reducing energy consumption and greenhouse gas emissions. There is a need for commitments made by relevant stakeholders and policymakers targeted at achieving sustainable economic growth and energy efficiency. In addition, we demonstrate that there is a need for maintaining a proper balance between economic development and environmental protection, which is a must for the EU sustainable energy development agenda and all its accompanying targets for all its Member States.

Preparation and Analysis of Ni–Co Catalyst Use for Electricity Production and COD Reduction in Microbial Fuel Cells

Microbial fuel cells (MFCs) are devices than can contribute to the development of new technologies using renewable energy sources or waste products for energy production. Moreover, MFCs can realize wastewater pre-treatment, e.g., reduction of the chemical oxygen demand (COD). This research covered preparation and analysis of a catalyst and measurements of changes in the concentration of COD in the MFC with a Ni–Co cathode. Analysis of the catalyst included measurements of the electroless potential of Ni–Co electrodes oxidized for 1–10 h, and the influence of anodic charge on the catalytic activity of the Ni–Co alloy (for four alloys: 15, 25, 50, and 75% concentration of Co). For the Ni–Co alloy containing 15% of Co oxidized for 8 h, after the third anodic charge the best catalytic parameters was obtained. During the MFC operation, it was noted that the COD reduction time (to 90% efficiency) was similar to the reduction time during wastewater aeration. However, the characteristic of the aeration curve was preferred to the curve obtained during the MFC operation. The electricity measurements during the MFC operation showed that power equal to 7.19 mW was obtained (at a current density of 0.47 mA·cm−2).