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Introduction

Electricity is currently the most versatile and easily controlled form of energy available today (Ram et al., 2018). It is non-polluting at point of use and practically loss-free. Its generation however can be from limited fossil fuels which majorly pollute our environment and is unsustainable or from renewable and non-polluting sources such as water, wind and sunlight (Aquila et al., 2017).

The fossil fuels used in electricity generation today, coal, oil and natural gas are very limited resources and with the current rates of mining and consumption, the world may be faced with a serious shortage of energy in a near future (MaaB and Mockel, 2020). The combustion of these fuels also releases many harmful pollutants into the environment such as various oxides of different elements, which contribute to climate changes, global warming, the greenhouse effect and ultimately adverse effects on all biological life. In order to lessen the hazardous concerns to the environment, future energy sources should be renewable with minimal negative environmental impact (Palanisamy et al., 2019). With the world turning to research in the field of energy production from renewable resources, the microbial fuel cell (MFC) offers the possibility of harvesting green electricity from organic waste and renewable biomass with little to no environmental footprint (Gajda et al., 2018).

The earliest concept of electricity generation from an MFC was demonstrated in 1910 by Potter where electrical energy was produced from living cultures of Escherichia Coli and Saccharomyces using platinum electrodes (Xu et al., 2018). This did not really attract global attention  until the discovery in the 1980s that the volume of current generated could be significantly improved upon by the implementation of electron mediators (Chakraborty et al., 2020). Most microbes are generally incapable of transferring electrons directly to the anode and this is due to the biological make-up of most microbes (Li et al., 2018). The outer layers of these species are composed of non-conductive lipid membrane, lipopolysaccharides and peptidoglycans which hinder direct electron transfer to the anode (Choudhury et al., 2021). Electron mediators accelerate this transfer (Ci et al., 2017). In an oxidized state, mediators can easily be reduced by capturing the electron from within the membrane (Hindatu et al., 2017). The mediators then move across the membrane releasing the electron to the anode and get oxidized again in the bulk solution to continue the cyclic process of electron transfer (Zhang et al., 2019).

A microbial fuel cell defines a system which utilizes the originally-occurring metabolisms of micro-organisms in order to synthesize electricity bio-electrochemically (Zhang et al., 2019). An absorption of the nutrients by the micro-organisms from within the environment occurs within the MFC (Xu et al., 2019). As a result of the aforementioned, energy is generated by the microbes. This electrical energy is a result of the chemical absorbed energy from within the microbes (Rossi et al., 2019). There is usually an anode and a cathode within the MFC; a membrane is usually utilized as a boundary (Yang et al., 2019). This membrane is usually cationic in nature (Hassan et al., 2019). The anode houses the micro-organisms, where a metabolism of various organic compounds by the microbes occur. Cellulose is a typical example of such organic compounds. As the metabolism takes place, electrons and protons are usually generated. These electrons would be observed on the anode, and are later transmitted to the cathode via an electric circuit. From within the electrolyte, the protons traverse to the membrane which acts as a form of separation. The existence of a load between the anode and a cathode allows for the utilization of the electrical energy.

Potato is the fourth main crop consumed worldwide and is an important constituent in human diets (Zhang et al., 2017). Consequently, potato is widely used in food-processing industries (El-Sharif et al., 2020). However, these industries generate massive amounts of potato peel (PPW) as a by-product, which is usually considered a waste, and thus discarded. Interestingly, recent research suggests that PPW is a valuable source of bioactive compounds, which can be converted into value-added products (Abdelraof et al., 2019). PP is a rich source of nutrients (Lu et al., 2020). In fact, compared with the pulp, PPW has higher amounts of various nutrients (Hijosa-Valsero et al., 2018). These peels can be used for a wide range of purposes. PPW is a potential source of bioactive compounds, including antioxidants, dietary fibers, pigments, vitamins, and minerals (Javed et al., 2019).

Problem Statement

Various unsustainable energy sources used in electricity generation today; coal, oil and natural gas are very limited resources and with the current geometric rates of mining and consumption, the world may be faced with a serious shortage of energy in a near future (Leonard et al., 2020). The combustion of these fuels also releases diverse harmful pollutants into the environment such as various oxides of different elements, which contribute to climate changes, global warming, the greenhouse effect and ultimately adverse effects on all biological life (Martins et al., 2018). In a bid to lessen the hazardous concerns to the environment, future energy sources should be renewable with minimal negative environmental impact. With the world turning to research in the field of energy production from renewable resources, the microbial fuel cell (MFC) offers the possibility of harvesting green electricity from organic waste and renewable biomass with little or no negative impact on the environment (Wu et al., 2020).

Aim and Objectives

The aim of this research is to evaluate the optimal anodic chamber composition required to deliver the best yield of electricity produced by an MFC operated in batch mode.

The objectives of this research work include:

• Objective 1: Generation of electricity from potato peel waste in a microbial fuel cell.
• Objective 2:  Evaluation and comparison of the voltage and current generated from various anodic chamber compositions (Kumar et al., 2018).
• Objective 3: Evaluation and comparison of the yield of electricity generated using microbial consortiums from poultry droppings and pig dung.

Research Questions

The identified research questions for this project are provided below:

• How do we generate electricity from potato people waste in a microbial cell?
• How do we evaluate the electricity generated?
• How does the compare the electricity yield achieved?

Deliverables

The deliverables of these project are a project report, the desired MFC and gotten results. The MFC would be evaluated.  Also, the report should contain a complete documentation of how the laboratory experiment was carried out, and how the results were arrived at.

Relevance

The relevance of this research work cannot be overemphasized as the need to generate clean and sustainable energy from zero-value food waste using green and locally sourced materials has intensified in recent years. Therefore, the relevance of this study spawns from the need to understand the effects of the various operating conditions on the overall production of electricity in an MFC.

Methodology

This project focuses on secondary research, laboratory experiments and process analysis, and they are discussed below:

Secondary research

The secondary research in this project will utilize a systematic approach (Johnson et al., 2016) to review the works of literature. The steps involved in the systematic review of the literature are provided below:

• Step 1: Identify the research questions that can be used for the project.
• Step 2: Identify the keywords that should be used to research the works of literature.
• Step 3: Extract the journals and books that are appropriate for this project.
• Step 4: Write the literature review chapter.

Laboratory experiments

The laboratory experiments would cover a large chunk of this project. They would be carried out in stages, and as such described below;

• Stage 1:  Sourcing for the required feedstock (potato peel wastes) and other required raw materials.
• Stage 2:   Fabrication of the MFC.
• Stage 3:  Developing an appropriate process route and optimal equipment arrangement for an efficient process setup.
• Stage 4:  Carrying out the process reaction.
• Stage 5:  Analyzing the process reaction.
• Stage 6:  Carrying out the phase separation.
• Stage 7:  Evaluation of the resultant bio-electricity.
• Stage 8:  Results Testing.

Process Analysis

The totality of the process reaction would be analyzed and this would also occur in stages;

• Stage 1:  Process Testing
• Stage 2:  Process Control
• Stage 3:  Process Optimization

Evaluation

The risk assessment conducted for this project is provided in the table below:

Table 1:  Risk assessment