Bio electrochemical Systems in STPs: Mechanisms and Future Prospects
The treatment of wastewater has been in progress and has evolved over the time of incorporating more advanced and ecofriendly technologies. Among others, Bio electrochemical system is one of the most promising innovations. STPs use these systems to cut down energy usage and increase treatment efficiency. Today in this blog, we are going to dive into their mechanisms, applications and future potential of these.
What is bio electrochemical systems in sewage treatment plants?
Biological electrochemical systems convert chemical energy into electrical energy through microbial activity. In sewage treatment plant, they provide treatment of wastewater as well as useful byproducts. These are systems that use electroactive bacteria. During the treatment of these bacteria electrons are transferred to electrodes. In the bio electrochemical systems, there are usually two electrodes and an anode and a cathode.
Electrons pass through the anode to cathode through an external circuit. The electricity or chemical reaction, such as production of hydrogen, is generated from this flow. These systems are dual-function technology. They use wastewater treatment to recover energy and resources. Within the bio electrochemical systems, there are several subtypes, such as microbial fuel cells (MFCs), microbial electrolysis cells (MECs) and microbial desalination cells (MDCs). STPs enjoy different operational benefits for each.
Core Mechanisms of Bio electrochemical Systems in Wastewater Treatment
The bio electrochemical systems use well defined mechanisms, which makes them effective in wastewater treatment. They work at the microbial and electrochemical levels.
1. Electron Transfer from Microorganisms to Electrodes- Organic pollutants in wastewater are oxidized by electroactive microbes. During this oxidation they give some electrons, which travel to the anode. They are collected and transferred to the cathode by the anode through a circuit.
2. Electrochemical Reactions at the Cathode- Electrons are used to support useful reactions at the cathode. For example, microbial fuel cells perform oxygen reduction. Hydrogen is produced at the cathode in microbial electrolysis cells.
3. Energy Recovery through Bioelectricity or Hydrogen- The process of energy recovery is possible due to the electron flow. An MFC is a power generation system that yields electricity and an MEC is a hydrogen generation system. BES, therefore, constitutes a sustainable alternative for energy positive STPs.
4. Pollutant Degradation and Resource Recovery- In addition to removing organic pollutants, bio-electrochemical system can recover nutrients such as nitrogen and phosphorus. It is consistent with the circular economy aims.
Types of Bio electrochemical Systems Used in STPs
1. Microbial Fuel Cells (MFCs)- MFCs produce electricity from sewage based on organic matter present in them. In ambient conditions, they work well. The decentralized wastewater systems are appropriate for MFCs.
2. Microbial Electrolysis Cells (MECs)- A small voltage input is needed for MECs. Hydrogen or methane results from the organic matter in wastewater. They have the potential as energy recovery in large STPs.
3. Microbial Desalination Cells (MDCs)- MDCs treat sewage by removing salt from water. It is a process in which wastewater treatment, desalination, and energy generation are integrated into one process.
4. Photo-Bio electrochemical Systems- Instead, these systems use light to improve the efficiency of treatment. As a booster of cathodic reactions, photosynthetic microorganisms improve oxygen production.
5. Hybrid BES Configurations- Some STPs use hybrid systems that incorporate MFCs and MECs. Maximum energy and nutrient recovery from sewage is possible in this process.
Benefits of Integrating BES Technology in Sewage Treatment Plants
Various other benefits of bio electrochemical systems support the energy efficiency and sustainable development goals.
1. Energy-Efficient Wastewater Treatment- Bio-electrochemical system input low energy and can produce bioelectricity or hydrogen. It also means STPs are able to cut their power bills and carbon footprints.
2. Resource Recovery and Circular Economy- These are important resources that can be recovered from systems like nitrogen, phosphorus, and biogas. This helps in recycling and reducing waste.
3. Compact and Modular Design- Bio-electrochemical system units have small footprints. Their modular structure makes them suitable for urban and decentralized wastewater treatment systems.
4. Scalable Technology with Versatile Applications- STPs of different sizes (small, medium or large scale) can be served by Bio-electrochemical system. Researchers apply them in rural setups as well as in industrial wastewater treatment.
5. Reduced Sludge Production- Conventional biological systems produce more sludge compared to Bio-electrochemical system. It reduces the cost of handling and disposal of the sludge.
Challenges Faced in Deploying Bio-electrochemical system for Large-Scale STPs
Despite these advantages, a number of factors limit established technologies in bio electrochemical systems, making them not favourable for widespread adoption in full size STPs.
1. High Initial Investment Costs- The system setup and electrode materials can be expensive.
2. Scalability and Long-Term Stability- Performance consistency in large scale applications is still difficult to maintain. Researchers want stable biofilms and long-lasting electrodes for BES.
3. Low Power Output in Real Conditions- In real world STP deployments, output power drops. Microbial activity and energy generation vary depending on sewage quality.
4. Complex Maintenance and Monitoring- The pH, temperature and electrode potential need to be checked on Bio-electrochemical system regular basis. To upkeep, the operators must have technical knowledge.
5. Limited Commercial Demonstration Projects- Researchers mainly conduct studies in laboratories or on pilot projects. While there are still few large-scale commercial success stories, this does little to instil confidence in the technology.
Recent Innovations in Bio electrochemical Wastewater Treatment
However, there is still much interest in STPs and Bio-electrochemical system in finding new ways to increase the efficiency and reliability of BES. New electrode materials increase in conductivity and accommodate microbial growth. Overall, graphene and carbon nanotubes have demonstrated excellent results. Such materials realize stable biofilms and efficient electron transfer. Combining BES with anaerobic digesters or membrane bioreactors (MBR) is termed as hybrid systems. The combination of these helps improves the energy output and treatment efficiency.
In some cases, companies integrate machine learning into the innovation. These smart systems monitor and control Bio-electrochemical system performance in real time. Techniques of bio-augmentation are also coming into favour. They add specific microbial strains to enhance the rate of electron transfer and the degradation of the pollutant. As a result, biological wastewater treatment technologies now include 3D electrode structures and self-healing biofilms. Built on these features, these technologies have the potential to deliver high power and long life.
Future Prospects of Bio electrochemical Systems in Sustainable Wastewater Management
Bio electrochemical systems have great potential for the future of wastewater management. The goal for governments and industries are net zero energy. These objectives align well with the objectives of Bio-electrochemical system. Therefore, we expect more hybrid Bio-electrochemical system models in the future. The three will combine in treatment, energy generation, and resource recovery. This technology is most applicable to the decentralized sewage systems in rural areas. Scaling up Bio-electrochemical system adoption may be contingent on public-private partnerships.
Industry confidence will grow from more pilot projects and commercial case studies. However, as the academic institutions will further develop cost-effective and durable electrode materials, there will also be times when the best batteries will be built in space. These advances will diminish the ownership of the adoption. With proper policy support and funding, the wastewater treatment plant sector can be revolutionised through Bio-electrochemical system. As a sustainable, low energy and resource-efficient solution to modern wastewater problems, they offer significant prospects.
