As a society, mankind is faced with an expanding population, increasing industrialization, and consequently, greater demands on water resources. This progress has also led to an increase in wastewater generation. That is where Bioelectrochemical Systems (BESs) can play a significant role. Not only can these systems treat wastewater, but they can also generate electricity, produce valuable chemicals, and desalinate seawater.
The Basics of Bioelectrochemical Wastewater Systems
Bioelectrochemical systems are emerging technologies that exploit naturally occurring bacteria’s metabolism to catalyze reactions at electrodes, creating a flow of electrons that constitutes electrical current. The general concept behind BESs is quite straightforward. In these systems, electrochemically active micro-organisms are employed as biocatalysts to generate current within an electrochemical cell.
Bioelectrochemical technologies make use of the metabolic functions of bacteria, specifically, some can transfer electrons either to or from a solid electrode. These are anode-respiring bacteria (ARB) and cathode-assisting bacteria (CAB), and their intriguing capabilities are the driving force behind the operation of BESs.
Applications of Bioelectrochemical Systems
Aside from their primary role of treating wastewater, BESs demonstrate promise for a wide range of value-added applications. These include:
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Electricity Generation: One of the most noteworthy aspects of BESs is their capability to generate electricity as a by-product of wastewater treatment. The most common system used for this purpose is the Microbial Fuel Cell (MFC).
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Chemicals Recovery: BESs can recover useful chemicals from waste streams such as ammonium and phosphates, which are valuable as fertilizers.
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Desalination: In recent years, there has been considerable interest in coupling BESs with desalination to produce clean water from both saline water and wastewater in an energy-efficient way.
Challenges and Future Directions
While BESs are promising, they are still in their developmental stages and have several challenges which need to be addressed. These include achieving the desired treatment efficiency and making these systems robust and cheap enough to be considered for large-scale applications.
Looking toward the future, ongoing research and technological advancements in the field of bioelectrochemical systems suggest a future where wastewater is not just treated, but also exploited as a valuable resource for energy production and valuable chemicals recovery.
However, the commercialization and large-scale implementation of these systems remain a considerable challenge due to several practical reasons, including high construction and maintenance costs and lack of regulatory guidelines.
Conclusion
Given the growing need for sustainable and efficient wastewater treatment technologies, BESs, such as MFCs, have the potential to be integrated into our approach to wastewater management. They not only provide a promising avenue for wastewater treatment but also offer the possibility of bioenergy production and resource recovery, thus adding a new subfield to what we can term ‘resource-oriented sanitation.’ Thus, BESs are poised to generate a paradigm shift necessary towards realizing an innovative, efficient, and sustainable approach to wastewater treatment.
In conclusion, while the journey of bioelectrochemical systems is just beginning, with ongoing advancements in this field, we can hope for a future where wastewater is viewed not just as a disposal problem, but also as an opportunity for resource recovery and energy production.
References:
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Pant, D., Van Bogaert, G., Diels, L., & Vanbroekhoven, K. (2010). A review of the substrates used in microbial fuel cells (MFCs) for sustainable energy production. Bioresource technology, 101(6), 1533-1543. Link
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Logan, B. E., & Rabaey, K. (2012). Conversion of wastes into bioelectricity and chemicals by using microbial electrochemical technologies. Science, 337(6095), 686-690. Link
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Heidrich, E. S., Curtis, T. P., & Dolfing, J. (2011). Determination of the internal chemical energy of wastewater. Environmental science & technology, 45(2), 827-832. Link