About this Research Topic
Biodegradation is an attractive method for many pollutants to be removed from the aquatic environment or converted to less toxic forms in drinking water treatment. In aquatic systems, pollutants such as nitrate, perchlorate, bromate and chromium are treated by bioreduction in bioreactors. As a result of the utilization of inorganic electron donors, the process is termed autotrophic reduction. The most used electron donors include hydrogen gas and reduced sulfur compounds, for example, elemental sulfur, sulfide and thiosulfate. Compared to organic electron sources, they have advantages such as low cost, clean nature and reduction of the risk of organic contamination of water in drinking water treatment. For such reasons, autotrophic reduction processes have gained popularity over the last few decades.
Although autotrophic reactions have many advantages, they also have some disadvantages, such as slow kinetics and the potential to generate secondary contaminates, for example, in the case of using reduced inorganic sulfur compounds, sulfate formation and increased acidity are observed. The selection of inorganic electron donors therefore greatly influences the biological reduction kinetics. The electron donor concentration, microbial affinity, hydrophilicity and particle size must be carefully tuned in order to achieve the desired reduction rate and efficiency. In some cases, the combination of different organic/inorganic electron sources can overcome the kinetic limitations of a single donor. In this way, the disadvantages belong to a single electron donor can be eliminated. Although intensive studies are carried out for some specific pollutants (for example, nitrate), there is still a need for studies on the use of different inorganic electron donors, alone, or in combination in the removal of other oxidized pollutants. Therefore combined utilization of inorganic electron donors is required to be studied more.
The goal of this Research Topic is to expand the use of inorganic electron donors in pollutant removal from drinking water. This Research Topic will accept Original Research, Perspectives and Review articles covering subjects related to autotrophic bioreduction, including but not limited to:
• Utilization of inorganic electron donors in the removal of oxidized pollutants such as nitrate, perchlorate, bromate or chromium.
• Combined utilization of inorganic electron donors
• Mixotrophic reduction processes
• Sequential reduction processes
• Elimination of disadvantages of inorganic electron donor utilization.
• Influence of electron donor origins
• Influence of reactor operational conditions on the inorganic electron donor utilization.
• Influence of macro and micro nutrient addition to autotrophic reduction.
Keywords: Autotrophic reduction, inorganic electron donors, water treatment
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