Mpongwana Ncumisa, Rathilal Sudesh, Tetteh Emmanuel K
Green Engineering Research Group, Department of Chemical Engineering, Faculty of Engineering and the Built Environment, Durban University of Technology, Durban 4000, South Africa.
Microorganisms. 2022 Sep 14;10(9):1834. doi: 10.3390/microorganisms10091834.
Biological nutrient removal is an integral part of a wastewater treatment plant. However, the microorganism responsible for nutrient removal is susceptible to inhibition by external toxicants such as heavy metals which have the potential to completely inhibit biological nutrient removal. The inhibition is a result of the interaction between heavy metals with the cell membrane and the deoxyribonucleic acid (DNA) of the cell. Several attempts, such as the addition of pretreatment steps, have been made to prevent heavy metals from entering the biological wastewater systems. However, the unexpected introduction of heavy metals into wastewater treatment plants result in the inhibition of the biological wastewater treatment systems. This necessitates the recovery of the biological process. The biological processes may be recovered naturally. However, the natural recovery takes time; additionally, the biological process may not be fully recovered under natural conditions. Several methods have been explored to catalyze the recovery process of the biological wastewater treatment process. Four methods have been discussed in this paper. These include the application of physical methods, chelating agents, external field energy, and biological accelerants. These methods are compared for their ability to catalase the process, as well as their environmental friendliness. The application of bio-accelerant was shown to be superior to other recovery strategies that were also reviewed in this paper. Furthermore, the application of external field energy has also been shown to accelerate the recovery process. Although EDTA has been gaining popularity as an alternative recovery strategy, chelating agents have been shown to harm the metal acquisition of bacteria, thereby affecting other metabolic processes that require heavy metals in small amounts. It was then concluded that understanding the mechanism of inhibition by specific heavy metals, and understanding the key microorganism in the inhibited process, is key to developing an effective recovery strategy.
生物营养物去除是污水处理厂不可或缺的一部分。然而，负责营养物去除的微生物易受外部毒物如重金属的抑制，这些重金属有可能完全抑制生物营养物去除。这种抑制是重金属与细胞膜及细胞脱氧核糖核酸（DNA）相互作用的结果。人们已进行了多种尝试，如增加预处理步骤，以防止重金属进入生物废水处理系统。然而，重金属意外进入污水处理厂会导致生物废水处理系统受到抑制。这就需要恢复生物处理过程。生物处理过程可能会自然恢复。然而，自然恢复需要时间；此外，在自然条件下生物处理过程可能无法完全恢复。人们已探索了多种方法来催化生物废水处理过程的恢复。本文讨论了四种方法。这些方法包括物理方法、螯合剂、外部场能和生物促进剂的应用。对这些方法催化该过程的能力及其环境友好性进行了比较。结果表明，生物促进剂的应用优于本文中也有综述的其他恢复策略。此外，外部场能的应用也已被证明能加速恢复过程。尽管乙二胺四乙酸（EDTA）作为一种替代恢复策略越来越受欢迎，但螯合剂已被证明会损害细菌对金属的获取，从而影响其他需要少量重金属的代谢过程。由此得出结论，了解特定重金属的抑制机制以及受抑制过程中的关键微生物，是制定有效恢复策略的关键。
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