Advanced Water Management Centre (AWMC), The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia.
Department of Civil and Environmental Engineering, University of Vermont, Burlington, VT 05405, USA.
Water Res. 2015 Mar 15;71:21-31. doi: 10.1016/j.watres.2014.12.029. Epub 2014 Dec 25.
The accumulation of the denitrification intermediates in wastewater treatment systems is highly undesirable, since both nitrite and nitric oxide (NO) are known to be toxic to bacteria, and nitrous oxide (N2O) is a potent greenhouse gas and an ozone depleting substance. To date, two distinct concepts for the modelling of denitrification have been proposed, which are represented by the Activated Sludge Model for Nitrogen (ASMN) and the Activated Sludge Model with Indirect Coupling of Electrons (ASM-ICE), respectively. The two models are fundamentally different in describing the electron allocation among different steps of denitrification. In this study, the two models were examined and compared in their ability to predict the accumulation of denitrification intermediates reported in four different experimental datasets in literature. The N-oxide accumulation predicted by the ASM-ICE model was in good agreement with values measured in all four cases, while the ASMN model was only able to reproduce one of the four cases. The better performance of the ASM-ICE model is due to that it adopts an "indirect coupling" modelling concept through electron carriers to link the carbon oxidation and the nitrogen reduction processes, which describes the electron competition well. The ASMN model, on the other hand, is inherently limited by its structural deficiency in assuming that carbon oxidation is always able to meet the electron demand by all denitrification steps, therefore discounting electron competition among these steps. ASM-ICE therefore offers a better tool for predicting and understanding intermediates accumulation in biological denitrification.
在废水处理系统中，硝酸盐还原中间产物的积累是极不理想的，因为亚硝酸盐和一氧化氮（NO）已知对细菌有毒，而氧化亚氮（N2O）是一种强大的温室气体和消耗臭氧物质。迄今为止，已经提出了两种用于硝酸盐还原模拟的不同概念，分别由氮（ASM-N）和间接电子耦合的活性污泥模型（ASM-ICE）表示。这两个模型在描述硝酸盐还原过程中不同步骤之间的电子分配方面存在根本差异。在这项研究中，在预测文献中四个不同实验数据集报告的硝酸盐还原中间产物积累方面，检查并比较了这两个模型的能力。ASM-ICE 模型预测的 N-氧化物积累与所有四个案例中测量的值非常吻合，而 ASM-N 模型仅能够复制四个案例中的一个。ASM-ICE 模型的性能更好，是因为它通过电子载体采用“间接耦合”建模概念将碳氧化和氮还原过程联系起来，从而很好地描述了电子竞争。另一方面，ASM-N 模型由于其结构缺陷而受到限制，该缺陷假设碳氧化总是能够满足所有硝酸盐还原步骤的电子需求，因此忽略了这些步骤之间的电子竞争。因此，ASM-ICE 为预测和理解生物硝酸盐还原中的中间产物积累提供了更好的工具。
