Department of Chemical Engineering, Institute of Technology, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain.
Department of Chemical Engineering, Institute of Technology, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain.
Water Res. 2014 Nov 15;65:371-83. doi: 10.1016/j.watres.2014.07.048. Epub 2014 Aug 8.
Cometabolism is the ability of microorganisms to degrade non-growth substrates in the presence of primary substrates, being the main removal mechanism behind the biotransformation of organic micropollutants in wastewater treatment plants. In this paper, a cometabolic Monod-type kinetics, linking biotransformation of micropollutants with primary substrate degradation, was applied to a highly enriched nitrifying activated sludge (NAS) reactor operated under different operational conditions (hydraulic retention time (HRT) and nitrifying activity). A dynamic model of the bioreactor was built taking into account biotransformation, sorption and volatilization. The micropollutant transformation capacity (Tc), the half-saturation constant (Ksc) and the solid-liquid partitioning coefficient (Kd) of several organic micropollutants were estimated at 25 °C using an optimization algorithm to fit experimental data to the proposed model with the cometabolic Monod-type biotransformation kinetics. The cometabolic Monod-type kinetic model was validated under different HRTs (1.0-3.7 d) and nitrification rates (0.12-0.45 g N/g VSS d), describing more accurately the fate of those compounds affected by the biological activity of nitrifiers (ibuprofen, naproxen, erythromycin and roxithromycin) compared to the commonly applied pseudo-first order micropollutant biotransformation kinetics, which does not link biotransformation of micropollutants to consumption of primary substrate. Furthermore, in contrast to the pseudo-first order biotransformation constant (k(biol)), the proposed cometabolic kinetic coefficients are independent of operational conditions such as the nitrogen loading rate applied. Also, the influence of the kinetic parameters on the biotransformation efficiency of NAS reactors, defined as the relative amount of the total inlet micropollutant load being biotransformed, was assessed considering different HRTs and nitrification rates.
共代谢是微生物在存在主要基质的情况下降解非生长基质的能力，是废水处理厂中有机微污染物生物转化的主要去除机制。本文应用一种共代谢 Monod 型动力学模型，将微污染物的生物转化与主要基质的降解联系起来，该模型应用于在不同操作条件（水力停留时间（HRT）和硝化活性）下运行的高度富集硝化活性污泥（NAS）反应器。考虑到生物转化、吸附和挥发，建立了生物反应器的动态模型。采用优化算法，根据共代谢 Monod 型生物转化动力学，在 25°C 下估算了几种有机微污染物的转化能力（Tc）、半饱和常数（Ksc）和固液分配系数（Kd）。在不同的 HRT（1.0-3.7 d）和硝化速率（0.12-0.45 g N/g VSS d）下验证了共代谢 Monod 型动力学模型，该模型比不将微污染物的生物转化与主要基质的消耗联系起来的常用伪一级微污染物生物转化动力学更准确地描述了受硝化生物生物活性影响的那些化合物的命运（布洛芬、萘普生、红霉素和罗红霉素）。此外，与伪一级生物转化常数（k(biol)）相比，所提出的共代谢动力学系数与所施加的氮负荷率等操作条件无关。此外，考虑到不同的 HRT 和硝化速率，评估了动力学参数对 NAS 反应器生物转化效率（定义为总入口微污染物负荷中被生物转化的相对量）的影响。
