Department of Chemical Engineering and Environmental Technology, University of Oviedo, E-33071 Oviedo, Spain.
Department of Chemical Engineering and Environmental Technology, University of Oviedo, E-33071 Oviedo, Spain.
J Hazard Mater. 2014 Feb 28;267:9-16. doi: 10.1016/j.jhazmat.2013.12.034. Epub 2013 Dec 26.
Starvation and changing feeding conditions are frequently characteristics of wastewater treatment plants. They are typical causes of unsteady-state operation of biological systems and provoke cellular stress. The response of a membrane bioreactor functioning under feed-induced stress conditions is studied here. In order to simplify and considerably amplify the response to stress and to obtain a reference model, a pure culture of Pseudomonas putida was selected instead of an activated sludge and a sole substrate (salicylic acid) was employed. The system degraded salicylic acid at 100-1100mg/L with a high level of efficiency, showed rapid acclimation without substrate or product inhibition phenomena and good stability in response to unsteady states caused by feed variations. Under starvation conditions, specific degradation rates of around 15mg/gh were achieved during the adaptation of the biomass to the new conditions and no biofilm formation was observed during the first days of experimentation using an initial substrate to microorganisms ratio lower than 0.1. When substrate was added to the reactor as pulses resulting in rapidly changing concentrations, P. putida growth was observed only for substrate to microorganism ratios higher than 0.6, with a maximum YX/S of 0.5g/g. Biofilm development under changing feeding conditions was fast, biomass detachment only being significant for biomass concentrations on the membrane surface that were higher than 16g/m(2).
饥饿和不断变化的喂养条件是污水处理厂的常见特征。它们是生物系统非稳态运行的典型原因，并引发细胞应激。本文研究了在进料诱导应激条件下运行的膜生物反应器的响应。为了简化和大大放大对压力的响应，并获得参考模型，选择了纯培养的恶臭假单胞菌（Pseudomonas putida）代替活性污泥，并且仅使用单一底物（水杨酸）。该系统以 100-1100mg/L 的高效水平降解水杨酸，表现出快速的驯化，没有底物或产物抑制现象，并且对由于进料变化引起的非稳态具有良好的稳定性。在饥饿条件下，在生物量适应新条件的过程中，实现了约 15mg/g h 的特定降解速率，并且在使用初始底物与微生物比例低于 0.1 的情况下，在实验的最初几天内没有观察到生物膜形成。当以脉冲形式向反应器中添加底物导致浓度迅速变化时，仅当底物与微生物的比例高于 0.6 时，才观察到恶臭假单胞菌的生长，最大 YX/S 为 0.5g/g。在不断变化的喂养条件下生物膜的发展非常迅速，仅当膜表面上的生物量浓度高于 16g/m 2 时，生物量才会明显脱落。
