Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian, People's Republic of China.
Environ Technol. 2021 Sep;42(23):3607-3617. doi: 10.1080/09593330.2020.1735526. Epub 2020 Mar 4.
Moving-Bed Biofilm Reactor (MBBR) process is an ideal preference for simultaneous nitrification and denitrification (SND) attributing to the longer sludge age and aerobic/anoxic microenvironment along biofilm. However, conventional carriers generally exhibit negative charge and surface hydrophobicity, which are unbeneficial for biofilm formation. In this study, novel surface-modified carriers with favourable hydrophilicity (surface contact angle dropped to 60.2 ± 2.3°) and positive surface charge (+11.7 ± 1.1 mV, pH 7.0) were prepared via polymer blending and implemented for SND in continuous flow MBBR system. Results indicated SND started up quickly with more biomass in MBBR filled with surface-modified carriers. At the operation condition of low dissolved oxygen level (0.75 ± 0.25 mg/L), pH of 7.5 ± 0.5, 23 ± 2°C and C/N ratio of 7, COD, NH-N and TN removal efficiencies were 90.5%, 88.6% and 76.6% respectively in MBBR filled with surface-modified carriers, which ensured the effluent met the first grade A of the Discharge Standard of China. On the contrary, COD, NH-N and TN removal efficiencies were 89.7%, 82.3% and 60.4% respectively in the control reactors filled with conventional polyethylene carriers. The worse performance of the control reactor was mainly attributed to the less biomass and lower functional bacteria abundance developed on conventional carriers. Moreover, novel carriers provided a favourable niche for more types of functional bacteria, of which autotrophic nitrification, anoxic denitrification, heterotrophic nitrification and aerobic denitrification co-existed and participated in nitrogen removal.
移动床生物膜反应器（MBBR）工艺因其较长的污泥龄和生物膜中好氧/缺氧微环境，是同步硝化反硝化（SND）的理想选择。然而，传统载体通常带负电荷和表面疏水性，不利于生物膜的形成。在这项研究中，通过聚合物共混制备了具有良好亲水性（表面接触角降至 60.2±2.3°）和正表面电荷（+11.7±1.1 mV，pH 7.0）的新型表面改性载体，并将其用于连续流 MBBR 系统中的 SND。结果表明，在填充有表面改性载体的 MBBR 中，SND 快速启动，生物量更多。在低溶解氧水平（0.75±0.25 mg/L）、pH 值为 7.5±0.5、23±2°C 和 C/N 比为 7 的操作条件下，在填充有表面改性载体的 MBBR 中，COD、NH-N 和 TN 的去除效率分别为 90.5%、88.6%和 76.6%，确保了出水满足中国《污水综合排放标准》一级 A 标准。相反，在填充有传统聚乙烯载体的对照反应器中，COD、NH-N 和 TN 的去除效率分别为 89.7%、82.3%和 60.4%。对照反应器的性能较差主要是由于传统载体上形成的生物量较少，功能细菌丰度较低。此外，新型载体为更多类型的功能细菌提供了有利的小生境，其中自养硝化、缺氧反硝化、异养硝化和好氧反硝化共存并参与氮的去除。
