Environmental Engineering Research Centre, Department of Civil Engineering, The University of Hong Kong, Pokfulam, Hong Kong, China.
Environmental Engineering Research Centre, Department of Civil Engineering, The University of Hong Kong, Pokfulam, Hong Kong, China; Tsinghua-Berkeley Shenzhen Institute, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; State Key Laboratory of Marine Pollution (City University of Hong Kong), Tat Chee Avenue, Kowloon, Hong Kong, China.
Sci Total Environ. 2021 Oct 15;791:148314. doi: 10.1016/j.scitotenv.2021.148314. Epub 2021 Jun 7.
Integrated fixed-film activated sludge (IFAS) reactors are suitable for partial nitritation-anammox (PNA) for autotrophic nitrogen removal; however, its start-up and biofilm formation are slow and difficult. In this study, a new sludge seeding strategy was developed for the start-up of PNA-IFAS by using the pre-cultivated anammox biofilms. Two bioreactors were used in the experimental study, including a reactor that was started conventionally with the pre-acclimated suspended PNA sludge and bare biocarriers (PA-S) and a reactor that used the new seeding method with anammox biofilms pre-acclimated on biocarriers and ammonia-oxidizing bacteria (AOB) sludge in the suspension (PA-B). The use of anammox biofilms as the seed biomass greatly shortened the start-up period of the PNA-IFAS reactor to 1 month or so. Moreover, reactor PA-B achieved a higher nitrogen removal rate (707.3 mg N/(L·d)), better nitrogen removal efficiency (86.8 ± 2.8%), and lower nitrate yield (9.4%) than reactor PA-S. The biofilm development in PA-B was accelerated and its biofilm content was nearly 10 times higher than that of PA-S. The initial segregation of anammox in the biofilm and AOB in the suspended sludge provided an environment that not only accelerated the start-up of PNA-IFAS but also helped suppress the enrichment of unwanted nitrite-oxidizing bacteria (NOB) in the bioreactor, as evidenced by the lower NOB abundance in PA-B (<0.5%) than in PA-S (>2.2%) according to microbial community analysis.
一体化固定膜生物膜（IFAS）反应器适合用于自养脱氮的亚硝态氮厌氧氨氧化（PNA）；然而，其启动和生物膜形成缓慢且困难。在本研究中，通过使用预培养的厌氧氨氧化生物膜，开发了一种新的污泥接种策略，用于启动 PNA-IFAS。实验研究中使用了两个生物反应器，一个是使用预驯化悬浮 PNA 污泥和裸生物载体（PA-S）常规启动的反应器，另一个是使用预驯化在生物载体上的厌氧氨氧化生物膜和悬浮氨氧化细菌（AOB）污泥的新接种方法的反应器（PA-B）。使用厌氧氨氧化生物膜作为种子生物量极大地缩短了 PNA-IFAS 反应器的启动时间，大约为 1 个月左右。此外，反应器 PA-B 实现了更高的氮去除率（707.3 mg N/（L·d））、更好的氮去除效率（86.8 ± 2.8%）和更低的硝酸盐生成量（9.4%），优于反应器 PA-S。PA-B 中的生物膜发展得到了加速，其生物膜含量几乎是 PA-S 的 10 倍。厌氧氨氧化在生物膜中的初始分离和 AOB 在悬浮污泥中的初始分离为环境提供了不仅加速了 PNA-IFAS 的启动，还有助于抑制生物反应器中不需要的亚硝酸盐氧化细菌（NOB）的富集，根据微生物群落分析，PA-B 中的 NOB 丰度（<0.5%）低于 PA-S（>2.2%），这证明了这一点。
