This study aims to address the suboptimal performance of conventional denitrifying strains in treating mariculture tail water (MTW) containing inorganic nitrogen (IN). The concentration of inorganic nitrogen in the mariculture tail water is about 5–20 mg·L. A biofilm treatment process was developed and evaluated using an anoxic-anoxic-aerobic biofilter composite system inoculated with the denitrifying strain Y8. The removal effect of total nitrogen (TN), IN, and Chemical Oxygen Demand (COD) from MTW was investigated. The results indicate that the AO composite biological filter has excellent pollutant removal efficiency within 25 days of operation, after the acclimation of the denitrifying microorganisms. The initial concentrations of TN, IN, and COD ranged between 10.24 and 12.89 mg·L, 7.84–10.49 mg·L, and 9.44–11.52 mg·L, respectively, and the removal rates of these indexes reached 38–68 %, 45–70 %, and 55–70 %, respectively. The experiments with different hydraulic retention times (HRT = 6 h, 8 h, 10 h) demonstrated that longer HRT was more conducive to the removal of inorganic nitrogen. Moreover, scanning electron microscopy observations revealed that the target strain successfully grew and attached to the filler in large quantities. The findings of this study provide practical guidance for the development of efficient biofilm processes for the treatment of MTW.

中文翻译：

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厌氧/缺氧/好氧（A2O）工艺净化海水养殖尾水中的无机氮

本研究旨在解决传统反硝化菌株在处理含有无机氮（IN）的海水养殖尾水（MTW）时性能不佳的问题。海水养殖尾水中无机氮浓度约为5～20mg·L。使用接种反硝化菌株Y8的缺氧-缺氧-好氧生物滤池复合系统开发并评估了生物膜处理工艺。研究了MTW对总氮(TN)、IN和化学需氧量(COD)的去除效果。结果表明，经过反硝化微生物的驯化后，AO复合生物滤池在运行25天内具有优异的污染物去除效率。 TN、IN、COD初始浓度分别为10.24~12.89 mg·L、7.84~10.49 mg·L、9.44~11.52 mg·L，去除率分别达到38~68 %、45分别为 –70% 和 55–70%。不同水力停留时间（HRT=6 h、8 h、10 h）的实验表明，较长的HRT更有利于无机氮的去除。此外，扫描电子显微镜观察表明，目标菌株成功生长并大量附着在填料上。这项研究的结果为开发治疗 MTW 的有效生物膜工艺提供了实用指导。