King Abdullah University of Science and Technology, Biological and Environmental Sciences and Engineering Division, Water Desalination and Reuse Research Center, Thuwal, 23955-6900, Saudi Arabia.
Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, Delft, The Netherlands.
Water Res. 2017 Nov 1;124:702-712. doi: 10.1016/j.watres.2017.08.026. Epub 2017 Aug 13.
Salinity can affect the performance of biological wastewater treatment in terms of nutrient removal. The effect of salt on aerobic granular sludge (AGS) process in terms of granulation and nutrient removal was examined in this study. Experiments were conducted to evaluate the effect of salt (15 g/L NaCl) on granule formation and nutrient removal in AGS system started with flocculent sludge and operated at DO of 2.5 mg/L (phase I). In addition, experiments were conducted to evaluate the effect of gradually increasing the salt concentration (2.5 g/L to 15 g/L NaCl) or increasing the DO level (2.5 mg/L to 8 mg/L) on nutrient removal in AGS system started with granular sludge (phase II) taken from an AGS reactor performing well in terms of N and P removal. Although the addition of salt in phase I did not affect the granulation process, it significantly affected nutrient removal due to inhibition of ammonia oxidizing bacteria (AOB) and phosphate accumulating organisms (PAOs). Increasing the DO to 8 mg/L or adapting granules by gradually increasing the salt concentration minimized the adverse effect of salt on nitrification (phase II). However, these strategies were not successful for mitigating the effect of salt on biological phosphorus removal. No nitrite accumulation occurred in all the reactors suggesting that inhibition of biological phosphorus removal was not due to the accumulation of nitrite as previously reported. Also, glycogen accumulating organisms were shown to be more tolerant to salt than PAO II, which was the dominant PAO clade detected in this study. Future studies comparing the salinity tolerance of different PAO clades are needed to further elucidate the effect of salt on PAOs.
盐度会影响生物废水处理的性能，表现在养分去除方面。本研究考察了盐度对好氧颗粒污泥（AGS）工艺中颗粒化和养分去除的影响。实验评估了盐（15g/L NaCl）对以絮状污泥为起始条件、DO 为 2.5mg/L（阶段 I）的 AGS 系统中颗粒形成和养分去除的影响。此外，实验还评估了逐渐增加盐浓度（从 2.5g/L 增加到 15g/L NaCl）或增加 DO 水平（从 2.5mg/L 增加到 8mg/L）对以具有良好氮和磷去除性能的 AGS 反应器中颗粒污泥为起始条件的 AGS 系统中养分去除的影响。尽管在阶段 I 中添加盐并未影响颗粒化过程，但由于氨氧化细菌（AOB）和聚磷菌（PAO）受到抑制，其对养分去除的影响显著。将 DO 增加到 8mg/L 或通过逐渐增加盐浓度使颗粒适应，可将盐对硝化的不利影响降至最低（阶段 II）。然而，这些策略在减轻盐对生物除磷的影响方面并不成功。所有反应器中均未出现亚硝酸盐积累，表明生物除磷的抑制并非如先前报道的那样归因于亚硝酸盐的积累。此外，研究表明，与 PAO II 相比，糖原积累菌对盐更具耐受性，而 PAO II 是本研究中检测到的主要 PAO 类群。需要进一步研究不同 PAO 类群的耐盐性，以阐明盐度对 PAO 的影响。
