S0/牡蛎壳比例对海水硫自养反硝化性能及微生物群落的影响研究

The effect of different S0/Oyster shell ratios on the performance of seawater sulfur autotrophic denitrification device

中文关键词: 硫自养反硝化(SAD)  脱氮性能  S₀  牡蛎壳  高通量测序

英文关键词: Sulfur Autotrophic Denitrification (SAD)  Denitrification performance  S_⁰  Oyster shell  High throughput sequencing

中文摘要:

      本研究以人工海水循环水养殖尾水为处理对象，比较了3个S0/牡蛎壳配比（5:1，3:1，1:1）的SAD装置在5个水力负荷（HLR，0.19-0.95 m3/m2·d）下的脱氮性能。结果表明，S0/牡蛎壳=5:1和3:1装置的脱氮性能较优。HLR为0.19-0.48 m3/m2·d时，不同HLR下及同一HLR下3个装置间NO3--N去除率无显著差异，分别为72.11 ± 12.64%-75.85 ± 7.95%，76.00 ± 6.91%-78.13 ± 6.45%，70.40 ± 7.78%-75.76 ± 8.98%；最高HLR（0.95 m3/m2·d）下，3个装置NO3--N去除率均显著降低，且S0/牡蛎壳=5:1（61.16 ± 9.31%）和3:1（56.62 ± 7.23%）装置的NO3--N去除率显著高于S0/牡蛎壳=1:1（38.98 ± 10.19%）。S0/牡蛎壳=5:1和3:1装置的NO3--N去除负荷随HLR升高而升高，最高HLR时分别为39.10 ± 6.18 mg N/(m3·d)和36.19 ± 4.66 mg N/(m3·d)。S0/牡蛎壳=3:1装置平均出水NO2--N最低，为0.59 ± 0.39 mg/L；3个装置间平均出水NH4+-N无显著差异，为0.17 ± 0.07-0.19 ± 0.11 mg/L。装置的出水pH随S0/牡蛎壳的比例和HLR的升高而降低。硫自养反硝化装置中优势菌门为具反硝化功能的弯曲杆菌门(Campilobacterota,6.47%~59.73%)，优势菌属为具硫自养反硝化功能的硫单胞菌属(Sulfurimonas,2.70%~49.50%)。随着S0/牡蛎壳的比例下降，装置内及装置上部牡蛎壳和S0交接处的硫单胞菌属丰度上升。pH与反硝化基因丰度呈正相关。该研究结果可为海水循环水养殖系统中SAD装置的设计与运行提供基础理论数据。

英文摘要:

      Seawater recirculating aquaculture is a sustainable aquaculture method with the advantages of water and land saving, high yield and environmental protection. The high concentration of NO3--N in the waste water has become one of the main factors limiting the discharge of waste water to meet the standard and restricting the sustainable development of seawater recirculation aquaculture. Biological denitrification is the main way to remove NO3--N in the water. Among them, sulfur autotrophic denitrification (SAD) has the advantages of no need to add organic carbon source and low sludge production, and thus it is more suitable for treating seawater recirculating aquaculture water with lower C/N. However, the SAD generates H+, which reduces the pH of the water, thus affecting the stability of the denitrification device in long-term operation. In the actual operation of the SAD device, oyster shells are often used as a filler substrate to regulate the pH of the water and to maintain the effectiveness of the device in denitrification. Oyster shells, as kitchen waste, are cheap and easy to obtain, and have received widespread attention. At present, there are few researches on the denitrification performance and microbial community structure of the SAD device under different HLRs for the waste water of marine recirculating aquaculture with different S0/Oyster shell filling ratios. In this study, we compared the denitrification performance of SAD devices with three S0/Oyster shell ratios (5:1, 3:1, 1:1) under five Hydraulic Loading Rates (HLR, 0.19, 0.24, 0.32, 0.48, 0.95 m3/m2·d) and the changes of influent and effluent pH and DO in the treatment of seawater recirculating aquaculture waste water, using artificial seawater recirculating aquaculture waste water as the treatment target. The effects of different S0/Oyster shell ratios on the nitrogen removal performance of the SAD device were evaluated in combination with microbial community characterization and functional gene prediction analysis. The results showed that when the HLR was 0.19-0.48 m3/m2·d, there was no significant difference in NO3--N removal rates among the four HLRs and three devices, which were 72.11 ± 12.64% -75.85 ± 7.95%, 76.00 ± 6.91% -78.13 ± 6.45%, 70.40 ± 7.78% -75.76 ± 8.98%, respectively; At the highest HLR (0.95 m3/m2·d), the NO3--N removal efficiency of the three devices significantly decreased, and the NO3--N removal efficiency of the S0/Oyster shell=5:1 (61.16 ± 9.31%) and 3:1 (56.62 ± 7.23%) devices was significantly higher than that of the S0/Oyster shell=1:1 (38.98 ± 10.19%). S0/Oyster shell=3:1 The average effluent NO2--N of the device is the lowest, at 0.59 ± 0.39 mg/L; There was no significant difference in the average effluent NH4+-N among the three devices, ranging from 0.17 ± 0.07 to 0.19 ± 0.11 mg/L. The denitrification performance of S0/Oyster shell=5:1 and 3:1 device is better. The effluent pH of the device decreases with the increase of S0/Oyster shell ratio and HLR. The dominant bacterial phyla in the SAD device are Campilobacterota (6.47%~59.73%) and Proteobacteria (16.46%~53.93%), with the dominant bacterial genus being Sulfurimonas (2.70%~49.50%). As the ratio of S0/Oyster shells decreased, the abundance of Sulfurimonas increased within the device and at the intersection of Oyster shells and S0 in the upper part of the device. pH was positively correlated with denitrification gene abundance. The research results can provide basic theoretical data for the design and operation of SAD devices in seawater RAS.