化工学报 ›› 2019, Vol. 70 ›› Issue (11): 4410-4419.DOI: 10.11949/0438-1157.20190522

• 能源和环境工程 • 上一篇    下一篇

曝气强度对SBBR同步生物脱氮及N2O释放影响

巩有奎1,2(),彭永臻2   

  1. 1. 烟台职业学院建筑工程系,山东 烟台 264670
    2. 北京工业大学城镇污水深度处理与资源化利用技术国家工程实验室,北京 100124
  • 收稿日期:2019-05-19 修回日期:2019-06-15 出版日期:2019-11-05 发布日期:2019-11-05
  • 通讯作者: 巩有奎
  • 作者简介:巩有奎(1977—),男,博士,副教授,260943813@qq.com
  • 基金资助:
    国家自然科学基金项目(51508008);烟职博士科研项目(2018002)

Effect of aeration intensity on simultaneous biological nitrogen removal and N2O release from SBBR

Youkui GONG1,2(),Yongzhen PENG2   

  1. 1. Department of Architecture Engineering, Yantai Vocational College, Yantai 264670, Shandong, China
    2. National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, Beijing 100124, China
  • Received:2019-05-19 Revised:2019-06-15 Online:2019-11-05 Published:2019-11-05
  • Contact: Youkui GONG

摘要:

以生活污水为处理对象,采用碳纤维填料制成序批式生物膜反应器(sequencing batch biofilm reactor,SBBR),采用N2+O2联合曝气的方式,通过改变N2和O2的比例,稳定系统内DO浓度为1.5 mg/L,考察不同曝气强度(30、20和10 L/h)下系统脱氮性能及N2O释放特性。异养菌和硝化菌共生于生物膜内,异养菌位于外层,硝化菌位于内层,曝气强度降低有利于外部异养菌大量增殖,生物膜厚度增加。曝气强度为30 L/h和10 L/h条件下,SBBR系统NH4+-N去除率分别为95%以上和79.2%±1.6%,同步脱氮效率分别为46.2%±2.6%和62.1%±2.3%,N2O产率分别为6.25%±0.6%和2.93%±0.43%。缺氧阶段,反硝化过程和PHA(聚β–羟基烷酸酯)积累同时发生;好氧阶段,PHA呈先增加后减少的趋势。初始阶段增加的PHA为后续同步发生的反硝化过程提供了电子供体。AOB的好氧反硝化过程和异养菌反硝化过程均可导致N2O的产生。曝气强度降低导致水力剪切力下降,生物膜内缺氧范围扩大,缺氧区N2O停留时间延长,利于其反硝化减量。曝气强度由30 L/h降至10 L/h,微生物胞外聚合物(EPS)分泌减少,PS/PN(多糖/蛋白质)由8.59 mg/mg降至6.58 mg/mg,生物膜致密性降低,碳源和N2O以扩散形式进入缺氧区域能力增强,N2O释放量降低。

关键词: 同步硝化反硝化, 曝气强度, N2O, PHA, EPS

Abstract:

Using domestic wastewater as influent and carbon fibre as biological carriers, the characteristics of SND(simultaneous nitrification and denitrification) process and N2O emission were studied under different aeration intensity (30,20,10 L/h), with the DO(dissolved oxygen) concentration controlled at 1.5 mg/L by adjusting the ratio of N2 and O2. Hetertrophic and nitrifying bacteria conexisted in the biofilm, which are located in the outer and inner layers of the biofilm, respectively. The decrease of aeration intensity was beneficial to the proliferation of the external heterotrophic bacteria. With the aeration intensity was controlled at 30 L/h and 10 L/h, the removal efficiency of NH4+-N in the SBBR system were more than 95% and 79.2%±1.6%, the SND efficiency was 46.2%±2.6% and 62.1%±2.3%, the N2O yield was 6.25%±0.6% and 2.93%±0.43%, respectively. During the anoxic phase, the denitrification process and the accumulation of PHA (poly-β-hydroxyalkanoate) occurred simultaneously. In the following aerobic process, the PHA increased first and then decreased, which indicated that PHA could be used as internal carbon sources in the following denitrification process. Both the aerobic denitrification process of AOB and the denitrification process of denitrifying bacteria at the presence of lower oxygen led to the emissions of N2O. The decrease of aeration intensity leads to a decrease in hydraulic shearing force, an increase in the anoxic range in the biofilm, and an increase in the N2O residence time in the anoxic zone, which is beneficial to the denitrification reduction. As the aeration intensity decreased from 30 L/h to 10 L/h, the extracellular polymer (EPS) secretion decreased, and the PS/PN (polysaccharide/protein) decreased from 8.59 mg/mg to 6.58 mg/mg, resulting the reduction of the biofilm density, which created the favorable conditions for N2O transferring into the biofilm to complete the reduction process.

Key words: simultaneous nitrification and denitrification, aeration intensity, N2O, PHA, EPS

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