中国科学院环境生物技术重点实验室知识库

        随着我国环境承载能力的日趋饱和，对污水处理排放标准提出了更严格的要求。 含 氮污染物的深度去除是目前污水处理厂提标 改造 的 重点和 难点，原因在于现行异养反硝化滤池技术存在运行成本高、污泥产量大、兼顾 COD 达标 困难等问题。 本研究 围绕电解过程中富氢水对 零价铁 ZVI 反硝化过程的影响，探讨溶解氢对反硝化性能的强化效果，拟 实现 ZVI 反硝化系统稳定运行与 微生物电化学系统产生的富氢水的资源再利用 。同时， 本 研究 创新性地 提出一种利用廉价单质硫和 亚铁矿石 作为活性滤料 驱动污水自养反硝化脱氮的活性滤池工艺 替代 目前普遍采用的有机碳源； 拟通过研究体系中单质硫与 亚铁矿石 的复配原则及其受水质条件影响的运行效果，明晰其 获得高效脱氮效能的 协同 机制及相较于现有技术的潜在优势。同时 通过解析各元素的转化及生物学信息 最终为污水处理厂深度脱氮 工艺向运行成本低、集约度高、稳定性好的方向发展提供技术和理论支撑。
        首先，由于ZVI 自养反硝化过程受限于 ZVI 腐蚀速率和硝酸盐与 ZVI 反应界面的 传输过程 通过电解的富氢水可以促进 ZVI 自养反硝化的 NO 3 的去除性能。在 DH 反应器中，硝酸盐去除率为 47.3 0.2 ％；在对照反应器中，硝酸盐去除率为 30.2 0.3 ％。此外 DH 反应器中亚硝酸盐的浓度为 0.04 mg/L而对照反应器中为 0.50 mg/L 。在两个自养反硝化反应器中均未发现其他中间体（例如 N 2 O ）。富氢水通过降低 pH 值减缓了 ZVI 的钝化过程，使得 ZVI 系统有望长期稳定获得高效的硝酸盐去除率。富氢水使反硝化细菌丰度明显增多，并且增加了特定功能基因 nir S 和 nos Z) 的丰度，有望将电化学产氢后 的 富氢水应用于二级生化出水的深度 脱氮 过程 。
        其次,为了考察 单质硫 亚铁矿 协同 驱动污水深度脱氮的可行性，本研究从不同尺寸的 单质 硫 亚 铁 矿 缓释电子供体 中 选取最佳尺寸 1.0 1.5 mm ，构建 单质硫 亚 铁 矿 填充床（ SICAD 系统），用其处理硝酸盐废水， 发现 SICAD 系统 获得高效的 深度脱氮 性能 。 当 HRT 为 0 .5 hT N 负荷高达 720.35 g∙N / m 3 d 中间体（ NO 2 和 N 2 O ）的积累较少 此外， SICAD 系统 减少了 硫酸盐 的生成 。 单质硫 与 亚铁矿石 协同脱氮过程中发现通过硫驱动 反硝化过程产生的酸可促进 Fe(II)的溶出，使得反应区域从固体表面扩展到溶液体系，从而积累了更多的生物量。亚铁矿石 通过富集 中性亚铁氧化细菌 ( 来促进电子转移速率，从而提高脱氮效率。另外， 通过 SICAD 系统 富集的微生物可以实现 Fe(II)/Fe(III) 的循环，使得较少的铁溶出既可实现硝酸盐去除效率 的提高。
        再次,为了 考察不同 单质 硫 亚 铁 矿 缓释电子供体复配原则及其受水质条件的 影响， 开展滤料 比例 优选 研究其处理模拟二级出水的能力。 结果表明， 当单质硫 与 亚铁矿石 的填充比例分别为 1:0 、 1:1 、 2:1 和 1:2 时 SICAD 1/1 系统的 TN 去除效率最高，其次是 SICAD 2/1 和 SICAD 1/2 。 主要归因于硫 自养反硝化 过程在 其表面附着的生物膜中进行，导致 单质硫 的比表面积是影响硝酸盐去除的重要因素。另外， 亚铁矿石 不仅 为 单质硫 提供微生物附着的场地，也参与 了 自养反硝化过程。 同时也发现 本研究中 SICAD 工艺 的 TN 去除效能是稳定的，并不受进水硝酸盐 浓度 的影响。
        最后，考察SICAD 系统对磷去除的影响，结果发现在 SICAD 系统中除磷机制与 亚铁矿石 一致，而其相较 ICAD 系统获得较高的除磷效率， 主要归因于含磷酸盐的三价铁沉淀物被过滤截留在滤池内， 并 附着在 亚铁矿石 颗粒间隙或表面，会进一步影响反硝化效果。然而硫自养反硝化过程 产生的 H 有助于沉淀不累积在 单质硫 亚铁矿石 表面，能够为反硝化过程持续提供反应界面， 从而 保证较高的 TN 去除效能。 SLAD 工艺 虽然对总磷也有一定的去除作用， 主要依靠 Ca 2+ 与 H 2 PO 4 和 HPO42 生成沉淀， 但 这种形式的沉淀并不稳定。 这项研究揭示了 SICAD 脱氮 除磷 的可行性和机理，为 污水深度 净化的实际应用提供了更大的潜力和可行性。

         The environmental carrying capacity has become increasingly saturated in china,requiring the sewage treatment plants implementing stricter discharge standards.However, current technology for deeply removing nitrogen pollutants, as represented by heterotrophic denitrification filter, suffers from high operating costs and sludge yield, and is difficult to balance the COD reaching standards. A hydrogen rich solution is to obtain by dual champers MFCs, which usually is directly discharged .The present study aims at demonstrating t he dissolved hydrogen can be feasibly applied in iron assisted autotrophic denitrification to accelerate the nitrate reduction during ZVI corrosion. If the hydrogen rich water was re cycle d for iron assisted denitrification , it could a chieve further hydrogen recovery and purification of wastewater. Meanwhile, t his project proposes a novel reactive filter for deeply removal of nitrate with low cost element sulfur and siderite as the bio carrier in order to replace traditional adding carbon sources . The composition principle of elemental sulfur and siderite for the removal of N, as well as the effects brought from the change of influent criteria will be investigated to understand the optim ized status of the composite system and the potential advantages compared to the existing technologies. In addition, the fate of each relevance element and the biological information in the system will be analyzed to clarify the correlated synergistic mech anism of elemental sulfur and siderite during the removal of N. This project is expected to technologically and theoretically support the deeply removal of nitrogen pollutants in sewage treatment plants more cost effective, integrated and stable.
        Firstly,H 2 producing by ZVI corrosion process plays an important role in the iron assist ed nitrate reduction process, which determines the nitrate reduction rate and the end product. The present study aims at demonstrating t he dissolved hydrogen can be feasibly ap plied in iron assisted autotrophic denitrification to accelerate the nitrate reduction during ZVI corrosion. It was observed that a continuous dissolved hydrogen supply with electrolysis promoted and stabilized the performance of iron assisted autotrophic denitrification. The average nitrate removal was 47.3% 0.2% in ZVI reactors with dissolved hydrogen rich water (DH reactor), and 30.2% 0.3% in the ZVI reactors without dissolved hydrogen rich water (control Moreover,the concentration of nitrite w as 0.0 4 mg/L in DH reactor compared with 0.50 mg/L in the control reactor No other intermediate s (e.g. N 2 O) were found in both the autotrophic denitrification reactor s. Finally, the hydrogen rich water enriched the denitrifying bacteria and increased the abundance of f unctional genes specific ,resulting in the promotion of h ydrophobic denitrification during the iron assisted nitrate removal process.
          Secondly,in order to investigate the feasibility of sulfur coupled with iron(II) carbonate ore (SICAD) to drive deeply removing nitrogen and phosphorus pollutants of wastewater, this study selected the optimal size of 1.0 1.5 mm from different sizes of sulfur and iron(II) carbonate ore to construct a SICAD system . The packed bed (SICAD system) is used to treat wastewater containing nitrogen and it is highly efficient for deepl y removing nitrogen and phosphorus pollutants. At a HRT of 0.5 h, the TN load ing is as high as 720.35 g∙N / m 3 d SICAD could decrease N2O or NO2 accumulation and produce less sulfate products. The acid produced through sulfur driven denitrification was found to promote the Fe(II) leaching from the ore and likely extend the reaction zone from the surface to the liquid. As a result, more biomass was accumulated in the SICAD system compared with the controls (sulfur,iron(II) carbonate ore and SLAD systems Moreover, iron(II) carbonate might promote the electron transfer by enrichment of FeOB in order to enhance the nitrogen removal efficiency . SICAD might bring out t he redox cycling of Fe in order to promote the transfer of electrons between two solids (ie. S ulfur and iron(II)carbonate particles ) or two bacteria by electron shuttles.
          Further, we study the effect of sulfur and siderite mixed principle and the water quality on the SICAD process . It was necessary to focus on the characteristics of the filter material consumption, the optimization of the filter material and the ability to treat the secondary effluent. The results show ed that the SICAD 1/1 system ha s the highest TN removal efficiency which was higher than that in SICAD 2/1 and SICAD 1/2 system, when the ratio of sulfur and siderite was 1:0, 1:1, 2:1 and 1:2 . This result was attributed to that the main process of autotrophic denitrification is carried out in this layer of biofilm. Therefore, t he specific surface area of sulfur is an important factor on nitrate removal efficiency . In addition, the addition of siderite provide d a site for microbial attachment on sulfur, and it act as electron donor for autotrophic denitrification. I n this study t he TN removal efficiency of was not affected by the influent nitrate.
        Finally, the effect of SICAD system on phosphorus removal was investigated. It was found that the phosphorus removal mechanism in SICAD sys tem was consistent with that of siderite . I t achieved higher phosphorus removal efficiency in SICAD than ICAD system . It wa s mainly attributed to t he ferric phosphate precipitate was filtered and trapped in the filter. These substances c ould adhere to the surface or gap of siderite , which will further affect the nitrate removal efficiency . However, the acid produced through sulfur also could help sedimentation not accumulate on the surface of sul f ur/siderite . It can provide a reaction interface for the deni trification process and ensure high er TN removal efficiency. The SLAD process also has a certain removal effect on phosphorus. It mainly relies on the hydrogen ions generated by denitrification could promote limestone to release Ca 2+ which react with H 2 PO 4 and HPO 4 2 to form precipitates. However, this form of precipitation is not stable. This study revealed both the feasibility and mechanism of SICAD, offering greater potential and feasibility for practical applications for secondary effluent purification.