State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu 610059, China.
State Environmental Protection Key Laboratory of Synergetic Control and Joint Remediation for Soil and Water Pollution, Chengdu University of Technology, Chengdu 610059, China.
Int J Environ Res Public Health. 2018 Apr 4;15(4):670. doi: 10.3390/ijerph15040670.
A constructed rapid infiltration (CRI) system is a new type of sewage biofilm treatment technology, but due to its anaerobic zone it lacks the carbon sources and the conditions for nitrate retention, and its nitrogen removal performance is very poor. However, a shortcut nitrification–denitrification process presents distinctive advantages, as it saves oxygen, requires less organic matter, and requires less time for denitrification compared to conventional nitrogen removal methods. Thus, if the shortcut nitrification–denitrification process could be applied to the CRI system properly, a simpler, more economic, and efficient nitrogen removal method will be obtained. However, as its reaction process shows that the first and the most important step of achieving shortcut nitrification–denitrification is to achieve shortcut nitrification, in this study we explored the feasibility to achieve shortcut nitrification, which produces nitrite as the dominant nitrogen species in effluent, by the addition of potassium chlorate (KClO₃) to the influent. In an experimental CRI test system, the effects on nitrogen removal, nitrate inhibition, and nitrite accumulation were studied, and the advantages of achieving a shortcut nitrification–denitrification process were also analysed. The results showed that shortcut nitrification was successfully achieved and maintained in a CRI system by adding 5 mM KClO₃ to the influent at a constant pH of 8.4. Under these conditions, the nitrite accumulation percentage was increased, while a lower concentration of 3 mM KClO₃ had no obvious effect. The addition of 5mM KClO₃ in influent presumably inhibited the activity of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB), but inhibition of nitrite-oxidizing bacteria (NOB) was so strong that it resulted in a maximum nitrite accumulation percentage of up to over 80%. As a result, nitrite became the dominant nitrogen product in the effluent. Moreover, if the shortcut denitrification process will be achieved in the subsequent research, it could save 60.27 mg CH₃OH per litre of sewage in the CRI system compared with the full denitrification process.
人工快速渗滤（CRI）系统是一种新型的污水生物膜处理技术，但由于其存在厌氧区，缺乏碳源和硝酸盐保留条件，因此脱氮性能很差。然而，短程硝化-反硝化过程具有明显的优势，因为与传统的脱氮方法相比，它节省氧气、需要更少的有机物，并且反硝化所需的时间更少。因此，如果能够将短程硝化-反硝化过程适当地应用于 CRI 系统，将获得一种更简单、更经济、更高效的脱氮方法。然而，由于其反应过程表明，实现短程硝化-反硝化的第一步也是最重要的一步是实现短程硝化，因此在本研究中，我们探索了通过向进水添加氯酸钾（KClO₃）来实现主导氮物种为亚硝酸盐的短程硝化的可行性。在实验 CRI 测试系统中，研究了氮去除、硝酸盐抑制和亚硝酸盐积累的影响，并分析了实现短程硝化-反硝化过程的优势。结果表明，通过向进水添加 5mM KClO₃并将 pH 保持在 8.4，成功地在 CRI 系统中实现并维持了短程硝化。在这些条件下，亚硝酸盐积累率增加，而添加 3mM KClO₃ 则没有明显效果。向进水中添加 5mM KClO₃ 可能会抑制氨氧化细菌（AOB）和亚硝酸盐氧化细菌（NOB）的活性，但对亚硝酸盐氧化细菌（NOB）的抑制作用很强，导致亚硝酸盐积累率高达 80%以上。因此，亚硝酸盐成为出水的主要氮产物。此外，如果在后续研究中实现短程反硝化过程，与完全反硝化过程相比，CRI 系统每升污水可节省 60.27mgCH₃OH。
