Faculty of Civil and Environmental Engineering, Gdan sk University of Technology, ul. Narutowicza 11/12, 80-952, Gdańsk, Poland.
Water Sci Technol. 2009;60(9):2463-70. doi: 10.2166/wst.2009.616.
The aim of this study was to investigate nitrogen mass balances occurring inside full-scale BNR activated sludge systems, with special attention to colloidal and dissolved organic nitrogen (CON and DON) transformations. For this purpose, laboratory experiments were carried out using process biomass from two large BNR plants in northern Poland. Two parallel batch reactors were operated in a 3-phase (anaerobic/anoxic/aerobic) cycle. In one reactor, the settled wastewater without any pretreatment was used, whereas the settled wastewater after coagulation-flocculation (to remove colloidal and particulate fractions) was added to another reactor. The chemical pretreatment of settled wastewater with ZnSO(4) did not adversely affect the observed nitrification rates in the (last) aerobic phase. It caused, however, a reduction of denitrification rates in the anoxic phase. Moreover, the chemical pretreatment did not appear to generally decrease DON but decreased CON. DON was explicitly produced in the aerobic phase and organic nitrogen conversion also occurred at a significant rate in the anoxic phase with biodegradable COD consumption and solids hydrolysis. The inorganic N mass balances revealed N losses up to approximately 10% which could be attributed to a few novel pathways of nitrogen removal, most likely aerobic denitrification or simultaneous nitrification/denitrification.
本研究旨在调查全规模 BNR 活性污泥系统内部发生的氮质量平衡，特别关注胶体和溶解有机氮（CON 和 DON）的转化。为此，使用来自波兰北部两个大型 BNR 工厂的工艺生物量进行了实验室实验。两个平行的批量反应器在三相（厌氧/缺氧/好氧）循环中运行。在一个反应器中，使用未经任何预处理的沉淀废水，而将沉淀废水在混凝-絮凝（去除胶体和颗粒部分）后添加到另一个反应器中。ZnSO4 对沉淀废水的化学预处理并没有对（最后）好氧相中观察到的硝化速率产生不利影响。然而，它导致缺氧相中反硝化速率降低。此外，化学预处理似乎并没有普遍降低 DON，而是降低了 CON。DON 在好氧相中明确产生，并且在缺氧相中也以相当高的速率发生有机氮转化，伴随着可生物降解 COD 的消耗和固体水解。无机 N 质量平衡表明氮损失高达约 10%，这可能归因于几种新的氮去除途径，最有可能是好氧反硝化或同时硝化/反硝化。
