Chemical Engineering Program, Federal University of Rio de Janeiro, P.O. Box 68502, CEP 21941-972, Rio de Janeiro, RJ, Brazil.
Environ Technol. 2011 May-Jun;32(7-8):837-46. doi: 10.1080/09593330.2010.514949.
Nitrification of wastewaters from chemical industries can pose some challenges due to the presence of inhibitory compounds. Some wastewaters, besides their organic complexity present variable levels of salt concentration. In order to investigate the effect of salt (NaCl) content on the nitrification of a conventional biologically treated industrial wastewater, a bench scale moving-bed biofilm reactor was operated on a sequencing batch mode. The wastewater presenting a chloride content of 0.05 g l(-1) was supplemented with NaCl up to 12 g Cl(-) l(-1). The reactor operation cycle was: filling (5 min), aeration (12 or 24h), settling (5 min) and drawing (5 min). Each experimental run was conducted for 3 to 6 months to address problems related to the inherent wastewater variability and process stabilization. A PLC system assured automatic operation and control of the pertinent process variables. Data obtained from selected batch experiments were adjusted by a kinetic model, which considered ammonia, nitrite and nitrate variations. The average performance results indicated that nitrification efficiency was not influenced by chloride content in the range of 0.05 to 6 g Cl(-) l(-1) and remained around 90%. When the chloride content was 12 g Cl(-) l(-1), a significant drop in the nitrification efficiency was observed, even operating with a reaction period of 24 h. Also, a negative effect of the wastewater organic matter content on nitrification efficiency was observed, which was probably caused by growth of heterotrophs in detriment of autotrophs and nitrification inhibition by residual chemicals.
由于存在抑制性化合物，化工废水的硝化可能会带来一些挑战。一些废水除了有机物复杂外，还具有不同程度的盐浓度。为了研究盐（NaCl）含量对常规生物处理工业废水硝化的影响，采用序批式移动床生物膜反应器在批处理模式下进行了中试规模的实验。进水氯离子浓度为 0.05 g l(-1)，用 NaCl 将氯离子浓度补充至 12 g Cl(-) l(-1)。反应器运行周期为：进水（5 min）、曝气（12 或 24 h）、沉淀（5 min）和排水（5 min）。每个实验运行持续 3 至 6 个月，以解决与废水固有变异性和过程稳定性相关的问题。一个 PLC 系统确保了自动操作和对相关过程变量的控制。从选定的批处理实验中获得的数据通过一个动力学模型进行了调整，该模型考虑了氨、亚硝酸盐和硝酸盐的变化。平均性能结果表明，在 0.05 至 6 g Cl(-) l(-1)的氯离子浓度范围内，硝化效率不受氯离子浓度的影响，保持在 90%左右。当氯离子浓度达到 12 g Cl(-) l(-1)时，硝化效率明显下降，即使反应时间为 24 h。此外，还观察到废水有机物含量对硝化效率的负面影响，这可能是由于异养菌的生长对自养菌的不利影响以及残留化学物质对硝化的抑制作用造成的。
