Pronk M, Bassin J P, de Kreuk M K, Kleerebezem R, van Loosdrecht M C M
Department of Biotechnology, Delft University of Technology, Julianalaan 67, Delft, 2628 BC, The Netherlands,
Appl Microbiol Biotechnol. 2014 Feb;98(3):1339-48. doi: 10.1007/s00253-013-4912-z. Epub 2013 May 30.
Salinity can adversely affect the performance of most biological processes involved in wastewater treatment. The effect of salt on the main conversion processes in an aerobic granular sludge (AGS) process accomplishing simultaneous organic matter, nitrogen, and phosphate removal was evaluated in this work. Hereto, an AGS sequencing batch reactor was subjected to different salt concentrations (0.2 to 20 g Cl(-) l(-1)). Granular structure was stable throughout the whole experimental period, although granule size decreased and a significant effluent turbidity was observed at the highest salinity tested. A weaker gel structure at higher salt concentrations was hypothesised to be the cause of such turbidity. Ammonium oxidation was not affected at any of the salt concentrations applied. However, nitrite oxidation was severely affected, especially at 20 g Cl(-) l(-1), in which a complete inhibition was observed. Consequently, high nitrite accumulation occurred. Phosphate removal was also found to be inhibited at the highest salt concentration tested. Complementary experiments have shown that a cascade inhibition effect took place: first, the deterioration of nitrite oxidation resulted in high nitrite concentrations and this in turn resulted in a detrimental effect to polyphosphate-accumulating organisms. By preventing the occurrence of the nitrification process and therefore avoiding the nitrite accumulation, the effect of salt concentrations on the bio-P removal process was shown to be negligible up to 13 g Cl(-) l(-1). Salt concentrations equal to 20 g Cl(-) l(-1) or higher in absence of nitrite also significantly reduced phosphate removal efficiency in the system.
盐度会对废水处理中涉及的大多数生物过程的性能产生不利影响。本研究评估了盐对好氧颗粒污泥（AGS）工艺中实现有机物、氮和磷同步去除的主要转化过程的影响。为此，一个AGS序批式反应器被置于不同的盐浓度（0.2至20 g Cl⁻/L）下。在整个实验期间，颗粒结构保持稳定，尽管颗粒尺寸减小，并且在测试的最高盐度下观察到显著的出水浊度。据推测，较高盐浓度下较弱的凝胶结构是造成这种浊度的原因。在所应用的任何盐浓度下，铵氧化均未受到影响。然而，亚硝酸盐氧化受到严重影响，尤其是在20 g Cl⁻/L时，观察到完全抑制。因此，出现了高亚硝酸盐积累。还发现，在测试的最高盐浓度下，磷的去除也受到抑制。补充实验表明发生了级联抑制效应：首先，亚硝酸盐氧化的恶化导致高亚硝酸盐浓度，这反过来又对聚磷菌产生不利影响。通过防止硝化过程的发生并因此避免亚硝酸盐积累，结果表明，在盐浓度高达13 g Cl⁻/L时，盐浓度对生物除磷过程的影响可忽略不计。在不存在亚硝酸盐的情况下，盐浓度等于或高于20 g Cl⁻/L也会显著降低系统中的磷去除效率。
