不同营养模式下固定化斜生栅藻和普通小球藻氨氮去除能力对比分析

Comparative Analysis of Ammonia Nitrogen Removal Capacity of Immobilized Scenedesmus obliquus and Chlorella vulgaris under Different Trophic Modes

微藻培养耦合污水处理是一项极具潜力的绿色生物技术,具有污染物减排和资源化的双重效应.为明确不同微藻固定化后对NH4+-N去除的差异及优势,以斜生栅藻和普通小球藻为研究对象,以自由生长为对照,通过5 d的批次培养试验对比分析了2种固定化微藻不同营养模式下对NH4^+-N污水的适应性及其生长特性.结果表明:①对比自由生长,固定化生长可有效提升斜生栅藻在自养和异养模式下的NH4^+-N去除能力,2种模式下最大去除率分别为98%和53%,而在混养模式下,最大去除率则从100%降至86%.②固定化生长对普通小球藻NH4^+-N去除率的提升较弱,仅在自养模式下发挥正效应,最大去除率可升至37%,在混养模式下,其自由生长优势强于固定化生长,当C/N为10时,NH4^+-N第4天即可完全去除.③固定化生长并未改变混养模式下2种微藻生长对ρ(CODCr)的依赖性,而该效应在异养模式下并不明显.④除自养模式外,固定化生长均略低于自由生长,并且普通小球藻的生长速率也显著高于斜生栅藻.研究显示,斜生栅藻单个细胞对NH4+-N的去除能力优于普通小球藻单个细胞,斜生栅藻污水培养的适应性更强,并且固定化自养模式最佳,而普通小球藻固定化优势微弱.

Microalgae cultivation is an eco-friendly biotechnology with great utilization potential for simultaneous pollutant removal and resource recovery in wastewater treatment. In order to identify the performance of different immobilized microalgae species on ammonia nitrogen (NH4^+-N) removal,the adaptability of Scenedesmus obliquus and Chlorella vulgaris in NH4^+-N-rich wastewater and their growth characteristics under different trophic modes were compared and investigated. The results showed that immobilized cultivation of S. obliquus in the autotrophic and heterotrophic modes could effectively improve NH4^+-N removal capacity up to 98% and 53%,respectively.However,the maximal NH4^+-N removal rate in mixotrophic mode was reduced from 100% to 86% compared with the naturally grown microalgae. The NH4^+-N removal by immobilized C. vulgaris was less than immobilized S. obliquus,achieving only a removal of 37%under autotrophic mode. Naturally grown C. vulgaris dominated in mixotrophic mode and promoted the complete removal of NH4^+-N with a C/N of 10. Furthermore,immobilization of both microalgae did not change their growth dependence on CODCrconcentration in mixotrophic mode,while this was not observed in the heterotrophic mode. The growth of immobilized microalgae was slightly slower than that of naturally grown microalgae in all environments,apart from autotrophic mode. The comprehensive growth rate of C. vulgaris under three trophic modes significantly outperformed that of S. obliquus. Accordingly,the observed NH4^+-N removal capacity of single cell of S. obliquus was significantly greater than that of single cell of C. vulgaris. In general,S. obliquus performed better than C. vulgaris in wastewater treatment,and immobilized microalgae in autotrophic mode had advantages in both nutrient removal and biomass enrichment in comparison to other trophic modes.