Clean Technology, Scion, Rotorua, New Zealand.
Department of Chemical & Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore, 117585, Singapore.
Appl Microbiol Biotechnol. 2019 Apr;103(8):3571-3580. doi: 10.1007/s00253-019-09696-0. Epub 2019 Feb 26.
Graesiella emersonii was cultivated in an osmotic membrane photobioreactor (OMPBR) for nutrients removal from synthetic wastewater in continuous mode. At 1.5 days of hydraulic retention time and under continuous illumination, the microalgae removed nitrogen (N) completely at influent NH-N concentrations of 4-16 mg/L, with removal rates of 3.03-12.1 mg/L-day. Phosphorus (P) removal in the OMPBR was through biological assimilation as well as membrane rejection, but PO-P assimilation by microalgae could be improved at higher NH-N concentrations. Microalgae biomass composition was affected by N/P ratio in wastewater, and a higher N/P ratio resulted in higher P accumulation in the biomass. The OMPBR accumulated about 0.35 g/L biomass after 12 days of operation under continuous illumination. However, OMPBR operation under 12 h light/12 h dark cycle lowered biomass productivity by 60%, which resulted in 20% decrease in NH-N removal and nearly threefold increase in PO-P accumulation in the OMPBR. Prolonged dark phase also affected carbohydrate accumulation in biomass, although its effects on lipid and protein accumulation were negligible. The microalgae also exhibited high tendency to aggregate and settle, which could be attributed to reduction in cell surface charge and enrichment of soluble algal products in the OMPBR. Due to a relatively shorter operating period, membrane biofouling and salt accumulation did not influence the permeate flux significantly. These results improve the understanding of the effects of N/P ratio and light/dark cycle on biomass accumulation and nutrients removal in the OMPBR.
格氏乳杆菌在渗透膜光生物反应器（OMPBR）中进行培养，以连续模式从合成废水中去除营养物。在水力停留时间为 1.5 天且连续光照的条件下，微藻在进水 NH-N 浓度为 4-16mg/L 的情况下完全去除氮（N），去除率为 3.03-12.1mg/L-day。OMPBR 中的磷（P）去除是通过生物吸收和膜排斥，但在较高的 NH-N 浓度下，微藻对 PO-P 的吸收可以得到改善。微藻生物量的组成受到废水中 N/P 比的影响，较高的 N/P 比导致生物量中积累更多的 P。在连续光照下运行 12 天后，OMPBR 积累了约 0.35g/L 的生物量。然而，OMPBR 在 12 小时光照/12 小时黑暗循环下运行会降低生物量生产力 60%，导致 NH-N 去除率降低 20%，PO-P 在 OMPBR 中的积累增加近三倍。延长黑暗阶段也会影响生物量中碳水化合物的积累，尽管其对脂质和蛋白质积累的影响可以忽略不计。微藻还表现出强烈的聚集和沉降趋势，这可能归因于细胞表面电荷减少和可溶性藻类产物在 OMPBR 中的富集。由于运行时间相对较短，膜污染和盐积累对渗透通量没有显著影响。这些结果提高了对 N/P 比和光/暗循环对 OMPBR 中生物量积累和养分去除影响的理解。
