CALAGUA - Unidad Mixta UV-UPV, Institut Universitari d'Investigació d'Enginyeria de l'Aigua i Medi Ambient - IIAMA, Universitat Politècnica de València, Camí de Vera s/n, 46022, Valencia, Spain.
CALAGUA - Unidad Mixta UV-UPV, Departament d'Enginyeria Química, Universitat de València, Avinguda de la Universitat s/n, 46100, Burjassot, Valencia, Spain.
Water Res. 2020 Apr 1;172:115518. doi: 10.1016/j.watres.2020.115518. Epub 2020 Jan 21.
Microalgae cultivation has been receiving increasing interest in wastewater remediation due to their ability to assimilate nutrients present in wastewater streams. In this respect, cultivating microalgae in membrane photobioreactors (MPBRs) allows decoupling the solid retention time (SRT) from the hydraulic retention time (HRT), which enables to increase the nutrient load to the photobioreactors (PBRs) while avoiding the wash out of the microalgae biomass. The reduction of the PBR light path from 25 to 10 cm increased the nitrogen and phosphorus recovery rates, microalgae biomass productivity and photosynthetic efficiency by 150, 103, 194 and 67%, respectively.The areal biomass productivity (aBP) also increased when the light path was reduced, reflecting the better use of light in the 10-cm MPBR plant. The capital and operating operational expenditures (CAPEX and OPEX) of the 10-cm MPBR plant were also reduced by 27 and 49%, respectively. Discharge limits were met when the 10-cm MPBR plant was operated at SRTs of 3-4.5 d and HRTs of 1.25-1.5 d. At these SRT/HRT ranges, the process could be operated without a high fouling propensity with gross permeate flux (J) of 15 LMH and specific gas demand (SGD) between 16 and 20 Nm·m, which highlights the potential of membrane filtration in MPBRs. When the continuous operation of the MPBR plant was evaluated, an optical density of 680 nm (OD680) and soluble chemical oxygen demand (sCOD) were found to be good indicators of microalgae cell and algal organic matter (AOM) concentrations, while dissolved oxygen appeared to be directly related to MPBR performance. Nitrite and nitrate (NO) concentration and the soluble chemical oxygen demand:volatile suspended solids ratio (sCOD:VSS) were used as indicators of nitrifying bacteria activity and the stress on the culture, respectively. These parameters were inversely related to nitrogen recovery rates and biomass productivity and could thus help to prevent possible culture deterioration.
微藻培养由于能够同化废水中存在的营养物质，因此在废水修复中受到越来越多的关注。在这方面，在膜光生物反应器 (MPBR) 中培养微藻可以将固体停留时间 (SRT) 与水力停留时间 (HRT) 解耦，从而可以增加营养物质向光生物反应器 (PBR) 的负荷，同时避免微藻生物质的冲洗。将 PBR 的光程从 25cm 减少到 10cm，提高了氮磷回收率、微藻生物量生产力和光合作用效率，分别提高了 150%、103%、194%和 67%。当光程减少时，比表面积生物量生产力 (aBP) 也增加了，反映了在 10cm MPBR 工厂中更好地利用了光。10cm MPBR 工厂的资本和运营支出 (CAPEX 和 OPEX) 也分别减少了 27%和 49%。当 10cm MPBR 工厂在 SRT 为 3-4.5d 和 HRT 为 1.25-1.5d 时，达到了排放标准。在这些 SRT/HRT 范围内，该过程可以在没有高结垢倾向的情况下运行，总渗透通量 (J) 为 15LMH，比需氧量 (SGD) 在 16 到 20Nm·m 之间，这突出了膜过滤在 MPBR 中的潜力。当评估 MPBR 工厂的连续运行时，发现 680nm 光密度 (OD680) 和可溶性化学需氧量 (sCOD) 是微藻细胞和藻类有机物质 (AOM) 浓度的良好指标，而溶解氧似乎与 MPBR 性能直接相关。亚硝酸盐和硝酸盐 (NO) 浓度以及可溶性化学需氧量:挥发性悬浮固体比 (sCOD:VSS) 分别用作硝化细菌活性和培养物应激的指标。这些参数与氮回收率和生物量生产力呈反比，因此有助于防止可能的培养恶化。
