Green Engineering and Sustainability Research Group, Department of Chemical Engineering, Faculty of Engineering and The Built Environment, Durban University of Technology, Durban 4001, South Africa.
Molecules. 2021 Oct 25;26(21):6434. doi: 10.3390/molecules26216434.
Digestate is characterized by high water content, and in the water and wastewater treatment settings, necessitates both large storage capacities and a high cost of disposal. By seeding digestate with four magnetic nanoparticles (MNPs), this study aimed to recover biogas and boost its methane potential anaerobically. This was carried out via biochemical methane potential (BMP) tests with five 1 L bioreactors, with a working volume of 80% and 20% head space. These were operated under anaerobic conditions at a temperature 40 °C for a 30 d incubation period. The SEM/EDX results revealed that the morphological surface area of the digestate with the MNPs increased as compared to its raw state. Comparatively, the degree of degradation of the bioreactors with MNPs resulted in over 75% decontamination (COD, color, and turbidity) as compared to the control system result of 60% without MNPs. The highest biogas production (400 mL/day) and methane yield (100% CH) was attained with 2 g of FeO-TiO MNPs as compared to the control biogas production (350 mL/day) and methane yield (65% CH). Economically, the highest energy balance achieved was estimated as 320.49 ZAR/kWh, or 22.89 USD/kWh in annual energy savings for this same system. These findings demonstrate that digestate seeded with MNPs has great potential to improve decontamination efficiency, biogas production and circular economy in wastewater management.
消化液的特点是含水量高，在水和废水处理环境中，既需要大容量的储存，又需要高成本的处理。本研究通过在消化液中接种四种磁性纳米颗粒（MNPs），旨在回收沼气并提高其甲烷潜力。这是通过 5 个 1L 生物反应器进行生化甲烷潜力（BMP）测试来实现的，工作体积为 80%，顶部空间为 20%。这些反应器在 40°C 的厌氧条件下运行，孵化期为 30 天。SEM/EDX 结果表明，与原始状态相比，接种 MNPs 的消化液的形态表面积增加。相比之下，与不含 MNPs 的对照组 60%的结果相比，MNPs 生物反应器的降解程度超过 75%，达到了 COD、颜色和浊度的净化效果。与对照组的沼气产量（350 毫升/天）和甲烷产率（65% CH）相比，2g 的 FeO-TiO MNPs 产生了最高的沼气产量（400 毫升/天）和甲烷产率（100% CH）。从经济角度来看，估计该系统的最高能量平衡为 320.49 南非兰特/千瓦时，或每年节省 22.89 美元/千瓦时。这些发现表明，接种 MNPs 的消化液具有提高去污效率、沼气产量和废水管理中循环经济的巨大潜力。
