Department of Water and Wastewater Engineering, School of Urban Construction, Wuhan University of Science and Technology, Wuhan 430065, China.
Department of Water and Wastewater Engineering, School of Urban Construction, Wuhan University of Science and Technology, Wuhan 430065, China.
Sci Total Environ. 2023 Jan 15;856(Pt 2):159175. doi: 10.1016/j.scitotenv.2022.159175. Epub 2022 Oct 1.
As an emerging green wastewater treatment technology, the microalgal-bacterial granular sludge (MBGS) process has attracted increasing interest under the current situation of global climate change. However, little information is available for its performance in treating municipal wastewater under outdoor conditions. Thus, this study evaluated the behaviors of MBGS for treating simulated and real municipal wastewater under natural diel conditions. The results showed that a significant accumulation of oxygen bubbles during daily operation led to the auto-floating of the conventional settable MBGS. The removal of organics was relatively stable during day-night cycles, while the removals of total nitrogen and total phosphorus were dependent on the saturated oxygen concentration over 10 mg/L in MBGS system. Furthermore, oxygen bubbles generated by photosynthesis of microalgae (Scenedesmaceae and Cyanobacteria) due to microalgae phototaxis were found to be attached onto the surface of granules, causing the auto-flotation of MBGS. The formation process of the auto-floating oxygenic MBGS was clarified and further analysis suggested that the non-aerated settable MBGS would be able to auto-float at an average outdoor light intensity of 140 μ mol/m/s. Overall, the auto-floating oxygenic MBGS process was demonstrated to be feasible for real municipal wastewater treatment, even under rainy and cloudy days, advancing the knowledge and adding theoretical basis for its further applications.
作为一种新兴的绿色废水处理技术，微藻-细菌颗粒污泥（MBGS）工艺在全球气候变化的当前形势下引起了越来越多的关注。然而，关于其在户外条件下处理城市污水的性能的信息却很少。因此，本研究评估了 MBGS 在自然昼夜条件下处理模拟和实际城市污水的行为。结果表明，日常运行过程中大量氧气气泡的积累导致常规可沉降的 MBGS 自动浮起。在昼夜循环过程中，有机物的去除相对稳定，而总氮和总磷的去除则取决于 MBGS 系统中超过 10 mg/L 的饱和氧浓度。此外，由于微藻趋光性导致的微藻光合作用产生的氧气气泡被发现附着在颗粒表面，导致 MBGS 自动浮起。澄清了含氧 MBGS 自动浮起的形成过程，进一步分析表明，在平均户外光强为 140 μmol/m/s 时，非充气可沉降的 MBGS 将能够自动浮起。总的来说，含氧 MBGS 自动浮起工艺被证明可用于实际城市污水处理，即使在雨天和阴天也是如此，为其进一步应用提供了知识和理论基础。
