Key Laboratory of Water Science and Water Environment Recovery Engineering, Beijing University of Technology, Beijing, 100123, China.
Key Laboratory of Water Science and Water Environment Recovery Engineering, Beijing University of Technology, Beijing, 100123, China.
Chemosphere. 2021 May;270:129464. doi: 10.1016/j.chemosphere.2020.129464. Epub 2020 Dec 28.
A pilot-scale aerobic granular sequencing batch reactor (SBR) with domestic wastewater was operated to evaluate the effects of the low organic loading rate (OLR) due to wet weather flow conditions on simultaneous nitrification, denitrification, and phosphorus removal (SNDPR). As the OLR decreased from 0.85 to 0.43 kg COD m d, the total nitrogen (TN) and total phosphorus (TP) removal efficiencies decreased from 84.0% and 94.1% to 51.3% and 73.8%, respectively, the sludge volume index (SVI) increased from 42.3 to 85.5 mL g, and the average granular size decreased from 1022 to 742 μm; however, no sludge disintegration and biomass loss were observed. The poor nutrient removal efficiencies and settling ability were due to the shrinking anoxic zone and substrate scarcity inside the granules, wherein the activity decay of ammonia-oxidizing bacteria and overgrowth of filamentous bacteria played an important role. Alternating the aeration intensity was effective in enhancing nitrogen removal and sludge settling by improving the anoxic activity in granules and inhibiting the proliferation of filamentous bacteria. Returning 20% of sludge from the end of one anaerobic stage to the beginning of the next anaerobic stage (midway sludge return) was beneficial for phosphorus removal as it improved phosphorus storage by phosphorus-accumulating bacteria. A smaller granular size with stronger stability and better nutrient removal performance was the new steady state of the SNDPR system under wet-weather flow conditions.
采用生活污水启动的序批式好氧颗粒污泥系统（SBR）进行中试研究，考察了低有机负荷（OLR）条件下（雨天进水时）对同步硝化反硝化除磷（SNDPR）的影响。当 OLR 从 0.85kgCOD/(m·d)降低至 0.43kgCOD/(m·d)时，TN 和 TP 的去除效率分别从 84.0%和 94.1%降低至 51.3%和 73.8%，污泥体积指数（SVI）从 42.3mL/g 升高至 85.5mL/g，平均粒径从 1022μm 降低至 742μm；但是没有观察到污泥解体和生物量损失。较差的营养物质去除效率和沉降性能归因于颗粒内部缺氧区的缩小和基质的缺乏，氨氧化细菌的活性衰减和丝状菌的过度生长在此过程中发挥了重要作用。交替曝气强度通过改善颗粒内部的缺氧活性和抑制丝状菌的增殖，有效地提高了脱氮效率和污泥沉降性能。将一个厌氧阶段末端的 20%污泥回流到下一个厌氧阶段的开始（半程污泥回流）有利于除磷，因为这可以通过聚磷菌提高磷的储存。在雨天进水条件下，较小的颗粒粒径、较强的稳定性和更好的营养物质去除性能是 SNDPR 系统的新稳定状态。
