Department of Environmental Engineering, The University of Seoul, 163 Seoulsiripdae-ro, Dongdaemun-gu, Seoul 02504, the Republic of Korea.
Department of Environmental Engineering, The University of Seoul, 163 Seoulsiripdae-ro, Dongdaemun-gu, Seoul 02504, the Republic of Korea.
Ecotoxicol Environ Saf. 2024 Sep 15;283:116820. doi: 10.1016/j.ecoenv.2024.116820. Epub 2024 Aug 1.
Wastewater treatment plants (WWTPs) can benefit from utilizing digital technologies to reduce greenhouse gas (GHG) emissions and to comply with effluent quality standards. In this study, the GHG emissions and electricity consumption of a WWTP were evaluated via computer simulation by varying the dissolved oxygen (DO), mixed liquor recirculation (MLR), and return activated sludge (RAS) parameters. Three different measures, namely, effluent water quality, GHG emissions, and energy consumption, were combined as water-energy-carbon coupling index (WECCI) to compare the effects of the parameters on WWTPs, and the optimal operating condition was determined. The initial conditions of the A2O process were set to 4.0 mg/L of DO, 100 % MLR, and 90.7 % RAS. Eighty scenarios with various DO, MLR, and RAS were simulated under steady-state condition to optimize the biological treatment process. The optimal operating conditions were found to be 1.5 mg/L of DO, 190 % MLR, and 90.9 % RAS, which had the highest WECCI of 2.40 when compared to the WECCI of the initial condition (1.07). This optimal condition simultaneously reduced GHG emissions by 1348 kg CO-eq/d and energy consumption by 11.64 MWh/d. This implies that controlling DO, MLR, and RAS through sensors, valves, and pumps offers a promising approach to operating WWTPs with reduced electricity consumption and GHG emissions while attaining effluent quality standards. Additionally, the nitrous oxide stripping rate exhibited linear relationships with the effluent total ammonia and nitrite concentrations in the aerobic reactor, suggesting that monitoring dissolved nitrogen compounds in the effluent and reactor could be a viable strategy to control MLR and DO in the biological reactor. The digital-based assessment and optimization tools developed in this study are expected to hold promise for application in broader environmental management efforts.
污水处理厂（WWTP）可以受益于利用数字技术来减少温室气体（GHG）排放并符合废水质量标准。在这项研究中，通过改变溶解氧（DO）、混合液回流（MLR）和回流活性污泥（RAS）参数，通过计算机模拟评估了 WWTP 的 GHG 排放和电力消耗。将三种不同的措施，即出水水质、GHG 排放和能源消耗，组合为水-能源-碳耦合指数（WECCI），以比较参数对 WWTP 的影响，并确定最佳运行条件。将 A2O 工艺的初始条件设置为 4.0 mg/L 的 DO、100%的 MLR 和 90.7%的 RAS。在稳态条件下模拟了 80 种具有不同 DO、MLR 和 RAS 的情景，以优化生物处理过程。最佳运行条件被发现为 1.5 mg/L 的 DO、190%的 MLR 和 90.9%的 RAS，与初始条件（1.07）相比，WECCI 最高可达 2.40。这种最佳条件同时减少了 1348 kg CO-eq/d 的 GHG 排放和 11.64 MWh/d 的能源消耗。这意味着通过传感器、阀门和泵控制 DO、MLR 和 RAS 提供了一种有前途的方法，可以在达到废水质量标准的同时，减少 WWTP 的电力消耗和 GHG 排放。此外，好氧反应器中硝态氮和亚硝态氮浓度与总氨氮呈线性关系，表明监测出水中溶解态氮化合物和反应器中的溶解态氮化合物可能是控制生物反应器中 MLR 和 DO 的可行策略。本研究中开发的基于数字的评估和优化工具有望在更广泛的环境管理工作中得到应用。
