Zhang Xiaoyu, Wang Xiaoling, Feng Weihao, Li Xueqi, Lu Hai
Key Laboratory of Songliao Aquatic Environment, Ministry of Education, Jilin Jianzhu University, Changchun City 130118, Jilin Province, The People's Republic of China.
School of Municipal and Environmental Engineering, Jilin Jianzhu University, Changchun City 113118, Jilin Province, The People's Republic of China.
ACS Omega. 2020 Feb 28;5(9):4576-4587. doi: 10.1021/acsomega.9b04016. eCollection 2020 Mar 10.
This study aimed to reveal the flow and distribution lows of chemical oxygen demand (COD) and nitrate-nitrogen under different main anoxic stage oxidation-reduction potential (ORP) conditions based on the analysis of material balance in each reaction stage of the modified university of cape town (MUCT) process, combined with the biochemical reaction principles of activated sludge. The rule of the carbon source saving effect was also clarified. The study adopted the programmable logic controller automatic control system and the feedback control structure using the inner circulation flow of nitrate as the controlled variable. The ORP setting values of control parameters were -140, -125, -110, -95, -70, and -60 mV, respectively. The results showed that when the ORP setting value was -95 mV, COD distribution ratios of phosphorus-accumulating bacteria reached the highest in the anaerobic stage and preanoxic stage, with the values of 51.74 and 7.70%, respectively. The COD was distributed between heterotrophic bacteria and denitrifying bacteria in the main anoxic stage, and the distribution ratios were 4.40 and 7.19%, respectively, when the ORP setting value was -95 mV. The study also showed the distribution of nitrate-nitrogen between denitrifying bacteria and denitrifying phosphorus-accumulating bacteria in the main anoxic stage, and when ORP increased from -140 to -60 mV, the distribution ratios of denitrifying phosphate-accumulating bacteria increased from 76.46 to 86.32%. When there was no denitrification and phosphorus absorption, the acetic acid dosage increased from 20.33 g/d at -140 mV to 24.76 g/d at -95 mV, and the carbon source saving rate increased from 23.19 to 26.56% under similar conditions. Therefore, in the MUCT process, the regulation of ORP changed the material flow direction and mass quality distribution of COD and nitrate nitrogen. When ORP set value was -95 mV, COD and nitrate-nitrogen got the best distribution and the carbon source saving effect was the most significant.
本研究旨在基于对改良型开普敦大学（MUCT）工艺各反应阶段物料平衡的分析，并结合活性污泥的生化反应原理，揭示不同主缺氧阶段氧化还原电位（ORP）条件下化学需氧量（COD）和硝态氮的流动及分布规律。同时阐明碳源节约效果的规律。本研究采用可编程逻辑控制器自动控制系统以及以硝态氮内循环流量为控制变量的反馈控制结构。控制参数的ORP设定值分别为-140、-125、-110、-95、-70和-60 mV。结果表明，当ORP设定值为-95 mV时，聚磷菌在厌氧阶段和缺氧前段的COD分配率达到最高，分别为51.74%和7.70%。在主缺氧阶段，COD在异养菌和反硝化菌之间分配，当ORP设定值为-95 mV时，分配率分别为4.40%和7.19%。研究还表明了主缺氧阶段硝态氮在反硝化菌和反硝化聚磷菌之间的分布情况，当ORP从-140 mV增加到-60 mV时，反硝化聚磷菌的分配率从76.46%增加到86.32%。在无反硝化吸磷时，乙酸投加量从-140 mV时的20.33 g/d增加到-95 mV时的24.76 g/d，在相似条件下碳源节约率从23.19%增加到26.56%。因此，在MUCT工艺中，ORP的调节改变了COD和硝态氮的物质流向及质量分布。当ORP设定值为-95 mV时，COD和硝态氮得到最佳分布，碳源节约效果最为显著。
