Regmi Pusker, Bunce Ryder, Miller Mark W, Park Hongkeun, Chandran Kartik, Wett Bernhard, Murthy Sudhir, Bott Charles B
Brown and Caldwell, 1600 Duke Street, Suite 310, Alexandria, Virginia, 22314.
Hazen and Sawyer, P.C.
Biotechnol Bioeng. 2015 Oct;112(10):2060-7. doi: 10.1002/bit.25611. Epub 2015 Jun 30.
This work describes the development of an intermittently aerated pilot-scale process (V = 0.45 m(3) ) operated for optimized efficient nitrogen removal in terms of volume, supplemental carbon and alkalinity requirements. The intermittent aeration pattern was controlled using a strategy based on effluent ammonia concentration set-points. The unique feature of the ammonia-based aeration control was that a fixed dissolved oxygen (DO) set-point was used and the length of the aerobic and anoxic time (anoxic time ≥25% of total cycle time) were changed based on the effluent ammonia concentration. Unlike continuously aerated ammonia-based aeration control strategies, this approach offered control over the aerobic solids retention time (SRT) to deal with fluctuating ammonia loading without solely relying on changes to the total SRT. This approach allowed the system to be operated at a total SRT with a small safety factor. The benefits of operating at an aggressive SRT were reduced hydraulic retention time (HRT) for nitrogen removal. As a result of such an operation, nitrite oxidizing bacteria (NOB) out-selection was also obtained (ammonia oxidizing bacteria [AOB] maximum activity: 400 ± 79 mgN/L/d, NOB maximum activity: 257 ± 133 mgN/L/d, P < 0.001) expanding opportunities for short-cut nitrogen removal. The pilot demonstrated a total inorganic nitrogen (TIN) removal rate of 95 ± 30 mgN/L/d at an influent chemical oxygen demand: ammonia (COD/NH4 (+) -N) ratio of 10.2 ± 2.2 at 25°C within the hydraulic retention time (HRT) of 4 h and within a total SRT of 5-10 days. The TIN removal efficiency up to 91% was observed during the study, while effluent TIN was 9.6 ± 4.4 mgN/L. Therefore, this pilot-scale study demonstrates that application of the proposed on-line aeration control is capable of relatively high nitrogen removal without supplemental carbon and alkalinity addition at a low HRT.
本研究描述了一种间歇曝气中试规模工艺（V = 0.45 m³）的开发，该工艺在体积、补充碳源和碱度需求方面进行了优化，以实现高效脱氮。间歇曝气模式采用基于出水氨氮浓度设定点的策略进行控制。基于氨氮的曝气控制的独特之处在于使用固定的溶解氧（DO）设定点，并根据出水氨氮浓度改变好氧和缺氧时间的长度（缺氧时间≥总循环时间的25%）。与连续曝气的基于氨氮的曝气控制策略不同，这种方法可以控制好氧固体停留时间（SRT），以应对波动的氨氮负荷，而不仅仅依赖于总SRT的变化。这种方法允许系统在具有小安全系数的总SRT下运行。在激进的SRT下运行的好处是减少了脱氮的水力停留时间（HRT）。由于这种运行方式，还实现了亚硝酸氧化细菌（NOB）的淘汰（氨氧化细菌[AOB]最大活性：400±79 mgN/L/d，NOB最大活性：257±133 mgN/L/d，P < 0.001），为短程脱氮提供了更多机会。该中试在25°C下，进水化学需氧量：氨氮（COD/NH4(+) -N）比为10.2±2.2，水力停留时间（HRT）为4小时，总SRT为5 - 10天的条件下，总无机氮（TIN）去除率为95±30 mgN/L/d。在研究期间观察到TIN去除效率高达91%，而出水TIN为9.6±4.4 mgN/L。因此，这项中试规模研究表明，应用所提出的在线曝气控制能够在低HRT下，无需添加补充碳源和碱度，实现较高的氮去除率。
