Civil and Environmental Engineering Department, Virginia Tech, Blacksburg, Virginia.
Hampton Roads Sanitation District, Virginia Beach, Virginia.
Water Environ Res. 2020 Nov;92(11):1999-2014. doi: 10.1002/wer.1359. Epub 2020 Jun 8.
A pilot scale process was operated with A-stage effluent (ASE) and primary clarifier effluent (PCE) in MLE, all tanks aerated, A/O, and A2O configurations. Continuous DO control at high DO (2 mg/L), low DO (0.1-0.3 mg/L), ammonia-based aeration control (ABAC), and ammonia versus NO (AvN) control (both continuous and intermittent operation) were compared on the basis of total inorganic nitrogen (TIN) removal, and simultaneous nitrification-denitrification (SND). The highly loaded adsorption/bio-oxidation (A/B) process configuration (4 hr HRT) with intermittent aeration was capable of achieving a maximum TIN removal of 80%, while the A2O process with PCE feed, an 11 hr HRT, and 0.2-0.3 mg/L DO continuous aeration achieved a maximum of 88% TIN removal. ABAC and AvN control did not always result in DO setpoints low enough to achieve SND, and even if setpoints were low enough to achieve SND that did not always result in increased overall TIN removal over continuous DO control of 2 mg/L. While there are other benefits to transitioning to sensor driven aeration control strategies such as ABAC and AvN, increased TIN removal during continuous aeration is not guaranteed. Results suggest that although low DO is a prerequisite for SND, carbon availability for denitrification in the aerobic zone is more likely to be the limiting factor once low DO conditions are met. PRACTITIONER POINTS: Intermittent aeration control results in higher TIN removal than continuous aeration at the same total SRT Continuous aeration AvN control is not likely to result in more TIN removal than continuous aeration ABAC for a given COD and nitrogen load Configurations that are designed to maximize predenitrification (e.g., MLE and A2O) are less likely to achieve increased SND in the aerobic zone from low DO operation than configurations that are not (e.g., A/O).
采用 A 段出水（ASE）和初沉池出水（PCE）在 MLE 中进行中试规模试验，所有池均进行曝气，采用 A/O 和 A2O 两种配置。高 DO（2mg/L）、低 DO（0.1-0.3mg/L）、氨基曝气控制（ABAC）和氨与硝酸盐（AvN）控制（连续和间歇操作）连续 DO 控制在总无机氮（TIN）去除和同时硝化反硝化（SND）方面进行了比较。高负荷吸附/生物氧化（A/B）工艺（4 小时 HRT）采用间歇曝气，最大 TIN 去除率可达 80%，而采用 PCE 进料、11 小时 HRT 和 0.2-0.3mg/L DO 连续曝气的 A2O 工艺，最大 TIN 去除率可达 88%。ABAC 和 AvN 控制并不总是导致 DO 设定值足够低以实现 SND，即使设定值足够低以实现 SND，但并不总是导致与连续 DO 控制 2mg/L 相比，总 TIN 去除率增加。虽然向基于传感器的曝气控制策略（如 ABAC 和 AvN）的过渡有其他好处，但连续曝气期间 TIN 去除率不一定会增加。结果表明，虽然低 DO 是 SND 的前提条件，但一旦满足低 DO 条件，好氧区反硝化的碳可用性更可能成为限制因素。从业者要点：在相同总 SRT 下，间歇曝气控制比连续曝气控制可实现更高的 TIN 去除率连续曝气 AvN 控制不太可能比连续曝气控制导致更多的 TIN 去除率对于给定的 COD 和氮负荷，设计用于最大限度地进行预反硝化的配置（例如 MLE 和 A2O）比不进行预反硝化的配置（例如 A/O）从低 DO 操作中在好氧区实现更多的 SND 的可能性更小。
