The sidestream sludge treatment by free ammonium (FA)/free nitrous acid (FNA) dosing was frequently demonstrated to maintain the nitrite pathway for the partial nitrification (PN) process. Nevertheless, the inhibitory effect of FA and FNA would severely influence polyphosphate accumulating organisms (PAOs), destroying the microbe-based phosphorus (P) removal. Therefore, a strategic evaluation was proposed to successfully achieve biological P removal with a partial nitrification process in a single sludge system by sidestream FA and FNA dosing. Through the long-term operation of 500 days, excellent phosphorus, ammonium and total nitrogen removal performance were achieved at 97.5 ± 2.6 %, 99.1 ± 1.0 % and 75.5 ± 0.4 %, respectively. Stable partial nitrification with a nitrite accumulation ratio (NAR) of 94.1 ± 3.4 was attained. The batch tests also reported the robust aerobic phosphorus uptake based on FA and FNA adapted sludge after exposure of FA and FNA, respectively, suggesting the FA and FNA treatment strategy could potentially offer the opportunity for the selection of PAOs, which synchronously have the tolerance to FA and FNA. Microbial community analysis suggested that Accumulibacter, Tetrasphaera, and Comamonadaceae collectively contributed to the phosphorus removal in this system. Summarily, the proposed work presents a novel and feasible strategy to integrate enhanced biological phosphorus removal (EBPR) and short-cut nitrogen cycling and bring the combined mainstream phosphorus removal and partial nitrification process closer to practical application.

通过添加游离铵 (FA)/游离亚硝酸 (FNA) 进行侧流污泥处理经常被证明可以维持部分硝化 (PN) 过程的亚硝酸盐途径。然而，FA和FNA的抑制作用会严重影响聚磷酸盐积累生物（PAO），破坏微生物对磷（P）的去除作用。因此，提出了一项战略评估，以通过侧流 FA 和 FNA 投加在单一污泥系统中通过部分硝化过程成功实现生物除磷。经过500天的长期运行，除磷、铵和总氮的效果分别达到97.5±2.6%、99.1±1.0%和75.5±0.4%。实现了稳定的部分硝化，亚硝酸盐积累比（NAR）为 94.1 ± 3.4。批量测试还报告了分别暴露 FA 和 FNA 后基于 FA 和 FNA 适应污泥的强劲好氧磷吸收，这表明 FA 和 FNA 处理策略可能为选择 PAO 提供潜在机会，这些 PAO 同时具有耐受性FA 和 FNA。微生物群落分析表明，Accumulibacter、Tetrasphaera和Comamonadaceae共同促进了该系统的除磷。总之，该工作提出了一种新颖且可行的策略，将强化生物除磷（EBPR）和短程氮循环相结合，使主流除磷和部分硝化工艺相结合，更接近实际应用。