The feasibility of converting full nitritation to partial nitritation/anammox (PN/A) at ambient temperature (20 °C) was investigated in a continuous granular reactor. The process was conducted without anammox bacteria inoculation for the treatment of 70 mg L⁻¹ of low-strength ammonium nitrogen wastewater. Following the stepwise increase of the nitrogen loading rate from 0.84 to 1.30 kg N m⁻³ d⁻¹ in 320 days of operation, the removal efficiency of total inorganic nitrogen (TIN) exceeded 80% under oxygen-limiting conditions. The mature PN/A granules, which had a compact structure and abundant biomass, exhibited a specific TIN removal rate of 0.11 g N g⁻¹ VSS d⁻¹ and a settling velocity of 70.2 m h⁻¹. This was comparable with that obtained at above 30 °C in previous reports. High-throughput pyrosequencing results revealed that the co-enrichment of aerobic and anaerobic ammonium-oxidizing bacteria identified as genera Nitrosomonas and Candidatus Kuenenia, which prompted a hybrid competition for oxygen and nitrite with nitrite-oxidizing bacteria (NOB). However, the overgrowth of novel NOB Candidatus Nitrotoga adapted to low temperatures and low nitrite concentration could potentially deteriorate the one-stage PN/A process by exhausting residual bulk ammonium under long-term excessive aeration.

在连续颗粒反应器中研究了在环境温度（20°C）下将完全硝化转化为部分硝化/厌氧氨（PN / A）的可行性。在没有接种厌氧菌细菌的情况下进行该工艺，以处理70 mg L ^-1的低强度氨氮废水。在运行320天后，氮的负载率从0.84逐步增加到1.30 kg N m ^-3  d ^-1，在限氧条件下，总无机氮（TIN）的去除效率超过80％。结构紧凑且生物量丰富的成熟PN / A颗粒，其TIN去除率为0.11 g N g ^-1 VSS d ^-1，沉降速度为70.2 m h^-1。这与以前的报道在30°C以上获得的结果相当。高通量焦磷酸测序结果表明，认定为属好氧和厌氧氨氧化细菌的共同富集亚硝化和暂定Kuenenia，这促使氧气和亚硝酸盐亚硝酸盐氧化细菌（NOB）的混合比赛。然而，新的NOB的过度生长暂定Nitrotoga适于低温和低浓度的亚硝酸盐通过在长期过量曝气排出剩余散装铵可能恶化一个级PN / A过程。