不同调控策略对CANON工艺快速适应氨氮浓度提升的影响

针对进水氨氮浓度变化会影响CANON颗粒污泥功能微生物间的协同导致系统不稳定的问题,通过接种常温下贮存2个月的自养颗粒污泥,并采用3种调控策略（维持HRT不变,快速提升氨氮浓度(R1);维持HRT不变,逐级提升氨氮浓度(R2);逐级提升进水氨氮浓度同时调整HRT,以125 mg·L⁻¹为进水氨氮增幅(R3)）,分别考察各种调控策略对系统适应275 mg·L⁻¹和400 mg·L^-1氨氮浓度的效能影响,探讨调控策略与污泥性能的关系及游离氨(FA)、溶解氧(DO)的影响。结果表明,污泥性能提升期,负荷变化最为平稳的策略R3率先适应进水氨氮浓度的提升,仅44 d内总氮去除负荷可达到3.5 kg·(m³·d)⁻¹;污泥性能成熟期,快速提升负荷的策略R1可缩短适应时间至25 d,总氮去除率稳定在80%以上,去除负荷达到5.3 kg·(m³·d)⁻¹。FA会影响功能微生物活性,策略R1在污泥性能提升期,FA浓度高达16.6~26.7 mg·L⁻¹,一定程度上抑制了好氧氨氧化菌(AOB)和厌氧氨氧化菌(AMX)的活性,导致系统适应期延长。在污泥适应高氨氮负荷过程中,比氨氧化速率(S_AOR)和比总氮去除速率(S_NRR)逐渐提高,污泥浓度和颗粒粒径逐渐增大。f值(Δ$ {rm{NO}}_3^{-}$-N/ΔTN)可作为DO调节的重要依据,DO与氨氮去除负荷呈良好的正相关性。

Influences of different regulating strategies on the fast adaptation to ammonia nitrogen concentration improvement in CANON process

Fluctuations of ammonia nitrogen concentrations in the influent are related to system instability caused by the synergies among functional microbes in granular sludge of the completely autotrophic nitrogen removal over nitrite (CANON) process. In this study, the autotrophic denitrification granular sludge stored at room temperature for 2 months was used as the inoculum. Three control strategies were adopted: rapidly increasing influent ammonia nitrogen concentration (R1) or stepwise increasing influent ammonia nitrogen concentration (R2) at stable HRT, and gradually increasing influent ammonia nitrogen load while adjusting HRT (R3). At the increase of influent ammonia nitrogen concentration by 125 mg·L−1, the effects of three control strategies on the adaption to ammonia nitrogen concentrations of 275 mg·L−1 and 400 mg·L−1 in the CANON process were studied, as well as the relations between various strategies and sludge properties and the effects of free ammonia (FA) and dissolved oxygen (DO). The results show that the strategy of R3 with a stable variation in sludge loading showed the fastest adaptation to the increase of influent ammonia nitrogen concentration during the period of sludge performance improvement, and the total nitrogen removal loading could reach 3.5 kg·(m3·d)−1 within 44 days. In the mature stage of sludge performance, the strategy R1 with rapidly enhancing the influence loading could shorten the adaptation time to 25 days and the total nitrogen removal loading reached 5.3 kg·(m3·d)−1 at the ammonia nitrogen loading of 6.4 kg·(m3·d)−1, and total nitrogen removal rate reached 80%. FA concentration affected the activity of functional microbial. During the sludge performance improvement period, FA concentration of the strategy R1 was as high as 16.6~26.7 mg·L−1, which inhibited the activity of aerobic ammonia oxidizing bacteria (AOB) and anaerobic ammonium oxidation bacteria (AMX) and prolonged system adaptation to some extent. When the sludge was adapted to high ammonia nitrogen loading, specific ammonia oxidation rate (SAOR) and specific nitrogen removal rate (SNRR) gradually increased, and the sludge concentration and particle size gradually increased. The f-value (Δ$ {rm{NO}}_3^{-}$-N/ΔTN) was used as an important basis for the DO regulation, and a good positive correlation between DO and the ammonia nitrogen removal loading occurred.