低温对亚硝化颗粒污泥系统的影响特性

考察了温度变化对亚硝化颗粒污泥反应器的长期和短期影响特性，结果表明:在进水ρ（NH₄+-N）为（35.8±5.2）mg/L、水力停留时间为2.0 h以及运行温度为7~17℃的条件下，反应器保持着95%的亚硝化率和0.18~0.25 kg/（m3·L）的NH₄+-N去除负荷；反应器中较低的ρ（DO）∶ρ（NH₄+-N）（<0.25）是实现亚硝酸盐氧化细菌（NOB）有效抑制的关键因素；长期低温运行造成颗粒污泥比NH₄+-N氧化速率（SAOR）从（237±14）g/（g·d）下降至（93±11）g/（g·d），但颗粒污泥中氨氧化细菌（AOB）的活化率（实际SAOR与最大SAOR之比）从48%升至约85%。批式实验结果表明，在7.1~28℃的短时温度变化内，亚硝化颗粒污泥NH₄+-N氧化反应的温度系数（θ）和活化能（E_a）分别为1.042~1.063，29.7~41.9 kJ/mol，均显著低于同等条件下絮体污泥的数值，表明颗粒污泥AOB比絮体污泥AOB具有更好的抗温度冲击能力。该研究结果可为基于颗粒污泥的高效城市污水亚硝化技术提供参考。

EFFECTS OF LOW TEMPERATURE ON PARTIAL NITRIFICATION GRANULAR SYSTEM

The long-and short-term effects of temperature change on partial nitrification granules was investigated. The results showed that nitrite accumulation efficiency and ammonium removal loading rates of the granular reactor were stably maintained at above 95% and 0.18~0.25 kg/(m3·L), when treating the influent of (35.8±5.2) mg/L with hydraulic retention time of 2.0 h at 7~17 ℃. The low DO/NH₄+-N ratio (<0.25) caused the efficient nitrite oxidizing bacteria (NOB) repression in the granular reactor. Though the lowering temperature caused the decrease of specific ammonia oxidation rates (SAOR) of partial nitrification granules from (237±14) g/(g·d) (at 17 ℃) to (93±11) g/(g·d) (at 8 ℃), the active AOB ratio (the ratio between actual SAOR and maximal SAOR of granules) increased from 48% to 85%. Batch tests results indicated that the temperature coefficient (θ) and activation energy (E_a) of the ammonia oxidizing bacteria (AOB) living in the granules was around 1.042~1.063, 29.7~41.9 kJ/mol respectively from 7.1 ℃ to 28 ℃, which were lower than that reported in flocculent sludge systems. These results suggested that the AOB living in the granules were less influenced by low temperatures than that living in the flocs. The research could provide practical support for the development of high-rate nitritation technology for municipal wastewater treatment with granular sludge.