人工湿地-EAS系统在污泥厌氧消化液脱氮中的应用

Application of constructed wetlands-EAS system to the nitrogen removal of sludge anaerobic digestive solution

采用多级垂直流人工湿地(MVF-CWs)处理城市污水处理厂剩余污泥厌氧消化液(ES-DW),以潮汐流方式运行强化硝化,以剩余活性污泥(EAS)为碳源强化反硝化,研究NH_4^+-N和TN的去除特征。结果表明:MVF-CWs系统中,NH_4^+-N平均去除率为(99.02±0.92)%,NH_4^+-N去除负荷为429.85 g/(m^2·d);TN平均去除率为(61.10±10.06)%,TN去除负荷为162.65 g/(m^2·d)。利用剩余活性污泥胞内碳源对人工湿地出水强化反硝化,当EAS与人工湿地出水的体积比为4∶1时,TN平均质量浓度由(79.87±27.02)mg/L降为(19.96±0.91)mg/L,平均反硝化速率为(1.47±0.58)g/(m^3·h)。该工艺条件下,可将城市污水处理厂剩余污泥厌氧消化液回流引起的氮循环累积量降低97.46%。

A lab-scale multi-step vertical flow constructed wetlands（MVF-CWs）has been applied to the treatment of the excess sludge digesting solution（ES-DW）in a wastewater treatment plant.The removing characteristics of NH4^＋-N and TN are researched,using tidal-flow mode for the enhanced nitrification,and using excess activated sludge（EAS）as a carbon source for the enhanced denitrification.The results show that in MVF-CWs system,the average NH4^＋-N removing rate is（99.02±0.92）%,NH4^＋-N removing loading 429.85 g/（m^2·d）.Average TN removing rate（61.10±10.06）%,and TN removing loading 162.65 g/（m^2·d）.Excess activated sludge intracellular carbon source is used for carrying out the constructed wetland effluent enhanced denitrification.When the volume ratio of EAS and constructed wetland effluent is 4∶1,TN average mass concentration is decreased from（79.87±27.02）mg/L to（19.96±0.91）mg/L,and average denitrification rate is（1.47±0.58）g/（m^3·h）.Under these technological conditions,97.46% of the nitrogen circulating cumulant caused by excess sludge anaerobic digestive solution in the city wastewater treatment plant can be decreased.