低温下逆流充氧强化去除地表原水中的氨氮和锰

利用中试滤柱系统,在低温条件下采用滤柱底部逆流充氧措施强化铁锰复合氧化膜滤料去除地表原水中的氨氮和锰,考察了充氧强度、运行参数(氨氮、锰浓度和滤速)等因素的影响,并对充氧前后氧化膜的微观特征(形态、组成、晶体结构)进行了分析。结果表明,在水温为8℃的条件下,当进水氨氮和锰浓度分别为2.0、3.0 mg/L时,逆流充氧后,完全去除锰所需的滤层厚度由80cm减少至60 cm,出水氨氮浓度由0.7 mg/L降至0,且随着充氧强度的增加,去除效率逐渐升高;当充氧强度为0.6 mL/(cm²·min)、滤速为7.0 m/h时,对氨氮和锰的去除效果最佳。此外,微观表征分析结果表明,逆流充氧使滤料表面形态在水力作用下发生了改变,但并未改变铁锰复合氧化膜的成分和晶体结构。因此,逆流充氧可显著提高低温条件下铁锰复合氧化膜滤料对地表原水中氨氮和锰的去除效率。

Enhanced Removal of Ammonia Nitrogen and Manganese from Surface Raw Water by Countercurrent Oxygenation at Low Temperature

Ammonia nitrogen and manganese in surface raw water were removed byiron-manganese composite oxide film filter material enhanced by countercurrent oxygenation at the bottomof a pilot-scale filter column test system at low temperature.The influences of oxygenation intensity andoperational parameters(ammonia nitrogen concentration,manganese concentration and filtration velocity)were investigated,and the microscopic characteristics(morphology,composition and crystal structure)ofthe oxide film before and after oxygenation were analyzed.When water temperature was 8℃,and theconcentrations of ammonia nitrogen and manganese in influent were 2.0 mg/L and 3.0 mg/L,the thicknessof the filter layer required for complete removal of manganese was reduced from 80 cm to 60 cm,and theammonia nitrogen concentration in the effluent decreased from 0.7 mg/L to 0 mg/L after countercurrentoxygenation.In addition,higher removal efficiency of ammonia nitrogen was obtained with the increase ofoxygenation intensity.When the oxygenation intensity was 0.6 m L/(cm²·min)and the filtration velocitywas 7.0 m/h,the removal efficiency of ammonia nitrogen and manganese was the largest.In addition,microscopic characterization analysis results showed that countercurrent oxygenation changed the surfacemorphology of the filter material under hydraulic action.However,the countercurrent oxygenation did notchange the composition and crystal structure of the iron-manganese composite oxide film.Therefore,countercurrent oxygenation can significantly improve the removal efficiency of ammonia nitrogen andmanganese in surface raw water by iron-manganese composite oxide film filter material at low temperature.