Effect of Dissolved Oxygen on Removal of Nitrate in Laboratory Columns Packed with Solid Organic Carbon

Effect of dissolved oxygen (DO) on removal of nitrate from groundwater was studied in laboratory columns packed with solid organic carbon. DO was measured at different height in the column to clarify that there were conditions, aerobic and anoxic, in the column. The paper reactor was not more sensitive than the cotton reactor in the DO effect. the cotton denitrification rate was 0.5181 mgN/(L·h) and the paper denitrification rate was 2.2333 mgN/(L·h) in 0-8 cm of the column with the influent DO 5 mg/L, and the cotton denitrification rate was 5.7823 mg N/(L·h)and the paper denitrification rate was 8.4135 mg N/(L·h) in 0-8cm of the column with the influent DO 1 mg/L. The effect of DO on the rate of denitrification was studied in a column that was maintained at the HRT 9.0h, influent nitrate concentrations 22.6mg N/L in the cotton reactor and influent nitrate concentrations 45.2mg N/L in the paper reactor and DO 0~8 mg/L. The total N removal rate of the two reactors was 100% and had not nitrite.