Notice of Retraction: The Effects of C/N and Acetic/Propionic Acid Ratio on the Denitrification in Constructed Wetlands

Abstract

The effects of acetic to propionic acid ratio and C/N ratio on the denitrification were investigated. Six constructed wetlands were built with acetic to propionic acid ratio (carbon molar ratio) were 8/1, 4/1, 2/1, 1.5/1, 1/1 and single acetic acid as carbon sources in the influent respectively. The experiments were carried out under C/N ratio 7.5 and 3.0. Result showed that with appropriate amount of the propionic acid adding into acetic acid, the denitrification ability enhanced. And under different C/N ratio conditions the acetic to propionic acid ratio was different for getting the the highest denitrification rate: when C/N=7.5, the highest denitrification rate would appear when the acetic to propionic acid ratio was 4/1, and the denitrification rate was 0.77 mg·L-1·min-1 which was 1.17 times as high as the single acetic acid employed for the carbon source; and when C/N=3, the ratio was 1/1, and the denitrification rate was 0.62 mg-L-1-min-1 which was 1.29 times as high as the one with single acetic acid added. Moreover, under both C/N ratio conditions, the consumption of the acetic acid and propionic acid was contemporary.