Nitrogen Removal through Heterotrophic Nitrification and Aerobic Denitrification by Heterotrophic Nitrifier of Bacillus sp. LY

Abstract

A set of batch assays was used to assess the characteristics of ammonium oxidation, nitrite and nitrate reduction by heterotrophic nitrifier of <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Bacillus</i> sp. LY. <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Bacillus</i> sp. LY is not only a heterotrophic nitrifier, but is also an aerobic denitrifier, and shows a surprising ability of aerobic nitrification- denitrification for nitrogen removal. C/N 15 and 30degC were the optimal conditions for aerobic nitrogen removal. Maximum removal efficiency of NH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> -N and TN was 100% and 78.9% respectively when the medium initially contained 40 mg/l of NH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> - N at C/N 15. The nitrogen conversion during the process was also analyzed. The production of N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O and N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> confirmed its aerobic nitrogen removal capability. This is important as the potential for single step nitrogen removal in wastewater treatment by heterotrophic nitrification-aerobic denitrification.