Study on the effect of Anammox/Fe0 coupling treatment of nitrate wastewater under neutral conditions

School of Municipal and Environmental Engineering, Shenyang Jianzhu University, Shenyang Liaoning 110168, P.R.China;

^* Corresponding author: 415494033@qq.com

Abstract

Batch experiments were conducted to explore the effect of Anammox bacteria on the nitrate reduction efficiency of Fe⁰ under neutral conditions and to analyze the ways of its enhancement. The effects of Fe²⁺ concentration on the activity of Anammox bacteria in the system were investigated by detecting the nitrate content in the system under neutral conditions. The upflow reactor was set to verify the possibility of stable operation of Fe⁰/Anammox system in continuous flow. The results showed that in neutral environment, Anammox bacteria can significantly promote the reduction of nitrate by Fe⁰, and the denitration rate can reach more than 75% under the dual biological and chemical effects. In the continuous flow system of nitrate reduction by Fe⁰/Anammox bacteria, the stable treatment period was about 7 days. Through regular replacement of iron powder, the denitration rate can be maintained at more than 75% for a long time, and the effluent NH_4⁺, NO_2^- concentration is low. The treatment of nitrate wastewater by zero-valent iron as a reducing agent has been widely paid attention, but the treatment effect is seriously affected by pH. Anammox bacteria were added to coupling with Fe⁰ can not only promote each other’s reactivity to adapt to more non-ideal environment, but also reduce secondary pollution, which provides a new idea for the practical application of nitrate wastewater treatment.