A novel sulfur-based fiber carrier fixed-bed reactor for nitrate-contaminated wastewater treatment: Performance, operational characteristics and cold-tolerant mechanism

In the view of the serious prejudice of nitrates, sulfur-based autotrophic denitrification filter (SADF) has been widely used for deep nitrate removal from electron-donor-deficient water. However, it faces many challenges like slow start-up, reliance on backwashing, and poor low-temperature tolerance. For these challenges, a novel sulfur-based fiber carrier fixed bed reactor (SFFR) was developed in this study. It was found that SFFR had great film-forming ability and flow field characteristics, which promoted it to obtain superior denitrification performance, and the maximum nitrogen removal rate of 0.53 kg-N/m³/d. Meanwhile, SFFR shows significant cold tolerance, and alleviating the acidification problem of effluent to a certain extent. To sum up, the SFFR possesses the potential to be widely used in real-world wastewater treatment applications, especially as a promising solution for nitrate removal in cold regions. This study can provide an important reference for the improvement of the elemental sulfur autotrophic denitrification process.