Enhanced Nitrogen Removal of Steel Rolling Wastewater by Constructed Wetland Combined with Sulfur Autotrophic Denitrification

Constructed wetlands (CWs), an ecological treatment technology, is suitable for advanced treatment, but has unsatisfying denitrification performance steel rolling wastewater with low C/N ratio. This study combined sulfur autotrophic (SAD) conventional constructed horizontal subsurface flow to treat wastewater, exploring the feasibility of applying SAD enhance CWs. The reactor consists two sections, one filled manganese sand and gravel (HFC) another ceramic, sulfur, lime (HFSAD). Results showed that HFC had a good on removing turbidity, DO, COD, TP, while average removal efficiency total nitrogen (TN) in was just 25.6%. On this basis, HFSAD could remove 45.6% TN subsequently, whose rate 4–6 times as high HFC. Increasing hydraulic retention time improve contaminants different degrees. analysis microbial community structure, observation results fillers monitored sulfate all provided proofs occurrence SAD. CWs can be applied carbon, which provide reference water saving, recycling iron enterprises.