Abstract: Aiming at the high ammonia-nitrogen concentration, low biodegradability and non-compliance issues of dry-spun acrylic fiber wastewater, the effluent of third-sedimentation tank was taken as experimental substrate to research the feasibility and performance of ANAMMOX bio-filter process for advanced treatment of dry-spun acrylic fiber wastewater. The results indicated that the ANAMMOX bio-filter had a good denitrification ability of dry-spun acrylic fiber wastewater after 130 days domestication, the effluent ammonia-nitrogen concentration decreased from 184.1-205.3 mg/L to 23.4-30.34 mg/L, and the removal efficiency of ammonia-nitrogen reached 83.5%. The removal efficiency of NO₂^--N reached up to 93.6%, the removal of NH₄⁺-N and NO₂^--N efficiencies were close to 1:1 (theoretical value 1:1.32), and the total nitrogen removal load reached 2.36-4.80 kg/(m³/d). However, the effluent concentration of total nitrogen was still as high as 165.9-180.7 mg/L, mainly exiting in the form of refractory organics. In addition, the removal of CODCr with ANAMMOX bio-filter process was confirmed, the removal load reached up to 2.39-2.56 kg/(m³/d), the effluent COD_Cr decreased from 487.9-532.1 mg/L to 188.6-212.3 mg/L, which could meet the requirement of Class II standard of National Discharge Standard for Petrochemical Industry (GB 8978-1996) in China.

Key words: ANAMMOX, acrylic fiber wastewater, bio-filter, nitrogen removal, advanced treatment