Pyrite and sulfur-coupled autotrophic denitrification system for efficient nitrate and phosphate removal.

The inefficiency of nitrogen removal in pyrite autotrophic denitrification (PAD) and the low efficiency of PO-P removal in sulfur autotrophic denitrification (SAD) limit their potential for engineering applications. This study examined the use of pyrite and sulfur coupled autotrophic denitrification (PSAD) in batch and column experiments to remove NO-N and PO-P from sewage. The effluent concentration of NO-N was 0.32 ± 0.11 mg/L, with an average Total nitrogen (TN) removal efficiency of 99.14%. The highest PO-P removal efficiency was 100% on day 18. There was a significant correlation between pH and the efficiency of PO-P removal. Thiobacillus, Thiomonas and Thermomonas were found to be dominant at the bacterial genus level in PSAD. Additionally, the abundance of Thermomonas in the PSAD was greater than that observed in the SAD reactor. This result indirectly indicates that the PSAD system has more advantages in reducing NO.