Deep Denitrification of the Simulated CoastalSecondary Effluent with High Chloride Ionby Electrolysis

In this study, we proposed electrolysis method to remove TN of the simulated coastal secondary effluent with high chloride ion concentration. TN, nitrate-N, ammonia-N nitrite-N were detected to evaluate the evolution of nitrogen. Under the set conditions, Nitrate-N, ammonia-N removal rate and nitrite-N concentration increased with the rising FRC concentration. The higher the initial nitrate-N, the lower the ammonia-N removal rate and the higher nitrite-N accumulation. The nitrate-N concentration was almost not influenced by ammonia-N, and nitrite-N accumulation was greatly influenced by the ammonia-N and nitrate-N. TN removal rate got up to from 87.6% to 50.0% without the influence of COD. COD could greatly influence the removal of ammonia-N but little for the removal of nitrate-N and nitrite-N accumulation. The TN removal rates reached from 68.0% to 57.2% with the influence of COD. All the TN index met the discharge standard no higher than 15 mg/L. The conversion between nitrate-N and ammonia-N did happen and intermediate product nitrite-N could be produced by nitrate-N and ammonia-N. The application of the electrolysis method on the removal of TN in effluent improved the understanding the TN removal mechanism and proposed a promising and reliable method for practical engineering.