Abstract: In order to grasp the emission law and standard stability of the main pollutants in the wastewater discharged of mineral processing from a certain enterprise，and provide a scientific basis for the accurate pollution control of the sewage enterprises and the supervision of the ecological environment de⁃ partment according to the evidence，aiming at the problems of large amount of wastewater and complex com⁃ position in the iron ore mining and dressing industry，the monitoring data of the mineral processing circu⁃ lating water discharge of a certain enterprise in 2022—2024 are analyzed，focusing on the evaluation of the emission law of COD，ammonia nitrogen，total phosphorus and total nitrogen and the sensory character⁃ istics of water quality.The results show that the average emission concentrations of COD，ammonia nitrogen and total phosphorus during the monitoring period can meet the requirements of the current emission stan⁃ dards，but there is an intermittent concentration peak of COD index，the highest concentration is 59 mg/L， and its emission stability needs to be strengthened. The emission concentration range of total nitrogen is 0.38～15.00 mg/L，and the overall concentration level is high. The number of samples close to the emis⁃ sion limit accounts for 19.44% of the total samples，and there is a large risk of exceeding the standard.Fur⁃ ther analysis shows that the discharged wastewater shows significant low carbon-nitrogen ratio characteris⁃ tics，and the proportion of samples with C/N value less than 5 is as high as 58.33%. This water quality characteristic seriously restricts the efficiency of traditional biological nitrogen removal process.In addi⁃tion，the wastewater has long been reddish brown and turbid，indicating the presence of a large number of suspended particles.Based on the above results，although some indexes of the discharged wastewater from the enterprise meet the standards，the risk of total nitrogen exceeding the standard is prominent and the po⁃ tential of biological nitrogen removal is limited. It is urgent to carry out accurate traceability of total nitro⁃ gen in wastewater and systematically evaluate the biodegradability of wastewater，so as to provide a solid theoretical basis and data support for the directional optimization of wastewater treatment process and the long-term stable discharge of pollutants.

Key words: beneficiation wastewater, self-monitoring, low carbon nitrogen ratio, traceability analysis