HIGH-EFFICIENCY WASTEWATER DENITRIFICATION AND DEPHOSPHORIZATION PROCESS AND SYSTEM

摘要

A wastewater denitrification and dephosphorization process and system. Total nitrogen and total phosphorus in wastewater are decreased to less than or equal to 1 mg/L and 0.2 mg/L, respectively. The process comprises: step a: subjecting wastewater to be treated to front-end treatment so that NH3-N in the wastewater has a concentration of less than 0.2 mg/L; step b: subjecting the wastewater obtained from the step a to anoxic denitrification treatment; and step c: subjecting the wastewater obtained from the step b to aerobic degradation of organics and phosphate removal with chemical precipitation at the same time. According to the process and system, wastewater is first subjected to front-end treatment to achieve a sufficient reduction in the concentration of ammonia nitrogen in the wastewater, i.e., a complete nitrification effect is attained, and thus it is ensured that a complete denitrification effect is attained by the subsequent anoxic denitrification treatment and that the concentration of nitrate nitrogen is substantially reduced; external carbon sources are ceaselessly supplemented during the process of anoxic denitrification, resulting in an increase in denitrification rate; and in the step of aerobic degradation of organics and phosphate removal with chemical precipitation, the redundant carbon sources in the previous step are removed while phosphate removal with chemical precipitation is carried out, so that treatment time is shortened.