Abstract: Dairy wastewater usually needs chemical dephosphorization to meet the requirements of total phosphorus discharge. In the actual operation process,there are problems such as large sludge production,high consumption of dephosphorization agent and unstable total phosphorus in drainage. By circulating the dephosphorized sludge into the aerobic system,it has the advantages of simple operation,reduced reagent consumption,reduced sludge volume,stable total phosphorus drainage,and no impact on the operation of the aerobic system. The operation cost and discharge stability have been significantly promoted and improved,which is worth promoting.

Key words: dephosphorizing agent, sludge decline, reagent reduction, stable operation