Processing method for reducing phosphorus content in sewage

The invention relates to a processing method for reducing the phosphorus content in sewage. The processing method comprises the following steps: adding lime milk with the concentration of 8-12 wt% to sewage required to be processed, and adjusting pH of the sewage to 8.0-8.5; stirring and adding a silicon-based flocculant; introducing the lime milk and carbon dioxide to the sewage simultaneously, wherein the addition of the lime milk is 0.1-0.5% of the volume of the sewage, stirring, adjusting pH to be stabilized to 8.0-8.5 through ventilation volume of carbon dioxide, after adding the lime milk, continuously introducing carbon dioxide, so that the pH of the sewage is reduced to 7.5-7.7; finally adding polyacrylamide with the concentration of 0.1%; then separating water from mud juice. According to the processing method, a plurality of pollutants are subjected to flocculation cohesion through an aggregation having various functional groups. The processing method is good in phosphorous removal effect, low in cost, pollution-free, and wide in source of raw materials and can be widely applied to treatment of municipal sewage and phosphorous removal treatment of industrial and sanitary wastewater.