Method for resourceful treatment of phosphorus-containing wastewater

A method for recycling a phosphorus-containing wastewater, comprising the following steps of:

• 1) subjecting the phosphorus-containing wastewater to membrane concentration until organic phosphorus in a membrane concentrate into a solid state to produce a first concentrate comprising solid-state organic phosphorus and a first permeate;
• wherein a system adopted for the membrane concentration comprises at least two stages, each of the at least two stages comprises three to six membrane elements connected in series;
• operating parameters of a first stage are as follows:
• a water recovery rate is controlled at 50% to 60% and an operating pressure is controlled at 50 bar to 70 bar;
• and operating parameters of a second stage are as follows:
• the water recovery rate is controlled at 40% to 50% and the operating pressure is controlled at 65 bar to 100 bar;
• and
• operating under the operating parameters of the first stage and the second stage until the organic phosphorus in the membrane concentrate precipitates in the solid state and suspends in the first concentrate;
• 2) subjecting the first concentrate produced in the step 1) to membrane separation to produce a second concentrate comprising the solid-state organic phosphorus and a second permeate comprising salts, and subjecting the second permeate comprising the salts to evaporative crystallization to produce an industrial salt;
• and
• 3) subjecting the second concentrate comprising the solid-state organic phosphorus to filtration to produce a filtration concentrate comprising the solid-state organic phosphorus and a filtration permeate, and subjecting the filtration concentrate comprising the solid-state organic phosphorus to drying to produce the solid-state organic phosphorus;
• wherein in the step 1), prior to the membrane concentration, the phosphorus-containing wastewater is subjected to temperature reduction or to pH adjustment by acid addition to a range of 2.0 to 2.5.