METHOD OF RECOVERING URINE-DERIVED NUTRIENT SALTS FROM USED DIAPERS AND THE LIKE

摘要

Provided is a method of recovering urine-derived nutrient salts from used diapers, incontinence pads, and the like. The method according to the present application is for recovering urine-derived nutrient salts from a used absorbent article containing urine, the method comprising: a deactivation step for immersing the used absorbent article in an aqueous solution containing a calcium compound to deactivate a superabsorbent polymer; a separation step for using a sieve to separate a solid-liquid mixture yielded by the deactivation step into a first fraction containing the constituent materials of the absorbent article, and a second fraction containing an aqueous solution containing the calcium compound and nutrient salts, and nutrient-salt-containing sediment that has passed through the sieve; a sedimentation step for producing nutrient-salt-containing sediment using a HAP method; and a concentration step for adjusting the pH of the aqueous solution in contact with the nutrient-salt-containing sediment to within a range of 5.6-7.0, dissolving at least some of a calcium compound other than hydroxyapatite in the sediment, and increasing the hydroxyapatite content of the sediment.