| 摘要 |
PROBLEM TO BE SOLVED: To provide an improved technique with which a water content of produced dewatered sludge is reduced from around 80% according to a conventional technique to 70% or less, or to around 60% in a suitable case, in performing an MAP method to recover phosphoric acid from human waste and septic tank sludge.SOLUTION: Following steps are performed: A) an undiluted solution composed of human waste and/or septic tank sludge is roughly crushed and finely crushed; B) the undiluted solution after fine crushing is passed to a coagulating sedimentation step using at least three tanks, and in the first tank pH adjustment is performed; C) in the second tank, coagulating sedimentation is started by adding an organic coagulant to the liquid and stirring the liquid; D) the coagulating sedimentation is completed in the third tank and subsequently; E) the liquid including the coagulated sediment is sent to a concentrator and is subjected to solid liquid separation of the preceding stage, and a liquid component is sent to an MAP reaction column; and F) by sending a solid component to a pressure dehydrator and dehydrating the solid component, dewatered sludge with a water content of 70% or less is obtained. Subsequent steps are performed in accordance with a known MAP method. |
