Alkaline Leaching of Phosphate from Sewage Sludge Ash

  • Ken-ichi SonodaEmail author


The alkaline technology has been applied to phosphate (Pi) recovery from sewage sludge ash (SSA) at wastewater treatment plants (WWTP). Pi is extracted from mono-incinerated sewage sludge with NaOH and recovered from the leachate using chemical precipitation with Ca(OH)2. Approximately 30–40% of Pi could be recovered from SSA as calcium Pi while minimizing the leaching of toxic heavy metals at high pH. The recovered P product can be recycled as a fertilizing material for agriculture.


Alkaline leaching Calcium phosphate Sewage sludge ash Phosphate fertilizer 


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© Springer Nature Singapore Pte Ltd. 2019

Authors and Affiliations

  1. 1.Business Strategy DivisionMETAWATER Co.TokyoJapan

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