Phosphate Recovery Using Amorphous Calcium Silicate Hydrates

  • K. OkanoEmail author
  • H. Ohtake
  • M. Kunisada
  • H. Takano
  • M. Toda


Amorphous calcium silicate hydrates (A-CSHs) can be chemically synthesized using abundantly available, inexpensive materials such as siliceous shale and calcium hydroxide. A-CSHs can serve as a bifunctional adsorption-aggregation agent for phosphate (Pi) recovery from aqueous solution. A-CSHs can also be prepared by soaking recyclable calcium silicates such as concrete sludge and steelmaking slag in a dilute hydrochloric acid solution. Since A-CSHs show high Pi removability, settleability, and filterability, they have the potential to offer a simple, cost-effective option to the recovery of Pi from Pi-rich waste streams. On-site experiments using a mobile, pilot-scale plant have showed that A-CSHs can recover approximately 80% Pi from a Pi-rich sidestream in a wastewater treatment plant. This chapter describes a simple process for Pi recovery from aqueous solution using A-CSHs as a bifunctional adsorption-aggregation agent.


Amorphous calcium silicate hydrates Bifunctional adsorption-aggregation agent Mobile pilot-scale plant By-product phosphate fertilizer 


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© Springer Nature Singapore Pte Ltd. 2019

Authors and Affiliations

  • K. Okano
    • 1
    Email author
  • H. Ohtake
    • 2
  • M. Kunisada
    • 3
  • H. Takano
    • 4
  • M. Toda
    • 5
  1. 1.Department of Biotechnology, Graduate School of EngineeringOsaka UniversitySuitaJapan
  2. 2.Phosphorus Atlas Research InstituteWaseda UniversityTokyoJapan
  3. 3.Mikuni Pharmaceutical Industrial Co., Ltd.ToyonakaJapan
  4. 4.Research & Development CenterTaiheiyo Cement Co.SakuraJapan
  5. 5.Research & Development LaboratoryOnoda Chemical Industry Co., Ltd.TokyoJapan

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