Microbial fuel cell enables phosphate recovery from digested sewage sludge as struvite

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• 作者：Fabian Fischer^a ; ^{fabian.fischer@hevs.ch"" rel=""nofollow} ; Christè ; le Bastian^a ; Manuel Happe^a ; Eric Mabillard^b ; Nicolas Schmidt^b
• 关键词：Phosphate ; Recycling ; Digested sewage sludge ; Struvite ; Microbial fuel cell
• 刊名：Bioresource Technology
• 出版年：2011
• 出版时间：May 2011
• 年：2011
• 卷：102
• 期：10
• 页码：5824-5830
• 全文大小：619 K

文摘

Orthophosphate was mobilized from iron phosphate (FePO₄) contained in digested sewage sludge by microbial fuel cell power. FePO₄ was reduced through electrons and protons obtained from metabolic activity of Escherichia coli. The process yielded up to 82 % or 600 mg/l. Optical emission spectroscopy was used for phosphate dosage. ³¹P NMR showed a singlet at δ_p = 3.72 ppm indicating that orthophosphate (H₃PO₄, , and ) was recovered. The phosphate containing supernatant solution was reacted with stoichiometric amounts of MgCl₂ and NH₄OH to precipitate struvite (MgNH₄PO₄·6H₂O). The crystalline fertilizer was analyzed by scanning electron microscopy comprising elemental analysis, revealing a composition accuracy of 90 % and the absence of any toxic metals such as As, Cd, Pb, or Cr. The phosphate extraction is also a means to reduce the volume of digested sewage sludge while increasing the heat of combustion. This study represents a concept for sustainable decentralized phosphate recycling.