Phosphorus recovery from sewage sludge ashes by chemical extraction: influence of precipitation conditions - The gradual depletion of phosphate rocks reserves leads to a growing importance of several technological solutions emerged for its recovery from sewage sludge. Selective phosphorus acid leaching from sewage sludge ashes followed by chemical precipitation is a feasible option. The present work investigates the potential of nutrient recovery by acid leaching under various process operating conditions at lab-scale on samples of ashes from different treatment plants and from ashes obtained from muffle-furnace incineration of pre-dried sewage sludge samples. Experimental results indicated that acid leaching is an effective alternative for selective phosphorus recovery (phosphorus extraction efficiency between 78 and 92%), while operating conditions for the precipitation are fundamental in determining process efficiency, with increasing precipitation efficiency at increasing pH (reaching a plateau at pH 5).
Phosphorus recovery from sewage sludge ashes by chemical extraction: influence of precipitation conditions
Gaia Boniardi;Enrico Gelmi;Andrea Turolla;Roberto Canziani
2021-01-01
Abstract
Phosphorus recovery from sewage sludge ashes by chemical extraction: influence of precipitation conditions - The gradual depletion of phosphate rocks reserves leads to a growing importance of several technological solutions emerged for its recovery from sewage sludge. Selective phosphorus acid leaching from sewage sludge ashes followed by chemical precipitation is a feasible option. The present work investigates the potential of nutrient recovery by acid leaching under various process operating conditions at lab-scale on samples of ashes from different treatment plants and from ashes obtained from muffle-furnace incineration of pre-dried sewage sludge samples. Experimental results indicated that acid leaching is an effective alternative for selective phosphorus recovery (phosphorus extraction efficiency between 78 and 92%), while operating conditions for the precipitation are fundamental in determining process efficiency, with increasing precipitation efficiency at increasing pH (reaching a plateau at pH 5).| File | Dimensione | Formato | |
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Boniardi et al. - IWA EcoSTP 2021 final.pdf
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