The removal and the recovery of nutrients, namely nitrogen (N) and phosphorus (P) from anaerobically digested and solid-liquid separated manure effluents via struvite precipitation were investigated. Both the liquid and the solid phases of the poultry manure digester effluent were subjected to struvite precipitation experiments. The Mg:N:P molar ratio of 1:1:1 in the liquid phase resulted in an average NH 4 - N removal efficiency of 86.4\%, which increased to 97.4\% by adjusting the Mg:N:P ratio to 1.5:1:1. The acidic phosphorus-dissolution process was applied to the solid phase of the effluent to obtain a phosphorus-enriched solution. Nutrient recovery experiments with NaOH as the buffering reagent were conducted with and without addition of external chemicals (Mg and P sources) to evaluate the influence of the Mg:N:P molar ratio, the Mg:P molar ratio and pH. All the experiments depicted complete PO 4 - P (99.6-100.0\%) and partial NH 4 - N (3.3-65.6\%) recoveries from the phosphorus-enriched solution. \textcopyright 2011 Taylor \& Francis.
|State||Published - 2011|