Nitrification denitrification via nitrite in a pilot-scale sbr treating the liquid fraction of co-digested piggery/poultry manure and agro-wastes

Nitrogen removal processes from the liquid fraction of digested agro-wastes become more and more important as reduced nitrogen loads can be applied to land due to stringent European regulations. A pilot-scale SBR short-cut nitrogen removal process has been tested for more than 200 days and proved technically feasible in spite of high influent variability. Nitritation rates of up to 0.5 gN/(L d) (MLVSS = 7 gSS/L, DO = 0.8 mg/L, pH = 8.4) and NO2/NOx > 80% have seen achieved as well as 95% denitrification efficiencies. N2O emissions was highly dependent on denitrification at limiting C/N ratios.