Mitigation of nitrous oxide (N2O) emission from swine wastewater treatment in an aerobic bioreactor packed with carbon fibers

Mitigation of nitrous oxide (N2O) emission from swine wastewater treatment was demonstrated in an aerobic bioreactor packed with carbon fibers (CF reactor). The CF reactor had a demonstrated advantage in mitigating N2O emission and avoiding NOx (NO3+NO2) accumulation. The N2O emission factor was 0.0003g N2O-N/gTN-load in the CF bioreactor compared to 0.03gN(2)O-N/gTN-load in an activated sludge reactor (AS reactor). N2O and CH4 emissions from the CF reactor were 42g-CO2 eq/m(3)/day, while those from the AS reactor were 725g-CO2 eq/m(3)/day. The dissolved inorganic nitrogen (DIN) in the CF reactor removed an average of 156mg/L of the NH4-N, and accumulated an average of 14mg/L of the NO3-N. In contrast, the DIN in the AS reactor removed an average 144mg/L of the NH4-N and accumulated an average 183mg/L of the NO3-N. NO2-N was almost undetectable in both reactors.