Preliminary trials of in situ ammonia stripping from source segregated domestic food waste digestate using biogas: Effect of temperature and flow rate

Batch experiments to remove ammonia from food waste digestate were set up, and preliminary runs undertaken. These experiments were based on gas stripping in a heated column reactor; the effects of different temperatures (35, 55 and 70 °C) and gas flow rates (0.125, 0.250 and 0.375 L biogas L digestate - 1 min−1) were considered using biogas as the stripping gas. At 35 °C, an increase in the ammonia removal rate by approximately 4.5 times was observed when the flow rate increased from 0.125 to 0.375 L biogas L digestate - 1 min−1. At 55 °C, and flow rates of 0.250 and 0.375 L biogas L digestate - 1 min−1, ammonia removal of 3.46 and 9.38% day−1, respectively, were achieved. The highest values of removal of ammonia were reached at 70 °C: 18.4 and 10.4% day−1, for 0.250 and 0.375 L biogas L digestate - 1 min−1 flow rates, respectively.