Partial Nitrification from Domestic Wastewater by Aeration Control at Ambient Temperature

The objective of this paper was to examine the feasibility of partial nitrification from raw domestic wastewater at ambient temperature by aeration control only. Airflow rate was selected as the sole operational parameter. A 14L sequencing batch reactor was operated at 23℃ for 8 months, with an input of domestic wastewater. There was a prolgrammed decrease of the airflow rate to 28L·h^-1, the corresponding average dissolved oxygen （DO） was 0.32mg·h^-1, and the average nitrite accumulation rate increased to 92.4% in 3 weeks. Subsequently, further increase in the airflow rate to 48L·h^-1 did not destroy the partial nitrification to nitrite, with average DO of 0.60mg·h^-1 and nitrite accumulating rate of 95.6%. The results showed that limited airflow rate to cause oxygen deficiency in the reactor would eventually induce only nitrification to nitrite and not further to nitrate and that this system showed relatively stability at higher airflow rate independent of pH and temperature. About 50% of influent total nitrogen was eliminated coupling with partial nitrification, taking the advantage of low DO during the reaction.

The objective of this paper was to examine the feasibility of partial nitrification from raw domestic wastewater at ambient temperature by aeration control only. Airflow rate was selected as the sole operational pa-rameter. A 14L sequencing batch reactor was operated at 23℃ for 8 months, with an input of domestic wastewater. There was a programmed decrease of the airflow rate to 28L·h-1, the corresponding average dissolved oxygen (DO) was 0.32mg·L-1, and the average nitrite accumulation rate increased to 92.4% in 3 weeks. Subsequently, further in-crease in the airflow rate to 48L·h-1 did not destroy the partial nitrification to nitrite, with average DO of 0.60mg·L-1 and nitrite accumulating rate of 95.6%. The results showed that limited airflow rate to cause oxygen deficiency in the reactor would eventually induce only nitrification to nitrite and not further to nitrate and that this system showed relatively stability at higher airflow rate independent of pH and temperature. About 50% of influent total nitrogen was eliminated coupling with partial nitrification, taking the advantage of low DO during the reaction.