The invention relates to a method and device for realizing the lasting and stable accumulation of
nitrite nitrogen under a low-temperature condition. The lasting and stable accumulation of the
nitrite nitrogen is completed in two stages of biological aerated filter systems. The method comprises the following steps: step a. starting a first-stage biological aerated filter and a secondary-stage biological aerated filter, cleaning a
filter material, soaking, forming a
biofilm, commissioning and operating; b. preparing testing
wastewater, and maintaining
water temperature at 6 to 10 DEG C; c. enabling
wastewater to flow out from a head tank and enter the first-stage biological aerated filter from below; and d. enabling yielding water of the first-stage biological aerated filter to enter the secondary-stage biological aerated filter from bottom to top in the same way. The
nitration types of the two stages of biological aerated filter are
nitrous acid-type
nitration, the stable accumulation of NO2--N in the yielding water is shown, the accumulation rate is 63.2% to 79.8%, and the accumulation time is up to 30 to 35 days. The method has the advantages that the
biofilm process adopting the two stages of biological aerated filters can be used for solving the problems of
high energy consumption at a high temperature (30 to 40 DEG C), and
sludge bulking under a low DO (Dissolved
Oxygen) condition, and the effective removal of organic matters in
wastewater with a low C / N ratio (less than 3) and the lasting and stable accumulation of NO2--N are realized.