| CPC C02F 3/305 (2013.01) [C02F 3/08 (2013.01); C02F 3/302 (2013.01); C02F 2101/16 (2013.01); C02F 2101/30 (2013.01); C02F 2101/38 (2013.01); C02F 2209/15 (2013.01); C02F 2301/043 (2013.01); C02F 2301/08 (2013.01); C02F 2301/10 (2013.01)] | 8 Claims |
|
1. A biological nitrogen removal method based on multistage feeding and multistage anoxic/aerobic (A/O) chambers for wastewater treatment at a low temperature, adopting a constant flow operation mode, the method comprising:
enabling influent subjected to primary treatment to respectively enter a first-stage A/O reaction unit and a second-stage A/O reaction unit from two position points;
refluxing an effluent from an outlet end of the first-stage A/O reaction unit to an influent end of the first-stage A/O reaction unit;
refluxing an effluent from an outlet end of the second-stage A/O reaction unit to an influent end of the second-stage A/O reaction unit; and
clarifying, separating and discharging an effluent from an outlet end of a third-stage A/O reaction unit, wherein
the low temperature is no more than 15° C.,
the first-stage A/O reaction unit comprises four sequentially connected biofilm reactors, including: an A1 anoxic influent carbon source denitrification reactor an A2 anoxic influent carbon source denitrification reactor an O3 aerobic organic matter degradation reactor; and an O4 aerobic nitrification reactor,
the second-stage A/O reaction unit comprises four sequentially connected biofilm reactors, including: an A5 anoxic influent carbon source denitrification reactor an A6 anoxic influent carbon source denitrification reactor an O7 aerobic organic matter degradation reactor; and an O8 aerobic nitrification reactor,
the third-stage A/O reaction unit comprises two sequentially connected biofilm reactors, including: an A9 anoxic external carbon source denitrification reactor; and an O10 aerobic residual organic matter degradation and nitrification reactor, a carbon source adding device being disposed in the A9 anoxic external carbon source denitrification reactor,
suspended biofilm carriers are disposed in all of the reactors,
in the anoxic reactors of the first-stage A/O reaction unit and the A/O second-stage reaction unit, facultative heterotrophic biofilms attached to surfaces of the suspended biofilm carriers remove nitrate nitrogen through influent carbon source denitrification,
in the first-stage A/O reaction unit and the second-stage A/O reaction unit, in the aerobic reactors for organic matter degradation, aerobic heterotrophic biofilms attached to surfaces of the suspended biofilm carriers remove organic matters in wastewater,
in the aerobic reactors for nitrification, aerobic autotrophic biofilms attached to surfaces of the suspended biofilm carriers remove organic nitrogen and ammonia nitrogen in wastewater, and
in the third-stage A/O reaction unit, nitrate nitrogen is removed by adding an external carbon source according to a total nitrogen discharge criterion for finally treated outlet water, so that the organic matters, total nitrogen and ammonia nitrogen of the finally treated outlet water reach the water quality indexes.
|