Direct-flow biological nitrogen removal sewage treatment method

Abstract

The invention relates to a direct-flow biological nitrogen removal sewage treatment method, and belongs to the field of sewage treatment. The full flow of sewage at an NH3-N concentration of less than 60mg / l flows from a first-stage aerobic pond at a beginning end to an anaerobic pond sequentially, then flows into a second-stage aerobic pond at a terminating end, and is discharged without refluxing. In the first-stage aerobic pond, the dissolved oxygen concentration is more than 5mg / l, and the BOD5 removal rate is less than 50 percent. A biological mass is put into the anaerobic pond, wherein the biological mass consists of a shell and an inner core; the shell is a ball with the porosity of 90 to 94 percent consisting of 10 to 12 pieces of arc plastic sheets; the inner core in the center of the ball is an aldehyde fiber ball; the porosity expands and increases from the inner core in the center of the ball to the outside gradually; and the volume of the put biological mass is 50 to 70 percent of the effective capacity of the anaerobic pond. By improving an A20 process flow and combining with the application of a three-phase biological mass, the method achieves the dynamic balance of overall amount of aerobic bacteria, facultative bacteria and anaerobic bacteria, shortens the time difference between the nitrification and the denitrification of ammonium nitrogen and between the anaerobic release and the aerobic release of phosphorus, stably improves the nitrogen removal efficiency to above 90 percent, and can save the energy consumption by 0.1 to 0.2kwh / m3 and the operating cost by 0.07 to 0.12 yuan / m3.

Description

technical field

[0001] The invention belongs to the field of sewage treatment and relates to an improved type A 2 The wastewater treatment method of the O process, in particular, refers to a once-through biological denitrification wastewater treatment method. Background technique

[0002] Traditional biological denitrification process (A 2 O process), the anoxic pool is set in front of the aerobic pool, that is: anoxic pool → aerobic pool, and then flows back from the aerobic pool to the anoxic pool, and the dissolved oxygen in the anoxic pool mainly depends on the backflow from the aerobic pool provided in the liquid. Since the ammonia nitrogen in sewage is difficult to be directly utilized by aerobic organisms in large quantities, only part of the ammonia nitrogen is utilized by biological metabolism and becomes a cell component. Therefore, the removal of ammonia nitrogen is mainly converted into nitrate nitrogen through the nitrification of aerobic bacteria in the aero...