The invention discloses a method fpr
coupling denitrifying dephosphatation and partial
nitrification, and belongs to the field of municipal
wastewater treatment. Firstly,
raw water enters an (A / A / O)-SBR reactor; carbon pick-up synthesis polyhydroxyalkanoate (PHA) and
phosphorus release reaction at an anaerobic phase are carried out; oxidation-
reduction potential (ORP) is controlled at -30mv to -240mv; dissolved
oxygen (DO) is smaller than or equal to 0.2mg / L, and then nitrifying
reflux liquid containing NO2<-> from N-SBR is injected to carry out anaerobic denitrifying dephosphorization reaction; the ORP is controlled at -90mv to -210mv; the DO is smaller than or equal to 0.2mg / L. The flow of the nitrifying
reflux liquid is adjusted at the stage according to the anaerobic
phosphorus-release condition. The transient
aeration,
nitrogen stripping and aerobic
phosphorus absorption are carried out after complete reaction; the DO is controlled to 2-3mg / L; sediments are stilled; discharged water enters the N-SBR reactor to carry out aerobic
aeration.
Nitration is controlled at a short-range stage through an '
ammonia valley' on a pH curve and an '
ammonia-
nitrogen jump point' on a DO curve in the process; still deposition is carried out after the reaction is ended; a part of supernate is returned and the other part is discharged; the discharged water quantity is equal to the initial water inflow of the
system. The denitrifying dephosphatation principle and the partial
nitrification principle are applied,
energy conservation and consumption reduction are achieved, and the method is applicable to a domestic
wastewater with low C / N ratio, so as to achieve a synchronous and deep
nitrogen and phosphorus removal effect.