Sewage treatment method based on PN/A coupled biochar SPD process

The invention discloses a sewage treatment method based on a PN/A coupled biochar SPD process, which comprises the following steps: after sewage enters a front-end SPD fixed bed from a front-end water inlet/outlet channel, removing organic matters in the sewage under the adsorption action of biochar bricks in the front-end SPD fixed bed; after the sewage enters a PN/A reactor from a front-end up-flow/down-flow tank, denitrifying the sewage by nitrosation sludge and full-autotrophic nitrogen removal granular sludge which are inoculated in the PN/A reactor; and after the sewage enters a rear-end SPD fixed bed from a rear-end up-flow/down-flow tank, denitrifying bacteria remove residual nitrate in the sewage by using organic matters adsorbed by the biological carbon bricks in the denitrifying bacteria as a carbon source, and finally, effluent is discharged from a rear-end water inlet/outlet channel. Whether biochar reaches adsorption saturation or not is judged by detecting the concentration of DO and the concen