NOVELTY - Device comprises raw water tank (1), water pump (2), a water inlet tube (3), an aerobic nitrification tank (4), a pH gauge (5), a pH sensor, an air blower, an aeration tube, an air diffuser, a sludge reflux tube, a sludge reflux pump, an aerobic nitrification tank water outlet tube, a sedimentation tank, a sedimentation tank water outlet tube and residual sludge discharging pipe. The water tank is connected with the nitrification tank through the water inlet tube and water pump. The nitrification tank is divided into multi-series cells, and a through-port is set between two adjacent cells.    USE - The device is useful for achieving partial nitrification by free ammonia and free nitrite synergistic inhibition of nitrifying bacteria activity (claimed).    ADVANTAGE - The method: achieves partial nitrification at room temperature; can quickly start and maintain stability; can solve the bottleneck problem of continuous flow process of partial nitrification; has high denitrification efficiency and quick reaction rate; saves the operation cost; and produces water with good quality.    DETAILED DESCRIPTION - Device comprises raw water tank (1), water pump (2), a water inlet tube (3), an aerobic nitrification tank (4), a pH gauge (5), a pH sensor, an air blower, an aeration tube, an air diffuser, a sludge reflux tube, a sludge reflux pump, an aerobic nitrification tank water outlet tube, a sedimentation tank, a sedimentation tank water outlet tube and residual sludge discharging pipe. The water tank is connected with the aerobic nitrification tank through the water inlet tube and the water pump. The aerobic nitrification tank is divided into multi-series cells, and a through-port is set between two adjacent cells, which are crossed up and down. The aerobic nitrification tank is connected with the sedimentation tank through aerobic nitrification tank water outlet tube. The sedimentation tank is set with the sedimentation tank water outlet tube. The sedimentation tank is connected with a first connecting cell of the aerobic nitrification tank through the sedimentation tank water outlet tube and the residual sludge discharging pipe. Each grid chamber of the aerobic nitrification tank is set with the pH sensor. The pH sensor is connected to the pH gauge. Each grid chamber of the aerobic nitrification tank is set with the air diffuser. The air diffuser is connected with the air blower through the aeration tube. An INDEPENDENT CLAIM is also included for achieving partial nitrification by free ammonia and free nitrite synergistic inhibition of nitrifying bacteria activity using the device, comprising (i) pumping high ammonia nitrogen water through the water pump from the water tank through the water inlet pipe, and continuously pump into the aerobic nitrification tank; (ii) aeration: starting the air blower, providing sufficient dissolved oxygen in the aerobic nitrification tank for nitrification bacteria, oxidizing dissolved ammonium as nitrogen (NH4+-N) to nitrite-nitrogen (NO2-N), then flowing along the aerobic nitration pool, continuously performing ammoxidation reaction, where free ammonia (FA) concentration is gradually reduced, nitrite-oxidizing bacteria (NOB) inhibition activity is gradually weakened, at the same time, along the flow direction of nitrification tank, nitrite-nitrogen concentration is gradually increased, resulting in gradually increase in the free nitrous acid (FNA) concentration, and gradually increasing NOB inhibition activity until the effluent achieves partial nitrification, regulating the water inlet, conveying into the first cell chamber of the aerobic nitrification tank, where the water influent FA concentration is controlled between 5.9-63.1 mg/l, detecting the reaction process of each cell chamber through the pH sensor, where the pH value of the nitration curve indicates the end point, by regulating the reaction time, aerobic nitration tank along the flow direction so that pH of cells in turn raises, ending the oxidation of ammonia nitrogen, draining into the sedimentation tank, discharging the deposited supernatant through a water outlet tube of the sedimentation tank, returning the deposited sludge next part under the action of sludge reflux pump, and then returning to the first chamber of the aerobic nitrification tank through a sludge reflux tube, and discharging the other sludge part through a surplus sludge pipe, where FA is equal to 17(NH4+-N)x 10pH/14 exp(6334/273+T)+10pH, where FA is the concentration of free ammonia, mg/l, (NH4-N) is ammonia nitrogen concentration, mg/l; and T is temperature.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic representation of the device for achieving partial nitrification by free ammonia and free nitrite synergistic inhibition of nitrifying bacteria activity.    Raw water tank (1)    Water pump (2)    Water inlet tube (3)    Aerobic nitrification tank (4)    PH gauge (5)