A wastewater treatment plant comprising an anoxic tank, in which a denitrification process takes place, an aerobic tank, which is designed to receive wastewater to be treated from said anoxic tank and in which a nitrification process takes place, a recirculation system, which is designed to transfer wastewater to be treated from the aerobic tank to the anoxic tank, and an assembly for the management of said wastewater treatment plant, wherein said assembly comprises a pH measuring probe, which is housed on the inside of said anoxic tank, a redox potential measuring probe, which is housed on the inside of the anoxic tank, a control unit, which is designed to receive signals from the pH measuring probe and the redox potential measuring probe, and a variable-capacity recirculation pump, which is inserted in said recirculation system and is controlled by the control unit; said control unit being designed: (a) to send a command to the variable-capacity recirculation pump to reduce the flow rate if the redox potential measuring probe detects a value higher than + 50 mV, and to begin monitoring the pH signal from the pH measuring probe, said signal from the pH measuring probe increasing until a maximum point is reached; - if the redox potential measuring probe detects a negative value corresponding to said maximum point, the internal recirculation flow rate being validated as a reference flow rate; - if the redox potential measuring probe detects a positive value corresponding to said maximum point, the recirculation flow rate being further reduced until when, at said maximum point, the redox potential measuring probe detects values tending to an asymptote within the range from -200 mV to -50 mV; (b) to send a command to the variable-capacity recirculation pump to increase the flow rate if the redox potential measuring probe detects a value lower than -250 mV; said control unit sending a command to the variable-capacity recirculation pump to increase the flow rate until when, monitoring signals from the pH measuring probe, the redox potential measuring probe detects a value within the range from -200 mV to -50 mV; (c) to not command the variable-capacity recirculation pump to modify its flow rate if the potential measuring probes detects a value ranging from -200 mV to -50 mV. (a) to send a command to the variable-capacity recirculation pump to reduce the flow rate if the redox potential measuring probe detects a value higher than + 50 mV, and to begin monitoring the pH signal from the pH measuring probe, said signal from the pH measuring probe increasing until a maximum point is reached; - if the redox potential measuring probe detects a negative value corresponding to said maximum point, the internal recirculation flow rate being validated as a reference flow rate; - if the redox potential measuring probe detects a positive value corresponding to said maximum point, the recirculation flow rate being further reduced until when, at said maximum point, the redox potential measuring probe detects values tending to an asymptote within the range from -200 mV to -50 mV; - if the redox potential measuring probe detects a negative value corresponding to said maximum point, the internal recirculation flow rate being validated as a reference flow rate; - if the redox potential measuring probe detects a positive value corresponding to said maximum point, the recirculation flow rate being further reduced until when, at said maximum point, the redox potential measuring probe detects values tending to an asymptote within the range from -200 mV to -50 mV; (b) to send a command to the variable-capacity recirculation pump to increase the flow rate if the redox potential measuring probe detects a value lower than -250 mV; said control unit sending a command to the variable-capacity recirculation pump to increase the flow rate until when, monitoring signals from the pH measuring probe, the redox potential measuring probe detects a value within the range from -200 mV to -50 mV; (c) to not command the variable-capacity recirculation pump to modify its flow rate if the potential measuring probes detects a value ranging from -200 mV to -50 mV.