Method for operating a water treatment plant, which plant is equipped with an apparatus for injecting a gas containing oxygen into an effluent, the method comprising a phase of detecting anomalies in the operation of the apparatus, characterized in that the anomaly-detecting phase comprises the implementation of the following measures: - data representative of the operating state of the apparatus are provided, said data comprising readings as a function of time of the gas flow rate injected by the apparatus and readings as a function of time of the flow rate of fluid passing through the apparatus; - a system for acquiring and processing these data is provided, said system being equipped with an algorithm for processing these data, which is capable of carrying out the following determinations: a) carrying out a training phase in which the system acquires said readings, establishes, over a determined training time period, the curve of variation in the flow rate of fluid passing through the apparatus as a function of the gas flow rate injected by the apparatus, and defines a zone/envelope encompassing this curve, which zone is considered to delineate a normal operation of the apparatus; and b) carrying out a phase of using the algorithm, in which the system acquires, in real time, over a determined period of time, the curve of variation in the flow rate of fluid passing through the apparatus as a function of the gas flow rate injected by the apparatus, and determining, if the signal departs from said zone/envelope during a period of time considered representative, that it must be concluded that an alarm should be raised, for example with a view to requesting predictive maintenance of the apparatus. - data representative of the operating state of the apparatus are provided, said data comprising readings as a function of time of the gas flow rate injected by the apparatus and readings as a function of time of the flow rate of fluid passing through the apparatus; - a system for acquiring and processing these data is provided, said system being equipped with an algorithm for processing these data, which is capable of carrying out the following determinations: a) carrying out a training phase in which the system acquires said readings, establishes, over a determined training time period, the curve of variation in the flow rate of fluid passing through the apparatus as a function of the gas flow rate injected by the apparatus, and defines a zone/envelope encompassing this curve, which zone is considered to delineate a normal operation of the apparatus; and b) carrying out a phase of using the algorithm, in which the system acquires, in real time, over a determined period of time, the curve of variation in the flow rate of fluid passing through the apparatus as a function of the gas flow rate injected by the apparatus, and determining, if the signal departs from said zone/envelope during a period of time considered representative, that it must be concluded that an alarm should be raised, for example with a view to requesting predictive maintenance of the apparatus. a) carrying out a training phase in which the system acquires said readings, establishes, over a determined training time period, the curve of variation in the flow rate of fluid passing through the apparatus as a function of the gas flow rate injected by the apparatus, and defines a zone/envelope encompassing this curve, which zone is considered to delineate a normal operation of the apparatus; and b) carrying out a phase of using the algorithm, in which the system acquires, in real time, over a determined period of time, the curve of variation in the flow rate of fluid passing through the apparatus as a function of the gas flow rate injected by the apparatus, and determining, if the signal departs from said zone/envelope during a period of time considered representative, that it must be concluded that an alarm should be raised, for example with a view to requesting predictive maintenance of the apparatus.