Abstract: A method for estimating incoming pollution loads during operation of a municipal wastewater treatment plant involves the step of continuously measuring the conductivity and turbidity of the raw water to be treated. The concentration of a pollutant in the raw water to be treated is estimated as a function of the measured conductivity and turbidity. The flow rate of the raw water to be treated is also continuously measured. The load of the pollutant in the raw water to be treated is estimated as a function of the estimated concentration of the pollutant and the measured flow rate. The estimated pollutant load allows adjustment of downstream treatment for eliminating the estimated total load of the pollutant.

Abstract: Process for controlling the retention time of the sludge undergoing clarification in a process for treating wastewater by activated sludge comprising a recirculation of the activated sludge from the clarification stage into the biological basins, characterized in that the rate of sludge recirculation (Qr) is varied so as to maintain a constant recirculated sludge concentration (Cr) while at the same time guaranteeing a retention time (RT) of the sludge undergoing clarification of less than a critical value (RTmax).

Abstract: A process is disclosed for regulating the aeration in a biological wastewater treatment plant using a carbon removal stage, a nitrification stage and a denitrification stage. The process includes the step of continuously measuring the value of oxidation-reduction potential of the treated medium as well as measuring oxygen concentration of the treated medium during aeration phases. This permits maintaining aeration if the oxygen concentration falls within a preselected reference range. Alternately there is reduction of the aeration if the oxygen concentration is above the preselected reference range, or increasing the aeration if the oxygen concentration falls below the preselected reference range.

Abstract: This method uses the on/off sequences of an aeration system of treatment basins. The sequences are imposed by the running of a treatment process, to estimate the respiration of biomass, the latter being measured during non-aeration phases. There is an initial determination, from the concentration of dissolved oxygen, of the change in the amount of oxygen contained in the aeration basin. There is a subsequent determination of the amount of oxygen leaving the aeration basin, the amount of oxygen entering the basin during the non-aeration phase being regarding as zero. Next is a determination, on the basis of the information collected in the above steps, of the respiratory capacity of the purifying biomass. There is then a determination of the mass of suspended matter in the purifying biomass and calculation, from the respiratory capacity of the biomass and from the sludge concentration, of the amount of oxygen consumed per unit mass of biological sludge and per unit time.

Abstract: The oxidoreduction potential is measured on each of a number of tanks. A data processing system analyzes the oxidoreduction potential evolution and establishes a diagnosis of the aeration/biology couple to ensure the degradation reactions of the carbonaceous and nitrogenous pollution. It is then determined whether to start, to continue, or to stop aeration in the tanks, depending on the required degree of purification. In the first tanks, priority is given to the treatment of carbonaceous pollution with specific parameter representation of the oxidoreduction potential threshold values. In the last tank, fine-tuning the treatment of the carbonaceous and nitrogenous pollution is accomplished by managing the aeration.

Abstract: A method of monitoring and managing biomass stock of treatment plants employs activated sludge. An aeration basin receives an effluent and a concentration of suspended matter in the basin is measured. A change in concentration is then analyzed and a maxima of this concentration is determined which corresponds to periods of hydraulic underperformance. A total biomass mass is estimated, and the rate of extraction of biomass is adjusted.

Abstract: Method of monitoring the efficiency of the aeration systems of biological basins of a wastewater treatment plant, characterized in that it consists in: i) measuring the throughput (Qt) of the plant and the rate (Qr) of recirculation of the mixed liquor from the clarifier to the aeration basin; and ii) measuring the concentration of dissolved oxygen in the aeration basin so as: a) to establish, during an aeration period, the material balance between oxygen supplied, oxygen consumed and oxygen discharged with the effluent; b) to establish, during a non-aeration period, the material balance between oxygen consumed and oxygen discharged with the effluent; c) to determine the amount of oxygen consumed by the biomass based on the two material balances established above; and d) to determine, from the data obtained at a), b) and c) , the value of the transfer coefficient &agr;kLa under the conditions of the measurement.