Biological treatment plant controlled by fluorescence sensors

A waste water purification plant operable for biological treatment and optionally for mechanical and/or chemical treatment of biodegradable material present in an aqueous environment, which plant in a biological treatment part contains at least one first sensor which is operable for measuring fluorescent emission and/or variations therein of at least one characteristic biogenic fluorophore present in the biological treatment part which comprises a first mixed culture of microorganisms, and which plant further comprises:

• a first data processing means connected to the at least one first sensor, which first data processing means is operable for converting a recording fluorescent emission signal to a measurement value and comparing said measurement value to a predetermined set point which indicates optimum or near optimum conditions for the first mixed culture of microorganisms with respect to the biodegradation of the biodegradable material.
• a first control means connected to the first data processing means, which first control means is adapted to control the biological and optionally mechanical and/or chemical treatment of the biodegradable material on the basis of the signal obtained from the first data processing means as the result of the comparison performed therein, so as to move subsequent fluorescence measurements toward the pre-determined set point, whereby conditions in the biological treatment part are adapted in the direction of optimum or near optimum conditions for the first mixed culture of microorganisms with respect to biodegradation of the biodegradable material,
• said at least one characteristic biogenic fluorophore being one which is present in the first mixed culture of microorganisms and acts as indicator of the metabolic activity of the first mixed culture of microorganisms;
• and
• a portion for determining quality and/or quantity of the biodegradable material which is to be treated in the plant, which portion comprises a biological system comprising a second mixed culture of microorganisms and a sample of the biodegradable material and at least one second sensor which is operable for measuring fluorescent emission and/or variations therein of at least one characteristic biogenic fluorophore present in the biological system.