SENSORS TO MONITOR BIOLOGICAL NITROGEN REMOVAL AND ACTIVATED-SLUDGE SETTLING

A brief overview of methods and sensors to characterize activated slud ge is presented, summarizing techniques related to two important activ ated sludge processes: biological nitrogen removal (nitrification and denitrification) and sludge settling. Traditional off-line methods, ty pically applied in a laboratory environment to determine nitrifying/de nitrifying sludge activities and sludge settling properties are briefl y described. The main part of the paper covers a more detailed descrip tion of on-line sensors which were recently developed to continuously provide information about important activated sludge properties in a f ull-scale plant. The most important future work in this research field is the development of control strategies based on the data provided b y these sensors. (C) 1998 Elsevier Science B.V.