Although degritters have been largely used, for more than a century, as preliminary treatment units of wastewater treatment plants (WWTP), their removal efficiency is yet poorly known due to the lack of standardized analytical methods to determine wastewater grit concentration. This paper brings up this subject and presents an original method to determine wastewater grit concentration based on use of well-known procedures, such as: Imhoff cone sedimentation, hydrogen peroxide oxidation, sequential rinse, calcination and analytical balance weighing. The application of the developed method demonstrated that grit concentration in the influent of WWTP Jardim das Flores varies significantly, with peak concentration of about 200 mg/l, and that the mean grit concentration seems to be among 20 mg/l and 73 mg/l.
Degritters; grit chambers; grit concentration; determination method; statistical evaluation; WWTP Jardim das Flores
