UTVÄRDERING AV SEDIMENTERINGSFÖRLOPP I AKTIVSLAMPROCESSEN / Evaluation of Sedimentation in Activated Sludge in a Secondary Clarifier
Nitrification and denitrification in activated sludge process will be applied at Kungsängsverket in Uppsala municipality to fulfill future effluent requirements. In order to obtain total nitriflcation, a higher sludge retention time is required than in a conventional activated sludge plant. The highest sludge concentration that can be used is dependent on sludge separation properties and operational modes.
This study was focused on the possibilities to find relationships between the applied solids flux to the imentation basin and the sludge blanket. Three different methods were evaluated: (1) the use of batch sedimentation tests, (2) the use of the Stirred Specific Volume Index (SSVI) and (3) the use of on-line measurements of the applied solids flux and of the sludge blanket. The last method seems to be promising and is recommended for future evaluations.