ONLINE FLUX-THEORY BASED CONTROL OF SECONDARY CLARIFIERS

A strategy for controlling secondary clarifiers during dry weather and rain is described. The strategy is now implemented and is being teste d on a full-scale wastewater treatment plant. The plant - Aalborg West Wastewater Treatment Plant - is operated by using the patented Bioden ipho process. The flux theory as formulated by A. Vesilind, in combina tion with measurements of sludge level, suspended solids and flow at c ritical points, form the bases for a dynamic on-line control of the cl arifiers. The settling velocity used in the flux theory is measured an d calculated on the basis of the installed sensors. In the test period it is expected that the control strategy will show capability of seve ral improvements compared to traditional control strategy. The dry wea ther strategy should result in a reduction of return sludge pumping an d thereby save energy. Moreover, improvement of the sludge characteris tics is expected because of less pumping of sludge. The rain strategy should show possibility of significant reduction in storm overflows in the plant and in the sewer system upstream to the treatment plant. Th ereby the capacity of the plant will be improved and the total effluen t load to the recipient reduced.