By what percentage and for how long can the Topas WWTP be overloaded and how does it cope?

Generally, the Topas WWTP can be temporarily overloaded up to double its designed capacity, both in terms of substance and hydraulics, for about 14 days. Activated sludge can bind pollutants into its cells and consume them later. In terms of hydraulics, the WWTP can handle more than double the flow. Prolonged overloading may lead to accumulation of pollutants in the activation volume, reducing dissolved oxygen and creating anoxic to anaerobic conditions. This can cause the complete die-off of activated sludge in the WWTP and collapse of the biological cleaning process. In such a case, it is usually necessary to evacuate the WWTP’s contents and re-seed with new sludge.