You receive a surge of high flow into your aeration basins, leading to an increasing sludge blanket in your secondary settling tanks. What adjustment should you make?

In situations where there is a surge of high flow leading to an increasing sludge blanket in the secondary settling tanks, increasing the return activated sludge (RAS) is a strategic adjustment to mitigate the issue. By increasing the RAS flow, more settled sludge is returned to the aeration basin, which not only helps maintain the appropriate concentration of biomass in the system but also assists in enhancing the settling characteristics of the sludge. This in turn helps to stabilize the treatment process by ensuring that the biomass remains concentrated enough to handle the increased loading effectively.

When there’s inflow surging, the resulting high surface loading can overwhelm the capacity of the settling tanks and lead to problems such as rising sludge and clarifier inefficiency. By augmenting the RAS, the operational balance can be restored, allowing for better settling performance and improved treatment of the incoming wastewater. This method effectively addresses the immediate challenges posed by high flow conditions and supports optimal operation of the wastewater treatment facility.