Concentration profiling of a horizontal sedimentation tank utilising a bespoke acoustic backscatter array and CFD simulations

•Characterisation of large-scale clarifier with OpenFOAM CFD & ultrasonic array.•CFD correlated closely to sampled concentration profiles with glass dispersions.•CFD under-predicted particle levels with calcite flocs, likely due to floc break-up.•Acoustic array was successful at profiling clarifier with backscatter power method.•Array was proven for high fidelity CFD validation data and process monitoring.