TruePoint was tasked with helping the client determine the amount of rock overfill in each trickling filter mechanism at a wastewater treatment plant. The exact requirement was to have one foot of rock filled evenly across the entire mechanism, but variations in overfill levels had occurred. To measure this accurately without a prolonged plant shutdown, TruePoint conducted 3D laser scanning to create a triangulated surface model of the existing rock fill. This model was used to determine the average height and volume of the rock using a known datum point within the mechanism.