Water Treatment Operator-in-Training (OIT) Practice Test 2026 - Free OIT Practice Questions and Study Guide

To determine the depth of sewage in the lagoon, you can use the formula for the volume of a rectangular prism, which is length × width × depth. In this case, you know the volume of sewage (224,000 liters) and the dimensions of the lagoon (10 meters long and 14 meters wide).

First, convert the volume from liters to cubic meters, since 1 cubic meter is equivalent to 1,000 liters. Therefore, 224,000 liters is equal to 224 cubic meters.

Next, set up the equation using the dimensions provided:

224 m³ = 10 m × 14 m × depth.

Calculating the area of the base of the lagoon:

Area = 10 m * 14 m = 140 m².

Now, substitute the area back into the equation for volume:

224 m³ = 140 m² × depth.

To solve for depth, divide the volume by the area:

depth = 224 m³ / 140 m² = 1.6 m.

This calculation confirms that the depth of the sewage in the lagoon is indeed 1.6 meters.