Wisconsin Mound Soil Absorption System and Area FillPractice Exam

Which type of trench design is not permitted in area fill absorption fields?

1. serial trenches

2. single trenches

3. parallel trenches

4. perpendicular trenches

The correct answer is: serial trenches

In area fill absorption fields, the design that is not permitted is the use of serial trenches. This design involves creating a series of trenches that are connected in a sequence, which can lead to inadequate absorption and treatment of wastewater. The impact of this design is that it may not allow for sufficient space between the trenches for proper air exchange and water percolation, ultimately reducing the system's effectiveness in filtering and absorbing the effluent. The other designs allowed—single trenches, parallel trenches, and perpendicular trenches—promote better distribution of wastewater and improve the overall function of the absorption system. These designs allow for adequate spacing and airflow between the trenches, which are crucial components for efficient soil absorption and the prevention of waterlogging. This ensures that the wastewater is adequately treated as it passes through the soil layers.