What type of materials are typically used in the composition of a conventional drain field?

The use of sand and gravel in the composition of a conventional drain field is essential for ensuring proper drainage and filtration of wastewater. Sand provides good percolation properties, allowing effluent from the septic tank to flow through the soil layers effectively. Gravel acts as a medium that supports the overall structure of the drain field while also allowing air circulation, which is necessary for the aerobic bacteria that break down waste.

This combination promotes optimal treatment as the wastewater passes through the soil, where various physical, biological, and chemical processes occur to purify the effluent before it reaches the groundwater or surface water. The choice of sand and gravel aligns with established engineering practices for effective septic system design, enhancing both the functionality and longevity of the drain field while preventing issues like clogging that could arise from less suitable materials.