Which type of soil is most suitable for subsurface absorption of wastewater?

The most suitable type of soil for subsurface absorption of wastewater is yellow, brown, or red soil, as these soil types generally provide a good balance of drainage and retention properties. This allows for the effective treatment and absorption of wastewater through natural processes.

Yellow, brown, or red soils often have favorable structures that promote adequate percolation, enabling wastewater to move through the soil while allowing for the biological breakdown of contaminants. They typically have a mix of sand, silt, and clay, which helps maintain moisture while still facilitating the necessary drainage to prevent pooling and potential failures in the absorption system.

In contrast, clay soils tend to have very low permeability, which can lead to slow drainage and increased risk of surface runoff or saturation. Sandy soils, while they drain quickly and don't hold water well, may not retain sufficient nutrients or allow enough time for effective treatment before the wastewater moves too quickly through the substrate. Peaty soils, on the other hand, can hold a lot of moisture and may decompose organic matter, but their high organic content can also lead to problems with stability and may not provide the desired percolation rates for effective wastewater absorption.

Thus, yellow, brown, or red soils are typically preferred for subsurface absorption systems, as they