When is soil replacement used?

When is soil replacement used?

• A. When Native Soil Is Suitable
• B. When Native Soil Is Unsuitable
• C. When There Is High Permeability
• D. When There Is Excessive Rainfall

Answer: (C)

Soil replacement is used to adjust how quickly water moves through the absorption area so that wastewater has time to be properly treated. If the native soil is too permeable, effluent can drain away too fast and not spend enough time in contact with the soil organisms that help treat it, which risks inadequate treatment and contamination of groundwater. Replacing that soil with material that has lower permeability slows down infiltration, improves filtration, and helps meet design requirements for the disposal field. That’s why the best reason is high permeability. Note that simply saying native soil is unsuitable is a broad statement; replacement specifically addresses soils that are too permeable to achieve the needed treatment and drainage characteristics.

Soil replacement is used to adjust how quickly water moves through the absorption area so that wastewater has time to be properly treated. If the native soil is too permeable, effluent can drain away too fast and not spend enough time in contact with the soil organisms that help treat it, which risks inadequate treatment and contamination of groundwater. Replacing that soil with material that has lower permeability slows down infiltration, improves filtration, and helps meet design requirements for the disposal field. That’s why the best reason is high permeability. Note that simply saying native soil is unsuitable is a broad statement; replacement specifically addresses soils that are too permeable to achieve the needed treatment and drainage characteristics.