Which feature helps prevent leachate from contaminating groundwater?

Which feature helps prevent leachate from contaminating groundwater?

• A. Gas collection system
• B. Groundwater monitoring wells
• C. Plastic liners only
• D. Clay in landfills

Answer: (D)

Controlling leakage through waste relies on barriers that slow or stop water moving downward. Clay forms a very low-permeability layer when properly compacted, so liquids trapped in the waste have a hard time seeping through. This makes clay a powerful physical barrier that reduces the chance leachate reaches groundwater. Gas collection systems deal with methane, not liquid movement. Groundwater monitoring wells are for detecting contamination after it happens, not preventing it. Plastic liners help stop leaks but are more effective when used as part of a broader barrier system; relying on plastic alone isn’t as robust as a clay-based barrier. Modern designs often combine both, but the clay component specifically minimizes leachate migration, which is why it’s the best answer.

Controlling leakage through waste relies on barriers that slow or stop water moving downward. Clay forms a very low-permeability layer when properly compacted, so liquids trapped in the waste have a hard time seeping through. This makes clay a powerful physical barrier that reduces the chance leachate reaches groundwater.

Gas collection systems deal with methane, not liquid movement. Groundwater monitoring wells are for detecting contamination after it happens, not preventing it. Plastic liners help stop leaks but are more effective when used as part of a broader barrier system; relying on plastic alone isn’t as robust as a clay-based barrier. Modern designs often combine both, but the clay component specifically minimizes leachate migration, which is why it’s the best answer.