Excavated pits, used for solid waste disposal, lined with impermeable synthetic liner and thick impermeable layers of clay are an example of

Correct option is B

The correct answer is secured landfills.
Secured landfills are designed specifically for the safe disposal of hazardous or toxic waste. These landfills incorporate impermeable synthetic liners and thick impermeable clay layers to prevent leachate (contaminated water) from escaping into the surrounding soil and groundwater.
Key Features of Secured Landfills:
1. Double Liners: Consist of layers of clay and synthetic materials (e.g., HDPE liners) to ensure impermeability.
2. Leachate Collection Systems: Designed to collect and treat leachate to prevent environmental contamination.
3. Monitoring Wells: Installed to monitor groundwater for any signs of leakage.
4. Capping Systems: After closure, secured landfills are covered with an impermeable cap to minimize water infiltration.
These landfills are often used for industrial, hazardous, or toxic waste, ensuring that contaminants do not seep into the environment.
Information Booster 1. Sanitary Landfills:
· Used for municipal solid waste (non-hazardous).
· Includes impermeable clay liners and leachate collection but may not have the strict requirements of secured landfills.
2. Secured Landfills:
· Designed for hazardous waste disposal.
· Incorporates multiple safety layers to prevent leachate migration.
3. Underground Dumps:
· Informal disposal sites with little to no environmental controls.
· Not suitable for waste management due to environmental hazards.
4. Composting Dumps:
· Sites where organic waste is biologically decomposed into compost.
· Involves aerobic decomposition and does not use synthetic liners.
Additional Knowledge · Leachate: A liquid that forms when water passes through waste material, potentially carrying contaminants.
· HDPE Liners: High-Density Polyethylene liners used in both sanitary and secured landfills to provide impermeable barriers.
· Cap Layers: Final cover systems in landfills to reduce water infiltration and gas emissions.
· Monitoring: Regular monitoring of soil and water quality around landfills ensures environmental safety.
Key Points:
· Secured landfills are designed for hazardous waste with stringent environmental safeguards.
· Sanitary landfills handle non-hazardous municipal waste.