Leachate is formed due to which circumstance?

• A. Water formed from biological reactions
• B. Water content in household waste
• C. Rain water passes through waste in a landfill
• D. Water content in WW treatment sludge

Answer: (C)

Leachate forms when water moves through waste in a landfill and percolates downward, dissolving soluble materials and picking up contaminants along the way. Rainfall is a common source, driving water through layers of garbage and creating this polluted liquid. This is different from just moisture already present in household waste or water produced by biological reactions, which do not involve water passing through waste to dissolve and carry away pollutants. It’s also not the same as water content in wastewater treatment sludge, which is a separate stream. So, rainwater infiltrating and passing through landfill waste best describes how leachate is formed.