Sanitary Landfill Properties Analysis

Sanitary landfills are designed waste disposal sites. Let's analyze the given properties:

• (a) Reduce trash volume in a short time: While compaction occurs in landfills to manage space, their primary function isn't rapid volume reduction like incineration. This statement is not a defining characteristic.
• (b) Release CH$_4$ and CO$_2$: The anaerobic decomposition of organic waste within a landfill generates landfill gas (LFG), which is primarily composed of methane ($CH_4$) and carbon dioxide ($CO_2$). This is a key process occurring in landfills.
• (c) Eventually produce leachate which contaminate ground water: Leachate (liquid formed from waste decomposition and precipitation) is indeed produced. However, modern sanitary landfills employ engineered liners and collection systems specifically to prevent or minimize groundwater contamination. Therefore, contamination is not an inevitable outcome of a properly designed and managed sanitary landfill.

Conclusion on Landfill Properties

Based on the analysis, only statement (b) accurately describes a fundamental process occurring in sanitary landfills.

• Statement (a) is misleading regarding the speed and primary purpose of volume reduction.
• Statement (c) describes a potential risk that modern landfills aim to mitigate, rather than an inherent, defining property.
• Statement (b) accurately reflects the generation of landfill gases ($CH_4$ and $CO_2$) from waste decomposition.

Correct Answer Determination

Since only property (b) is definitively and universally characteristic of the decomposition process within sanitary landfills, the correct option includes only (b).

The correct choice is the one that states (b) only.