Grit cannot be broken down in biological treatment processes because it:

Grit cannot be broken down in biological treatment processes because it:

• A. Is mostly organic
• B. Settles rapidly
• C. Is mostly inorganic
• D. Settles slowly

Answer: (C)

Biological treatment relies on microorganisms to oxidize and break down organic matter. Grit is made mostly of inorganic material like sand and gravel, which microbes cannot biodegrade. Because it isn’t biodegradable, grit passes through the biological process intact and is instead removed by physical separation (settling or grit chambers) rather than by microbial digestion. The fact that it settles quickly or slowly isn’t what prevents biodegradation—the key point is its inorganic composition, which makes it resistant to biological breakdown.

Biological treatment relies on microorganisms to oxidize and break down organic matter. Grit is made mostly of inorganic material like sand and gravel, which microbes cannot biodegrade. Because it isn’t biodegradable, grit passes through the biological process intact and is instead removed by physical separation (settling or grit chambers) rather than by microbial digestion. The fact that it settles quickly or slowly isn’t what prevents biodegradation—the key point is its inorganic composition, which makes it resistant to biological breakdown.