Solid waste management terminology The biological decomposition of organic substances in wastes under controlled conditions (temperature, moisture, aeration) is called:

Introduction / Context:
In environmental engineering, different unit operations and processes are used to stabilise municipal solid waste and organic residues. When the goal is to convert putrescible matter into a stable, humus-like product using microorganisms under managed conditions, the process has a specific name that distinguishes it from burning, uncontrolled decay, or purely liquid-phase biodegradation. Knowing this term helps in selecting appropriate treatment technology and in designing facilities for cities and industries.

Given Data / Assumptions:

• The waste contains biodegradable organics such as kitchen waste, yard trimmings, and agricultural residues.
• Conditions are controlled: moisture, temperature, aeration, and carbon to nitrogen ratio are adjusted.
• The target is a stable, soil-conditioner product rather than energy recovery by combustion.

Concept / Approach:
Biological stabilisation can be aerobic or anaerobic. Aerobic management with forced or natural aeration and active turning typically produces heat, accelerates microbial activity, and yields a finished compost. The process parameters include moisture around 50–60%, C/N ratio about 25–30, and pile temperatures that pass through mesophilic and thermophilic phases. This set of controlled, engineered steps is called composting. It differs fundamentally from incineration (thermal oxidation) and from generic “biological oxidation” which is a broad descriptor often used for wastewater treatment reactions.

Step-by-Step Solution:

Verification / Alternative check:
Design manuals for solid waste processing describe windrow, aerated static pile, and in-vessel composting systems, all emphasising control of air, moisture, and temperature to produce compost safely and efficiently.

Why Other Options Are Wrong:

• Incineration: High-temperature combustion for volume reduction and energy, not biological decomposition.
• Biological oxidation: Too generic; not the specific engineered solid waste process name.
• None of these: Incorrect because a standard term exists.
• Anaerobic digestion: Biological but oxygen-free, produces biogas rather than compost as the main product.

Common Pitfalls:
Confusing any biodegradation with composting; ignoring the requirement for controlled aeration and management parameters.

Final Answer:
Composting