How does thermal treatment reduce waste volume?

• A. By burying waste underground
• B. By converting waste into compost
• C. By incinerating waste at high temperatures
• D. By extracting metals from waste

Answer: (C)

Thermal treatment effectively reduces waste volume through incineration, where waste materials are subjected to high temperatures. This process causes the organic components of the waste to combust, which significantly reduces the mass and volume of the waste. The thermal breakdown of materials results in the formation of gaseous byproducts and ash; the remaining ash typically constitutes a small fraction of the original waste volume.

Incineration not only diminishes the physical footprint of waste but also, depending on the technology used, allows for energy recovery through the heat generated, which can be harnessed for electricity or heating. In contrast, methods such as burying waste underground do not reduce its volume effectively, nor do they mitigate the environmental impact of the waste. Composting transforms organic materials into soil amendments but does not significantly reduce waste volume in the same manner as thermal treatment. Similarly, extracting metals from waste focuses on resource recovery rather than volume reduction. Therefore, the incineration process stands out as a primary method for reducing waste volume through thermal treatment.