What type of materials is predominantly treated in a fire incinerator?

The correct choice is organic waste, as fire incinerators are primarily designed to handle biological materials that can be efficiently combusted. Organic waste includes materials such as food scraps, yard waste, and other biodegradable substances. When incinerated, these materials combust completely, reducing their volume significantly and transforming them primarily into ash, gases, and heat. This process not only helps in waste management by minimizing landfill use but also in energy recovery.

In contrast, while fire incinerators can occasionally process metal scraps or hazardous materials, their primary function is to deal with organic material due to the higher rates of combustion and energy recovery associated with these types of waste. Plastic waste can also be incinerated, but it poses challenges in terms of emissions and potential toxins released during combustion, which makes it less desirable as a primary material for incineration compared to organic waste.