Which of the following sludge waste applications involves the treatment of waste through combustion?

The application that involves the treatment of sludge waste through combustion is incineration. Incineration is a waste management process that involves the burning of organic materials, including sludge, at high temperatures. This method not only reduces the volume of waste significantly but also helps to destroy harmful pathogens and organic contaminants present in the sludge, leading to a safer end product.

Incineration is particularly advantageous in urban areas where land availability is limited, as it decreases the need for landfilling by converting waste into ash, which can be disposed of more easily. The process also generates energy in the form of heat, which can be harnessed for electricity or heating purposes, contributing to energy recovery from waste.

In contrast, landfill involves burying waste in designated areas, ocean disposal refers to the dumping of waste in ocean waters, and land application is the practice of using treated sewage sludge as fertilizer in agricultural fields. None of these methods involve the combustion of waste like incineration does. Thus, incineration stands out as the correct answer in this context.