What are the most common chemical elements found in sewage?

The most common chemical elements found in sewage include a variety of substances, and the correct answer encompasses all the options listed. Sewage typically contains solids such as organic matter, bacteria, and inorganic materials, which contribute to the solid content. Additionally, gases like carbon dioxide, methane, and hydrogen sulfide are produced during the decomposition of organic matter in sewage. Fats and greases are also prevalent, often originating from food waste and household products, which can affect the treatment processes in sewage systems.

Each of these components plays a significant role in the overall composition of sewage, influencing treatment methods and environmental considerations. Recognizing that sewage is a complex mixture illustrates the necessity for comprehensive treatment processes that can effectively address all these elements. Thus, the inclusion of solids, gases, and fats and greases in the answer highlights the multifaceted nature of sewage composition.