What is equivalent to organic solids in wastewater treatment?

Organic solids in wastewater treatment refer primarily to the biodegradable substances present in the wastewater, which include materials such as food waste, paper, and other organic matter. These solids are significant in the treatment process because they provide a source of energy for microorganisms during the biological treatment phase.

Volatile solids are specifically defined as the portion of the solids that can be vaporized or lost during heating to a certain temperature, typically around 550 degrees Celsius. These solids are mainly organic in nature and are what are actually being measured when discussing the organic content of wastewater. In wastewater treatment, the amount of volatile solids often indicates the level of biodegradable material, which is a key factor in understanding the organic loading on treatment systems.

The other types of solids mentioned do not equate to organic solids in the same way. Fixed solids primarily consist of inorganic materials that do not decompose, while inert solids are substances that do not react chemically and remain unchanged within the environment. Settleable solids refer to those that can settle out of suspension under gravity, which may include both organic and inorganic components but do not specifically indicate the organic fraction alone.

Thus, volatile solids are the most directly related to organic solids, providing a measure of the biodegradable portion of the solids in wastewater treatment systems