What term describes wastewater solids that have been decomposed to relatively inert solids?

The term that describes wastewater solids that have been decomposed to relatively inert solids is referred to as "Stable." This term highlights the condition of the solids after they have undergone a significant biodegradation process, resulting in a material that is less likely to undergo further breakdown or pose environmental risks.

Stable solids are often found in mature compost or treated biosolids, where microbial activity has effectively reduced the organic content, allowing for safe handling and potential use in various applications, such as soil amendments. This stability is crucial for ensuring that the materials do not generate odors, leach harmful substances, or contribute to environmental pollution when used.

In contrast, the other terms do not accurately describe the condition of these solids. "Septic" refers to a state where the wastewater is in a condition of decomposition, typically producing odors and lacking in stable solids. "Fresh" indicates a state of newly generated solids that have not yet undergone significant decomposition, while "Organic" describes any substance derived from living organisms, which does not specifically connote the inert nature of the solids after decomposition. Therefore, "Stable" is the most appropriate and accurate term in this context.