Texas Class C Wastewater Treatment License Practice Exam 2026 - Free Wastewater Treatment Practice Questions and Study Guide

A wastewater stabilization pond is designed to improve the quality of treated water primarily by reducing biochemical oxygen demand (BOD) and bacteria levels. BOD measures the amount of oxygen required by microorganisms to decompose organic matter in water; a high BOD value indicates a higher concentration of organic material, which can lead to oxygen depletion in receiving waters.

In the stabilization pond, natural processes involving microorganisms break down organic matter, thereby lowering BOD levels over time. Additionally, the pond environment supports the treatment of bacteria present in wastewater, reducing pathogen levels and making the water safer for discharge or additional treatment steps.

The other options do not accurately reflect the primary functions of a stabilization pond: while nutrients and organic matter may see some reduction due to aquatic plant uptake and microbial activity, options related to heavy metals, chlorine, and fluorine do not fall under the typical scope of what stabilization ponds are designed to treat effectively. Thus, the effectiveness of a stabilization pond is best characterized by its ability to reduce BOD and bacteria levels in treated effluent.