Texas Wastewater Class B Practice Exam

Which type of treatment relies primarily on bacterial action to decompose organic matter?

1. Chemical treatment

2. Physical treatment

3. Aerobic treatment

4. Filtration

The correct answer is: Aerobic treatment

The choice of aerobic treatment is the correct answer because this method primarily utilizes bacteria in the presence of oxygen to break down organic matter. In aerobic treatment systems, bacteria metabolize the organic constituents in the wastewater, ultimately converting them into carbon dioxide, water, and new cellular biomass. This biological process is crucial for reducing the organic load of wastewater before it is discharged or undergoes further treatment. Chemical treatment, while important in wastewater processing, typically involves the addition of substances that can react chemically with pollutants, rather than relying on biological processes. Physical treatment mainly focuses on the removal of solids through techniques like sedimentation or filtration, which do not involve the decomposition of organic matter through bacterial action. Filtration, on the other hand, is a physical method used to separate particles from liquids and does not utilize bacteria for breaking down organic materials. Therefore, aerobic treatment stands out as the approach fundamentally reliant on the natural biological action of bacteria to decompose organic matter.