California Wastewater Treatment Operator Practice Exam

What factors affect the biodegradation rate of pollutants?

1. Temperature, pH, nutrient availability, and presence of oxygen

2. Salinity, pressure, flow rate, and time

3. Type of chemical, concentration, humidity, and air flow

4. Only temperature and pH

The correct answer is: Temperature, pH, nutrient availability, and presence of oxygen

The biodegradation rate of pollutants is influenced significantly by several environmental and chemical factors, making the first option the most comprehensive and accurate choice. Temperature plays a crucial role in the activity of microorganisms involved in the biodegradation process. Higher temperatures typically enhance enzymatic reactions, leading to increased metabolic rates of bacteria and fungi that break down pollutants. Conversely, extremely high or low temperatures can inhibit microbial activity and slow down the degradation process. pH is another critical factor, as different microorganisms thrive in different pH ranges. Most biological processes are optimized between pH 6 to 8. If the environment is too acidic or too alkaline, microbial activity may be negatively affected, thus impacting the biodegradation rate. Nutrient availability is essential for the growth of microorganisms. For effective biodegradation, an adequate supply of nutrients (such as nitrogen and phosphorus) must be present. Limited nutrients can slow down the growth of the microbial population, subsequently reducing the degradation of pollutants. The presence of oxygen is also important, especially for aerobic biodegradation, where microorganisms use oxygen to break down organic matter more efficiently. In anaerobic conditions, the degradation process can occur at a slower pace or lead to the production of different by-products, further affecting the rate of biodegradation.