Tennessee Wastewater Operator Practice Exam

What effect does increasing sludge wasting have on clarifier performance after observing improved settling in a settleometer?

1. Improves overall treatment efficiency

2. Causes further settling issues

3. Increases retention time

4. Maintains current performance level

The correct answer is: Improves overall treatment efficiency

Increasing sludge wasting can lead to improved overall treatment efficiency in a wastewater treatment process. When sludge is wasted, it helps to maintain an appropriate concentration of solids in the clarifier. This action can alleviate issues related to excessive solids, such as decreased settling rates and poor clarification performance. With improved settling, as initially observed in a settleometer test, the increase in sludge wasting means that the system can enhance the removal of suspended solids, thus optimizing the clarity of the effluent. By effectively managing the solids retention time and ensuring that the MLSS (Mixed Liquor Suspended Solids) levels are ideal, the treatment system can maintain its performance and contribute to improved biological activity and nutrient removal. Maintaining the right proportion of biomass promotes a healthier microbial community, which in turn supports better breakdown of organic matter and overall treatment performance. Therefore, increasing sludge wasting ultimately reinforces the efficiency of the clarifiers and the wastewater treatment system as a whole.