Alabama Wastewater Collection Grade 1C Practice Test 2025 - Free Wastewater Collection Practice Questions and Study Guide

Adding chlorine can effectively manage filamentous bulking, which is a common issue in secondary settling processes. Filamentous bulking occurs when certain types of filamentous bacteria proliferate excessively in the activated sludge system. This overgrowth can lead to poor settling characteristics, causing the sludge to remain in suspension and reduce the efficiency of the clarification process.

Chlorine acts as a disinfectant and can selectively reduce the population of specific filamentous bacteria responsible for the bulking issue. By doing so, it helps restore a balanced microbial community in the activated sludge, enhancing the settling properties of the biomass. This is crucial for ensuring that the treated effluent meets quality standards and is suitable for discharge or further treatment.

In contrast, viscous activated sludge, dispersed growth bulking, and denitrification are influenced by different factors and require different management strategies. While some treatments like changes in aeration or adjustments in nutrient levels may help with these issues, chlorine is particularly effective in addressing filamentous bulking.