Tennessee Wastewater Operator Practice Exam

What chemical is commonly used to remove excess biofilm from trickling filter media?

1. Sodium hypochlorite

2. Hydrochloric acid

3. Calcium carbonate

4. Potassium permanganate

The correct answer is: Sodium hypochlorite

Sodium hypochlorite is widely used in wastewater treatment facilities to remove excess biofilm from trickling filter media due to its effective disinfection properties. This chemical acts as a strong oxidizing agent, which helps to break down the biofilm that can accumulate on filter media, thus enhancing the overall treatment efficiency of the system. Using sodium hypochlorite not only helps in cleaning the media but also reduces the organic load and pathogen levels in the wastewater, making it a valuable tool in maintaining operational efficiency in trickling filters. This process is important, as an excess biofilm can lead to decreased oxygen transfer rates, reduced treatment effectiveness, and operational challenges. The other options do not serve the same purpose in removing biofilm. Hydrochloric acid is primarily used for pH adjustment and might not be effective for biofilm removal. Calcium carbonate serves as a buffering agent and is not suitable for cleaning biofilms. Potassium permanganate acts as an oxidizing agent but is more typically utilized for iron and manganese removal in water treatment rather than for biofilm management.