Basic Wastewater Operator Practice Exam

What is the most common type of activated sludge package plants?

1. Extended aeration

2. Sequential batch reactor

3. Oxidation ditch

4. Bardenpho

The correct answer is: Extended aeration

The most common type of activated sludge package plants is extended aeration. This method involves a prolonged aeration process, where wastewater is kept in a tank for a longer period, allowing for more complete organic matter degradation and better nutrient removal. Extended aeration systems operate continuously, which helps to maintain desired levels of microorganisms and promotes efficient treatment of the effluent. This type of package plant is highly favored for its simplicity and reliability, making it suitable for small to moderate flow applications, such as those found in rural or less densely populated areas. The energy-efficient nature of extended aeration systems, combined with their ability to produce high-quality effluent, makes them a popular choice in various wastewater treatment scenarios. In contrast, the other options represent different technologies and approaches to wastewater treatment, often with specific applications or configurations that might not be as commonly used in package plants. For example, a sequential batch reactor operates in a batch mode, treating wastewater in cycles, which is less common for small package installations. Oxidation ditches are typically larger systems that use a more complex design to facilitate aeration and flow. The Bardenpho process is a specific type of biological nutrient removal that requires multiple treatment steps, which may not lend itself to the compact, modular