Tennessee Wastewater Operator Practice Exam

A long-term approach to managing foam in the digester involves what action?

1. Identifying the root cause and correcting it

2. Increasing the feed rate

3. Using chemical additives

4. Heating the digester

The correct answer is: Identifying the root cause and correcting it

Identifying the root cause and correcting it is the most effective long-term approach to managing foam in a digester. Foam formation in a digester can be caused by various factors, including the characteristics of the feed material, the microbial population, operational conditions, and the presence of surfactants or fats. When operators focus on understanding and addressing the underlying issues that contribute to foam, they can implement lasting solutions that optimize the digestion process and improve overall efficiency. For instance, if foam is attributed to excess fats, oils, or greases in the feed, adjusting the feed composition or pre-treating these materials can significantly reduce foam generation. Similarly, if the foam is a result of an imbalance in microbial populations, tweaking the operational parameters to enhance the growth of beneficial microorganisms can help restore stability in the system. This proactive strategy not only mitigates foam formation but also enhances the overall performance of the digester, leading to better gas production and improved treatment outcomes. While other methods like increasing the feed rate, using chemical additives, or heating the digester may provide temporary relief or adjustment, they do not address the root cause and may even exacerbate the issue in the long run if the underlying problems are not resolved. Therefore, a targeted approach aimed at