Ace the California Wastewater Treatment Operator Exam 2026 – Dive In and Purify Your Career!

Excessive alkalinity, or excess alkaline substances, can actually help to reduce foaming in an anaerobic digester. This is due to the buffering capacity of these substances, which can help balance the pH and prevent the formation of foam. High dissolved oxygen levels can also contribute to foaming, as it can disrupt the balance of microorganisms in the digester. Low organic content, on the other hand, would not provide enough material for the microorganisms to break down, resulting in a lack of foam. Furthermore, organic overload, while often a cause of foaming, is not the only factor that can contribute to it. Overall, the most likely cause of foaming in an anaerobic digester is organic overload, making C the correct answer.