Texas Wastewater Class B Practice Exam

Increasing the recirculation ratio in a trickling filter can effectively address filter flies, which are a common nuisance in wastewater treatment operations. A higher recirculation ratio refers to returning a larger volume of treated effluent back to the filter, which can enhance the moisture and organic content in the filter. This leads to improved microbial activity, helping to break down organic matter more efficiently. By promoting a healthier microbial environment, the conditions that attract and support filter fly populations can be reduced. These pests thrive in poorly maintained environments with excessive organic material and stagnant conditions. The increased flow and recirculation improve the overall treatment process, making it less hospitable for filter flies, thereby reducing their presence. In contrast, other issues like odor problems, pH imbalance, and foaming typically arise from different factors within the treatment process. Odor issues may stem from anaerobic conditions or the presence of certain compounds, while pH balance depends on the characteristics of the wastewater and the treatment process itself. Foaming is usually related to the presence of surfactants or specific microbial activity, which increasing recirculation may not directly resolve.