The effect of seasonal variations on floc morphology in the activated sludge process.

The effect of seasonal variations on floc formation in the activated sludge process (ASP) was studied in a municipal wastewater treatment plant in Finland nearly 16 months. Floc formation was measured with an online optical monitoring device, and results were correlated with the temperature of the upcoming wastewater and the treatment efficiency of the ASP. Results showed that floc formation has a clear, seasonal pattern, with flocs in summer being larger and rounder and having fewer filaments and small particles.

A comparison between floc morphology and the effluent clarity at a full-scale activated sludge plant using optical monitoring.

A charge-coupled device camera was used for the optical monitoring of activated sludge flocs and filaments, and the image analysis results were compared with the effluent clarity at a full-scale activated sludge plant during a three-month period. The study included a maintenance stoppage at the wastewater treatment plant, which was followed by a settling problem. Thus, the study presents the development of floc morphology from poor flocculation to good flocculation.