An investigation by company personnel, headed by Dave English, operations supervisor, revealed that short circuiting was taking place in the final polishing lagoon. Not only were they experiencing short circuiting in the lagoon, but the levels of BOD and SS were higher at the discharge than at the inlet. In the wïnter they noticed that ice formed around the edges of the lagoon and they could see a straight path of flowing water from the inlet to the outlet. The ice was able to form because of slower or stagnant flow velocities in the greater part of the lagoon. The majority of the wastewater was traveling quickly straight from the inlet to the outlet, without allowing enough retention time needed for the biological process necessary for the reduction of BOD and SS work.
Environetics has dealt with many industries and municipalities struggling with the same short circuiting problem in their lagoons. The solution is to install a floating baffle system to prevent short circuiting, improve mixing, increase retention time, and improve the overall efficiency of the lagoon. The Director fioating baffle system guides the wastewater through a serpentine pattern in the lagoon, utilizing the entire lagoon area and increasing retention time. This provides extended time for the natural biological treatment process to take place. Citizens Utilities installed one 300' baffle and one 100' baffle in their existing lagoon. Since the installation of the Director fioating baffle system, they have reduced their BOD and SS excursions by 90%.
An added (and unexpected) benefit of installing this system was the elimination of a beaver problem. Prior to installation, beavers had been building dams in the area and causing debris to get trapped in the outfall.