A Wastewater Treatment Facility's Experience with a Fresh Water Sponge Infestation and Methods Used in Control and Eradication

When a fungus–like growth was discovered at the Prescott Valley, Ariz., wastewater treatment facility, staff had to identify the invaders and then find a suitable eradication method. Chlorine was initially considered, but could cause many secondary issues at the facility. After extensive online research, as well as asking other facilities, the staff found out they were dealing with bryozoans, or freshwater sponges. Using methods proven successful in Asia as a starting point, which included dosing with potassium permanganate, staff developed a laboratory to test the eradication method before using it on the entire facility. After a thorough cleaning and dosing with potassium permanganate, the staff noticed a decline in the sponges. Subsequent treatments have been required, but the sponge pollution remains under control and no longer affects plant operation.