Foaming and excessive surface scum build-up are two process problems that can seriously affect a digester’s ability to operate at full capacity. Vaughan Co. has available a scum nozzle and Foambuster foam suppression system that can help in controlling surface scum and digester foam when all else fails.

Located at the upper level of the digester, the scum nozzle is designed to provide added upper mixing just below the surface to effectively re-suspend floating solids and to prevent stratification, while the Foambuster nozzle creates an even spray across the top of the sludge surface to break down foam after it is generated. Because Rotamix’s mixing energy will rotate the upper surface of the tank below the stationary Foambuster, most of the upper digester surface foam is broken down by the Foambuster spray.

Unlike other forms of foam control that use liquids from outside of the process, Vaughan Co.’s scum and Foambuster nozzles are designed to be integrated with the main mixing system. By using digester sludge with flow provided from the Vaughan mixing chopper pump, digester dilution problems are avoided.