Aspects provide for a Whitewater processing system suitable for managing an ejected Whitewater spray during operation of a paper or board making machine. A de-air system may provide for improved removal of air from the Whitewater. A calming system may reduce turbulence in a liquid flow, reducing turbulence in the flume. The de-air system and calming system may be disposed together or separately. Certain aspects may be implemented with a turbine (e.g., used to generate electricity from the Whitewater spray). Some aspects may provide for improved handling of variable spray velocities.