Abstract: An apparatus and method for forming a fluid-tight seal at an aperture where a rotatable shaft passes through a barrier into a barred fluid. A mechanical seal is mounted on the rotatable shaft. A stationary portion of the mechanical seal is elastomerically joined to the barrier by an elastomeric joint to form a substantially fluid-tight chamber bounded by the mechanical seal, the elastomeric joint and the barrier. The stationary portion of the mechanical seal is sealingly positioned adjacent to the rotatable portion of the mechanical seal. The elastomeric joint absorbs relative radial and axial motion between the barrier and the mechanical seal. The chamber is flushed with a flushing fluid. The stationary portion of the mechanical seal is rigidly anchored to the stationary shaft drive housing. The rotatable portion of the mechanical seal is attached to the rotatable shaft at such a distance from a stationary drive shaft housing that the resistance of the shaft to radial deflection is substantially maximum.

Abstract: Biofouling in recirculating water systems may be controlled by admixing or otherwise providing 1-bromo-3-chloro-5, 5-dimethylhydantoin ("BCDMH") to the water at a level effective to control biological film-forming organisms and thereafter maintaining the BCDMH concentration at a level sufficient substantially to inhibit regrowth of such organisms.