AN INVESTIGATION OF FINE SEDIMENT MIXING WITHIN FREE-FLOWING AND SURCHARGED MANHOLES

Previous studies of the effects of manholes on longitudinal dispersion has concentrated on the spreading of solutes, This papers presents ne w data describing the influence of a surcharged and free-flowing manho le structure on the longitudinal dispersion of a fine suspended materi al, The effects of benching within the manhole structure are also illu strated. Laser Induced Fluorescence (LIF) techniques have been used to provide a qualitative description of the mixing processes present wit hin a surcharged manhole, Nephelometric results have provided estimate s of the parameters required to simulate the mixing effects using eith er increase in variance or aggregated dead zone techniques, A prelimin ary attempt at describing these observations using available software is discussed and recommendations for future developments are made. (C) 1998 IAWQ. Published by Elsevier Science Ltd.