FILTRATION APPARATUS COMPRISING VACUUM PRESSURE AND GRAVITY FILTERS-NAMELY, DRUM, DISC, LEAF, PAN, AND ENDLESS BELT VACUUM AND PRESSURE FILTERS; AND SAND, CARBON, CHEMICAL AND OTHER GRANULAR SOLIDS MEDIA GRAVITY FILTERS; DRAINAGE SCREENS; FILTER PRESSES; TRICKLING FILTERS; FILTER MEDIA; AND PARTS AND COMPONENTS FOR THE ABOVE FILTRATION APPARATUS