A fiber bed assembly for a forward-flow fiber bed mist eliminator used to remove aerosols from a moving gas stream, the fiber bed assembly comprising: a fiber bed support having an upper end, a lower end, and a substantially cylindrical wall extending between the upper and lower ends defining an exterior upstream space outside the wall and an interior downstream space inside the wall, the wall including openings therein to permit the gas stream to move generally freely through the wall from the exterior upstream space to the interior downstream space; a fiber bed supported by the fiber bed support and generally blocking the wall openings so that the gas stream passes through the fiber bed moving from the exterior upstream space to the interior downstream space, the fiber bed comprising collecting fiber media and having a top, a bottom, a length extending between the top and the bottom, an upstream surface and a downstream surface; a base adjacent the lower end of the fiber bed support blocking movement of the gas stream down through a lower end of the interior downstream space; an opening adjacent an upper end of the fiber bed support for exit of the gas stream from the interior downstream space; characterized in that: said base comprising a top wall for blocking downward flow of the gas stream in the interior downstream space, a side wall projecting down from the top wall and in generally opposing relation with a portion of the downstream surface of the fiber bed for blocking the flow of the gas stream from the fiber bed into the downstream space through said downstream surface portion, and a flange extending from the side wall under the bottom of the fiber bed, the side wall having a length extending between the top wall and the flange whereby the side wall extends upward into the interior downstream space a distance such that aerosols collected in said interior downstream space develop a pressure head sufficient to cause the aerosols to drain by the influence of gravity from the top wall toward the flange; wherein the length of said side wall is in the range of 5-30% of the overall length of the fiber bed. a fiber bed support having an upper end, a lower end, and a substantially cylindrical wall extending between the upper and lower ends defining an exterior upstream space outside the wall and an interior downstream space inside the wall, the wall including openings therein to permit the gas stream to move generally freely through the wall from the exterior upstream space to the interior downstream space; a fiber bed supported by the fiber bed support and generally blocking the wall openings so that the gas stream passes through the fiber bed moving from the exterior upstream space to the interior downstream space, the fiber bed comprising collecting fiber media and having a top, a bottom, a length extending between the top and the bottom, an upstream surface and a downstream surface; a base adjacent the lower end of the fiber bed support blocking movement of the gas stream down through a lower end of the interior downstream space; an opening adjacent an upper end of the fiber bed support for exit of the gas stream from the interior downstream space; characterized in that: said base comprising a top wall for blocking downward flow of the gas stream in the interior downstream space, a side wall projecting down from the top wall and in generally opposing relation with a portion of the downstream surface of the fiber bed for blocking the flow of the gas stream from the fiber bed into the downstream space through said downstream surface portion, and a flange extending from the side wall under the bottom of the fiber bed, the side wall having a length extending between the top wall and the flange whereby the side wall extends upward into the interior downstream space a distance such that aerosols collected in said interior downstream space develop a pressure head sufficient to cause the aerosols to drain by the influence of gravity from the top wall toward the flange;