Abstract: A clarifier can comprise a floor, inner and outer walls that each extends upwardly from the floor such that a tank is at least partially defined by the inner wall and a launder channel is at least partially defined between the inner and outer walls and is disposed along at least a majority of a periphery of the tank. A launder cover comprising one or more flexible sheets can be disposed over at least a majority of the launder channel. Each of the sheet(s) can have opposing inner and outer edges, the inner edge coupled to the inner wall and the outer edge coupled to the outer wall, and can be configured such that, when a single one of the inner and outer edges is decoupled from the inner and outer walls, the sheet is deformable to at least partially uncover the launder channel.

Abstract: A clarifier can comprise a floor, inner and outer walls that each extends upwardly from the floor such that a tank is at least partially defined by the inner wall and a launder channel is at least partially defined between the inner and outer walls and is disposed along at least a majority of a periphery of the tank. A launder cover comprising one or more flexible sheets can be disposed over at least a majority of the launder channel. Each of the sheet(s) can have opposing inner and outer edges, the inner edge coupled to the inner wall and the outer edge coupled to the outer wall, and can be configured such that, when a single one of the inner and outer edges is decoupled from the inner and outer walls, the sheet is deformable to at least partially uncover the launder channel.

Abstract: A clarifier can comprise a floor, inner and outer walls that each extends upwardly from the floor such that a tank is at least partially defined by the inner wall and a launder channel is at least partially defined between the inner and outer walls and is disposed along at least a majority of a periphery of the tank. A launder cover comprising one or more flexible sheets can be disposed over at least a majority of the launder channel. Each of the sheet(s) can have opposing inner and outer edges, the inner edge coupled to the inner wall and the outer edge coupled to the outer wall, and can be configured such that, when a single one of the inner and outer edges is decoupled from the inner and outer walls, the sheet is deformable to at least partially uncover the launder channel.

Abstract: A clarifier can comprise a floor, inner and outer walls that each extends upwardly from the floor such that a tank is at least partially defined by the inner wall and a launder channel is at least partially defined between the inner and outer walls and is disposed along at least a majority of a periphery of the tank. A launder cover comprising one or more flexible sheets can be disposed over at least a majority of the launder channel. Each of the sheet(s) can have opposing inner and outer edges, the inner edge coupled to the inner wall and the outer edge coupled to the outer wall, and can be configured such that, when a single one of the inner and outer edges is decoupled from the inner and outer walls, the sheet is deformable to at least partially uncover the launder channel.

Abstract: A method of treating subsurface layers of the earth to either control movement of the subsurface water or build strength of the subsurface layers, or both, characterized by injecting at a predetermined depth and at a plurality of predetermined, spaced apart locations a limefly ash slurry consisting essentially of water, particulate hydrated lime, particulate fly ash and a surfactant. Also disclosed are the preferred proportions, or concentrations, of the components of the slurry; and a finished product; such as, a railroad track subgrade and ballast supporting cross-ties and rails, the subgrade having been injected with masses of lime and fly ash slurry to leave residual masses of lime and fly ash disposed in fissures and any ballast pockets along the railroad track, the masses having a proportion of lime to fly ash in the range of one to 1:1 to 1:3.