A grit removal unit for a wastewater system for removing grit from a fluid, comprising: a grit removal chamber defined by a bottom surface and a vertical wall extending up from said bottom surface, said grit removal chamber having a substantially central vertical axis; a grit storage chamber disposed below said grit removal chamber, and at least one opening through said grit removal chamber bottom surface through which grit from said grit removal chamber may pass into said grit storage chamber; first, second and third layer plates (40a, 40b, 40c) in said grit removal chamber, said layer plates (40a, 40b, 40c) being inverted truncated cones annular around said central vertical axis and vertically spaced from one another, wherein said first and third layer plates (40a, 40c) are spaced from the grit removal chamber vertical wall to allow fluid flow between the first and third layer plates (40a, 40c) and the grit removal chamber vertical wall, and said second layer plate is between said first and third layer plates (40a, 40c) and is substantially adjacent the grit removal chamber vertical wall to substantially block fluid flow between the second layer plate and the grit removal chamber wall; lamella settlers in said grit removal chamber around said central vertical axis and above said layer plates (40a, 40b, 40c); an influent opening in said grit removal chamber vertical wall below said layer plates (40a, 40b, 40c) wherein fluid and grit enters said grit removal chamber through said influent opening; and an effluent opening in said grit removal chamber vertical wall above said lamella settlers wherein said fluid exits said grit removal chamber through said effluent opening. a grit removal chamber defined by a bottom surface and a vertical wall extending up from said bottom surface, said grit removal chamber having a substantially central vertical axis; a grit storage chamber disposed below said grit removal chamber, and at least one opening through said grit removal chamber bottom surface through which grit from said grit removal chamber may pass into said grit storage chamber; first, second and third layer plates (40a, 40b, 40c) in said grit removal chamber, said layer plates (40a, 40b, 40c) being inverted truncated cones annular around said central vertical axis and vertically spaced from one another, wherein said first and third layer plates (40a, 40c) are spaced from the grit removal chamber vertical wall to allow fluid flow between the first and third layer plates (40a, 40c) and the grit removal chamber vertical wall, and said second layer plate is between said first and third layer plates (40a, 40c) and is substantially adjacent the grit removal chamber vertical wall to substantially block fluid flow between the second layer plate and the grit removal chamber wall; said first and third layer plates (40a, 40c) are spaced from the grit removal chamber vertical wall to allow fluid flow between the first and third layer plates (40a, 40c) and the grit removal chamber vertical wall, and said second layer plate is between said first and third layer plates (40a, 40c) and is substantially adjacent the grit removal chamber vertical wall to substantially block fluid flow between the second layer plate and the grit removal chamber wall; lamella settlers in said grit removal chamber around said central vertical axis and above said layer plates (40a, 40b, 40c); an influent opening in said grit removal chamber vertical wall below said layer plates (40a, 40b, 40c) wherein fluid and grit enters said grit removal chamber through said influent opening; and an effluent opening in said grit removal chamber vertical wall above said lamella settlers wherein said fluid exits said grit removal chamber through said effluent opening.