There is provided a computer-implemented method of executing a query plan against a database. In a particular embodiment, the system includes a series of alternating baffles disposed along a length of a tank, where the series of alternating baffles define a vertical tortuous flow path of the fluid from a first end of the tank to a second end of the tank to cause solids to settle out of the fluid. In addition, a digital pad is provided along aside facing in a second direction opposite to the first direction, that is, a second side facing the first side. The DCT hardware unit implements an orthogonal 4\xd74 DCT having an odd portion that applies first and second internal factors that are related to a scaled factor such that the scaled factor equals a square root of a sum of a square of the first internal factor plus a square of the second internal factor.