Wasp Model, an Effective Method to Improve Water Quality in Water Treatment Process

WASP Model, an Effective Method to
      EUTRO predicts dissolved oxygen (DO), carbonaceous biochemical   oxygen demand (CBOD), phytoplankton, carbon, chlorophyll-a,   ammonia, nitrate, organic nitrogen, and orthophosphate   in bed and overlying waters by combining a kinetic structure   adapted from the Potomac Eutrophication Model with the WASP   transport structure.
      DYNHYD simulates variable tidal cycles, wind, and unsteady   flows. It also produces an output file that supplies flows,   volumes, velocities, and depths (time averaged) for the WASP   modeling system.
    TOXI, EUTRO, and DYNHYD can be achieved because of the basic principle of the WASP model that is based on the fundamental form of conservation equations.
Model Principle
proper loading, transport, and transformation parameters, and via expanding
infinitesimally small control volumes into larger adjoining”segments” (Zuxin Xu et al., 2006). The volume and dimensions of the control volume are given by the differential lengths (dx, dy, and dz) along each of the axes(x, y, and z) where the volume is the product of these lengths (V= dxdydz). The conservation equation can be simply illustrated as:
Eq (1) means the time rate of change or accumulation per unit volume within the control volume is equal to the sum of the fluxes ( rate of transport an intrinsic property), through all control surfaces(open boundaries or faces of the control volume). The flux change per unit length along the axis is equal to the flux in minus flux out. And the change in the flux is also the rate of the change per unit length along the axis multiplied by the differential length of the control volume. Thus, a six fluxes conservation equation becomes:
Eq (3) can be defined as the basic principle of WASP.
When the water quality model is three dimensional, the equation can be defined as:
When the water quality model is two dimensional, the equation might be