Treatment Devices

You can select from several treatment devices including:

MUSIC uses the Universal Stormwater Treatment Model (USTM) to calculate the treatment processes that take place in most of the treatment devices - wetlands, vegetated swales, ponds, tanks and sediment basins, as well as in the ponding (extended detention) zones of infiltration, bioretention and media filtration systems. For more information regarding the details of the USTM, you should read The Universal Stormwater Treatment Model.

As with source nodes, you can edit the properties of the treatment nodes by:

Double clicking the left mouse button over the treatment device icon; or

Clicking the right mouse button on the selected treatment device icon and then selecting the Edit Properties menu item.

You will then be presented with a dialogue box, which contains different parameters regarding the physical characteristics of the treatment node. The dialogue box also contains the k and C* parameters used to describe the first order kinetic model used to simulate the treatment processes taking place within the treatment node.

Note: In music and above, you can view a simple summary of the water balance (e.g. evapotranspiration, infiltration, overflow, etc) within a node by using the Node Water Balance item under the Statistics sub-menu; refer to MUSIC Output.

Number of CSTR Cells

The USTM models the treatment of each of the contaminants using a series of continuously stirred tank reactors (CSTR), each with a first order kinetic model to describe the exponential decay of the contaminant. Below Figure shows the most appropriate CSTR for various shapes.

k and C* Values

The first order kinetic model adopted in the USTM is described by definition of k, the exponential decay rate constant and C*, the background concentration. Refer to the Universal Stormwater Treatment Model and Appendix G: Selecting Appropriate k and C* Values.

C** Values

Defines the baseflow background concentration which applies when the flow conditions are operating around baseflow. For more information regarding the C* and C** properties, see Universal Stormwater Treatment Model.

Threshold Hydraulic Loading for C**

Defines the threshold hydraulic loading, below which the C** concentration is adopted in the first order kinetic model. The threshold is defined in m/year.