A gross pollutant trap is a treatment device designed to capture coarse sediment, trash and vegetation matter carried in the stormwater. music assumes that gross pollutant traps have very small pool volumes, and therefore, no hydrological routing is simulated within the GPT node.
In MUSIC-X, Generic Treatment Node represents the GPT as well. music requires you to describe the performance of the GPT (using a graphical function editor) for each pollutant type, and does not provide default performance figures. The reason for this is that there are many GPTs available, including several proprietary products, which may perform very differently. Appendix C provides a summary of one study of GPT performance, undertaken by the CRC for Catchment Hydrology (Allison et al., 1996; Walker et al., 1999).
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When the stormwater inflow rate exceeds the user-defined High Flow Bypass amount (in units of m3/s), only a flow rate equal to the High Flow Bypass (less that specified in any Low Flow Bypass) will enter and be treated by the GPT. All of the stormwater flow in excess of the High Flow Bypass will bypass the trap and will not be treated by the trap.
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Transfer Functions
For each pollutant (TSS, TN, TP and gross pollutants), performance of the GPT can be described using one of three options:
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- 50% of the flow with 50.2 mg/L reduced to 50.2•0.4 = 20 mg/L and 50% of the flow not captured, at 50.2 mg/L gives the final value of 0.5•20+0.5•50.2 = 35.1mg/L.
Time | Inflow (m3/s) | Totaloutflow (m3/s) | TSSinflow(mg/l) | TSSoutflow(mg/l) | TSStotaloutflow(mg/l) |
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25/04/1970 19:54 | 0.237 | 0.237 | 234 | 93.5 | 93.5 |
25/04/1970 20:00 | 1.63 | 1.63 | 50.2 | 35.1 | 35.1 |
To use the function editor:
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