|  |   | 
| Item Number | Description | 
|---|---|
| 1 | Inflow from catch basin | 
| 2 | Grit-filter bag | 
| 3 | Inverted elbow for trapping oil and other floatables | 
| 4 | Series of (4) skimmers which transfer clarified water from 7.6-10.2 cm below the surface of water to next chamber | 
| 5 | Slotted PVC pipe infiltrates partially-treated storm water from last chamber into constructed wetland gravel substrate | 
| 6 | Water flows through root zone of wetlands where microbes metabolize petroleum hydrocarbons, nitrogen, and other pollutants. Plants uptake metals, and gravel soils filter bacteria, phosporus and metals. | 
| 7 | Slotted PVC pipe exfiltrates treated water to outlet | 
| 8 | Outlet control valve regulates discharge rate (normally set at 0.95 L/m and can be closed in the event of a hazardous materials spill | 
| 9 | Pent-nuts are removed to open manhole cover for maintenance purposes. |