From: Revisiting Design Criteria for Stormwater Treatment Systems, Part 4
Figure One
| Figure 1. Unit Processes in Wet Basins |
Water |
Aerobic |
Dissolved oxygen (DO) >3 mg/L |
Eh > 300 mv |
- Diurnal pH: CaCO3/PO4 precipitation
- Bacteria nitrification - organic N to NH3, NH3 to NO3
- Aerobic reduction of organics
- Free floating plant/algae uptake
- Algae/bacteria biofilm uptake of N,P, metals
- Sorption of colloids to plants/biofilm
|
Soil |
Aerobic |
DO 1 to 3 mg/L |
Eh > 300 mv |
- Bacteria nitrification - organic N to NH3, NH3to NO3
- Metals sorb to organics in soils
- Precipitation PO4 with Al, Fe+3, Ca in soil
- Sorption of toxic organics to humic organics
- Aerobic reduction of organics
- Rooted plant uptake
- Metals sorb to Fe-Al Oxide complexes
|
|
Facultative |
DO<1 mg/L |
Eh = 100 to 300 mv |
- Bacteria denitrification - NO3 to N2
- Reduction of Fe+3 to Fe+2 with loss of PO4
- Precipitation PO4 with Al, Ca in soil
- Rooted plant uptake
|
|
Facultative |
DO<1 mg/L |
Eh = -100 to -100 mv |
- Reduction of Fe+3 to Fe+2 with loss of PO4
|
|
Anaerobic |
DO 0 mg/L |
Eh = -200 to -100 mv |
- Reduction of SO4 to S-
- S- complex with metals
- Anaerobic reduction of organics
- Rooted plant uptake
|
May-June 2005
From: Revisiting Design Criteria for Stormwater Treatment Systems, Part 4
Figure One
| Figure 1. Unit Processes in Wet Basins |
Water |
Aerobic |
Dissolved oxygen (DO) >3 mg/L |
Eh > 300 mv |
- Diurnal pH: CaCO3/PO4 precipitation
- Bacteria nitrification - organic N to NH3, NH3 to NO3
- Aerobic reduction of organics
- Free floating plant/algae uptake
- Algae/bacteria biofilm uptake of N,P, metals
- Sorption of colloids to plants/biofilm
|
Soil |
Aerobic |
DO 1 to 3 mg/L |
Eh > 300 mv |
- Bacteria nitrification - organic N to NH3, NH3to NO3
- Metals sorb to organics in soils
- Precipitation PO4 with Al, Fe+3, Ca in soil
- Sorption of toxic organics to humic organics
- Aerobic reduction of organics
- Rooted plant uptake
- Metals sorb to Fe-Al Oxide complexes
|
|
Facultative |
DO<1 mg/L |
Eh = 100 to 300 mv |
- Bacteria denitrification - NO3 to N2
- Reduction of Fe+3 to Fe+2 with loss of PO4
- Precipitation PO4 with Al, Ca in soil
- Rooted plant uptake
|
|
Facultative |
DO<1 mg/L |
Eh = -100 to -100 mv |
- Reduction of Fe+3 to Fe+2 with loss of PO4
|
|
Anaerobic |
DO 0 mg/L |
Eh = -200 to -100 mv |
- Reduction of SO4 to S-
- S- complex with metals
- Anaerobic reduction of organics
- Rooted plant uptake
|