R. S. Govindaraju, J. E. Alleman, T. J. Cooper,R. S. Govindaraju, J. E. Alleman, T. J. Cooper,T. P. Chan, V. JainT. P. Chan, V. Jain
School of Civil EngineeringSchool of Civil EngineeringPurdue UniversityPurdue University
(SPR-2455, SPR-2456, SPR-2487)(SPR-2455, SPR-2456, SPR-2487)
I-70 Greenfield Rest AreaI-70 Greenfield Rest AreaConstructed Wetland Constructed Wetland Wastewater Treatment Wastewater Treatment System Research ProjectSystem Research Project
March 19, 2004March 19, 2004
April 21, 2023 2
Project location
April 21, 2023 3
ST-2 ST-1
W-1 W-2W-3
Bio
fiel
d
F-2
AS-3
AS-2
AS-1
AS-4
F-3
F-1
M-1
M-2
LS-2
LS-1
LS-3
LS-4
M-3
M-4
EffluentInflow
Septic tank
Automatic sampler
V-notch weir
Lift station / dosing chamberMagnetic flow meter
Wetland cell
Rec
ircu
lati
on
North RestStop
South RestStop
Design layout
April 21, 2023 4
Hydraulic issues
Undersized wetland dosing pumps (LS-1) Surges from the eastbound side High rate of recirculation (~83%)
Solutions Reduce recirculation rate Addition of surge tank
April 21, 2023 5
Flow measurements
Weir / flume measurements are NOT accurate Backup due to overcapacity of LS-1 and LS-4 Inadequate calibration Inherent error due to low flows
Magnetic flow meters More reliable Erroneous spikes in the data
April 21, 2023 6
02/01 02/08 02/15 02/220
1000
2000
3000
4000
5000
6000
Date
Da
ily F
low
To
tal (
ga
l)Inflow (M-1)
Outflow (M-4)
Flume 1
Flume 2
Flume 3
April 21, 2023 7
9/25/2003
April 21, 2023 8
02/01 02/08 02/15 02/22 02/29 03/070
2000
4000
6000
8000
10000
12000
Date
Da
ily F
low
To
tal (
ga
l)Inflow (M-1)
Outflow (M-4)
Biofield (M-3)
02/01 02/08 02/15 02/22 02/29 03/07150
200
250
300
350
400
450
Da
ily S
tre
am
flow
(cf
s)
Big Blue River
April 21, 2023 9
Wastewater test results 12/22/2003
Sample pHTSS
(mg/L)NH3-N(mg/L)
BOD5
(mg/L)
Sampler #1 8.80 110 83 280
Sampler #3 8.24 60 62 225
Sampler #4 8.17 60 65 215
April 21, 2023 10
Wastewater test results 3/5/2004
Sample pHTSS
(mg/L)NH3-N(mg/L)
BOD5
(mg/L)
Sampler #1 8.40 140 136 310
Sampler #2 7.94 110 122 294
Sampler #3 7.72 60 131 310
Sampler #4 7.65 60 80 226
April 21, 2023 11
Current status
Only receiving wastewater from west-bound side
No recirculation Flow-through with no drain-and-fill Biofield shut down till desired effluent quality
is attained
April 21, 2023 12
To-do list
Installation of SCADA system Surge tank addition Installation of weather station Re-calibration of weir and flume meters