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 18, 2023 2

Project location

April 18, 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 18, 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 18, 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 18, 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 18, 2023 7

9/25/2003

April 18, 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 18, 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 18, 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 18, 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 18, 2023 12

To-do list

Installation of SCADA system Surge tank addition Installation of weather station Re-calibration of weir and flume meters