11th International Drainage Symposium August 30-September 2, 2022 Des Moines, Iowa

1. Can woodchip
bioreactors be
used at a
watershed scale?
Gary Feyereisen USDA-ARS, St. Paul, MN
Ehsan Ghane MI State U., East Lansing, MI
Mark Williams USDA-ARS, West Lafayette, IN
Jeffrey Coulter U. of MN, St. Paul, MN
Denitrification bioreactors as a structural water
quality measure at watershed scale:
Performance & lessons learned

2. 45% Nutrient load reduction: How?
• Approaches
• In-field, management
• Land use, vegetative changes
• Structural practices; edge-of-field, ditch, or stream
• Reduce concentrations by 45%, same flow
• Reduce flow by 45%, same concentrations
• Combination of reductions in flow & conc’ns
• Treat a % of flow with corresponding % conc’n reduction

3. 2016 2017
10% 22%
60%
53% 59%
57%

4. 80% 85%
77% 78%

5. Nitrate Removal Rates (NRR)
Date Temp (°C) BR-1 BR-2 BR-3
5/2/17 7.0 2.6 0.7 -0.7
5/10/17 7.3 4.6 3.0 0.0†
5/16/17 8.0 4.7 2.4
5/30/17 9.2 5.6 2.7 0.4
6/6/17 9.7 9.8 10.9
6/13/17 11.6 4.0 7.8 3.4
6/19/17 12.2 6.3 6.4 0.6†
6/27/17 12.2 4.2 6.0
7/5/17 12.2 1.8† 6.5†
7/11/17 12.5 1.9†
7/18/17 12.8 1.3†
7/25/17 13.1 1.2†
Average 4.0 5.1 0.8
𝑁𝑅𝑅(𝑚𝑔 𝑁 𝑚−3
𝑑−1
) = 𝐶𝑖 − 𝐶𝑜 ∗ 𝑄/𝑉𝑜𝑙𝑏𝑒𝑑
Avg. NRR May thru July
(mg N m-3 d-1)
BR1: 4.0
BR2: 5.1
BR3: 0.8

6. Total – P Concs:
Mostly
reduction, but
episodic losses
apparent.

8. Recharge: August – September 2020

9. Rock Inlet; Sediment Cut-Off

10. Lessons Learned
+s / Benefits
• Involvement of local
Drainage Dept., SWCD
personnel, engineers,
and producers
• Centralized
management
• Potential for nutrient
reduction verification
• Longer flow duration
between events
• Performance as
expected / cascading
design can work
Challenges
• Costs: design,
construction, m&r
• Design: head/plumbing
• Media quality, availability,
& cost
• Sediment
• Increase in frequency of
extreme events
• Cold performance (e.g.
<5°C)
45% Reduction: A way to do it
Fraction of Flow Treated: 60%
Required Removal Efficiency: 75%

11. Lessons Learned
+s / Benefits
• Involvement of local
Drainage Dept., SWCD
personnel, engineers,
and producers
• Centralized
management
• Potential for nutrient
reduction verification
• Longer flow duration
between events
• Performance as
expected / cascading
design can work
Challenges
• Costs: design,
construction, m&r
• Design: head/plumbing
• Media quality, availability,
& cost
• Sediment
• Increase in frequency of
extreme events
• Cold performance (e.g.
<5°C)
45% Reduction: A way to do it
Fraction of Flow Treated: 60%
Required Removal Efficiency: 75%

12. Thank you! Questions & Discussion
Funding acknowledgments &
thanks:
• Faribault County Drainage
Authority & SWCD
• Merissa Lore
• Michele Stindtman
• Minn. Dept. Agriculture
• Mark Dittrich
• Margaret Wagner
• University of Minn.
• Minn. Corn Research & Promotion
Council
• USDA-ARS St. Paul, Minn.
Technicians:
(R) Todd Schumacher, USDA-ARS
(L) Scott Matteson, Minn. Dept. Ag.
(C) Chad Viland, Faribault Co. SWCD

14. Questions for me
• Design criteria used? Treat 25% of peak flow.

15. 616 mm (45-y avg. 364 mm)
87 mm

17. Average county
tile line (Inlet)
NO3-N + NO2-N
concentration:
16.1 mg N L-1
Bioreactor
Outlets, Avg.:
BR1: 12.7
BR2: 11.9
BR3: 12.8

18. Total-P Concs:
Mostly
reduction,
BUT
episodic losses
apparent.

19. Lessons Learned
+s / Benefits
• Involvement of local
Drainage Dept., SWCD
personnel, engineers,
and producers
• Centralized
management
• Potential for nutrient
reduction verification
• Longer flow duration
between events
• Performance as
expected / cascading
design can work
Challenges
• Costs: design,
construction, m&r
• Design: head/plumbing
• Media quality, availability,
& cost
• Sediment
• Increase in frequency of
extreme events
• Cold performance (e.g.
<5°C)
45% Reduction: A way to do it
Fraction of Flow Treated: 60%
Required Removal Efficiency: 75%