DENITRIFICATION WOODCHIP BIOREACTORS FOR NITRATE TREATMENT Laura Christianson, Ph.D. The Conservation Fund

Transcription

1 DENITRIFICATION WOODCHIP BIOREACTORS FOR NITRATE TREATMENT Laura Christianson, Ph.D. The Conservation Fund July 2014 Des Moines, Iowa

2 Wood-Based Enhanced-Denitrification Need to transform reactive nitrogen to reduce the global nitrogen cascade Hypoxic zones Human health Balance with food production History Canada Alternative septic-system design Tile drainage treatment New Zealand Groundwater treatment Millenium Ecosystem Assessment, 2005 Diaz and Rosenburg, 2008

3 Wood-Based Enhanced-Denitrification Need to transform reactive nitrogen to reduce the global nitrogen cascade Hypoxic zones Human health Balance with food production History Canada Alternative septic-system design Tile drainage treatment New Zealand Groundwater treatment (Source: Matt Collins, Scientific American)

4 Wood-Based Enhanced-Denitrification Need to transform reactive nitrogen to reduce the global nitrogen cascade Hypoxic zones Human health Balance with food production Opportunity to enhance denitrification in the landscape Carbon source Anoxic conditions Terminal electron acceptor: nitrate Novel wood-based designs in the 1990 s 5C + 4NO 3 + 2H 2 O = N 2 +4HCO 3 + CO 2

5 Christianson and Helmers, 2011

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7 Other Wood-based Applications

8 Three drainage bioreactors in Iowa Bioreactor Location Installed Drainage Area (ha) Design Flow Rate (gpm) L x W x D (m) Vol. (m 3 ) L:W Greene Co. Central Iowa Aug (47 ac) gpm 15.2 x 7.6 x Hamilton Co. Central Iowa June (50 ac) gpm 30.5 x 3.7 x Research Farm Northeast Iowa April (35 ac) gpm 36.6 x 2.4 (bottom) x Christianson et al., 2012 (Trans. ASABE); Project partner: Iowa Soybean Association

9 Three drainage bioreactors in Iowa Bioreactor Location Installed Drainage Area (ha) Design Flow Rate (gpm) L x W x D (m) Vol. (m 3 ) L:W Greene Co. Central Iowa Aug (47 ac) gpm 15.2 x 7.6 x Hamilton Co. Central Iowa June (50 ac) gpm 30.5 x 3.7 x Research Farm Northeast Iowa April (35 ac) gpm 36.6 x 2.4 (bottom) x Christianson et al., 2012 (Trans. ASABE); Project partner: Iowa Soybean A.

10 Three drainage bioreactors in Iowa Bioreactor Location Installed Drainage Area (ha) Design Flow Rate (gpm) L x W x D (m) Vol. (m 3 ) L:W Greene Co. Central Iowa Aug (47 ac) gpm 15.2 x 7.6 x Hamilton Co. Central Iowa June (50 ac) gpm 30.5 x 3.7 x Research Farm Northeast Iowa April (35 ac) gpm 36.6 x 2.4 (bottom) x Christianson et al., 2012 (Trans. ASABE)

11 Where have wood-based enhanceddenitrification technologies been used?

12 Wood-based Denitrification Performance Source Site Influent NO 3 - -N Conc. Percent Reduction Nitrate-N Removal Rate van Driel et al., 2006 Ontario, Canada 11.8 mg/l g N/m 2 /d Jaynes et al., 2008 Central Iowa 19.1 to 25.3 mg/l 40% - 65% 0.62 g N/m 3 /d Woli et al., 2010 East-Central Illinois 2.8 to 18.9 mg/l 23% - 50% 6.4 g N/m 3 /d Christianson et al., 2012 Central Iowa 1.2 to 8.5 mg/l 22% - 74% g N/m 3 /d Christianson et al., 2012 Northeast Iowa 9.9 to 13.2 mg/l 12% - 14% g N/m 3 /d Christianson et al., 2012 Central Iowa 7.7 to 15.2 mg/l 27% - 33% g N/m 3 /d Christianson et al., 2012 Central Iowa 7.7 to 9.6 mg/l 49% - 57% g N/m 3 /d Christianson et al., 2012 (Applied Eng. In Ag.)

13 Factors affecting nitrate removal Christianson et al., 2013 (Eco. Eng. 52: ) Sample Date Flow rate (L min -1 ) Retention time* (hours) Water temp. ( C) Inlet DO (mg/l) N load reduction (% Mass) May May June July August *Modified based upon conservative tracer testing

14 HRT is a primary reactor design parameter Hydraulic Retention Time (τ) V Q ρ is the porosity of the packing media Total porosity vs. effective/drainable porosity V is the active reactor volume Q is the volumetric flow rate through the reactor. Courtesy: MnDrive Bioreactor Project, University of Minnesota

15 Christianson and Helmers, 2011 Illustration by John Petersen

16 Retention Time: Ideal Example Inflow: 5 mg/l Dissolved Oxygen 15 mg/l Nitrate-N (ideal flow rate) Example Internal Sample: 0 mg/l Dissolved Oxygen 15 mg/l Nitrate-N Example Outflow: 0 mg/l Dissolved Oxygen 3 mg/l Nitrate-N Christianson and Helmers, 2011 Illustration by John Petersen

17 Retention Time: Too short Example Inflow: 5 mg/l Dissolved Oxygen 15 mg/l Nitrate-N (high flow rate) Example Internal Sample: 0 mg/l Dissolved Oxygen 15 mg/l Nitrate-N Example Outflow: 0 mg/l Dissolved Oxygen 12 mg/l Nitrate-N Christianson and Helmers, 2011 Illustration by John Petersen

18 Retention Time: Too long Example Inflow: 5 mg/l Dissolved Oxygen 15 mg/l Nitrate-N (slow flow rate) Example Internal Sample #2: 0 mg/l Dissolved Oxygen 0 mg/l Nitrate-N Example Internal Sample #1: 0 mg/l Dissolved Oxygen 15 mg/l Nitrate-N Example Outflow: 0 mg/l Dissolved Oxygen 0 mg/l Nitrate-N Christianson and Helmers, 2011 Illustration by John Petersen

19 Factors affecting nitrate removal Christianson et al., 2013 (Eco. Eng. 52: ) Sample Date Flow rate (L min -1 ) Retention time* (hours) Water temp. ( C) Inlet DO (mg/l) N load reduction (% Mass) May May June July August *Modified based upon conservative tracer testing

20 Factors affecting nitrate removal Christianson et al., 2013 (Eco. Eng. 52: )

21 Why woodchips? Many organic carbon sources have been trialed: Shredded newspaper Cardboard fibers Almond and walnut shells Barley straw Wheat straw Corn cobs Corn stover Date palm leaves Rice husks Pine bark Pine needles Mulch/compost/green waste Woody media: Low cost Physical, chemical, and biological properties Durability

22 What do bioreactors cost? Christianson et al., 2012 (Trans. ASABE) Average: $152.07/ac Christianson et al., 2013

23 What is the life? Life estimated at 10 to 20 years Stoichiometric estimates: 20 to >50 yrs Empirical evidence: Robertson et al., 2008: 15 yr septic treatment wall Long et al., 2011: 14 yr sawdust groundwater wall Moorman et al., 2010: 9 yr woodchip drainage wall Depth of woodchips Moorman et al.,

24 Many research questions remain in order to maximize bioreactor performance Outflow waters contain organics during start-up An incomplete denitrification product is nitrous oxide, a greenhouse gas Sulfate reduction: bacteria can produce hydrogen sulfide gas at high retention times Mercury methylation possible Potential downsides

25 Potential downsides Many research questions remain in order to maximize bioreactor performance Outflow waters contain organics during start-up An incomplete denitrification product is nitrous oxide, a greenhouse gas Sulfate reduction: bacteria can produce hydrogen sulfide gas at high retention times Mercury methylation possible t=7 hr t=14 hr t=21 hr t=54 hr Christianson, Unpublished

26 Potential downsides Many research questions remain in order to maximize bioreactor performance Outflow waters contain organics during start-up An incomplete denitrification product is nitrous oxide, a greenhouse gas Sulfate reduction: bacteria can produce hydrogen sulfide gas at high retention times Mercury methylation possible Christianson et al., 2013 (ASABE Proceedings)

27 Many research questions remain in order to maximize bioreactor performance Outflow waters contain organics during start-up An incomplete denitrification product is nitrous oxide, a greenhouse gas Sulfate reduction: bacteria can produce hydrogen sulfide gas at high retention times Mercury methylation possible YSI, 2008 ( Potential downsides

28 Interest continues to grow Good press coverage and outreach Expansion of technology to new areas NRCS acceptance in several states

29 Interest continues to grow Good press coverage and outreach Expansion of technology to new areas NRCS acceptance in several states Filterbädd vid Börringe. Dräneringsrör, makadam, flis, spridarrör och fördelningsbrunn sysns på bilden.

30 And new ideas continue to develop New design ideas New fill media and revisiting ag. residues Treatment of new kinds of waters Removal of other contaminants Pairing with P technologies Zhang and Magner, 2014 (J Geol Geosci); Kata Sharrer, The Conservation Fund

31 And new ideas continue to develop New design ideas New fill media and revisiting ag. residues Treatment of new kinds of waters Removal of other contaminants Pairing with P technologies Biochar G. Feyereisen, USDA ARS; Christianson et al., 2011 FLRC Proceedings

32 And new ideas continue to develop New design ideas New fill media and revisiting ag. residues Treatment of new kinds of waters Removal of other contaminants Pairing with P technologies Nitrate (mg N/L) Aquaculture (effluent or supernatant from solids settling cones) Agricultural drainage (subsurface) 50->

33 And new ideas continue to develop New design ideas New fill media and revisiting ag. residues Treatment of new kinds of waters Removal of other contaminants Pairing with P technologies

34 And new ideas continue to develop New design ideas New fill media and revisiting ag. residues Treatment of new kinds of waters Removal of other contaminants Pairing with P technologies P. Kleinman, USDA ARS; SERA-17 G. Goodwin, 2012, 2014 Thesis Annual Univ. IL; Meeting K. King, USDA ARS; Penn et al., 2013: structures to removephosphorus...;

35 Acknowledgements Cooperative agreement with the USDA ARS (No ) MnDrive: University of Minnesota; Dr. Gary Feyereisen (USDA ARS) Midshore Riverkeepers Conservancy (Easton, MD) Tides Canada The Leopold Center for Sustainable Agriculture UDSA NIFA Agriculture and Food Research Initiative Competitive Grant no GNC from the USDA SARE North Central Region Graduate Student Grant Program Keegan Kult and Todd Sutphin at the Iowa Soybean Association Agriculture s Clean Water Alliance The Sand County Foundation Coldwater Palmer Watershed Association More information L.Christianson@freshwaterinstitute.org