Performance Investigation of Woodchip Bioreactor for Nitrate Removal from Wastewater

Document Type : Research Paper


1 Student, MSc Irrigation and Drainage Engineering, Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili, Ardabil, Iran.

2 Assistant Professor. Department of Water Engineering Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili, Ardabil, Iran.

3 Associate Professor. Department of Soil Science Engineering, Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili, Ardabil, Iran

4 Associate Professor. Department of Water Engineering, Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili, Ardabil, Iran


Wood chip bioreactors are one of the low-cost methods to remove nitrate from effluents, including wastewater effluents. This research was conducted in Ardabil plain and in the research farm of Mohaghegh Ardabil University during the autumn of 2021. Two types bioreactors; one including wood chip and the other including a mixture of wood chip and iron chip, each with four replications  were implemented in a factorial design. Three levels of nitrate concentration (50, 150, and 300 mg.l-1) were passed through the reactors and their effluents were measured after 3, 6, 12, 24, 48, 72, and 96 hours retention time in the bioreactor. The results showed that the performance of reactors with wood chip core (54.7% removal) was better than the wood and iron chip (45.9% removal). Also, the results demonstrated that the removal percentage was in descending order at concentrations of 150, 300, and 50 mg.l-1, with the average values of 54.6, 50.3, and 45.5%, respectively. The results of variance analysis showed that the retention time have a significant effect on the amount of nitrate removal by reactors so that the minimum and the maximum removal (4.3% and 89.3%) were obtained from 3-hours and 96-houres retention time, respectively. In general, it can be concluded that under the conditions of this research, bioreactors with wood chip have acceptable performance in nitrate removal. Also, it was found for the suggested drainage coefficient in Iran (2 and with a retention time of 96 hours, less than 2% of the land area is needed for bioreactor construction.


Aalto, S.L., Suurnäkki, S., von Ahnen, M., Siljanen, H.M., Pedersen, P.B. and Tiirola, M. (2020). Nitrate removal microbiology in woodchip bioreactors: A case-study with full-scale bioreactors treating aquaculture effluents. Science of the Total Environment, 723, p.138093.
Abdi, D.E., Owen Jr, J.S., Brindley, J.C., Birnbaum, A.C., Wilson, P.C., Hinz, F.O., Reguera, G., Lee, J.Y., Cregg, B.M., Kort, D.R. and Fernandez, R.T. (2020). Nutrient and pesticide remediation using a two-stage bioreactor-adsorptive system under two hydraulic retention times. Water Research, 170, p.115311.
 Akhavan, S., Zare Abyaneh, H., Bayat Rokshi, M. (2014). A systematic review of studies on nitrate concentrations in Iranian water resources. Journal of Health and Environment Journal of Iranian Scientific Association of Environmental Health, 7(2), 205-228. (In Farsi)
Asgari, H., Azizi Mobaser, J., Rasoulzadeh, A., Ramezani Moghaddam, J. (2020). 'Evaluating the Efficiency of Bioreactor with Triangular Cross Section to Remove Nitrate from Agricultural Wastewater', Iranian Journal of Soil and Water Research, 51(5), pp. 1105-1113. (In Farsi)
Asgari, M., Liaghat, A., Parsinezhad, M. (2011). 'Effectiveness of Collector Drain on Drainage Coefficient (A Case Study: Amir-Kabir Agriculture and Industry Department, Khuzestan Province)', Water and Soil, 25(4).  (In Farsi)
Ashoori, N., Teixido, M., Spahr, S., Lefebvre, G.H., Sedlak, D.L. and Luthy, R.G. (2019). Evaluation of pilot-scale biochar-amended woodchip bioreactors to remove nitrate, metals, and trace organic contaminants from urban storm water runoff. Water research, 154, pp.1-11.
Baird, R.B., )2017(. Standard Methods for the Examination of Water and Wastewater, 23rd. Water Environment Federation, American Public Health Association, American Water Works Association.
Christianson, L.E. (2011). Design and performance of denitrification bioreactors for agricultural drainage. Digital Repository, Iowa State University.
Christianson, L.E., Lepine, C., Sibrell, P.L., Penn, C. and Summerfelt, S.T. (2017). Denitrifying woodchip bioreactor and phosphorus filter pairing to minimize pollution swapping. Water research, 121, pp.129-139.
Corbett, T.D., Dougherty, H., Maxwell, B., Hartland, A., Henderson, W., Rys, G.J. and Schipper, L.A. (2019). Utility of Diffusive Gradients in Thin Films’ for the measurement of nitrate removal performance of denitrifying bioreactors. Science of the Total Environment, p.135267.
Feyereisen G W., Moorman T B., Christianson L E., Venterea R T., Coulter J A., and Tschirner U W. (2016). Performance of Agricultural Residue Media in Laboratory Denitrifying Bioreactors at Low Temperatures. Journal of environmental quality, 45 (3), 779-87.
Haghayeghi Moghadam, S., Akhavan, K., Khojeabdolahi, M., Azizi, A., Naseri. (2005). Evaluation of relations governing the design of underground drains in Ardabil (Moghan) and Khuzestan. Institute of Technical Research and Agricultural Engineering, Karaj, (84): 1572. (In Farsi)
Jin, S., Feng, C., Tong, S., Chen, N., Liu, H., & Zhao, J. (2019). Effect of sawdust dosage and hydraulic retention time (HRT) on nitrate removal in sawdust/pyrite mixotrophic denitrification (SPMD) systems. Environmental Science: Water Research & Technology, 5(2), 346-357.
Kaetzl, K., Lübken, M., Gehring, T. and Wichern, M., (2018). Efficient low-cost anaerobic treatment of wastewater using biochar and woodchip filters. Water, 10(7), p.818.
Kim, I. (2018). Denitrification by Zero-Valent Iron-Supported Mixed Cultures (Doctoral dissertation, University of Delaware).
Kraft, D.J., (2019). Nutrient Removal Performance of a Wood Chip Bioreactor Treatment System Receiving Silage Bunker Runoff.
Lepine, C., Christianson, L., Sharrer, K. and Summerfelt, S. (2016). Optimizing hydraulic retention times in denitrifying woodchip bioreactors treating recirculating aquaculture system wastewater. Journal of environmental quality, 45(3), 813-821.
Lopez-Ponnada, E.V., Lynn, T.J., Peterson, M., Ergas, S.J. and Mihelcic, J.R. (2017). Application of denitrifying wood chip bioreactors for management of residential non-point sources of nitrogen. Journal of biological engineering, 11(1), p.16.
Mardani, S., McDaniel, R., Bleakley, B.H., Hamilton, T.L., Salam, S. and Amegbletor, L. (2020). The effect of woodchip bioreactors on microbial concentration in subsurface drainage water and the associated risk of antibiotic resistance dissemination. Ecological Engineering: X, p.100017.
Martin E A., Davis M P., Moorman T B., Isenhart T M., Soupir M L. (2019). Impact of hydraulic residence time on nitrate removal in pilot-scale woodchip bioreactors. Journal of Environmental Management, 237, 424-432.
Maxwell, B.M., Díaz-García, C., Martinez-Sánchez, J.J., Brigand, F. and Álvarez-Rogel, J. (2020). Temperature sensitivity of nitrate removal in woodchip bioreactors increases with woodchip age and following drying–rewetting cycles. Environmental Science: Water Research & Technology, 6(10), pp.2752-2765.
Ministry of Energy, Office of Deputy for Strategic Supervision. (2009). A Guideline for Estimation of Subsurface Drainage Coefficient of Irrigated Lands in Arid and Semi-arid Regions, No. 492, p.62. (In Farsi)
Orlando, U.S., Baes, A.U., Nishijima, W. and Okada, M., (2002). Preparation of agricultural residue anion exchangers and its nitrate maximum adsorption capacity. Chemosphere, 48(10), pp.1041-1046.
Raoof, M. (2019). Determining plant sugar beet coefficient using lysimetric in Ardabil plain and comparing it with FAO global data. Journal of Water Research in Agriculture, 23(2). (In Farsi)
Raoof, M., Azizi Mobaser, J. (2016). Evaluation of eighteen reference evapotranspiration models in climatic conditions of Ardabil plain. Journal of Soil and Water Conservation Research, 24(6). (In Farsi)
Rivas, A., Barkle, G., Stenger, R., Moorhead, B., & Clague, J. (2020). Nitrate removal and secondary effects of a woodchip bioreactor for the treatment of subsurface drainage with dynamic flows under pastoral agriculture. Ecological Engineering, 148, 105786.
Sharrer, K.L., Christianson, L.E., Lepine, C. and Summerfelt, S.T. (2016). Modeling and mitigation of denitrification ‘woodchip ’bioreactor phosphorus releases during treatment of aquaculture wastewater. Ecological Engineering, 93, pp.135-143.
Soupir, M.L., Hoover, N.L., Moorman, T.B., Law, J.Y. and Bearson, B.L. (2018). Impact of temperature and hydraulic retention time on pathogen and nutrient removal in woodchip bioreactors. Ecological Engineering, 112, pp.153-157.
Suzuki, T., Oyama, Y., Moribe, M., Niinae, M., (2012). An electro kinetic/Fe0 permeable reactive barrier system for the treatment of nitrate-contaminated subsurface soils, Water Res. 46, 772 – 778.
Yao, Z., Yang, L., Wang, F., Tian, L., Song, N. and Jiang, H. (2020). Enhanced nitrate removal from surface water in a denitrifying woodchip bioreactor with a heterotrophic nitrifying and aerobic denitrifying fungus. Bio resource Technology, 303, p.122948.
Zhang, L., Sun, H., Zhang, X., Ren, H., Ye, L., (2018). High diversity of potential nitrate-reducing Fe (II)-oxidizing bacteria enriched from activated sludge. Appl. Microbiol. Biotechnol. 102, 4975 – 4985.
Zhang, W., Bai, Y., Ruan, X., & Yin, L. (2019). The biological denitrification coupled with chemical reduction for groundwater nitrate remediation via using SCCMs as carbon source. Chemosphere, 234, 89-97.
Zhao, J., He, Q., Chen, N., Peng, T. and Feng, C. (2020). Denitrification behavior in a woodchip packed bioreactor with gradient filling for nitrate contaminated water treatment. Biochemical Engineering Journal, 154, p.107454.