Removing chemical pollution in surface water using wood chip denitrification

Nitrate contamination from nitrogen fertilizers is a considerable environmental and human health problem. A study published in California Agriculture evaluated the ability of a wood chip denitrification bioreactor to remove nitrates from contaminated water in a tile drainage.

  • The researchers built denitrification bioreactors in two vegetable farms in Monterey County.
  • Over several years of operation, the bioreactors steadily reduced the levels of nitrate-nitrogen (NO3-N) in water by 8 to 10 milligrams per liter (mg/L-1) per day in summer and 5 mg L-1 per day in winter.
  • Unfortunately, the high concentration of nitrate in the water (60 to 190 mg L-1) meant the bioreactors couldn’t reduce the nitrate levels down to the regulatory target of < 10 mg L-1.
  • The researchers decided to use a carbon enrichment system with methanol to stimulate the denitrification process.

The carbon enrichment system increased the rate of denitrification, enabling the bioreactors to remove nearly all of the NO3-N from the water without causing any significant adverse impact on the environment.

Read the full text of the study at this link.

Learn about the harmful effects of nitrate contamination at

Journal Reference

Hartz T, Smith R, Cahn M, Bottoms T, Bustamante SC, Tourte L, Johnson K, Coletti L. WOOD CHIP DENITRIFICATION BIOREACTORS CAN REDUCE NITRATE IN TILE DRAINAGE. California Agriculture. 9 February 2017;71(1):41–47. DOI: 10.3733/ca.2017a0007

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