Iranian Journal of

Backgrounds and Objectives: Nitrate is a water contaminant that can cause health problems in human and animals, in addition to eutrophication of the water body. So, Nitrate-contaminated water may be treated by treatment systems. In this study, hydrogenotrophic denitrification using hydrogen produced by Fe0 as an electron donor to nitrate removal was evaluated to assess the feasibility of employing Fe0 in the biological nitrate treatment.
Materials andMethods : Batch experiments were conducted using 250 ml amber bottles at 20-35oC under anoxic conditions. The nitrate concentration in each reactor was 20 mg N/L and triplicate samples were prepared for the following treatment: Fe0 plus cells, Fe0 only, and control. The effect of Fe+2 and temperature on nitrate reduction was evaluated.
Results : 97 percent of Nitrate was reduced within 2 day in a Fe0-cell reactor, while only 30% of the nitrate was abiotically reduced over 2 day at 30 oC. Fe+2, which is produced during anaerobic iron corrosion in the Fe0-cell system, might act as an electron donor for nitrate. Abiotic reduction and microbial reduction of nitrate was significantly affected by temperature conditions. The reduction rate decreased as the temperature deceased.
Conclusion:This study demonstrated the potential applicability of employing Fe0 as a source of electrons for biological nitrate reduction. Use of Fe0 for microbial nitrate reduction can obviate the disadvantages associated with traditional biological denitrification that relies on the use of organic substrates or explosive hydrogen gas.