Huang,G., Fallowfield,H., Guan,H. and Liu,F.(2012): Remediation of nitrate-nitrogen contaminated groundwater by a heterotrophic-autotrophic denitrification approach in an aerobic environment. Water Air Soil Pollut., 223, 4029-4038.

『好気環境での独立栄養－従属栄養脱窒アプローチによる硝酸塩－窒素汚染地下水の改善』

『Abstract
　A novel heterotrophic-autotrophic denitrification (HAD) approach supported by mixing granulated spongy iron, methanol, and mixed bacteria was proposed for the remediation of nitrate-nitrogen (NO3-N) contaminated groundwater in a dissolved oxygen (DO)-rich environment. The HAD process involves biological deoxygenation, chemical reduction (CR) of NO3-N and DO, heterotrophic denitrification (HD), and autotrophic denitrification (AD). Batch experiments were performed to: (1) investigate deoxygenation capacities of HAD; (2) determine the contributions of AD, HD, and CR to the overall NO3-N removal in the HAD; and (3) evaluate the effects of environmental parameters on the HAD. There were 174, 205, and 2,437 min needed to completely reduce DO by the HAD, spongy iron-based CR, and by the mixed bacteria, respectively. The HAD depended on abiotic and biotic effects to remove DO. CR played a dominant role in deoxygenation in the HAD. After 5 days, approximately 100, 63.0, 20.1, and 9.7 ％ of the initial NO3-N was removed in the HAD, HD, AD+CR, and CR incubations, respectively. CR, HD, and AD all contributed to the overall NO3-N removal in the HAD. HD was the most important NO3-N degradation mechanism in the HAD. There existed symbiotic, synergistic, and promotive effects of CR, HD, and AD within the HAD. The decrease in NO3-N and the production of nitrite-nitrogen (NO2-N) and ammonium-nitrogen (NH4-N) in the HAD were closely related to the C to N weight ratio. The C to N ratio of 3.75:1 was optimal for complete denitrification. Denitrification rate at 27.5℃ was 1.36 times higher than at 15.0℃.

Keywords: Nitrate-nitrogen; Groundwater; Heterotrophic-autotrophic denitrification (HAD); Spongy iron; Methanol』

1. Introduction
2. Materials and methods
　2.1. Chemicals and reagents
　2.2. Enrichment culture protocol to establish a denitrifying bacterial population
　2.3. Batch experiments
　2.4. Analytical measurements
3. Results and discussion
　3.1. Deoxygenation capacities of HAD, chemical reduction, and mixed bacteria
　3.2. Contributions of chemical reduction, heterotrophic denitrification, and autotrophic denitrification to the performance of HAD
　3.3. Effect of C to N ratio on HAD
　3.4. Effect of water temperature on HAD
4. Conclusions
Acknowledgments
References

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