Enhanced Biogas Production from Nanoscale Zero Valent Iron-Amended Anaerobic Bioreactors.
Addition of nanoscale zero valent iron (NZVI) to anaerobic batch reactors to enhance methanogenic activity is described. Two NZVI systems were tested: a commercially available NZVI (cNZVI) slurry and a freshly synthesized NZVI (sNZVI) suspension that was prepared immediately before addition to the reactors. In both systems, the addition of NZVI increased pH and decreased oxidation/reduction potential compared with unamended control reactors. Biodegradation of a model brewery wastewater was enhanced as indicated by an increase in chemical oxygen demand removal with both sNZVI and cNZVI amendments at all concentrations tested (1.25-5.0 g Fe/L). Methane production increased for all NZVI-amended bioreactors, with a maximum increase of 28% achieved on the addition of 2.5 and 5.0 g/L cNZVI. Addition of bulk zero-valent iron resulted in only a 5% increase in methane, indicating the advantage of using the nanoscale particles. NZVI amendments further improved produced biogas by decreasing the amount of CO2 released from the bioreactor by approximately 58%. Overall, addition of cNZVI proved more beneficial than the sNZVI at equal iron concentrations, due to decreased colloidal stability and larger effective particle size of sNZVI. Although some have reported cytotoxicity of NZVI to anaerobic microorganisms, work presented here suggests that NZVI of a certain particle size and reactivity can serve as an amendment to anaerobic digesters to enhance degradation and increase the value of the produced biogas, yielding a more energy-efficient anaerobic method for wastewater treatment.
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Related Subject Headings
- Environmental Engineering
- 4104 Environmental management
- 4011 Environmental engineering
- 4004 Chemical engineering
- 0907 Environmental Engineering
- 0904 Chemical Engineering
- 0502 Environmental Science and Management
Citation
Published In
DOI
EISSN
ISSN
Publication Date
Volume
Issue
Start / End Page
Related Subject Headings
- Environmental Engineering
- 4104 Environmental management
- 4011 Environmental engineering
- 4004 Chemical engineering
- 0907 Environmental Engineering
- 0904 Chemical Engineering
- 0502 Environmental Science and Management