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Methanogenesis from wastewater stimulated by addition of elemental manganese.

Qiao S, Tian T, Qi B, Zhou J - Sci Rep (2015)

Bottom Line: The results indicated that elemental manganese effectively enhanced both the methane yield and the production rate.Besides, more acetate consumption and less propionate generation were observed during the methanogenesis with manganese.Further studies demonstrated that the elemental manganese served as electron donors for the methanogenesis from carbon dioxide, and the final proportion of methane in the total generated gas with 4 g/L manganese addition reached 96.9%, which was 2.1-fold than that of the control (46.6%).

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, P.R. China.

ABSTRACT
This study presents a novel procedure for accelerating methanogenesis from wastewater by adding elemental manganese into the anaerobic digestion system. The results indicated that elemental manganese effectively enhanced both the methane yield and the production rate. Compared to the control test without elemental manganese, the total methane yield and production rate with 4 g/L manganese addition increased 3.4-fold (from 0.89 ± 0.03 to 2.99 ± 0.37 M/gVSS within 120 h) and 4.4-fold (from 6.2 ± 0.1 to 27.2 ± 2.2 mM/gVSS/h), respectively. Besides, more acetate consumption and less propionate generation were observed during the methanogenesis with manganese. Further studies demonstrated that the elemental manganese served as electron donors for the methanogenesis from carbon dioxide, and the final proportion of methane in the total generated gas with 4 g/L manganese addition reached 96.9%, which was 2.1-fold than that of the control (46.6%).

No MeSH data available.


CH4 production and CO2 consumption(a) and Mn2+ concentration (b) with CO2 as the sole carbon source. Error bars represent standard deviations of triplicate tests.
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f5: CH4 production and CO2 consumption(a) and Mn2+ concentration (b) with CO2 as the sole carbon source. Error bars represent standard deviations of triplicate tests.

Mentions: As mentioned above, the excess generated methane in the anaerobic systems was assumed to be converted from CO2 with elemental manganese as electron donors on the basis of the simultaneous CO2 and manganese consumptions and CH4 and manganous ions productions. In order to confirm this assumption, another test was carried out with CO2 as the sole carbon source in the anaerobic mixture and a manganese concentration of 4 g/L. Figure 5a depicted the CH4 production and CO2 consumption in the gaseous phase. The final CH4 accumulation reached about 0.46 ± 0.01 M/gVSS, which was almost equivalent to the actual loss in CO2 (the actual loss in CO2 was about 0.48 ± 0.02 M/gVSS and the excess consumption of CO2 in Fig. 5a was caused by multiple sampling of gas components from the head space). As expected, manganous ions were also detected (Fig. 5b) and no decrease trend in the manganous ions concentration was found, which was consistent with the preceding discussion, due to the short of organic carbon sources for the heterotrophic manganese-oxidizing microorganisms. Consequently, it was proved that the loss of CO2 in the batch experiments with manganese added was utilized by methanogens to create CH4 with electrons supplied by elemental manganese through cathodic depolarization. Thus the whole methanogenesis process with manganese addition could be represented as the following reaction:


Methanogenesis from wastewater stimulated by addition of elemental manganese.

Qiao S, Tian T, Qi B, Zhou J - Sci Rep (2015)

CH4 production and CO2 consumption(a) and Mn2+ concentration (b) with CO2 as the sole carbon source. Error bars represent standard deviations of triplicate tests.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4525485&req=5

f5: CH4 production and CO2 consumption(a) and Mn2+ concentration (b) with CO2 as the sole carbon source. Error bars represent standard deviations of triplicate tests.
Mentions: As mentioned above, the excess generated methane in the anaerobic systems was assumed to be converted from CO2 with elemental manganese as electron donors on the basis of the simultaneous CO2 and manganese consumptions and CH4 and manganous ions productions. In order to confirm this assumption, another test was carried out with CO2 as the sole carbon source in the anaerobic mixture and a manganese concentration of 4 g/L. Figure 5a depicted the CH4 production and CO2 consumption in the gaseous phase. The final CH4 accumulation reached about 0.46 ± 0.01 M/gVSS, which was almost equivalent to the actual loss in CO2 (the actual loss in CO2 was about 0.48 ± 0.02 M/gVSS and the excess consumption of CO2 in Fig. 5a was caused by multiple sampling of gas components from the head space). As expected, manganous ions were also detected (Fig. 5b) and no decrease trend in the manganous ions concentration was found, which was consistent with the preceding discussion, due to the short of organic carbon sources for the heterotrophic manganese-oxidizing microorganisms. Consequently, it was proved that the loss of CO2 in the batch experiments with manganese added was utilized by methanogens to create CH4 with electrons supplied by elemental manganese through cathodic depolarization. Thus the whole methanogenesis process with manganese addition could be represented as the following reaction:

Bottom Line: The results indicated that elemental manganese effectively enhanced both the methane yield and the production rate.Besides, more acetate consumption and less propionate generation were observed during the methanogenesis with manganese.Further studies demonstrated that the elemental manganese served as electron donors for the methanogenesis from carbon dioxide, and the final proportion of methane in the total generated gas with 4 g/L manganese addition reached 96.9%, which was 2.1-fold than that of the control (46.6%).

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, P.R. China.

ABSTRACT
This study presents a novel procedure for accelerating methanogenesis from wastewater by adding elemental manganese into the anaerobic digestion system. The results indicated that elemental manganese effectively enhanced both the methane yield and the production rate. Compared to the control test without elemental manganese, the total methane yield and production rate with 4 g/L manganese addition increased 3.4-fold (from 0.89 ± 0.03 to 2.99 ± 0.37 M/gVSS within 120 h) and 4.4-fold (from 6.2 ± 0.1 to 27.2 ± 2.2 mM/gVSS/h), respectively. Besides, more acetate consumption and less propionate generation were observed during the methanogenesis with manganese. Further studies demonstrated that the elemental manganese served as electron donors for the methanogenesis from carbon dioxide, and the final proportion of methane in the total generated gas with 4 g/L manganese addition reached 96.9%, which was 2.1-fold than that of the control (46.6%).

No MeSH data available.