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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.


Gas composition without anaerobic sludge supplement(a) and with BES addition (b) and Mn2+ concentration with BES addition (c). Error bars represent standard deviations of triplicate tests.
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f4: Gas composition without anaerobic sludge supplement(a) and with BES addition (b) and Mn2+ concentration with BES addition (c). Error bars represent standard deviations of triplicate tests.

Mentions: First, the anaerobic sludge was removed from the digestion system and other conditions were kept the same as the batch experiment with 4 g/L manganese added. Figure 4a described the gas composition during the whole operation without anaerobic sludge supplement. It was obviously that no CH4 was determined during the whole operation period, though the CO2 decreased to 6.59 ± 0.31 M at 46 h. Moreover, a much higher level of manganous ions of 415.0 mg/L was observed in the end. It was reasonably considered that the high CO2 pressure in the gas phase resulted in an increase in the bicarbonate ion in the liquid phase, which accelerated the cathodic depolarization of elemental manganese. Furthermore, the created manganous ions could not be further oxidized in the absence of the manganese-oxidizing microorganisms. Therefore, the manganous ions concentration in this test was higher than that of the batch experiments. Besides, due to the lack of methanogens in the anaerobic system, the consumed CO2 could not be utilized to synthetize CH4, though electrons could be provided by the elemental manganese. These results indicated that the simultaneous consumption of CO2 and manganese was mediated by chemical reaction and microorganisms were required to participate in the CH4 production process.


Methanogenesis from wastewater stimulated by addition of elemental manganese.

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

Gas composition without anaerobic sludge supplement(a) and with BES addition (b) and Mn2+ concentration with BES addition (c). 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

f4: Gas composition without anaerobic sludge supplement(a) and with BES addition (b) and Mn2+ concentration with BES addition (c). Error bars represent standard deviations of triplicate tests.
Mentions: First, the anaerobic sludge was removed from the digestion system and other conditions were kept the same as the batch experiment with 4 g/L manganese added. Figure 4a described the gas composition during the whole operation without anaerobic sludge supplement. It was obviously that no CH4 was determined during the whole operation period, though the CO2 decreased to 6.59 ± 0.31 M at 46 h. Moreover, a much higher level of manganous ions of 415.0 mg/L was observed in the end. It was reasonably considered that the high CO2 pressure in the gas phase resulted in an increase in the bicarbonate ion in the liquid phase, which accelerated the cathodic depolarization of elemental manganese. Furthermore, the created manganous ions could not be further oxidized in the absence of the manganese-oxidizing microorganisms. Therefore, the manganous ions concentration in this test was higher than that of the batch experiments. Besides, due to the lack of methanogens in the anaerobic system, the consumed CO2 could not be utilized to synthetize CH4, though electrons could be provided by the elemental manganese. These results indicated that the simultaneous consumption of CO2 and manganese was mediated by chemical reaction and microorganisms were required to participate in the CH4 production process.

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.