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Role of nickel in high rate methanol degradation in anaerobic granular sludge bioreactors.

Fermoso FG, Collins G, Bartacek J, O'Flaherty V, Lens P - Biodegradation (2008)

Bottom Line: The reactor was operated at pH 7.0 and an organic loading rate (OLR) of 5-15 g COD l(-1) day(-1) for 191 days.The methanol removal efficiency during these 129 days was 99%, no volatile fatty acid (VFA) accumulation was observed and the size of the Methanosarcina population increased compared to the seed sludge.On day 165, 77% of the methanol fed to the system was converted to acetate and the Methanosarcina population size had substantially decreased.

View Article: PubMed Central - PubMed

Affiliation: Sub-department of Environmental Technology, Wageningen University, Biotechnion-Bomenweg 2, Wageningen, The Netherlands.

ABSTRACT
The effect of nickel deprivation from the influent of a mesophilic (30 degrees C) methanol fed upflow anaerobic sludge bed (UASB) reactor was investigated by coupling the reactor performance to the evolution of the Methanosarcina population of the bioreactor sludge. The reactor was operated at pH 7.0 and an organic loading rate (OLR) of 5-15 g COD l(-1) day(-1) for 191 days. A clear limitation of the specific methanogenic activity (SMA) on methanol due to the absence of nickel was observed after 129 days of bioreactor operation: the SMA of the sludge in medium with the complete trace metal solution except nickel amounted to 1.164 (+/-0.167) g CH(4)-COD g VSS(-1) day(-1) compared to 2.027 (+/-0.111) g CH(4)-COD g VSS(-1) day(-1) in a medium with the complete (including nickel) trace metal solution. The methanol removal efficiency during these 129 days was 99%, no volatile fatty acid (VFA) accumulation was observed and the size of the Methanosarcina population increased compared to the seed sludge. Continuation of the UASB reactor operation with the nickel limited sludge lead to incomplete methanol removal, and thus methanol accumulation in the reactor effluent from day 142 onwards. This methanol accumulation subsequently induced an increase of the acetogenic activity in the UASB reactor on day 160. On day 165, 77% of the methanol fed to the system was converted to acetate and the Methanosarcina population size had substantially decreased. Inclusion of 0.5 muM Ni (dosed as NiCl(2)) to the influent from day 165 onwards lead to the recovery of the methanol removal efficiency to 99% without VFA accumulation within 2 days of bioreactor operation.

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Evolution of the reactor performance with time. (A) Calculated influent methanol (- - -), measured influent methanol (□), effluent methanol (■), and effluent VFA (▴) concentrations. (B) Total VFA (▴), acetate (x), propionate (•), butyrate (♦), and valerate (*) concentration. (C) CH4 production (Δ), note that gas production was not measured from day 137 onwards due to technical problems. (D) pH (◊) of UASB reactor mixed liquor
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Fig4: Evolution of the reactor performance with time. (A) Calculated influent methanol (- - -), measured influent methanol (□), effluent methanol (■), and effluent VFA (▴) concentrations. (B) Total VFA (▴), acetate (x), propionate (•), butyrate (♦), and valerate (*) concentration. (C) CH4 production (Δ), note that gas production was not measured from day 137 onwards due to technical problems. (D) pH (◊) of UASB reactor mixed liquor

Mentions: After a start-up period of 12 days, methanol was fully converted to methane in the UASB reactor (Fig. 4). The OLR was increased twice during PI, first from 5 to 10 g COD l−1 day−1 on day 64 and then from 10 to 15 g COD l−1 day−1 on day 113, without resulting in methanol or VFA accumulation in the effluent (Fig. 4). The methanol effluent concentration started to accumulate on day 130, reaching a maximum value of 1,380 mg COD-MeOH l−1 on day 133, corresponding to 31% of the influent methanol concentration (4,500 mg COD-MeOH l−1). On day 137, the applied OLR was reduced from 15 to 5 g COD l−1 day−1 in order to avoid overloading of the reactor due to the sludge removal to perform kinetic studies on the reactor sludge. Methanol was completely removed without any VFA accumulation from day 137 (PII) until day 142. From day 142 onwards, however, methanol accumulation was observed in the UASB reactor, reaching 819 mg COD-MeOH l−1 by day 147. From day 149, the concentration of accumulated methanol decreased. This was accompanied by an increase in the VFA concentration, mainly acetate (around 86%). On day 163, VFA effluent concentrations reached a maximum of 1,150 mg COD-VFA l−1, corresponding to 95% of the influent methanol being converted to VFA.Fig. 4


Role of nickel in high rate methanol degradation in anaerobic granular sludge bioreactors.

Fermoso FG, Collins G, Bartacek J, O'Flaherty V, Lens P - Biodegradation (2008)

Evolution of the reactor performance with time. (A) Calculated influent methanol (- - -), measured influent methanol (□), effluent methanol (■), and effluent VFA (▴) concentrations. (B) Total VFA (▴), acetate (x), propionate (•), butyrate (♦), and valerate (*) concentration. (C) CH4 production (Δ), note that gas production was not measured from day 137 onwards due to technical problems. (D) pH (◊) of UASB reactor mixed liquor
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2493520&req=5

Fig4: Evolution of the reactor performance with time. (A) Calculated influent methanol (- - -), measured influent methanol (□), effluent methanol (■), and effluent VFA (▴) concentrations. (B) Total VFA (▴), acetate (x), propionate (•), butyrate (♦), and valerate (*) concentration. (C) CH4 production (Δ), note that gas production was not measured from day 137 onwards due to technical problems. (D) pH (◊) of UASB reactor mixed liquor
Mentions: After a start-up period of 12 days, methanol was fully converted to methane in the UASB reactor (Fig. 4). The OLR was increased twice during PI, first from 5 to 10 g COD l−1 day−1 on day 64 and then from 10 to 15 g COD l−1 day−1 on day 113, without resulting in methanol or VFA accumulation in the effluent (Fig. 4). The methanol effluent concentration started to accumulate on day 130, reaching a maximum value of 1,380 mg COD-MeOH l−1 on day 133, corresponding to 31% of the influent methanol concentration (4,500 mg COD-MeOH l−1). On day 137, the applied OLR was reduced from 15 to 5 g COD l−1 day−1 in order to avoid overloading of the reactor due to the sludge removal to perform kinetic studies on the reactor sludge. Methanol was completely removed without any VFA accumulation from day 137 (PII) until day 142. From day 142 onwards, however, methanol accumulation was observed in the UASB reactor, reaching 819 mg COD-MeOH l−1 by day 147. From day 149, the concentration of accumulated methanol decreased. This was accompanied by an increase in the VFA concentration, mainly acetate (around 86%). On day 163, VFA effluent concentrations reached a maximum of 1,150 mg COD-VFA l−1, corresponding to 95% of the influent methanol being converted to VFA.Fig. 4

Bottom Line: The reactor was operated at pH 7.0 and an organic loading rate (OLR) of 5-15 g COD l(-1) day(-1) for 191 days.The methanol removal efficiency during these 129 days was 99%, no volatile fatty acid (VFA) accumulation was observed and the size of the Methanosarcina population increased compared to the seed sludge.On day 165, 77% of the methanol fed to the system was converted to acetate and the Methanosarcina population size had substantially decreased.

View Article: PubMed Central - PubMed

Affiliation: Sub-department of Environmental Technology, Wageningen University, Biotechnion-Bomenweg 2, Wageningen, The Netherlands.

ABSTRACT
The effect of nickel deprivation from the influent of a mesophilic (30 degrees C) methanol fed upflow anaerobic sludge bed (UASB) reactor was investigated by coupling the reactor performance to the evolution of the Methanosarcina population of the bioreactor sludge. The reactor was operated at pH 7.0 and an organic loading rate (OLR) of 5-15 g COD l(-1) day(-1) for 191 days. A clear limitation of the specific methanogenic activity (SMA) on methanol due to the absence of nickel was observed after 129 days of bioreactor operation: the SMA of the sludge in medium with the complete trace metal solution except nickel amounted to 1.164 (+/-0.167) g CH(4)-COD g VSS(-1) day(-1) compared to 2.027 (+/-0.111) g CH(4)-COD g VSS(-1) day(-1) in a medium with the complete (including nickel) trace metal solution. The methanol removal efficiency during these 129 days was 99%, no volatile fatty acid (VFA) accumulation was observed and the size of the Methanosarcina population increased compared to the seed sludge. Continuation of the UASB reactor operation with the nickel limited sludge lead to incomplete methanol removal, and thus methanol accumulation in the reactor effluent from day 142 onwards. This methanol accumulation subsequently induced an increase of the acetogenic activity in the UASB reactor on day 160. On day 165, 77% of the methanol fed to the system was converted to acetate and the Methanosarcina population size had substantially decreased. Inclusion of 0.5 muM Ni (dosed as NiCl(2)) to the influent from day 165 onwards lead to the recovery of the methanol removal efficiency to 99% without VFA accumulation within 2 days of bioreactor operation.

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Related in: MedlinePlus