Kinetic characterization of mass transfer limited biodegradation of a low water soluble gas in batch experiments—Necessity for multiresponse fitting

heyder, B. De; Vanrolleghem, Peter A.; Langenhove, Herman Van; Verstraete, Willy

doi:10.1002/(sici)1097-0290(19970805)55:3<511::aid-bit7>3.0.co;2-f

Cited by 18 publications

(8 citation statements)

References 17 publications

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“…Alternatively, mass flow through macropores may avoid zones of high methanotrophic activity (Jensen et al , 1998; Geohring et al , 2001). The hydrophobicity of CH 4 may also make advected CH 4 less available to methanotrophs at the surface, as this CH 4 may be in disequilibrium with the pore water, and may not reside in the 0–15 cm depth long enough to adequately dissolve into bacterial biofilms (Bogner et al , 1997; De Heyder et al , 1997; Holden et al , 1997). Advective transport is thus likely to generate a vertical δ 13 C‐CH 4 profile that is similar to the one observed in our data.…”

Section: Discussionmentioning

confidence: 99%

Oxygen effects on methane production and oxidation in humid tropical forest soils

Teh

Silver

Conrad

2005

Global Change Biology

148

194

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We investigated the effects of oxygen (O 2 ) concentration on methane (CH 4 ) production and oxidation in two humid tropical forests that differ in long-term, time-averaged soil O 2 concentrations. We identified sources and sinks of CH 4 through the analysis of soil gas concentrations, surface emissions, and carbon isotope measurements. Isotope mass balance models were used to calculate the fraction of CH 4 oxidized in situ.Complementary laboratory experiments were conducted to determine the effects of O 2 concentration on gross and net rates of methanogenesis. Field and laboratory experiments indicated that high levels of CH 4 production occurred in soils that contained between 9 AE 1.1% and 19 AE 0.2% O 2 . For example, we observed CH 4 concentrations in excess of 3% in soils with 9 AE 1.1% O 2 . CH 4 emissions from the lower O 2 sites were high (22-101 nmol CH 4 m À2 s À1 ), and were equal in magnitude to CH 4 emissions from natural wetlands. During peak periods of CH 4 efflux, carbon dioxide (CO 2 ) emissions became enriched in 13 C because of high methanogenic activity. Gross CH 4 production was probably greater than flux measurements indicated, as isotope mass balance calculations suggested that 48-78% of the CH 4 produced was oxidized prior to atmospheric egress. O 2 availability influenced CH 4 oxidation more strongly than methanogenesis. Gross CH 4 production was relatively insensitive to O 2 concentrations in laboratory experiments. In contrast, methanotrophic bacteria oxidized a greater fraction of total CH 4 production with increasing O 2 concentration, shifting the d 13 C composition of CH 4 to values that were more positive. Isotopic measurements suggested that CO 2 was an important source of carbon for methanogenesis in humid forests. The d 13 C value of methanogenesis was between À84% and À98%, which is well within the range of CH 4 produced from CO 2 reduction, and considerably more depleted in 13 C than CH 4 formed from acetate.

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Section: Discussionmentioning

confidence: 99%

Oxygen effects on methane production and oxidation in humid tropical forest soils

Teh

Silver

Conrad

2005

Global Change Biology

148

194

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“…It is possible that methanotrophs depleted local pore waters of dissolved CH 4 where methanotrophic activity was high. Mass transfer of CH 4 from the gas to the aqueous phase may have limited methanotrophic activity due to the poor solubility of CH 4 in water [ Bogner et al , 1997; De Heyder et al , 1997]. Under conditions like this, methanotrophs probably oxidized a larger fraction of the dissolved CH 4 pool, resulting in less isotopic fractionation as the reaction progressed toward completion [ Criss , 1999].…”

Section: Discussionmentioning

confidence: 99%

Carbon isotope fractionation by methane‐oxidizing bacteria in tropical rain forest soils

et al. 2006

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[1] Humid tropical forests have the potential to be significant sources or sinks of atmospheric methane (CH 4 ), a radiatively important trace gas. Methane oxidation can consume a large fraction of the CH 4 produced in tropical soils, although controls on this process are poorly understood. Using soil incubation experiments, we investigated the effects of CH 4 and oxygen (O 2 ) concentrations on C isotope fractionation and CH 4 oxidation in tropical rain forest soils. We also explored the effects of these environmental variables on the isotope fractionation factor for CH 4 oxidation (a), which is widely used to evaluate the relative contributions of CH 4 production and oxidation to the atmospheric CH 4 pool. Methane oxidation was sensitive to CH 4 at lower CH 4 concentrations (<850 ppmv) and insensitive to O 2 concentrations between 3 and 21%. Maximum rates of CH 4 oxidation were between 8.2 ± 1.2 and 11.3 ± 1.5 nmol CH 4 hour À1 g dry soil À1. Measured values for a were sensitive to both CH 4 oxidation rate and CH 4 concentration. Alpha was inversely proportional to CH 4 oxidation rate (r 2 = 0.86, P < 0.001) and positively correlated with CH 4 concentration (r 2 = 0.52, P < 0.01). A multiple regression model that included CH 4 oxidation rate, CH 4 concentration, and the interaction of the two terms explained a high proportion of the variability in a (r 2 = 0.94, P < 0.0001). These data suggest that it is possible to accurately determine a, allowing for more precise estimates of CH 4 oxidation by isotope mass balance.

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“…An alternative to directly measuring k L a N 2 O is to estimate its value from k L a O 2 and the ratio of diffusivity coefficients. 32 Here, this would underestimate k L a O 2 for the range of Q air used (e.g., 17% for highest Q air ). Therefore, this approach should be used with caution, and experimentally verified, when possible.…”

Section: Mass Transfermentioning

confidence: 96%

Aeration Strategies To Mitigate Nitrous Oxide Emissions from Single-Stage Nitritation/Anammox Reactors

Domingo-Félez

Mutlu

Jensen

et al. 2014

Environ. Sci. Technol.

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Autotrophic nitrogen removal is regarded as a resource efficient process to manage nitrogen-rich residual streams. However, nitrous oxide emissions of these processes are poorly documented and strategies to mitigate emissions unknown. In this study, two sequencing batch reactors performing single-stage nitritation/anammox were operated under different aeration strategies, gradually adjusted over six months. At constant but limiting oxygen loading, synthetic reject water was fed (0.75 g-N/L · d) and high nitrogen removal efficiencies (83 ± 5 and 88 ± 2%) obtained. Dynamics of liquid phase nitrous (N2O) and nitric oxide (NO) concentrations were monitored and N2O emissions calculated. Significant decreases in N2O emissions were obtained when the frequency of aeration was increased while maintaining a constant air flow rate (from >6 to 1.7% ΔN2O/ΔTN). However, no significant effect on the emissions was noted when the duration of aeration was increased while decreasing air flow rate (10.9 ± 3.2% ΔN2O/ΔTN). The extant ammonium oxidation activity (mgNH4(+)-N/gVSS · min) positively correlated with the specific N2O production rate (mgN2O-N/gVSS · min) of the systems. Operating under conditions where anaerobic exceeds aerobic ammonium oxidation activity is proposed to minimize N2O emissions from single-stage nitritation/anammox reactors; increasing the frequency of aeration cycling is an efficient way of obtaining those conditions.

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Kinetic characterization of mass transfer limited biodegradation of a low water soluble gas in batch experiments—Necessity for multiresponse fitting

Cited by 18 publications

References 17 publications

Oxygen effects on methane production and oxidation in humid tropical forest soils

Oxygen effects on methane production and oxidation in humid tropical forest soils

Carbon isotope fractionation by methane‐oxidizing bacteria in tropical rain forest soils

Aeration Strategies To Mitigate Nitrous Oxide Emissions from Single-Stage Nitritation/Anammox Reactors

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