The Biochemical Methane Potential (BMP) test is increasingly recognised as a tool for selecting and pricing biomass material for production of biogas. However, the results for the same substrate often differ between laboratories and much work to standardise such tests is still needed. In the current study, the effects from four environmental factors (i.e. ambient temperature and pressure, water vapour content and initial gas composition of the reactor headspace) on the degradation kinetics and the determined methane potential were evaluated with a 2(4) full factorial design. Four substrates, with different biodegradation profiles, were investigated and the ambient temperature was found to be the most significant contributor to errors in the methane potential. Concerning the kinetics of the process, the environmental factors' impact on the calculated rate constants was negligible. The impact of the environmental factors on the kinetic parameters and methane potential from performing a BMP test at different geographical locations around the world was simulated by adjusting the data according to the ambient temperature and pressure of some chosen model sites. The largest effect on the methane potential was registered from tests performed at high altitudes due to a low ambient pressure. The results from this study illustrate the importance of considering the environmental factors' influence on volumetric gas measurement in BMP tests. This is essential to achieve trustworthy and standardised results that can be used by researchers and end users from all over the world.
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http://dx.doi.org/10.1016/j.wasman.2014.07.018 | DOI Listing |
JDS Commun
January 2025
Teagasc, Animal and Grassland Research and Innovation Centre, Moorepark, Fermoy, Co. Cork, Ireland, P61 P302.
Although 3-nitrooxypropanol (3-NOP; Bovaer10) has been proven to reduce enteric methane (CH) by ∼30% in indoor systems of dairying when the additive is mixed throughout TMR and partial mixed ration (PMR) diets, there has been limited research to date on the CH abatement potential of 3-NOP when mixed within a diet based on perennial ryegrass silage only and fed to pregnant nonlactating dairy cows. To investigate the effect of 3-NOP supplementation on enteric CH emissions of pregnant nonlactating dairy cows, a 6-wk study was undertaken in which treatment cows were supplemented with 3-NOP mixed within grass silage, whereas control cows were offered grass silage without additive supplementation. Enteric CH, hydrogen (H), and carbon dioxide (CO) were measured using a GreenFeed machine.
View Article and Find Full Text PDFMicrolife
January 2025
Environmental Metagenomics, Research Center One Health Ruhr of the University Alliance Ruhr, Faculty of Chemistry, University of Duisburg-Essen, 45141 Essen, Germany.
Oil reservoirs are society's primary source of hydrocarbons. While microbial communities in industrially exploited oil reservoirs have been investigated in the past, pristine microbial communities in untapped oil reservoirs are little explored, as are distribution patterns of respective genetic signatures. Here, we show that a pristine oil sample contains a complex community consisting of bacteria and fungi for the degradation of hydrocarbons.
View Article and Find Full Text PDFFor what we believe to be the first time, we propose a general design method for ultralong optical path length (OPL) multipass matrix cells (MMCs) based on the multicycle mode of two-sided field mirrors. Based on the classical Pickett Bradley White cell (PBWC), the design idea of the dual-circulation mode based on two-sided field mirrors is described in detail, with the example of the MMC based on the PBWC-PBWC. Its simple design method and optical stability analysis are given.
View Article and Find Full Text PDFJ Chem Inf Model
January 2025
Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States.
In the field of computational chemistry, predicting bond dissociation energies (BDEs) presents well-known challenges, particularly due to the multireference character of reactive systems. Many chemical reactions involve configurations where single-reference methods fall short, as the electronic structure can significantly change during bond breaking. As generating training data for partially broken bonds is a challenging task, even state-of-the-art reactive machine learning interatomic potentials (MLIPs) often fail to predict reliable BDEs and smooth dissociation curves.
View Article and Find Full Text PDFEnviron Microbiol Rep
February 2025
Department of Biology, University of Regina, Regina, Saskatchewan, Canada.
Prairie wetland ponds on the Great Plains of North America offer a diverse array of geochemical scenarios that can be informative about their impact on microbial communities. These ecosystems offer invaluable ecological services while experiencing significant stressors, primarily through drainage and climate change. In this first study systematically combining environmental conditions with microbial community composition to identify various niches in prairie wetland ponds, sediments had higher microbial abundance but lower phylogenetic diversity in ponds with lower concentrations of dissolved organic carbon ([DOC]; 10-18 mg/L) and sulfate ([SO ]; 37-58 mg/L) in water.
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