Suppression of Methane Generation during Methanogenesis by Chemically Modified Humic Compounds

Abstract

The introduction of various concentrations of chemically modified humic compounds (HC) with different redox characteristics into the media with free and immobilized anaerobic consortia accumulating landfill gases was studied as approach to their functioning management. For this purpose, quinone (hydroquinone, naphthoquinone or methylhydroquinone) derivatives of HC were synthesized, which made it possible to vary the redox and antioxidant properties of HC as terminal electron acceptors in methanogenic systems. The highest acceptor properties were obtained with potassium humate modified by naphthoquinone. To control possible negative effect of HC on the cells of natural methanogenic consortia, different bioluminescent analytical methods were used. The addition of HC derivatives, enriched with quinonones, to nutrient media at concentrations above 1 g/L decreased the energetic status of cells and the efficiency of the methanogenesis. For the first time, the significant decrease in accumulation of biogas was reached as effect of synthetic HC derivatives, whereas both notable change of biogas composition towards increase in the CO2 content and decrease in CH4 were revealed. Thus, modification with quinones makes it possible to obtain low-potential HC derivatives with strongly pronounced acceptor properties, promising for inhibition of biogas synthesis by methanogenic communities.

Directed Synthesis of Humic and Fulvic Derivatives with Enhanced Antioxidant Properties

“…It could be concluded that the directed modification of HS with phenolic centers is a promising tool for preparing humic antioxidants with the desired properties (Figure 8). We have recently demonstrated good prospects of this approach for suppressing methane emission by consortium of methanogenic bacteria [46]: addition of 2-OH-naphthoquinone-HA-derivative into cultivation medium substantially reduced the rate and the amount of the emitted methane, while addition of fulvic acids and their hydroquinone derivatives stimulated the production of methane. From an agricultural perspective, it might be suggested that fulvic acids, in particular, those modified with hydroquinones, could possess enhanced electron-shuttling capacity, which is related to ability of humic substances for eliciting biostimulating activity on plant growth [47].…”

The EU Training Network for Resource Recovery through Enhanced Landfill Mining—A Review

“…This LCA publication was cited with respect to the site selection for landfills [153,154] and in a study which yielded the controversial statement that "recycling metals except gold had more negative environmental impacts than mining" [155]. Further citing studies deal with environmental impacts of combustion-based energy production [156], composting on closed landfill sites [157], bioreactor landfills [158], suppression of methane generation [159], modelling of landfill gas production [160], organic waste enrichment [161]. Within NEW-MINE, LCA was also applied to compare smelting of MSWI bottom ash with the state-of-the-art mineral process-ing approach and revealed that the energy demand for smelting processes overrules, with respect to global warming, the positive effect of secondary raw material production [162].…”

Sixth International Conference of the CIS IHSS on humic innovative technologies "Humic substances and ecoadaptive technologies" (HIT-2021)

“…The addition of HC derivatives enriched with quinonones at concentrations above 1 g/l notably reduced the energy status of cells and the efficiency of methanogenesis catalyzed by various anaerobic consortia [3].…”