Simultaneous Denitrification and Bio-Methanol Production for Sustainable Operation of Biogas Plants

Abstract

This study was conducted to secure the sustainability of biogas plants for generating resources from food waste (FW) leachates, which are prohibited from marine dumping and have been obligated to be completely treated on land since 2013 in South Korea. The aim of this study is to reduce the nitrogen load of the treatment process while producing bio-methanol using digested FW leachate diverted into wastewater treatment plants. By using biogas in conditions where methylobacter (M. marinus 88.2%) with strong tolerance to highly chlorinated FW leachate dominated, 3.82 mM of methanol production and 56.1% of total nitrogen (TN) removal were possible. Therefore, the proposed method can contribute to improving the treatment efficiency by accommodating twice the current carried-in FW leachate amount based on TN or by significantly reducing the nitrogen load in the subsequent wastewater treatment process. Moreover, the produced methanol can be an effective alternative for carbon source supply for denitrification in the subsequent process.

Encapsulation of Methanotrophs within a Polymeric Matrix Containing Copper- and Iron-Based Nanoparticles to Enhance Methanol Production from a Simulated Biogas

“…Previously, M. stellata and M. trichosporium OB3b produced much lower methanol concentration accumulation of up to 0.13 mmol/L from biogas [ 29 ]. An undefined mixed culture of methanotrophs grown on CH 4 as an inoculum was reported to have a methanol concentration accumulation of 3.82 mmol/L [ 30 ]. In contrast, ammonia-metabolizing Candidatus nitrosoglobus exhibited a low methanol concentration accumulation of 1.5 mmol/L from CH 4 [ 31 ].…”

“…Overall, we developed a suitable strategy for renewable methanol production using NPs during inoculation preparation and encapsulation within polymeric matrix stages to enhance methanol production for the first time. Furthermore, the use of alternative feeds to simulated biogas, such as raw biogas derived from anaerobic digestion bioprocesses, is desirable for sustainable development using polymeric-matrix-and NP-based methanotroph systems [ 30 , 34 ].…”

An Experimental Study on the Biological Fixation and Effective Use of Carbon Using Biogas and Bacterial Community Dominated by Methanotrophs, Methanol-Oxidizing Bacteria, and Ammonia-Oxidizing Bacteria

“…Compared to previous studies that used methane (a pure synthetic gas) and chemically defined or commercially sold culture media, our previous studies using biogas generated by wastewater treatment plants as a carbon source, as well as nutrient-rich sewage and wastewater as culture media, were different [21][22][23][24]. The biggest difference was that maintaining an effective single species as a dominant species, using wastewater and biogas, was not possible owing to biological contamination and interference, unlike in controlled laboratory environments.…”

“…In a previous study, for the first time, we used sewage flowing into an urban wastewater treatment plant as a culture medium, as well as biogas generated from a wastewater treatment plant in bio-methanol production [21]. In subsequent studies, we produced methanol using biogas as a carbon source and sewage as a culture medium and proposed a treatment process using the generated methanol as a carbon source for denitrification [22,23]. Furthermore, we investigated the bacterial community formation and the dominance of effectives species in reject water containing high concentrations of ammonia generated by anaerobic digesters in wastewater treatment plants, as well as the mutual roles and correlations between each bacterial cluster involved in the process [24].…”

“…Bacterial clusters of different taxa accumulated to form a bacterial community in which the bacteria are interdependent. The formed bacterial communities were useful in methanol production and wastewater processing [21][22][23][24]. Another key difference from controlled laboratory conditions, where only pure methane was used, was the existence of new effectives species under high CO 2 ratio of ≥30%.…”