Impact of Granular Activated Carbon on Anaerobic Process and Microbial Community Structure during Mesophilic and Thermophilic Anaerobic Digestion of Chicken Manure

Abstract

In this work, the impact of granular activated carbon (GAC) on the mesophilic and thermophilic anaerobic digestion of chicken manure and the structure of microbial communities was investigated. These results demonstrated that GAC supplementation effectively enhanced the consumption of produced organic acids in the mesophilic and thermophilic batch tests, accompanied by faster biomethane production in the presence of GAC than from reactors without GAC. However, since the free ammonia level was 3–6 times higher in the thermophilic reactors, this led to the instability of the anaerobic digestion process of the nitrogen-rich substrate at thermophilic temperatures. Bacteroidia and Clostridia were the two main bacterial classes in the mesophilic reactors, whereas the class Clostridia had a competitive advantage over other groups in the thermophilic systems. The archaeal communities in the mesophilic reactors were mainly represented by representatives of the genera Methanosarcina, Methanobacterium, and Methanotrix, whereas the archaeal communities in the thermophilic reactors were mainly represented by members of the genera Methanosarcina, Methanoculleus, and Methanothermobacter. New data obtained in this research will help control and manage biogas reactors in the presence of GAC at different temperatures.

Anaerobic Digestion of Chicken Manure in the Presence of Magnetite, Granular Activated Carbon, and Biochar: Operation of Anaerobic Reactors and Microbial Community Structure

“…Our results are consistent with the positive effects of GAC, biochar, and magnetite on CH 4 production during the anaerobic digestion of different other substrates as reported in several other works [ 15 , 16 , 17 , 18 , 19 , 20 , 21 , 26 , 27 ]. Yang et al [ 16 ] indicated that the addition of GAC to biogas reactors (33.3 g L −1 ) enhanced the CH 4 production by 17.4% over the course of anaerobic sludge digestion.…”

“…Total solids, volatile solids, pH, volatile organic acids (VOA), and total ammonia nitrogen (TAN) were measured following standard methods as explained in detail previously [ 20 , 21 ]. Samples for these analyses were periodically collected, and the analyses were repeated three times.…”

“…Amplicon sequencing was conducted using an Illumina MiSeq system with 2 × 300 bp reads. The sequence data were then analyzed as detailed previously [ 15 , 20 , 21 , 22 ] and available on request.…”

“…For example, high concentrations of volatile fatty acids (VFAs), including acetic, propionic, and butyric acids, can acidify the content of anaerobic reactors, leading to inhibition of the activity of the methanogenic communities [ 14 , 15 ]. In recent years, it has been demonstrated that an effective approach to enhance the methanogenic transformation of various VFAs is the process with the addition of conductive materials [ 16 , 17 , 18 , 19 , 20 , 21 ]. Among the explanations for the optimization of anaerobic biomass conversion using conductive materials, the researchers note the provision of direct interspecies electron transfer (DIET) between bacteria, which are involved in the decomposition of organic matter, and archaea, which directly produce methane.…”

“…The process in which electrons transfer directly from electron donors to electron acceptors via microbial nanowires or non-biological conductive materials in anaerobic systems (e.g., iron oxides, GAC, and biochar) is called DIET. The introduction of these conductive materials to anaerobic digesters may ultimately stimulate the more efficient degradation of various VFAs into biomethane under acidic conditions [ 14 ], high ammonium concentrations [ 19 , 21 ], and different temperature conditions [ 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ]. However, little research has been conducted to date on the effects of adding various conductive additives, either alone or together, on the anaerobic digestion of nitrogen-rich chicken manure.…”