Effects of free ammonia on volatile fatty acid accumulation and process performance in the anaerobic digestion of two typical bio-wastes

Shi, Xuchuan; Jia, Lin; Zuo, Jiane; Li, Peng; Li, Xiaoxia; Guo, Xuerang

doi:10.1016/j.jes.2016.07.006

Cited by 155 publications

(53 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…As shown in Figure 3b, as a result of high protein content, the T3 reactor showed two times higher NH4 + -N content compared to other groups with low protein content. Shi et al [31] reported that hydrolyzing protein induced a continuous release of ammonia, which placed a premium on decreasing the activity of acidogenic bacteria and methanogens. Thus, the reason that the T3 reactor had relatively high theoretical methane potential but the lowest bio-methane potential and gasification rate could be explained.…”

Section: Chemical Parameters and Process Stabilitymentioning

confidence: 99%

Interactive Effects of Chemical Composition of Food Waste during Anaerobic Co-Digestion under Thermophilic Temperature

et al. 2019

View full text Add to dashboard Cite

The effects of chemical composition (carbohydrates, lipids, and protein) on the anaerobic co-digestion performance of food wastes (FW) were investigated from the viewpoints of methane production, dynamic parameters, and microbial community structure. The results of this study showed that a notable gasification rate was positively correlated with the proportion of the composition. A T2 reactor, which consisted of 60% carbohydrates, 20% lipids, and 20% protein, held a higher gasification rate of 65.09% compared to other groups, while its process parameters showed some deficiency regarding the stability of digestion, especially for low biochemical methane potential (BMP), which was not beneficial for the actual practice. A T4 reactor, with a highest gasification rate of 70.68%, held the maximum BMP (497.44 mL/g VS). The stable chemical parameters achieved the optimal proportion, consisting of 40% carbohydrates, 40% lipids, and 20% protein. Furthermore, its microbial populations were rich and achieved a balance of the two main dominant communities of acetoclastic methanogens and hydrogenotrophic methanogens, whose relative abundance was close. It was obvious that interactive effects were caused by different proportional composition, which led to constantly changing chemical parameters and microbial community.

show abstract

Section: Chemical Parameters and Process Stabilitymentioning

confidence: 99%

Interactive Effects of Chemical Composition of Food Waste during Anaerobic Co-Digestion under Thermophilic Temperature

et al. 2019

View full text Add to dashboard Cite

show abstract

“…However, ammonia and VFAs, except carbonates, in the ternary buffer system are both recognized as potential inhibitors on anaerobes [6], and their potential to depress methanogenesis is more prominent than sulfides, humic acids and long chain fatty acids that have been reported [7]. Furthermore, the increased VFA concentration, associated with steady but depressed methane production from nitrogen-rich substrates, is considered to be the result of ammonia inhibition [8], because methanogenesis is much more sensitive to ammonia than hydrolysis and acidogenesis [9]. Too many VFAs in the HSAD system may also result in low pH and thus the failure of HSAD [10].…”

Section: Introductionmentioning

confidence: 99%

Biochemical Conversion and Microbial Community in Response to Ternary pH Buffer System during Anaerobic Digestion of Swine Manure

et al. 2018

View full text Add to dashboard Cite

The ternary pH buffer system with ammonia-carbonates-volatile fatty acids (VFAs) is essential to anaerobes for bioenergy recovery via anaerobic digestion (AD). However, ammonia and VFAs are recognized as potential inhibitors that depress methanogenesis. In this study, biochemical conversion and the microbial community in batch AD at total solid (TS) from 4% to 14% were investigated to reveal their response to the ternary pH buffer system. The rapid ammonia release, probably promoted by Anaerosphaera and Eubacterium inferred from the concurrent peak of their relative abundance, triggered total ammonia (TAN) inhibition with the accumulation of VFAs in the start-up stage of high solid AD (HSAD, TS ≥ 8%). Along with evolution of the microbial community to resist high TAN and VFAs, methanogenesis recovered with improved degradation of VFAs and reduction of COD. When exposed to 3500 mg·N·L−1 TAN at 8% TS, aceticlastic Methanosarcina became dominant first and then together with hydrogenotrophic Methanoculleus, achieved the optimal biochemical conversion. While in HSAD at 11–14% TS, the main pathway of methanogenesis appeared to have shifted from the aceticlastic pathway to the hydrogenotrophic pathway, as inferred by changes in the relative abundance of methanogens, and this could have been induced by the increasing concentration of high free ammonia (FAN, ≥588 mg·N·L−1). Although the anaerobes had acclimatized to high TAN, the propionate-oxidizing bacteria and acetate-oxidizing bacteria might have again been inhibited by high FAN, frustrating the H2 supply for FAN-tolerant Methanoculleus and causing an 8.2–11.3% depression of COD reduction (mainly propionate residual).

show abstract

“…These AD intermediates have been shown to build up when methanogenesis is inhibited by coenzyme M during AD of ferulic acid (an intermediate of lignin degradation) [25]. Isovaleric and isobutyric acid are considered to be the most sensitive indicators of digestion imbalance [4,26], and their occurrence in R-MS could have inhibited methanogenic activity. This could also explain why the observed methane yield was 31% lower than the methane yield that theoretically could be produced in these experimental conditions.…”

Section: Vfas Formationmentioning

confidence: 99%

“…Degradation of propionate is known to be the most thermodynamically unfavorable step in the AD system. It is degraded under a relatively low partial pressure of hydrogen because only under these conditions is the process thermodynamically favorable [26]. Thus, the high concentration of propionate in the digestates from R-ZM and R-MS indicted that propionate degradation was inhibited by a high partial pressure of hydrogen, and also indicated that hydrogenotrophic methanogens were inhibited [27].…”

Section: Vfas Formationmentioning

confidence: 99%

Effect of Individual Components of Lignocellulosic Biomass on Methane Production and Methanogen Community Structure

Pokój

Klimiuk

Bułkowska

et al. 2018

Waste Biomass Valor

View full text Add to dashboard Cite

One of the major factors that influences the economic feasibility of biogas production is the availability of digestible feedstocks. There is little research on the influence of the chemical composition of biomass on biogas synthesis, especially with regard to the content of lignocellulosic materials. Therefore, the aim of this study was to estimate how differences in the content of cellulose and lignin in lignocellulosic biomass influence the concentrations of individual volatile fatty acids (VFAs) and biogas production. Additionally, the structure of the methanogenic community was examined. The removal of fibrous and non-fibrous materials, the concentrations of individual VFAs, methane production and methanogen community structure were examined during digestion of Zea mays L. and Miscanthus sacchariflorus silages. Organics were removed with higher efficiency during the digestion of Z. mays silage than during digestion of M. sacchariflorus. This was due to the higher non-fibrous carbohydrates content in Z. mays than in M. sacchariflorus. In both digesters, propionate predominated throughout experiment. The methanogenic community in the digester fed with Z. mays was more diverse than that in the digester with M. sacchariflorus. Analysis of 16S rRNA sequences showed that six acetoclastic and four hydrogenotrophic methanogens were present in the digester fed with Z. mays L., while five acetoclastic and three hydrogenotrophic methanogens were in the digester fed with M. sacchariflorus. The abundance of Methanosarcina correlated significantly with the concentration of all analyzed VFAs.Keywords Crop silage · Anaerobic digestion · Syntrophic volatile fatty acids oxidation · Archaeal community structure · Methane yield Statement of NoveltyTo introduce novel biomass types for biogas production, an integrated evaluation approach has to be applied. The present study delivers a combination of technological and microbial data about the process of anaerobic digestion of the commonly used substrates Zea mays L. silage and Miscanthus sacchariflorus silage, the latter of which has a high content of lignin and cellulose. The correlations between the abundance of methanogenic microorganisms and the concentrations of individual VFAs produced during digestion of these substrates were estimated. The results reveal novel associations between the type of substrate used, the rate of methane production and the structure of the methanogenic community. The use of materials with a high lignin content limits biodiversity in the anaerobic digesters, which can result in decreases in anaerobic digestion performance and biogas production.

show abstract

Effects of free ammonia on volatile fatty acid accumulation and process performance in the anaerobic digestion of two typical bio-wastes

Cited by 155 publications

References 32 publications

Interactive Effects of Chemical Composition of Food Waste during Anaerobic Co-Digestion under Thermophilic Temperature

Interactive Effects of Chemical Composition of Food Waste during Anaerobic Co-Digestion under Thermophilic Temperature

Biochemical Conversion and Microbial Community in Response to Ternary pH Buffer System during Anaerobic Digestion of Swine Manure

Effect of Individual Components of Lignocellulosic Biomass on Methane Production and Methanogen Community Structure

Contact Info

Product

Resources

About