Methanogenic Research Articles

Biogas generation from biomass as a cleaner alternative towards a circular bioeconomy: Artificial intelligence, challenges, and future insights

In recent years, the growing trend of energy consumption from fossil fuels in the world has faced mankind with two major crises of environmental pollution and the increasing acceleration in the depletion of energy resources, hence the movement towards the provision of clean and renewable energy is placed as one of the main programs and strategy in the world. Biogas is a flammable mixture that is produced by fermentation of organic materials in a certain temperature range and a certain pH in anaerobic conditions by microbes. Fermentation reactions in the biogas device include sets of chemical and biological activities of two groups of acid-producing and methanogenic bacteria in the fermentation chamber, whose growth, survival, and the amount of biogas produced depends on the conditions of the fermentation environment. The produced biogas has a calorific value of 4580 to 5495 kcal/m3 for the degree of purity of 50 % to 65 % methane. This review focuses on recent developments and achievements for biogas generation from biomass towards a circular bioeconomy. Besides, the utilization of artificial intelligence to model the processes leading to the generation of biogas from biomass are highlighted, and finally, the challenges and opportunities of biogas generation from biomass are examined in detail, and solutions are mentioned to motivate researchers in this field.

Effect of organic shock loading on anaerobic performance of pumice-reinforced up-flow anaerobic sludge bed for incineration leachate treatment

The research and application of leachate in the treatment of leachate in UASB reactors are increasing, but UASB also has problems such as poor resistance to organic load impact and unstable operation. In order to improve the anaerobic performance stability of an up-flow anaerobic sludge bed reactor (UASB) subjected to high organic loading shock, pumice was added to the leachate from the incineration. The reinforcement effect of pumice on the anaerobic efficiency of the reactor was studied by increasing the influent load. The results showed that with a gradual increase in the influent organic load [11.6‒66.6 kg COD/(m3∙d)] and without the addition of pumice, irreversible acidification took place in the reactor (R1) when the influent load reached 14.51 kg COD/(m3∙d). The average methane output and content were reduced to 39.7 L/d and 66.16%, respectively. In contrast, the reactor (R2) with pumice could still be operated stably when the influent organic load reached 40.04 kg COD/(m3∙d). The COD removal rate reached 91.80%, and the average methane output and content were increased by 42.30% and 15.20%, respectively. The results of analyzing the sludge microbial community structure in the reactor showed that the adding of pumice could selectively enrich the methanogenic bacterium methanosaeta, promote the decomposition of volatile fatty acid (VFA), effectively mitigate the acid inhibition effect of VFA on the anaerobic reactor, and enhance the balance between acidogenic bacteria (Chloroflexi and Proteobacteria) and methanogenic bacterium (Methanosaeta) to a great degree. These results prove that the addition of pumice filler can reinforce the resistance of UASB to organic loading.

Can digestate recirculation promote biohythane production from two-stage co-digestion of rice straw and pig manure?

Digestate recirculation is often considered an important way to improve system stability (system acidification, ammonia inhibition, hydrolysis limitations, etc.) and gas production performance. However, it is not clear how the promotion of biohythane production works in anaerobic co-digestion with digestate recirculation of rice straw (RS) and pig manure (PM). Two sets of laboratory-scale two-stage continuous stirred tank reactors were operated continuously for 95d to investigate the performance of biohythane production in the first/second phase under mesophilic (M)/thermophilic (T) and digestate recirculation conditions. Firstly, biohythane was not produced by PM with RS under digestate recirculation. The main reasons were: 1) Digestive recirculation promoted the growth of hydrogenotrophic methanogenic bacteria; and 2) limitations in hydrolysis. Secondly, digestate recirculation has positive effects on the removal rates (removal rates of TS, VS, polysaccharide, protein and TCOD increased by 30.4%, 22.3%, 9.9%, 31.4%, and 11.9%, respectively) and energy yield (up to 68.7%). Finally, there was a higher abundance of hydrogen-producing bacteria (Fervidobacterium [44.9%] and Coprothermobacter [18.8%]) in T2, accounting for >80% of the total, and of which the huge hydrogen production potential cannot be ignored. The results provide new ideas for alleviating the energy crisis and developing green energy in the future.

Effect of Cow Manure on Biogas Production Based on Rice Husk Waste in SSAD Conditions

The development of biogas technology is currently very fast along with the increasing need for energy and expensive costs used to buy fossil energy. Rice husk-based biogas has begun to be widely developed because of the high potential that can be utilized from the biomass. The aim of this study was to study the effect of the addition cow manure combined with rice husks for biogas production under SSAD conditions. Variable comparison of rice husk and cow manure as follows: 4:1, 3:1, 2:1, 1:1, 1:2, 1:3, and 1:4. The study was carried out in duplicate on laboratory scale with C/N ratio 35, 27% total solids and rumen fluid as a source of methanogenic bacteria. Biogas is observed every two days until its productivity decreases. It was found that the best biogas productivity was in the 2:1 variable range, namely 39.49 mL/grTS followed by 1:1 21.91 mL/grTS, 3:1 13.80 mL/grTS, 1:2 13.31 mL/grTS, 1:3 10.90 mL/grTS, 1:4 82 mL/grTS and 4:1 9.41 mL/grTS. After calculating the biogas production rate constant with Gompertz, the highest productivity was obtained at 1:1 variable, with maximum biogas (A): 65.69 mL/grTS, daily biogas production (U): 0.37 mL/grTS.day, and minimal time for biogas formation (\U0001d706): 25th day.

Study of cattle microbiota in different regions of Kazakhstan using 16S metabarcoding analysis

Methane (CH4) is an important greenhouse gas (GHG). Enteric methane emissions from farmed ruminant livestock account for approximately 15% of global GHG emissions, with approximately 44% of livestock emissions in the form of methane. The purpose of the research is to study the influence of feeding types and regional characteristics of Kazakhstan on the microbiota of feces and the number of methane-forming archaea of beef and meat-and-dairy cattle productivity. For this purpose, fecal samples were taken rectally from 37 cattle heads from four regions of Kazakhstan (Western, Southern, Northern and Southeast). The taxonomic composition of the community in all samples was determined by 16S metabarcoding; additionally alpha and beta diversities were calculated. The dominant phyla were: Firmicutes (57.30%), Bacteroidetes (17.00%), Verrucomicrobia (6.88%), Euryarchaeota (6.49%), Actinobacteria (4.77%) and Patescibacteria (3.38%). Significant differences with regard to methanogens bacteria were found: Euryarchaeota were less present in animals from Western Kazakhstan (2.40%), while Methanobacteriales and Methanobrevibacter were prevalent in Southeast, and less abundant in Western region. Western Kazakhstan differs from the other regions likely because animals are mainly grazed in the pasture. Thus, grazing animals has an impact on their microbiota thus leading to a decrease in methane emissions.

A simulation of acetate consumption and electricity generation in a single microbial fuel cell considering the diversity of nonelectrogenic bacteria.

To simulate acetate consumption and electricity generation in a cycle of a microbial fuel cell (MFC) treating synthetic acetate-based wastewater with low concentration, nonelectrogenic bacteria (NEB), which had no contribution in electricity generation, was incorporated with methanogen's kinetic parameters into a previous biofilm model proposed by Marcus et al. (Biotechnol Bioeng 98:1171-1182, 2007). However, the Coulombic efficiency was estimated to be 40.1%, whereas the experiment showed 13.6%, as the presence of NEB was obviously underestimated. Thus, the maximum NEB reaction rate (qmaxC) was temporarily calibrated, and a sensitivity analysis was then conducted. As a result, the growth parameters of NEB, the growth of the exoelectrogenic bacteria, and the biofilm detachment were identified as influential parameters. qmaxC and a half rate constant of NEB (KsC) were selected as potential calibration parameters. The two sets of calibrated parameters (0.342mmol-acetate (Ac)/mg-volatile solids (VS)/d of qmaxC and 33.8mg-carbon (C)/L of KsC; 0.274mmol-Ac/mg-VS/d of qmaxC and 16.9mg-C/L of KsC) showed a good agreement with the experimental results at 100mg-C/L of initial acetate. However, the calibrated parameter values obviously differed from those in previous models. The calibrated model also showed good agreement with the experimental results at 50 and 200mg-C/L of the initial acetate. In view of the different values of qmaxC and KsC from those of methanogenic bacteria in previous models and the previous findings on anode microbial community, which showed that NEB are not only methanogenic bacteria, we concluded that the diversity of NEB should be considered to simulate performances in a cycle of MFC treating low organic matter concentrations.

Clean utilization of lignite to produce biomethane by optimizing the microbial community

Optimization of microbial community is requisite to boost methane production from inferior coal biodegradation. Here is reported an efficient method of converting lignite into methane by microorganisms, which takes lignite as substrate and obtains efficient microbial flora from sludge by means of enrichment and domestication. The Single Factor Experiment and Response Surface Methodology were carried out to regulate the operating conditions and optimize the medium. The results showed that the optimized gas production of biodegradable lignite reached 79.29 mL (54.32% methane)/2 g coal, which is much higher than the other microbial conversions of lignite to methane reported to date. Furthermore, the combined most probable number counting method and high-throughput sequencing technique revealed that the main bacteria in the fermentation process are acid forming bacteria, sulfate-reducing bacteria and methanogenic bacteria. This study provides new insight into methanation and the clean utilization of lignite.

PSVII-16 Evaluation of the Population Profile of Methanogenic Microorganisms in Animals Treated with the Additive Fator P

Abstract The effects caused by climatic variations in the world, have been attributed to the increase in the emission of greenhouse gases and as a consequence of worsening global warming. The improper handling of animals can contribute to the emission of gases of enteric origin, which are harmful to the environment. The use of additives in the diet of animals tends to be more advantageous as it will equilibrate the ruminal microbial flora, modulate the ruminal metabolism, and reduce the emission of greenhouse gases to environment. Fator P is a natural additive that was developed to attend the current needs of the livestock market, and make the management system more productive and sustainable, and reduce impacts on the environment. The aim of this work was to evaluate the profile of methanogenic microorganisms by the method of relative quantification by qPCR in animals treated with the natural additive Fator P. The experiment was carried out in triplicate, with a total of six animals, in pasture, receiving 6 gr of the Fator P additive and control. Over 28 days of experiment, the ruminal liquid was collected in days 0, 2, 4, 7, 10, 14, 21, 28, and the DNA was extracted using the Qiagem 51604 kit. The reaction of qPCR was realized using a primers sequence of total bacteria and methanogenic bacteria. The population profile of microorganisms over the days, Factor P showed a statistically significant reduction (p < 0,05) on days 2 (55,7%; p = 0,0188), 7 (72,08%; p = 0,0445), 14 (56,31%, p = 0,0123), 21 (46,62%, p = 0,0049), 28 (53,28%, p = 0,0499). The result indicates that the reduction in the population of methanogens can reduce the emission of gases of enteric origin and shows the efficiency of the additive in management system more productive and sustainable.

Iron sulfate and molasses treated anthocyanin-rich black cane silage improves growth performance, rumen fermentation, antioxidant status, and meat tenderness in goats.

This study investigated the effects of feeding anthocyanin-rich black cane treated with ferrous sulfate and molasses on animal performance, rumen fermentation, microbial composition, blood biochemical indices, and carcass characteristics in meat goats. Thirty-two Thai-native×Anglo-Nubian crossbred male goats (14.47±2.3 kg) were divided equally into two groups (n = 16) to investigate the effect of feeding diet containing 50% untreated anthocyanin-rich black cane silage (BS) vs diet containing anthocyaninrich black cane silage treated with 0.03% ferrous sulfate and 4% molasses (TBS) on average daily gain (ADG) and dry matter intake (DMI). At the end of 90 d feeding trial, the goats were slaughtered to determine blood biochemical indices, rumen fermentation, microbial composition, and carcass characteristics differences between the two dietary groups. Goats fed the TBS diet had greater ADG and ADG to DMI ratio (p<0.05). TBS diet did not affect rumen fluid pH; however, goats in the TBS group had lower rumen ammonia N levels (p<0.05) and higher total volatile fatty acid concentrations (p<0.05). Goats in the TBS group had a higher (p<0.05) concentration of Ruminococcus albus but a lower (p<0.05) concentration of methanogenic bacteria. The TBS diet also resulted in lower (p<0.05) thiobarbituric acid-reactive substances concentration but higher (p<0.05) total antioxidant capacity, superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase concentrations in blood plasma, while having no effect on plasma protein, glucose, lipid, immunoglobin G, alanine transaminase, and aspartate aminotransferase. Meat from goats fed the TBS diet contained more intramuscular fat (p<0.05) and was more tender (p<0.05). In comparison to goats fed a diet containing 50% untreated anthocyanin-rich black cane silage, feeding a diet containing 50% anthocyanin-rich black cane silage treated with 0.03% ferrous sulfate and 4% molasses improved rumen fermentation and reduced oxidative stress, resulting in higher growth and more tender meat.

Effect of the degradation performance on carbon tetrachloride by anaerobic co-metabolism under different external energy sources

In this research, a comprehensive study was carried out on the removal of carbon tetrachloride (CT) in the anaerobic co-metabolism (ACM) reactor. The experiments showed that when the hydraulic retention time (HRT) was 36 h, pH was 7, and influent CT was 2.5mg/L, the average removal efficiency reached 82.45 ± 2.56% in the glucose co-metabolism substrate reactor, exhibiting a dramatic excellent difference in reaction performance from the other two reactors (p < 0.05) and a favorable tolerance on the CT shock loading. The content of extracellular polymeric substances (EPS) and volatile fatty acids (VFA) demonstrated that glucose could supply more energy to protect the microorganisms, which was the appropriate external energy source. Moreover, microbial community structure and biostatistics analysis demonstrated that Pseudomonas was the most important dechlorination bacteria in ACM reactors, which might via dehalogenation process mediate the transformation of CT. The succession of methanogenic bacteria further demonstrated that CT degradation using co-digestion require to destroy hydrogenotrophic methane generation pathway and the external energy substances could make up the lack of hydrogen in the treatment of CT. The change of intermediate products hinted that anaerobic dechlorination process of CT in an ACM reactor was a sequential dechlorination process, and major transformation products measured were CF. Overall, this study has improved our understanding of the roles of CT degradation process in ACM reactors.

Long-term effects of duckweed cover on the performance and microbial community of a pilot-scale waste stabilization pond

Duckweed-based ponds (DP), as a modified type of waste stabilization ponds (WSP) are receiving growing attention due to the sustainable production of high-quality duckweed biomass. However, the comprehensive effects of duckweed cover on nutrient removal, greenhouse gas emission and microbial community of the WSP have rarely been studied. In this study, two pilot-scale WSP (12 m2) with (DP) and without (OP) a duckweed mat on the surface were compared over 1 year to determine the effects. The results showed that, compared to OP, DP had higher TP, but lower TN and NH4+-N removal efficiencies, and lower pH, dissolved oxygen (DO) and sedimentation rate of settling detritus. For both nitrogen and phosphorus removal, the dominant pathway was duckweed uptake (66.95% and 93.18%, respectively) in DP; however, it became other pathways (mainly nitrification/denitrification, 82.27%) and sedimentation (87.65%), respectively, in OP. Meanwhile, DP had lower N2O, but higher CH4 emission fluxes than OP, resulting in comparable global warming potential between OP and DP (approximately 2800 g CO2/m2/yr). Microbial community analysis indicated that the greater nitrogen removal and N2O emission in OP could be attributed to higher abundance of ammonia-oxidizing bacteria in the water and denitrifiers in the sediment, supported by higher DO and settling organic carbon, respectively. Meanwhile, the greater CH4 emission in DP could be attributed to higher abundance of methanogens and syntrophic methanogenic bacteria in the sediment. Thus, despite favourable effects on nutrient recovery and phosphorus removal mainly attributed to duckweed uptake, duckweed cover had unfavourable effects on nitrogen removal and CH4 emission reduction of the WSP mainly attributed to microbial taxa which were influenced by environmental conditions (such as DO and settling detritus) in the WSP. These findings help to clarify the influencing mechanism of duckweed cover, providing overall insight into the function and application of the DP.

Robust state and input estimation with enhanced convergence rate for monitoring anaerobic digestion

In this study, an observer for estimating the state and unknown inputs is proposed for monitoring anaerobic digestion processes. This estimator is based on a dynamic model considering acidogenesis and methanogenesis, and consists of three sub-observers: (a) a gramian-based fixed-time convergent observer for the inlet chemical oxygen demand (COD) and the acidogenic bacteria population, (b) an asymptotic observer for the methanogenic bacteria population, and (c) a super-twisting observer for systems with time-varying parameters to estimate the inlet volatile fatty acid (VFA) concentration. These sub-observers can be designed independently, which greatly simplifies the tuning process. Proofs of convergence are developed and simulation tests show the performance of the estimation scheme as compared to classical extended Kalman filtering.

Anaerobic biological treatment of dye bearing water in anaerobic sequencing batch reactor: Performance and kinetics studies

Textile and dye industries are main sources of dye bearing effluent. In present studies the anaerobic biological degradation of Acid Red 3BN dye water (AR3BNDW) and mixed dye water (MDW) for reduction of color and COD were studied in sequential batch reactor (SBR). The sludge as sources of microorganism was arranged from maize processing bio methanation wastewater treatment plant, which was acclimatized for treatment of AR3BNDW and MDW. After the acclimatization, dyes degradation were studied in SBR At optimum operation condition of hydraulics retention time (HRT) = 2.5 d, and treatment time (tR) = 16 h, AR3BNDW have gone maximum 87% color reduction of 500 mg/L dye, and 82.8% COD reduction of 380 mg/L COD. At same operating condition, 84.5% color reduction of 500 mg/L dye, and 79.42% COD reduction of 413 mg/L COD achieved for MDW. The second order Grau model was fitted well for COD and dye reductions. The kinetics parameter were evaluated for both the dye water.

Dietary inclusion of anthocyanin-rich black cane silage treated with ferrous sulfate heptahydrate reduces oxidative stress and promotes tender meat production in goats.

Pre-treating anthocyanin-rich black cane with ferrous sulfate heptahydrate (FSH) produces high-quality silage with anthocyanin and nutritional losses. However, it's unclear how to apply this to studies on how FSH-treated silage affects animal performance and meat quality. Therefore, this study aimed to investigate the effects of a standard total mixed ration (TMR) containing anthocyanin-rich black cane silages either with or without dilutions of FSH on animal performance, blood biochemical indices, rumen fermentation, microbial community, and carcass characteristics in meat goats. Forty healthy crossbred Thai-native Anglo-Nubian male goats (14.42 ± 1.4 kg) were used to compare the feasibility of using anthocyanin-rich black cane silage (ABS) as a functional feed resource as opposed to anthocyanin-rich black cane treated with 0.030% commercial FSH silage (ABSF). All goats received a 90-day routine feeding of two isocaloric and isonitrogenous experimental diets: the control group received TMR containing 50% anthocyanin-rich black cane silage (ABS; n = 20), and one group received TMR containing 50% FSH-treating anthocyanin-rich black cane (ABSF; n = 20). As performance indicators, average daily weight gain (ADG) and dry matter intake (DMI) were measured. Samples of meat, blood, and rumen were taken at the end of the experiment. There were no differences in final body weight, ADG, DMI, or ADG/DMI between the two groups. The ABSF group did not differ from the ABS group in terms of rumen pH, but the ABSF had a tendency to lower rumen ammonia N levels, and to higher total volatile fatty acid (VFA) concentrations. Individual VFA concentrations differed, with the ABSF group having more Ruminococcus albus and the ABS group having more methanogenic bacteria. Blood biochemical indices differed, with the ABSF group having lower TBARS concentrations and the ABS group having lower TAC, SOD, CAT, GSH-Px, and GSH-Rx concentrations. In comparison to goat meat from the ABS group, goat meat from the ABSF group contained more intramuscular fat and was more tender. The current results indicate that the feeding of a TMR containing 50% anthocyanin-rich black cane, along with FSH pre-treatment prior to ensiling, reduces oxidative stress and promotes the production of tender meat without affecting animal performance.

Differences in the methanogen community between the nearshore and offshore sediments of the South Yellow Sea.

The differences in methanogen abundance and community composition were investigated between nearshore and offshore sediments in the South Yellow Sea (SYS). Shannon, Simpson, and Chao1 indices revealed a higher diversity of methanogens in the nearshore sediments than in the offshore sediments. The Mann-Whitney U test demonstrated that the relative abundance of Methanococcoides was significantly higher in the offshore sediments, while the relative abundances of Methanogenium, Methanosarcina, Methanosaeta, Methanolinea, and Methanomassiliicoccus were significantly higher in the nearshore sediments (P < 0.05). The abundance of the mcrA gene in the nearshore sediments was significantly higher than that in the offshore sediments. Furthermore, a similar vertical distribution of the methanogen and sulfate-reducing bacteria (SRB) abundances was observed in the SYS sediments, implying there is potential cooperation between these two functional microbes in this environment. Finally, total organic carbon (TOC) was significantly correlated with methanogen community composition.

Overview of Nanoparticles effects as well as Enhancement of Biogas from Bio methanation of Press mud

Overview of Nanoparticles effects as well as Enhancement of Biogas from Bio methanation of Press mud

Isolation, Screening, and Characterization of Methane-Utilizing Bacteria From the Sediment of Lowland Rice

Methane is a major greenhouse gas that contributes to climate change. Methanogen and methanotrophic group microbes play a role in methane emissions in lowland rice fields. Methane is produced by methanogenic bacteria that decompose organic matter in anaerobic conditions. These bacteria will be active if the soil is inundated for an extended period of time. Some of this methane will be oxidized by methanotrophic bacteria in the rhizosphere. The researchers aimed to isolate, screen, and characterize methane-utilizing bacteria in lowland rice sediment from several Indonesian provinces. 27 methane- utilizing bacteria were isolated from rice field sediments in Lampung, West Java, and East Nusa Tenggara Province. Six of them had the potential to reduce methane emissions by more than half. A pmoA-like gene could be found in all of the selected isolates. The bacterial isolates were identified as Mycobacterium senegalense, Bacillus marisflavi, Bacillus methylotrophicus, Flavobacterium tirrenicum, Providencia stuartii, and Rhizobium rhizoryzae after characterization and identification with the Biolog OmniLog® ID system. These were all capable of nitrogen fixation, phosphorus solubilization, and IAA production. These isolates have the potential to be used as biofertilizers and methane mitigation agents.&#x0D; Keywords: biofertilizers, greenhouse gas, lowland rice, methane-utilizing bacteria

Effects of nZVI and Fe3O4 NPs on anaerobic methanogenesis, microbial communities and metabolic pathways for treating domestic wastewater at ambient temperature

Anaerobic methanogenesis from domestic wastewater is one of the promising way to wastewater resource utilization. In this study, the effects of nanoscale zero-valent iron (nZVI) and nano ferroferric oxide (Fe3O4 NPs) on organic matter removal, methanogenesis, microbial communities, and metabolic pathways in the anaerobic biofilm system for treating domestic wastewater at ambient temperature were studied. The results showed nZVI and Fe3O4 NPs not only promoted the hydrolytic fermentation process of the anaerobic biofilm system, but also facilitated the removal of refractory organic matter. Especially, Fe3O4 NPs improved the methanogenic efficiency, shortened the lag time, and entered the rapid methanogenic stage rapidly. Fe3O4 NPs formed direct interspecies electron transfer (DIET) and symbiotic relationship between the acetic acid oxidizing bacteria and the methanogenic bacteria. Furthermore, Fe3O4 NPs promoted the biosynthesis of F420. In the Fe3O4 NPs system, the CO2-reduced methanogenesis, as the main methanogenic pathway, was enhanced.

Optimizing Anthocyanin-Rich Black Cane (Saccharum sinensis Robx.) Silage for Ruminants Using Molasses and Iron Sulphate: A Sustainable Alternative

Anthocyanin-rich black cane (aBC) is a grass rich in lignin and carbohydrates, with an abundance of anthocyanins. Silages of aBC produced with molasses (MS) and/or ferrous sulphate (FS) mixtures may have beneficial effects on silage quality and animal performance in ruminants. However, the addition of MS and FS to ensiled grass is relatively unexplored. Therefore, this study systematically evaluated the effect of their administration at different doses to select an effective treatment to modulate the ensiling characteristics of aBC. In the first trial, fresh or pre-ensiled materials (PBC) were compared with ensiled PBC treated with: 0% MS 0% FS, 4% MS, 8% MS, 0.015% FS, 0.030% FS, 4% MS + 0.015% FS, 4% MS + 0.030% FS, 8% MS + 0.015% FS, and 8% MS + 0.030% FS on a fresh matter basis. The quality of ensiling characteristics was determined in laboratory-scale silos after 42 d of preservation. Based on these results, the second trial was further conducted in rumen cultures to ensure that the selected treatment would not impair rumen fermentation. For this, ruminal biogases, rumen fermentation profiles, and microbial communities were evaluated. Ensiled PBC with the incremental addition of MS and FS resulted in the observations for anthocyanin contents and the ensiling characteristics of the aBC silages. The combination of MS (4%) and FS (0.030%) incorporated into silages had the highest silage production effect among the experimental treatments. This combination demonstrated the sustainable mitigation of the ruminal biogases of methane and carbon dioxide without impairment of total gas production. Concurrently, this combination improved total volatile fatty acid concentrations, modulated cellulolytic bacteria, and suppressed methanogenic bacteria in rumen fluids. The results presented here indicated that addition of a mixture of 4% MS and 0.030% FS to aBC resulted in an optimal balance of ensiling characteristics and is suitable for use in ruminants.

Application of the EGSB-CMBR Process to High-Concentration Organic Wastewater Treatment

To decrease the cost of wastewater treatment at the plant, the Wuzhou Shenguan Protein Enteric Coating Production Plant designed and built an expanded granular sludge bed (EGSB)-ceramic membrane bioreactor reactor (CMBR) process for treating high-concentration organic wastewater with a capacity of 25 m3/d. The EGSB is divided into anaerobic and microaerobic sections. The purpose of the anaerobic section is to substantially degrade COD, and the main functions of the microaerobic section are to coordinate the relationship between hydrolytic acid-producing bacteria, methanogenic bacteria (MBP), and sulfate-reducing bacteria (SRB) and to mitigate the inhibitory effects between them to simultaneously remove COD and sulfate. Anaerobic ammonia-oxidizing bacteria were added to the CMBR reactor to remove both COD and ammonia nitrogen. The results of the operation showed that more than 99% of the COD was removed by the EGSB-CMBR process, while the removal rates of NH4+-N and SS were greater than 70% and 90%, respectively. In addition, the effluent met the requirements of the secondary standard of the Comprehensive Wastewater Discharge Standard (8978-1996). Economic and technical analyses showed that the modified EGSB-CMBR reactor has a high treatment efficiency, which greatly saves on the cost of the “commissioned treatment” of high-concentration organic waste liquid in the plant. Specifically, it can save more than 800,000 CNY for the plant annually.