Anaerobic Digester

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Identification of metabolically active methanogens in anaerobic digester by DNA Stable-Isotope Probing using 13C-acetate

Identification of metabolically active methanogens in anaerobic digester by DNA Stable-Isotope Probing using 13C-acetate

4 Conclusions: Using stable isotope probing and DGGE approaches we investigated methanogenic community in anaerobic digesters treating food waste of institute mess. All 3 archaeal DGGE band sequences were affiliated to hydrogenotrophic methanogens, particularly the order Methanomicrobiales. The bands were closely related to the species Methanocorpusculum labreanum, this is one of the first reports of this species being identified in food waste digesters. Strains of Methanocorpusculum were considered to be psychrotolerant, suggesting it can be a potential candidate in consortia for anaerobic digesters running at very low temperatures during winter season facilitating in continuous running of the digester without process failure. Further understanding of the entire microbial community structure and dynamics in anaerobic digester will help to optimize efficient functioning of anaerobic digestion process for renewable energy.
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Anaerobic Biodegradability of Dairy Wastewater Pretreated with Porcine Pancreas Lipase

Anaerobic Biodegradability of Dairy Wastewater Pretreated with Porcine Pancreas Lipase

treated with porcine pancreas lipase on the characteristics of sludge developed in an anaerobic digester was investigated by comparison with crude wastewater. Two enzyme concentrations were used to perform the hydrolysis of lipids present in the wastewater from dairy industries employing low cost lipase preparation (US$ 0.12.g -1 solid). The selection of this lipase preparation was based on previous work carried out in our laboratory (Mendes and Castro, 2005). Moreover, it contained others hydrolytic enzymes as proteases and amylases that could be also important for the process, since wastewater from dairy industries contained lipids, proteins and starch compounds (Mendes et al., 2006 a,b).
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Anaerobic digestion of sludge from marine recirculation aquaculture systems

Anaerobic digestion of sludge from marine recirculation aquaculture systems

Oh et al. (2008), using batch tests, studied the effect of compatibles solutes (glycine betaine, choline, carnitine and trehalose) on the anaerobic digestion of salt-containing food wastes (17.5 g sodium chloride (NaCl)/l). The anaerobic seed sludge used was taken from an anaerobic digester in a municipal wastewater treatment plant. First, to test the inhibition of anaerobic digestion by NaCl, the sludge was washed with distilled water and the NaCl concentration was adjusted to 10, 35, 60, 75 and 100 g/L. The methane production decreased 50% with 10 g/l NaCl, 80% with 35 g/L NaCl and for higher concentrations no methane was produced. To overcome NaCl inhibition, 1 g/l of compatible solutes was added separately to the washed sludge with 10 and 35 g/L NaCl and to the non-washed sludge with 11.6 g/L NaCl (original salt-containing food waste diluted 80:20 (distilled water:food waste)). For the sludge with 10 g/l NaCl, glycine betaine and choline increased the methane about twofold compared to the control. The same result was achieved for the sludge with 35 g/l NaCl but only with the addition of glycine betaine. For the non-washed sludge, betaine and choline increased methanogenic activity about five to sixfold. For glycine betaine, it was found that the optimal concentration was 1.5 g/l. It was also observed that the addition of betaine in the beginning of the batch tests and only after 7 days increased the methane production in the same proportion. The addition of betaine after only 14 days of incubation did not improve the methane production, which could not be explained. Finally, the accumulation of intracellular glycine betaine in the anaerobic biomass was reported, and it started to occur after 5 days of incubation.
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Anaerobic Digestion for Sustainable Energy: A Brief Review

Anaerobic Digestion for Sustainable Energy: A Brief Review

very important parameter due to the fact that this greatly affects the anaerobic digester's design process. This affection arises from the fact that OLR indicates a number of volatile solids to be fed into the digester during each cycle. The actual OLR depends on the types of wastes fed to the reactor because the types of waste determine the rate of decomposition [29]. Variations in the chemical composition of the influent and the loading rate cause an upset in the balance between methanogens and acid fermentation [9]. Research have been conducted on the effects of loading rate in biogas production. Aslanzadeh et al. [30] evaluated the effect of OLR and hydraulic retention time (HRT) by comparing single and two stage anaerobic processes using food waste. As a result of the study, it was found that the volume of the reactor in the two-stage system is reduced by 26% while the retention time is decreased by 65%. In addition to this finding, he stated that single-stage systems are limited by the OLR since high OLRs cause inhibition due to the level of the accumulated VFAs. Dermirer and Chen [31] supported the statement by saying that at high OLRs, two stage systems have HRT that is sufficient for the microorganisms to have enough time to degrade the substrate when the hydrolysis-acid genic tank operates in thermophilic conditions while the methanogenic tank is in mesophilic conditions for optimum operation. These conditions lead to the reduction in retention time of the overall process (from 80 days to 15 days maximum) [30],[32]. The statement was supported by the findings of Nickolausz’ experiment. According to Nickolausz et al. [33], the rate at which the reactor is loaded has a major impact on gas production. They proved that alternating the feeding regimes of a reactor can lead to maximizing biogas production. This was achieved in 2 different experiments where the team compared the production rates of 2 similar digesters loaded using different rates. In one digester, organic matter was fed once per day while in the other one, organic matter was fed every 2 days. The results showed that the reactor fed once a day had a 14% CH 4 and a 16%
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Anaerobic Digestion Performance in the Energy Recovery of Kiwi Residues

Anaerobic Digestion Performance in the Energy Recovery of Kiwi Residues

Abstract. World production and trade of fruits generate losses in the harvest, post-harvest, handling, distribution and consumption phases, corresponding to 6.8% of total production. These residues present high potential as a substrate for the anaerobic digestion process and biogas generation. Thus, the energy valuation of the agro-industrial residues of kiwi production was evaluated by anaerobic digestion, aiming at optimizing the biogas production and its quality. Ten assays were carried out in a batch reactor (500 mL) under mesophilic conditions and varying a number of operational factors: different substrate/inoculum ratios; four distinct values for C: N ratio; inoculum from different digesters; and inoculum collected at different times of the year. The following parameters were used to control and monitor the process: pH, alkalinity, volatile fatty acids (VFA), volatile solids (VS) and chemical oxygen demand (COD). Among the tests performed, the best result obtained for the biogas production corresponded to the use of 2 g of substrate and 98 mL of inoculum of the anaerobic digester of the Wastewater Treatment Plant (WWTP) of Bragança, with addition of 150 mg of bicarbonate leading to a production of 1628 L biogas.kg -1 VS (57% methane). In relation to the biogas
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SWINE EFFLUENT TREATMENT USING ANAEROBIC DIGESTION AT DIFFERENT LOADING RATES

SWINE EFFLUENT TREATMENT USING ANAEROBIC DIGESTION AT DIFFERENT LOADING RATES

ABSTRACT: The industrial swine production is characterized by generation of significant effluent amounts that require treatment. The most adopted practices by Brazilian swine farmers have been wastewater storage in lagoons and its subsequent use as a biofertilizer. Nutrient accumulation in soil and water creates the need for an effective management of these residues. The anaerobic digestion process is an important alternative and low-cost treatment for organic matter reduction. However, its efficiency is limited by the digester capacity of solid degradation, especially at low hydraulic retention times. Thus, the present study aimed to verify the behavior of an upflow anaerobic digester by increasing the organic loading rate. This was accomplished in three stages using, as a parameter, volatile solids at 0.5; 1.0 and 1.5 kgVS m -3 d -1 , respectively. This digester model proved to be quite robust and effective in swine manure treatment, achieving high efficiency of volatile solid removal at all stages of the study (stage 1: 61.38%; stage 2: 55.18%; and stage 3: 43.18%). Biogas production was directly related to the increasing organic load, reaching 0.14, 0.85, and 0.86 Nm 3 kgVS -1 add. , respectively, with no significant difference (p<0.05) of biogas methane
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Anaerobic Threshold Biophysical Characterisation of the Four Swimming Techniques

Anaerobic Threshold Biophysical Characterisation of the Four Swimming Techniques

an individual assessment is the better option. It was also possible to establish the AnT as a biophysical boundary for all competitive swim- ming techniques, allowing very practical information for coaches. Although it may be easier to determine the AnT using biomechani- cal variables, it is important to initially analyse the swimmers’ AnT through a physiological approach, to determine whether the differ- ence between the two approaches is significant in actual practice.  The BLIS indicator was useful for assessing swimmers anaerobic be- haviour and training exercises above AnT.
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Ammonia determines transcriptional profile of microorganisms in anaerobic digestion

Ammonia determines transcriptional profile of microorganisms in anaerobic digestion

ducted in triplicate at 37 ◦ C. Seed slurry was prepared by anaerobic digestion of swine manure (obtained from a pig farm in Neijiang, Sichuan Province, China) at 37 ◦ C, for one hydraulic retention time (HRT). After methane production reached the first peak (6th day) in the reactor, we performed a semi-continuous feeding mode that 500 mL of digestate was exchanged every three days with HRT of 15 days and organic loading rate of 4.5 g VS (volatile solid) L −1 day −1 . The anaero- bic digestion was performed for two HRT. The feeding slurry was adjusted to the corresponding NH 4 + concentration using
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Simulação de biodigestor de fluxo tubular com e sem sistemas de recirculação e aquecimentoSimulation of plug flow digester with and without agitation and heating systems

Simulação de biodigestor de fluxo tubular com e sem sistemas de recirculação e aquecimentoSimulation of plug flow digester with and without agitation and heating systems

Sendo assim apresenta (i) uma revisão sobre o princípio de funcionamento dos reatores anaeróbios, os principais parâmetros e tipos de biodigestores empregados neste processo, bem co[r]

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Transcriptome changes associated with anaerobic growth in Yersinia intermedia (ATCC29909).

Transcriptome changes associated with anaerobic growth in Yersinia intermedia (ATCC29909).

ratios (X-axis) which are plotted against posterior probability of differential expression for each of the genes derived using EBarrays (Y-axis) to generate a volcano plot to visualize differential expression. Significant and insignificant genes are represented by black and grey diamonds, respectively. Red diamonds represent orthologs of genes identified as constituting the core anaerobic transcriptome of three enterobacterial members grown in the presence of glucose. A set of 20 genes were identified as likely to constitute the minimal core anaerobic transcriptome of the Enterobacteriaceae in the presence of glucose as the carbon source [22]. These 20 genes shared a 1-1-1 orthologous relationship between three members of the Enterobacteriaceae, namely E. coli K-12-MG1655, Dickeya dadantii 3937 and Pectobacterium atrosepticum SCRI1043 and for all of the 20 genes the pattern of expression was similar, the magnitude of change was greater than 3-fold and the genetic architecture was highly conserved. While the exact functions of most of these genes are established in the model organism E. coli that of few others still remain elusive. τf these 20 genes, 18 were differentially expressed and showed similar pattern of expression in Y. intermedia in this study. These are frdABCD (fumarate reductase), focA, yfiD, (pyruvate formate lyase), adhE (aldehyde dehydrogenases), ynfK (dethiobiotin synthetase), hypC (hydrogenase components), nrdD (anaerobic ribonucleotide reductase), dcuB (dicarboxylate transporter), yhbUV (collagenase-like proteins), pepT (peptidase), ycbJ (uncharacterized protein), exbB (the membrane-spanning protein of the TonB-exbBD complex), yceJ (cytochrome), yceI (uncharacterized protein). Except for five genes (yfiD, yhbV,ycbJ, yceJ, yceI), all of the remaining 13 genes showed fold changes greater than 3 (our stringent criteria established in a previous study) in Y. intermedia. The only gene which is present in the core but missing in the differentially expressed set in Y. intermedia is nrdG (anaerobically functioning ribonucleotide reductase).
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Recovery of gastrointestinal swine parasites in anaerobic biodigester systems

Recovery of gastrointestinal swine parasites in anaerobic biodigester systems

Some countries of the world use the feces of livestock and even humans as an energy source, fertilizer, or incorporated into animal diets (SEMENAS et al., 1999; TOPP et al., 2009), and in the same way there are few regulations around the use of these wastewaters (KUNZ et al., 2009). Anaerobic digesters have been developed as an alternative to solve this problem (CRUZ et al., 2004). Yet, improper handling conditions of these systems and resultant wastewater can cause risks to human and animal health, and to the environment (ANGONESE et al., 2006).

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Adapting Dynamic Mathematical Models to a Pilot Anaerobic Digestion Reactor

Adapting Dynamic Mathematical Models to a Pilot Anaerobic Digestion Reactor

Anaerobic digestion (AD) of animal wastes can pro- duce biogas with methane to be used as an energy source, and a liquid effluent containing valuable nutri- ents. Moreover, AD reduces methane emission, odours and contaminants. AD bioreactors are effective as they allow for relatively high load rates (feed rates) and small reactor volumes. AD reactors may become un- stable, i.e. a persistent decrease of gas production, be- cause of inhibitory effects on methane-forming micro- organisms due to large concentrations of volatile fatty acids (VFA) and ammonia and too low pH. Instability can also occur because of washout of microbes when the feed (load) rate is too large.
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BATCH ANAEROBIC TREATMENT OF FRESH LEACHATE FROM TRANSFER STATION

BATCH ANAEROBIC TREATMENT OF FRESH LEACHATE FROM TRANSFER STATION

method (380 HACH DR/2500 spectrophotometer) and phosphorous by the React PV method (490 HACH DR/2500 spectrophotometer). The pH of the anaerobic process was not controlled throughout the running of the entire treatment study and there was no microbial inoculum added. Initial analytical data shows that the untreated leachate contain high quantity of COD (55000 mg/L), ammonia nitrogen (490 mg/L), TS (39000 mg/L), TSS (4700 mg/L) and VSS (3900 mg/L). The experiments were repeated three times to obtain a consistent average. All analyses were undertaken at room temperature of 28±2°C.
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Design and operational considerations of an Anaerobic Membrane Bioreactor

Design and operational considerations of an Anaerobic Membrane Bioreactor

Anaerobic membrane bioreactor (AnMBR) as a technology has grown as a prominent means of sustainable biological treatment, especially in the recent due to environmental concerns, due to less energy and space requirements, less sludge production, and methane production, which, through cogeneration can make help the system reach energy neutrality. However, membrane cost and the problem of membrane fouling remain the major issues in its widespread use. Pastry production and the resulting wastewater poses a threat to the environment due to its high biological oxygen demand (BOD) and chemical oxygen demand (COD) concentrations which can result in significant costs on the treatment plant. High organic strength in such wastewater make AnMBR a good choice for its treatment.
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Genome analysis of the anaerobic thermohalophilic bacterium Halothermothrix orenii.

Genome analysis of the anaerobic thermohalophilic bacterium Halothermothrix orenii.

Genes encoding for rubrerythrin (Hore_15600, Hore_19080), alkyl hydroperoxide reductase (Hore_18200), two manganese dependent catalases (Hore_23050 and Hore_03960) and a superoxide dismutase (SOD) (Hore_08070) were identified. Rubrerythrin is found in anaerobic sulphate-reducing bacteria and acts as a protectant against oxygen. SOD catalyses the dismutation of superoxide into molecular oxygen and hydrogen peroxide preventing damage from oxygen-mediated free radicals and catalases and alkyl hydroperoxide reductase also exhibit antioxidant activity. Catalases and SOD are involved in antioxidative defense in aerobic and facultative anaerobic microbes but their presence has also been demonstrated in strict anaerobes like H.orenii. Strict anaerobes are not uniformly sensitive to oxygen and a broad range of oxygen tolerance exists - some species are very sensitive to oxygen and those at the other end of the spectrum are viable for extended periods in the presence of oxygen. A link between SOD activity and aerotolerance has been noted - the highest SOD activities have been observed in the most aerotolerant strict anaerobe and low SOD activity in those species which are oxygen sensitive [18]. It remains to be determined whether both catalase and SOD are expressed in H. orenii and whether the enzyme activities increase in response to dosing the growth medium with oxygen.
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Mathematical models of anaerobic digestion for the treatment of swine effluents

Mathematical models of anaerobic digestion for the treatment of swine effluents

Sieving the effluent is a way to improve the efficiency of the process, since it separates the highly biodegradable liquid fraction from the solid fraction, which has slower degradation (Orrico Junior. et al. 2010). Despite these benefits in the anaerobic digestion process, many producers do not separate the effluents, because the solid fraction retained on the sieve must undergo additional slower treatment steps, such as composting, what often discourages the producer (Orrico Junior et al. 2009).

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Evaluation of anaerobic threshold in non-pregnant and pregnant rats

Evaluation of anaerobic threshold in non-pregnant and pregnant rats

Several studies present different methodologies and results about intensity exercise, and many of them are performed in male rats. However, the impact of different type, intensity, frequency and duration of exercise on female rats needs more investigation. From the analysis of blood lactate concentration during lactate minimum test (LacMin) in the swimming exercise, the anaerobic threshold (AT) was identified, which parameter is defined as the transition point between aerobic and anaerobic metabolism. LacMin test is considered a good indicator of aerobic conditioning and has been used in prescription of training in different exercise modalities. However, there is no evidence of LacMin test in female rats. The objective was to determine AT in non-pregnant and pregnant Wistar rats. The LacMin test was performed and AT defined for mild exercise intensity was from a load equivalent to 1% of body weight (bw), moderate exercise as carrying 4% bw and severe intensity as carrying 7% bw. In pregnant rats, the AT was reached at a lower loading from 5.0% to 5.5% bw, while in non-pregnant the load was from 5.5% to 6.0% bw. Thus, this study was effective to identify exercise intensities in pregnant and non-pregnant rats using anaerobic threshold by LacMin test.
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Evaluation and characterization of the anaerobic profile in soccer players

Evaluation and characterization of the anaerobic profile in soccer players

position. These results may be justified by the intermittent nature of the game, pointing out that peak power probably is not a discriminative performance variable between positions. For Pmean, it was verified that the goalkeepers presented the lowest values, followed by forwards, defenders and midfielders. On the other hand, goalkeepers are the ones who presented the highest values in the variable FI, followed by defenders and midfielders. The results found for these two variables are probably a consequence of the adaptations resulting from the activity profile of the players playing these positions, since the midfielders players are the ones that travel the longest distances in the game and the goalkeepers are the ones that run less (Stolen et al., 2005). These data are in line with other studies (Gil, Gil, Ruiz, Irazusta, & Irazusta, 2007; Nikolaidis, 2014) that found differences, both in the anaerobic and aerobic profile between different positions. On the other hand, in the paper 2, the forwards had the best results in all the performance variables comparatively to the other positions, including in the variables Ppeak and Pmean. These results may be caused by coaches and technical staff selecting stronger soccer players with the best physiological attributes for the forward position, reflecting the idea that the success of a game depends essentially on the quality of the players playing in that position (Gil, Gil, Ruiz, Irazusta, et al., 2007). The differences found in Ppeak and Pmean between the two interventions may be justified by the fact that the samples present in both paper 1 and paper 2 and the samples from other relevant researches mentioned are different.
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Reduction of azo dyes by anaerobic bacteria:  and biochemical aspects

Reduction of azo dyes by anaerobic bacteria: and biochemical aspects

The information described here indicates that several distinct biochemical mechanisms are involved in the reductive decolourisation of azo dyes by bacterial communities. Moreover, several bacterial groups com- monly active in anaerobic wastewater treatment sys- tems, such as fermentative, methanogenic, sulphate- reducing and azo-reducing microorganisms, appeared to have important contribution during the reduction of azo dyes under anaerobic conditions. Nevertheless, several microbiological and biochemical aspects need to be further investigated in order to better understand the mechanisms involved in the bacterial reduction of azo dyes and to enhance the applicability of bacterial consortia for textile wastewater treatment. For instance, most studies have been conducted under ideal culture conditions and the impact of pollutants co-existing in textile effluents (e.g. surfactants, disinfectants, size agents, etc.) on the reduction of azo dyes has poorly been assessed. Moreover, the role of syntrophic interactions of different bacterial groups on azo dyes reduction needs to be addressed in order to optimize decolourising processes.
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