scholarly journals Methanogenesis at High Temperature, High Ionic Strength and Low pH in the Volcanic Area of Dallol, Ethiopia

2021 ◽  
Vol 9 (6) ◽  
pp. 1231
Author(s):  
Jose L. Sanz ◽  
Nuria Rodríguez ◽  
Cristina Escudero ◽  
Daniel Carrizo ◽  
Ricardo Amils ◽  
...  
Keyword(s):  
Methane Production ◽  
Extreme Environment ◽  
Hot Water ◽  
Volcanic Area ◽  
Mineral Concentration ◽  
Methanogenic Activity ◽  
Tectonic Plates ◽  
System A ◽  
Complementary Techniques ◽  
Positive Hybridization

The Dallol geothermal area originated as a result of seismic activity and the presence of a shallow underground volcano, both due to the divergence of two tectonic plates. In its ascent, hot water dissolves and drags away the subsurface salts. The temperature of the water that comes out of the chimneys is higher than 100 °C, with a pH close to zero and high mineral concentration. These factors make Dallol a polyextreme environment. So far, nanohaloarchaeas, present in the salts that form the walls of the chimneys, have been the only living beings reported in this extreme environment. Through the use of complementary techniques: culture in microcosms, methane stable isotope signature and hybridization with specific probes, the methanogenic activity in the Dallol area has been assessed. Methane production in microcosms, positive hybridization with the Methanosarcinales probe and the δ13CCH4-values measured, show the existence of extensive methanogenic activity in the hydrogeothermic Dallol system. A methylotrophic pathway, carried out by Methanohalobium and Methanosarcina-like genera, could be the dominant pathway for methane production in this environment.

Sludge accumulation and methanogenic activity in an anaerobic lagoon

2000 ◽  
Vol 42 (10-11) ◽  
pp. 247-255 ◽  
Author(s):  
J. Paing ◽  
B. Picot ◽  
J. P. Sambuco ◽  
A. Rambaud
Keyword(s):  
Anaerobic Digestion ◽  
Methane Production ◽  
Anaerobic Degradation ◽  
Volatile Fatty Acids ◽  
Anaerobic Fermentation ◽  
Methanogenic Activity ◽  
Start Up ◽  
Anaerobic Lagoon ◽  
Methane Production Rate ◽  
Sludge Accumulation

Sludge accumulation and the characteristics of anaerobic digestion in sludge had been investigated in a primary anaerobic lagoon. Methanogenic potential of sludge was evaluated by an anaerobic digestion test which measured the methane production rate. Sludge was sampled at several points in the lagoon to determine spatial variations and with a monthly frequency from the start-up of the lagoon to observe the development of anaerobic degradation. Maximum amounts of sludge accumulated near the inlet. The mean methane production of sludge was 2.9 ml gVS–1 d–1. Sludge near the outlet presented a greater methanogenic activity and a lesser concentration of volatile fatty acids than near the inlet. The different stages of anaerobic degradation were spatially separated, acidogenesis near the inlet and methanogenesis near the outlet. This staged distribution seemed to increase efficiency of anaerobic fermentation compared with septic tanks. Methane release at the surface of the lagoon was estimated to be very heterogeneous with a mean of 25 l m–2 d–1. The development of performance and sludge characteristics showed the rapid beginning of methanogenesis, three months after the start-up of the anaerobic lagoon. Considering the volume of accumulated sludge, it could however be expected that methanogenic activity would further increase.

Analysis of environmental factors affecting methane production from high-solids organic waste

1997 ◽  
Vol 36 (6-7) ◽  
pp. 493-500 ◽  
Author(s):  
J. J. Lay ◽  
Y. Y. Li ◽  
T. Noike ◽  
J. Endo ◽  
S. Ishimoto
Keyword(s):  
Moisture Content ◽  
Methane Production ◽  
Organic Waste ◽  
High Solids ◽  
Methanogenic Activity ◽  
Factors Affecting ◽  
Bacterial System ◽  
Sludge Cake ◽  
Production Curve ◽  
Ph Range

A simple model developed from the Gompertz equation was used to describe the cumulative methane production curve in the batch culture. By using this model, three key parameters, namely methane production rate, potential and lagphase time, in a cumulative methane production curve were exactly estimated based on the experimental data. The results indicate that each gram of dry organic waste of a sludge cake, meat, carrot, rice, potato and cabbage had a methane production potential of 450, 424, 269, 214, 203 and 96 mL, respectively. The methanogenic activity of these digesters decreased with a decrease in the moisture content. The moisture content threshold limit, at which the methanogenic activity dropped to zero, was found to be 56.6% for the sludge cake, but greater than 80% for meat, carrot and cabbage. In the high-solids sludge digestion, the relative methanogenic activity dropped from 100% to 53% when the moisture content decreased from 96% to 90%. The rate of methane production at moisture contents of 90% to 96% functioned in a pH range between 6.6 and 7.8, but optimally at pH 6.8, and the process may fail if the pH was lower than 6.1 or higher than 8.3. On the other hand, the methanogenic activity was dependent on the level of ammonium, NH4+, but not free ammonia, NH3, indicating that the NH4+ was the more significant factor rather than the NH3 in affecting the methanogenic activity of a well-acclimatized bacterial system. In the wide pH range of 6.5 to 8.5, the methanogenic activity decreased with the increase in the NH4+; dropped 10% at the NH4+-N concentration of 1670-3720 mg·L−1, 50% at 4090-5550 mg·L−1 and dropped to zero at 5880-6600 mg·L−1. However, the lagphase time was dependent on the NH3 level, but not on NH4+, and when NH3-N was higher than 500 mg·L−1, a notable shock was observed. This suggests that the NH3 level was the more sensitive factor than the NH4+ level for an unacclimatized bacterial system.

scholarly journals Design of a New Solar Thermal Collector with Ceramic Materials Integrated into the Building Facades

Designs ◽  
2018 ◽  
Vol 2 (4) ◽  
pp. 44
Author(s):  
Jordi Roviras Miñana ◽  
Vicente Sarrablo Moreno
Keyword(s):  
Ceramic Materials ◽  
Building Envelope ◽  
Hot Water ◽  
Solar Thermal ◽  
Collector System ◽  
System A ◽  
Solar Thermal Collector ◽  
Building Facades ◽  
Solar Thermal Collectors ◽  
High Degree

The work presented here aims to demonstrate the technical, architectural, and energy viability of solar thermal collectors made with ceramic materials and their suitability for domestic hot water (DHW) and building heating systems in the Mediterranean climate. The proposal is for the design of a ceramic shell, formed by collector and non-collecting panels, which forms part of the building system itself, and is capable of responding to the basic requirements of a building envelope and harnessing solar energy. Ceramics considerably reduce the final cost of the collector system and offer the new system a variety of compositional and chromatic finishes, occupying the entire building surface and achieving a high degree of architectural integration, although less energy-efficient compared to a conventional metallic collector.

Multiple System Configurations in a 32-bit Extreme Environment

2012 ◽  
Vol 2012 (HITEC) ◽  
pp. 000301-000306 ◽  
Author(s):  
Michael C. Brown
Keyword(s):  
Error Detection ◽  
Extreme Environments ◽  
Extreme Environment ◽  
Silicon On Insulator ◽  
Cmos Process ◽  
System A ◽  
External Sources ◽  
System Configurations ◽  
Simple Systems ◽  
Computational Systems

Full computational systems are needed at extreme environments (to 300°C) to increase functionality and reduce cost in the ever advancing oil/gas, geothermal, aeronautic, and automotive industries. Commercially available electronic components are not available to build a reliable system. A single microcontroller device can be used in systems of varying complexity, from small, mid, large, and multiprocessor scale. The 32-bit microcontroller will use a low power silicon-on-insulator CMOS process to increase long term reliability. Communication ports are provided to allow for simple systems with a single processor to complex multiprocessor systems with multiple controlled devices and external memory. As no adequate non-volatile solution is available for extreme conditions, multiple boot options are available to load instructions from external sources. Fault tolerance should be provided by system error detection. Battery backup must be provided for program and data retention. The resulting microcontroller will allow a wide variety of extreme environment systems, from simple to complex.

scholarly journals Tailoring Carbon Nanotubes to Enhance their Efficiency as Electron Shuttle on the Biological Removal of Acid Orange 10 Under Anaerobic Conditions

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2496
Author(s):  
Ana Rita Silva ◽  
O. Salomé G.P. Soares ◽  
M. Fernando R. Pereira ◽  
M. Madalena Alves ◽  
Luciana Pereira
Keyword(s):  
Carbon Nanotubes ◽  
Methane Production ◽  
Carbon Nanomaterials ◽  
Reduction Rate ◽  
Granular Sludge ◽  
Biological Reduction ◽  
Methanogenic Activity ◽  
Acid Orange ◽  
Biological Removal ◽  
Acid Orange 10

Anaerobic treatments have been described for the biodegradation of pollutants. However, the reactions proceed slowly due to the recalcitrant nature of these compounds. Carbon nanomaterials (CNM) intermediate in, and favor, the electron transfer, accelerating the anaerobic reduction of pollutants, which act as final electron acceptors. In the present work, different carbon nanotubes (CNT) with modified surface chemistry, namely CNT oxidized with HNO3 (CNT_HNO3) and CNT doped with nitrogen in a ball milling process (CNT_N_MB) were prepared using commercial CNT as a starting material. The new CNM were tested as redox mediators (RM), 0.1 g L−1, in the biological reduction of the azo dye, Acid Orange 10 (AO10), with an anaerobic granular sludge, over 48 h of reaction. Methane production was also assessed to verify the microorganism’s activity and the CNM’s effect on the methanogenic activity. An improvement in the biological removal of AO10 occurred with all CNM (above 90%), when compared with the control without CNM (only 32.4 ± 0.3%). The best results were obtained with CNT_N_MB, which achieved 98.2 ± 0.1% biological AO10 removal, and an 11-fold reduction rate increase. In order to confer magnetic properties to the CNM, tailored CNT were impregnated with 2% of iron-samples: CNT@2%Fe, CNT@2%Fe_N_MB, and CNT@2%Fe_HNO3. The better performance of the CNT doped with nitrogen was confirmed with CNT@2%Fe_N_MB, and the magnetic character facilitated its recovery after treatment, and did not affect its good catalytic properties. No dye removal was observed in the abiotic assays, so the removal was not due to adsorption on the CNM. Furthermore, the microorganism’s viability was maintained during the assay and methane production was not affected by the presence of the CNM. Despite the toxic character of the aromatic amines formed, detoxification was observed after the biological process with thermally treated CNT.

scholarly journals Direct Measurement of Basal Water Pressures: Progress and Problemss

1979 ◽  
Vol 23 (89) ◽  
pp. 309-319 ◽  
Author(s):  
Steven M. Hodge
Keyword(s):  
Large Scale ◽  
Water Pressure ◽  
Water System ◽  
Water Levels ◽  
Hot Water ◽  
Overburden Pressure ◽  
Well Control ◽  
System A ◽  
Pressure Water ◽  
Internal Change

AbstractIn 1975 and 1977, 24 bore holes were drilled to the bed of South Cascade Glacier, Washington, U.S.A., using both electrothermal and hot-water drills. Only two holes connected directly with the basal water system, a significant decrease from the four to five such connections in 13 holes drilled in 1973 and 1974 (Hodge, 1976). Most of the bed, possibly as much as 90%, appears to be hydraulically inactive and isolated from a few active subglacial conduits. Bore holes which penetrate these inactive areas initially should connect eventually with the active basal water system due to bed pressurization by the water standing in the bore hole, provided there is a sufficient supply of water available to form and maintain the connection passageway. These sealed-off areas probably consist of the sub-sole drift and permeability barriers found recently at the bed of Blue Glacier by Engelhardt and others (1978); an increase in the area of bed covered by these features probably caused the decrease in chance of bore-hole connection. This apparently was not due to any external cause but rather was the result of a real internal change in the subglacial hydraulic system which occurred between 1974 and 1975.If most of the area of a glacier bed is hydraulically isolated sub-sole drift, or something similar, such features may well control large-scale glacier sliding changes, since changes in the amount of water having access to the glacier bed will take considerable time to affect the interstitial water pressure in the more widespread sub-sole drift.Water pressures in the active part of the basal water system of South Cascade Glacier are generally in the range of 50–75% of the ice overburden pressure. Water levels in a connected bore hole are probably representative over an area of the bed 100 m or more in extent. A correlation of bore-hole water levels with changes in surface motion supports the idea that the sliding of a temperate glacier is controlled largely by the basal water pressure.

scholarly journals Effects of bismuth subsalicylate and encapsulated calcium-ammonium nitrate on enteric methane production, nutrient digestibility, and liver mineral concentration of beef cattle

2020 ◽  
Vol 98 (8) ◽  
Author(s):  
Darren D Henry ◽  
Francine M Ciriaco ◽  
Rafael C Araujo ◽  
Pedro L P Fontes ◽  
Nicola Oosthuizen ◽  
...  
Keyword(s):  
Beef Cattle ◽  
Ammonium Nitrate ◽  
Methane Production ◽  
Nutrient Digestibility ◽  
Negative Effects ◽  
Mineral Concentration ◽  
Nonprotein Nitrogen ◽  
Calcium Ammonium Nitrate ◽  
Bismuth Subsalicylate ◽  
Enteric Methane

Abstract Two randomized block designs were performed to evaluate the effects of bismuth subsalicylate (BSS) and encapsulated calcium-ammonium nitrate (eCAN) on enteric methane production, nutrient digestibility, liver mineral concentration, and performance of beef cattle consuming bahiagrass hay (Paspalum notatum; ad libitum) and sugar cane molasses [1.07 kg/d; dry matter basis]. Experiment 1, used 25 crossbred steers [335 ± 46 kg of initial body weight (BW)] with a 2 × 2 + 1 factorial arrangement of treatments for two 20 d periods. Factors were nonprotein nitrogen (NPN) source (350 mg/kg BW of nitrate or 182 mg/kg BW of urea), BSS (0 or 58.4 mg/kg BW), and a negative control (NCTRL; bahiagrass hay and molasses only). Steers were re-randomized for a second period (n = 10/treatment total). Intake, apparent total tract digestibility and enteric methane were evaluated. Experiment 2 used 75 crossbred heifers in 25 pens (3 heifers/pen; 279 ± 57 kg of initial BW), consuming the same diet and treatments as experiment 1, to determine liver mineral concentration and growth performance over 56 d. Orthogonal contrasts were used to evaluate the effects of NPN (NCTRL vs. others), source of NPN (NS; urea vs. eCAN), BSS, and NS × BSS. For experiment 1, no interactions were observed for any variables, nor were there any effects of NPN on total tract digestibility of nutrients, except for crude protein. Digestibility of all nutrients was reduced (P ≤ 0.021) for steers consuming eCAN compared with urea. There was no effect (P > 0.155) of BSS on digestibility of nutrients; however, BSS reduced (P = 0.003) apparent S retention. Enteric CH4 emission (g/kg BW0.75) was decreased (P = 0.051) by 11% with the addition of eCAN compared with urea. For experiment 2, no NS × BSS interactions (P ≥ 0.251) were observed to affect liver mineral concentration; however, the addition of BSS decreased liver concentration of Cu (P = 0.002) while increasing Fe concentration (P = 0.016). There was an NS × BSS interaction (P = 0.048) where heifers consuming eCAN and BSS had lesser final BW compared with heifers consuming urea and BSS. While eCAN may be a viable resource for mitigating enteric CH4 production of forage-fed cattle, the negative effects on digestibility should be considered. Furthermore, BSS, at the amount provided, appears to have no negative effects on digestibility of nutrients in forage-fed cattle; however, there may be deleterious impacts on performance depending upon what nitrogen source is supplied.

Association of methanogenic bacteria with rumen protozoa

1983 ◽  
Vol 29 (6) ◽  
pp. 676-680 ◽  
Author(s):  
Lee R. Krumholz ◽  
Cecil W. Forsberg ◽  
Douglas M. Veira
Keyword(s):  
Fluorescence Microscopy ◽  
Methane Production ◽  
Urease Activity ◽  
Rumen Fluid ◽  
Methanogenic Bacteria ◽  
Methanogenic Activity ◽  
Rumen Protozoa ◽  
Complex Population ◽  
Gravity Sedimentation

Methanogenic bacteria superficially associated with rumen entodiniomorphid protozoa were observed by fluorescence microscopy. A protozoal suspension separated from strained rumen fluid (SRF) by gravity sedimentation exhibited a rate of methane production six times greater (per millilitre) than SRF. The number of protozoa (per millilitre) in the protozoal suspension was three times greater than that of SRF; however, the urease activity of this fraction was half that of SRF. The methanogenic activity of SRF and the discrete fractions obtained by sedimentation of protozoa correlated with the numbers of protozoa per millilitre in each fraction. Gravity-sedimented protozoa, washed four times with cell-free rumen fluid, retained 67–71% of the recoverable methanogenic activity. Thus it is evident from our observations that many methanogens adhere to protozoa and that the protozoa support methanogenic activity of the attached methanogens. When protozoa-free sheep were inoculated with rumen contents containing a complex population of protozoa, methanogenic activity of the microflora in SRF samples was not significantly enhanced.

The microbial diversity, methane production, operational routine of an anaerobic reactor treating maize processing wastewater

2012 ◽  
Vol 7 (2) ◽  
Author(s):  
B. Ince ◽  
Z. Cetecioglu ◽  
S. Celikkol ◽  
O. Ince
Keyword(s):  
Microbial Diversity ◽  
Methane Production ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Organic Content ◽  
Cod Removal ◽  
Anaerobic Sludge ◽  
Methanogenic Activity ◽  
Monitoring Period ◽  
Industrial Wastewaters ◽  
Three Samples

Industrial wastewaters have turned out to be a significant problem during the last decades. The best alternative for maize processing wastewaters due to high organic content and slow biodegradability characteristics is anaerobic treatment, which is successfully used in the treatment of medium-high strength industrial wastewaters. This study investigates a full-scale anaerobic expanded granular sludge bed reactor treating a maize industry wastewater in terms of reactor operation, methanogenic activity of reactor sludge, changes in composition and numbers of microbial populations during a 5-month period. Three samples were taken in 2-months intervals when the reactor was re-operated after a shut-down of 2 months. Combination of denaturing gradient gel electrophoresis (DGGE), quantitative real time polymerase chain reactions (Q-PCR) and specific methanogenic activity tests were used to investigate composition, diversity and quantity of microbial community with activity of acetoclastic methanogens. During monitoring period, COD removal efficiencies and organic loading rates varied in ranges of 79–95% and 0.65–3.85 kg COD/m3.d, respectively. Potential methane production rates of the reactor sludges decreased 27% with time that is from 394 to 287 mL CH4/gVSS.d. Archaea, bacteria, and methanogens in the sludge samples were quantified by Q-PCR and the results showed that while amount of archaea was decreasing, quantity of methanogens increased during the monitoring time. The DGGE results of the anaerobic sludge revealed that the microbial diversity dramatically changed, particularly in the last sample. Among these, the differences in archaeal community were more remarkable. Although an average COD removal efficiency of 86%±8.2 which was quite a reasonably stable performance was maintained during the monitoring period, remarkable differences were observed on both acetoclastic methanogenic activity and the methanogenic community. The increase in the numbers of total methanogens despite the decrease of acetoclastic methanogenic activity might be an indicator of dominating hydrogenotrophic methanogenic pathway. Further, construction of clone library was necessary to identify the species and their changes within the all three samples.

Automated manometric method to assess anaerobic toxicity of chemicals

2006 ◽  
Vol 54 (2) ◽  
pp. 95-101 ◽  
Author(s):  
F. Fdz-Polanco ◽  
P. Nieto ◽  
S.I. Pérez-Elvira ◽  
M. Fdz-Polanco
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plant ◽  
Methane Production ◽  
Treatment Plant ◽  
Inhibitory Effect ◽  
Commercial Products ◽  
Methanogenic Activity ◽  
Substrate Removal ◽  
Manometric Method ◽  
Methane Production Rate

Industrial additives eventually used for different purposes (antifoaming, cleaning, bactericides, antiscale, etc) are discharged to the wastewater treatment plant. The anaerobic toxicity of these commercial products is not provided by suppliers. A new manometric method is developed and tested to evaluate anaerobic toxicity or inhibition using four different commercial products. Antifoaming Cleron 6 (50–200 ppm), bactericide Divosan-forte (0.05–1.0% v/v), bleach (0.1–1.0% v/v) and cleaning agent Topax 66 (0.10–1.0% v/v). According to the different methods proposed in the literature, from the methane production rate, it is possible to calculate both methanogenic activity evolution and final substrate removal and quantify the potential inhibitory effect of commercial additives. The experimental method is simple and reliable.

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