scholarly journals Methods for the Evaluation of Industrial Mechanical Pretreatments before Anaerobic Digesters

Molecules ◽  
2020 ◽  
Vol 25 (4) ◽  
pp. 860 ◽  
Author(s):  
Helen Coarita Fernandez ◽  
Diana Amaya Ramirez ◽  
Ruben Teixeira Franco ◽  
Pierre Buffière ◽  
Rémy Bayard
Keyword(s):  
Particle Size ◽  
Rheological Properties ◽  
Production Rate ◽  
Methane Production ◽  
Water Retention Capacity ◽  
Retention Capacity ◽  
Anaerobic Digesters ◽  
Before And After ◽  
Methane Potential ◽  
Methane Production Rate

Different methods were tested to evaluate the performance of a pretreatment before anaerobic digestion. Besides conventional biochemical parameters, such as the biochemical methane potential (BMP), the methane production rate, or the extent of solubilization of organic compounds, methods for physical characterization were also developed in the present work. Criteria, such as the particle size distribution, the water retention capacity, and the rheological properties, were thus measured. These methods were tested on samples taken in two full-scale digesters operating with cattle manure as a substrate and using hammer mills. The comparison of samples taken before and after the pretreatment unit showed no significant improvement in the methane potential. However, the methane production rate increased by 15% and 26% for the two hammer mills, respectively. A relevant improvement of the rheological properties was also observed. This feature is likely correlated with the average reduction in particle size during the pretreatment operation, but these results needs confirmation in a wider range of systems.

scholarly journals A Single-Culture Bioprocess ofMethanothermobacter thermautotrophicusto Upgrade Digester Biogas by CO2-to-CH4Conversion with H2

Archaea ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Matthew R. Martin ◽  
Jeffrey J. Fornero ◽  
Rebecca Stark ◽  
Laurens Mets ◽  
Largus T. Angenent
Keyword(s):  
Production Rate ◽  
Conversion Efficiency ◽  
Methane Production ◽  
Dry Weight ◽  
Laboratory Culture ◽  
Methane Content ◽  
Anaerobic Digesters ◽  
Single Culture ◽  
Methane Production Rate ◽  
Methanothermobacter Thermautotrophicus

We optimized and tested a postbioprocessing step with a single-culture archaeon to upgrade biogas (i.e., increase methane content) from anaerobic digesters via conversion of CO2into CH4by feeding H2gas. We optimized a culture of the thermophilic methanogenMethanothermobacter thermautotrophicususing: (1) a synthetic H2/CO2mixture; (2) the same mixture with pressurization; (3) a synthetic biogas with different CH4contents and H2; and (4) an industrial, untreated biogas and H2. A laboratory culture with a robust growth (dry weight of 6.4–7.4 g/L; OD600of 13.6–15.4), a volumetric methane production rate of 21 L/L culture-day, and a H2conversion efficiency of 89% was moved to an industrial anaerobic digester facility, where it was restarted and fed untreated biogas with a methane content of ~70% at a rate such that CO2was in excess of the stoichiometric requirements in relation to H2. Over an 8-day operating period, the dry weight of the culture initially decreased slightly before stabilizing at an elevated level of ~8 g/L to achieve a volumetric methane production rate of 21 L/L culture-day and a H2conversion efficiency of 62%. While some microbial contamination of the culture was observed via microscopy, it did not affect the methane production rate of the culture.

Effects of thermochemical pretreatment on the anaerobic digestion of waste activated sludge

1997 ◽  
Vol 35 (8) ◽  
pp. 209-215 ◽  
Author(s):  
Shuzo Tanaka ◽  
Toshio Kobayashi ◽  
Ken-ichi Kamiyama ◽  
Ma. Lolita N. Signey Bildan
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Production Rate ◽  
Methane Production ◽  
Waste Activated Sludge ◽  
Batch Experiments ◽  
Industrial Wastewaters ◽  
Thermochemical Pretreatment ◽  
Chemical Heating ◽  
Methane Production Rate

Effects of pretreatment on the anaerobic digestion of waste activated sludge (WAS) were investigated in terms of VSS solubilization and methane production by batch experiments. The methods of pretreatment studied are NaOH addition (chemical), heating (thermal) and heating with NaOH addition (thermochemical) to the domestic WAS and to the combined WAS from domestic, commercial and industrial wastewaters. The thermochemical pretreatment gave the best result among three methods in the combined WAS, i.e., the VSS was solubilized by 40-50% and the methane production increased by more than 200% over the control when the WAS was heated at 130°C for 5 minutes with the dose 0.3 g NaOH/g VSS. In the domestic WAS, the VSS solubilization rate was 70-80% but the increase of the methane production was about 30% after thermochemically pretreated. The domestic WAS consists of 41% protein, 25% lipid and 14% carbohydrate on COD basis, and the solubilization rate of protein, which is the largest constituent of the WAS, was 63% in the thermochemical pretreatment. Although the effect of the thermochemical pretreatment on the methane production was higher to the combined WAS than to the domestic WAS, the methane production rate was 21.9 ml CH4/g VSSWAS·day in the domestic WAS and 12.8 ml CH4/g VSSWAS·day in the combined WAS.

Upflow anaerobic sludge blanket (UASB) treatment of supernatant of cow manure by thermal pre-treatment

2006 ◽  
Vol 54 (9) ◽  
pp. 221-227 ◽  
Author(s):  
Y. Yoneyama ◽  
A. Nishii ◽  
M. Nishimoto ◽  
N. Yamada ◽  
T. Suzuki
Keyword(s):  
Production Rate ◽  
Methane Production ◽  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge ◽  
Methane Fermentation ◽  
Methane Production Rate ◽  
Pre Treatment ◽  
Anaerobic Sludge Blanket ◽  
Solid Liquid ◽  
Solid Liquid Separation

Upflow anaerobic sludge blanket (UASB) methane fermentation treatment of cow manure that was subjected to screw pressing, thermal treatment and subsequent solid–liquid separation was studied. Conducting batch scale tests at temperatures between 140 and 180 °C, the optimal temperature for sludge settling and the color suppression was found to be between160–170 °C. UASB treatment was carried out with a supernatant obtained from the thermal treatment at the optimal conditions (170 °C for 30 minutes) and polymer-dosed solid–liquid separation. In the UASB treatment with a CODCr loading of 11.7 kg/m3/d and water temperature of 32.2 °C, the CODCr level dropped from 16,360 mg/L in raw water to 3,940 mg/L in treated water (CODCr removal rate of 75.9%), and the methane production rate per CODCr was 0.187 Nm3/kg. Using wastewater thermal-treated at the optimal conditions, also a methane fermentation treatment with a continuously stirred tank reactor (CSTR) was conducted (CODCr in raw water: 38,000 mg/L, hydraulic retention time (HRT): 20 days, 35 °C). At the CODCr loading of 1.9 kg/m3/d, the methane production rate per CODCr was 0.153 Nm3/kg. This result shows that UASB treatment using thermal pre-treatment provides a CODCr loading of four times or more and a methane production rate of 1.3 times higher than the CSTR treatment.

scholarly journals Treatment of sago mill effluent for methane production using anaerobic sequencing batch reactor (ASBR)

2018 ◽  
Vol 2 (1) ◽  
pp. 18-22
Author(s):  
Rafiqqah Mohamad Sabri ◽  
Keyword(s):  
Anaerobic Digestion ◽  
Production Rate ◽  
Methane Production ◽  
Sequencing Batch Reactor ◽  
Batch Reactor ◽  
Cod Removal ◽  
Production Yield ◽  
Anaerobic Sequencing Batch Reactor ◽  
Methane Production Rate

In this research, sago mill effluent was treated using anaerobic sequencing batch reactor (ASBR). Seven HRT from 10 to 1.5 days were tested to evaluate the methane production from sago mill effluent. The findings revealed the highest methane production rate was found at 1.288 L CH4/L reactor. d under HRT of 2 days The results showed that COD removals decreased from 70% to 47% as HRT was reduced from 10 to 2 days. The HRT 1.5 days was found critical for the studied system, which leads to decreased in methane production, yield and COD removal. Overall, ASBR was capable to treat sago mill effluent in producing methane by means of anaerobic digestion.

scholarly journals PHYSICOCHEMICAL AND FUNCTIONAL PROPERTIES OF DIETARY FIBER FROM BAMBOO SHOOTS (PHYLLOSTACHYS PRAECOX)

2017 ◽  
pp. 509 ◽  
Author(s):  
Cai-Hong Wang ◽  
Yi-Long Ma ◽  
Dan-Ye Zhu ◽  
Hao Wang ◽  
Ya-Fei Ren ◽  
...  
Keyword(s):  
Particle Size ◽  
Dietary Fiber ◽  
Functional Properties ◽  
Chemical Properties ◽  
Water Retention Capacity ◽  
Retention Capacity ◽  
Bamboo Shoots ◽  
Health Products ◽  
Potential Applications ◽  
Physicochemical And Functional Properties

Dietary fiber are non-digestible constituents of plant cell walls, and comprise a necessary component of diet and its positive connection with human health. Till now, there is no report about the extraction and physicochemical and functional properties of dietary fiber from bamboo shoots. To find the potential applications of dietary fiber from bamboo shoots in food and health products, the effects of chemical, enzymatic methods and particle size distribution on the chemical and structural composition, physicochemical, and functional properties of dietary fibers (DFs) from bamboo shoots were studied. The results showed that BSEDF and BSCDF had higher total DF and higher soluble DF, respectively. The crystalline regions calculated to be higher in latter and both had irregular surfaces and diverse monosaccharide composition. Both fibers showed good functional properties [water retention capacity (WRC) (11.24-15.13g/g), water swelling capacity (WSC) (18.84-28.75 mL/g), oil holding capacity (OAC) (6.71-10.15 g/g), glucose adsorption capacity (GAC) (0.08-6.89 mmol/g) and glucose retardation index (GRI) (3.57-40.92%)]. WRC of BSCDF and BSEDF decreased with the increase in the mesh size (40-200) while, WSC and OAC increased with mesh sizes (40 to 120), followed by decrease above mesh120. Both particle size and extraction methods significantly affected GRI. In conclusion, physico-chemical properties of fibers can be manipulated through treatments (chemical and enzymatic) to improve their overall functionality. Therefore, both BSCDF and BSEDF can find potential applications in food and health products as a functional ingredient in different aspects.

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