scholarly journals Performance Evaluation of Pressurized Anaerobic Digestion (PDA) of Raw Compost Leachate

Fermentation ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 15
Author(s):  
Alessio Siciliano ◽  
Carlo Limonti ◽  
Giulia Maria Curcio
Keyword(s):  
Anaerobic Digestion ◽  
High Pressures ◽  
Applied Pressure ◽  
Organic Loading Rate ◽  
Operating Pressure ◽  
Low Co2 ◽  
Negative Impacts ◽  
Compost Leachate ◽  
First Time ◽  
Positive Effect

Anaerobic digestion (AD) represents an advantageous solution for the treatment and valorization of organic waste and wastewater. To be suitable for energy purposes, biogas generated in AD must be subjected to proper upgrading treatments aimed at the removal of carbon dioxide and other undesirable gases. Pressurized anaerobic digestion (PDA) has gained increasing interest in recent years, as it allows the generation of a high-quality biogas with a low CO2 content. However, high pressures can cause some negative impacts on the AD process, which could be accentuated by feedstock characteristics. Until now, few studies have focused on the application of PAD to the treatment of real waste. The present work investigated, for the first time, the performance of the pressurized anaerobic digestion of raw compost leachate. The study was conducted in a lab-scale pressurized CSTR reactor, working in semi-continuous mode. Operating pressures from the atmospheric value to 4 bar were tested at organic loading rate (OLR) values of 20 and 30 kgCOD/m3d. In response to the rise in operating pressure, for both OLR values tested, a decrease of CO2 content in biogas was observed, whereas the CH4 fraction increased to values around 75% at 4 bar. Despite this positive effect, the pressure growth caused a decline in COD removal from 88 to 62% in tests with OLR = 20 kgCOD/m3d. At OLR = 30 kgCOD/m3d, an overload condition was observed, which induced abatements of about 56%, regardless of the applied pressure. With both OLR values, biogas productions and specific methane yields decreased largely when the pressure was brought from atmospheric value to just 1 bar. The values went from 0.33 to 0.27 LCH4/gCODremoved at 20kgCOD/m3d, and from 0.27 to 0.18 LCH4/gCODremoved at 30 kgCOD/m3d. Therefore, as the pressure increased, although there was an enhanced biogas quality, the overall amount of methane was lowered. The pressured conditions did not cause substantial modification in the characteristics of digestates.

scholarly journals Effect of nursery substrate on the growth of Pterocarpus erinaceus Poir. seedlings

2021 ◽  
Vol 8 (9) ◽  
pp. 17-27
Author(s):  
ALABA Pyoabalo ◽  
Atti TCHABI ◽  
Komla Elikplim ABOTSI ◽  
Kossi ADJONOU ◽  
Kossi Novinyo SEGLA ◽  
...  
Keyword(s):  
West Africa ◽  
Soil Microorganisms ◽  
High Pressures ◽  
Production Constraints ◽  
Pterocarpus Erinaceus ◽  
Number Of Leaves ◽  
The Mean ◽  
Negative Impacts ◽  
Natural Stands ◽  
Positive Effect

The high pressures on Pterocarpus erinaceus Poir. severely affect its natural stands in West Africa. The measures taken to reverse this trend are still inefficient due to plantlets production constraints. This study aims to understand the importance of growing substrates on seedlings growth in nursery. Composite soil samples were collected at 20 cm depth from 4 seed trees in 5 different sites in Togo (West Africa). Two batches were made for each site, one of which was sterilized by autoclave and the other has received no treatment. Three growing parameters (length of stem, number of buds and number of leaves) of the plantlets obtained from sterilized seeds were measured during 20 weeks in the nursery. Results show for each site a significantly better growing rate of seedlings on unsterilized substrates, compared to sterilized substrates. At the end of the experiment, plantlets were 8.75 ± 2.32 cm mean height on sterilized substrates when they reach 19.20 ± 5.00 cm on unsterilized substrates. The mean number of buds and leaves per plantlet varies from 2.23 ± 1.71 buds and 3.00 ± 1.86 leaves to 10.73 ± 3.28 buds and 11.09 ± 2.48 leaves at the same date, respectively on sterilized and unsterilized substrates. The low growing rate on sterilized substrates should be linked to the low capacity of plantlets in mobilizing phosphorus, potassium and nitrogen without microorganisms. Negative impacts of sterilization were highlighted on seedlings by necrosis of buds and leaves from the 7th week of growth, demonstrating a positive effect of soil microorganisms on the proper development of the seedlings.

Impact of organic loading rate and reactor design on thermophilic anaerobic digestion of mixed supermarket waste

2021 ◽  
Vol 123 ◽  
pp. 52-59
Author(s):  
L. Megido ◽  
L. Negral ◽  
Y. Fernández-Nava ◽  
B. Suárez-Peña ◽  
P. Ormaechea ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Loading Rate ◽  
Reactor Design ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Thermophilic Anaerobic Digestion

scholarly journals Stimulation of Biomethane Productivity in Anaerobic Digestion Using Electro-Conductive Carbon-Nanotube Hollow-Fiber Media

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 179
Author(s):  
Seongmin Yang ◽  
Seungyeob Han ◽  
Yeo-Myeong Yun ◽  
Seoktae Kang
Keyword(s):  
Carbon Nanotube ◽  
Anaerobic Digestion ◽  
Production Rate ◽  
Hollow Fiber ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Ch4 Production ◽  
Microscopic Morphology ◽  
Positive Effect

The production of biogas was promoted via direct interspecies electron transfer (DIET) by employing electro-conductive carbon-nanotube hollow-fiber media (CHM) in anaerobic digestion. Experimental results showed a positive effect of CHM presence on CH4 productivity with 34% higher CH4 production rate than that of in the presence of non-electroconductive polymeric hollow fiber media. An increased CH4 production rate was due to the shift in the microbiome with more abundant Pelobacter (10.0%), Geobacter (6.9%), and Methanosaeta (15.7%), which play key roles in promoting CH4 production via syntrophic metabolism associated with DIET. Microscopic morphology analysis, using confocal laser scanning microscopy and scanning electron microscopy, exhibited that several living cells were attached with electro-conductive pili on the CHM surface, thereby facilitated electron transport between microbial cells.

scholarly journals Wheat Bread with Grape Seeds Micropowder: Impact on Dough Rheology and Bread Properties

2020 ◽  
Vol 30 (1) ◽  
pp. 138-150
Author(s):  
Veronika Valková ◽  
Hana Ďúranová ◽  
Jana Štefániková ◽  
Michal Miškeje ◽  
Marián Tokár ◽  
...  
Keyword(s):  
Wheat Flour ◽  
Dough Rheology ◽  
Wheat Bread ◽  
Grape Seeds ◽  
Rheological Analysis ◽  
First Time ◽  
Positive Effect ◽  
Bread Properties ◽  
Electronic Eye ◽  
Different Levels

AbstractThe current study was designed to enhance the functionality of white bread by replacement of wheat flour with different levels (1%, 2%, 5%, and 8%) of grape seeds micropowder (GSMP) with nanosized particles (10 µm). Chemical composition of GSMP, volume and sensory attributes, evaluated with the panel of evaluators and an electronic nose (e-nose) and an electronic eye (e-eye) were investigated in the tested breads. It has been found out that GSMP contained appreciable amounts of flavonoids including catechin, epicatechin, gallic acid and minerals especially, Ca, K and Mg. The data from rheological analysis showed that the addition of GSMP (mainly at 5% and 8% levels) to the wheat flour had a positive effect on dough manifesting with rheology by increased dough stability. The volume of the experimental breads (above 1% concentration) was demonstrably declined (P < 0.0001) in comparison with the control bread. Sensory rating revealed that the bread fortified with 1% GSMP was judged by the consumer panelists as the most acceptable with the highest scores for all quality attributes which was also confirmed by the data of e-nose and e-eye. Our results suggest for the first time that 1% GSMP addition appears to be a promising functional ingredient to improve bread with required qualitative and sensory properties.

scholarly journals Development of Red Clay Ultrafiltration Membranes for Oil-Water Separation

Crystals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 248
Author(s):  
Saad A. Aljlil
Keyword(s):  
Ceramic Membrane ◽  
Applied Pressure ◽  
Operating Pressure ◽  
Permeate Flux ◽  
Carbon Membrane ◽  
Red Clay ◽  
Water Separation ◽  
Water Emulsion ◽  
Cross Flow Filtration ◽  
Oil Water

In this study, a red clay/nano-activated carbon membrane was investigated for the removal of oil from industrial wastewater. The sintering temperature was minimized using CaF2 powder as a binder. The fabricated membrane was characterized by its mechanical properties, average pore size, and hydrophilicity. A contact angle of 67.3° and membrane spore size of 95.46 nm were obtained. The prepared membrane was tested by a cross-flow filtration process using an oil-water emulsion, and showed a promising permeate flux and oil rejection results. During the separation of oil from water, the flux increased from 191.38 to 284.99 L/m2 on increasing the applied pressure from 3 to 6 bar. In addition, high water permeability was obtained for the fabricated membrane at low operating pressure. However, the membrane flux decreased from 490.28 to 367.32 L/m2·h due to oil deposition on the membrane surface; regardless, the maximum oil rejection was 99.96% at an oil concentration of 80 NTU and a pressure of 5 bar. The fabricated membrane was negatively charged, as were the oil droplets, thereby facilitating membrane purification through backwashing. The obtained ceramic membrane functioned well as a hydrophilic membrane and showed potential for use in oil wastewater treatment.

Simultaneous Spectral Imaging of C2*/CH* at Low-to-High Pressure Combustion

2017 ◽  
Author(s):  
Jonathan Reyes ◽  
Kareem Ahmed
Keyword(s):  
Intensity Ratio ◽  
High Pressures ◽  
Diffusion Flames ◽  
Laminar Flames ◽  
Great Promise ◽  
Fuel Distribution ◽  
Premixed Laminar ◽  
The Cost ◽  
Indexing Technique ◽  
First Time

This paper presents the correlation of the intensity ratio of the C2* and CH* radicals to fuel-air measurements over a range of pressures using 93% octane gasoline as the fuel. The measurements are conducted for the first time at high pressures. The study utilizes beam splitting technology to simultaneously view C2* and CH* as a line of sight, global measurement at the cost of resolution. A heavily instrumented constant volume combustor, with optical access, was employed to acquire the data. The ratio of C2* and CH* has been proven to be a good index of the equivalence ratio of premixed laminar flames. This index is attained, quite simply, by filtering each at their respected emissive peaks and taking the ratio of C2* over CH*. This technique shows great promise for use in turbomachinery as it will allow for identification of rich and lean locations in a combustor. By knowing the fuel-air field, combustor inefficiencies can be addressed to allow for greater energy release in combustion. The issue lies with the application of the indexing technique. Presented data to date has been performed on laboratory based diffusion flames exhausting to atmosphere, or premixed, steady, combustor type flames at low pressure (1atm) conditions. These types of flames are not relevant for engine combustor conditions. Understanding the fuel distribution at relevant regimes will reveal where inefficiencies may lie in injector or combustor design. Propagating flame kernels pose a problem in that they do not produce as much light as a steady flame, this makes spectral data difficult to obtain. Steady flames also do not address the effects that pressure may have on the index of C2* and CH*. The authors of this work seek to address three main issues associated with the indexing technique: The feasibility of its application to combustors (hardware design), The ability to operate at low-light ignition events, and the effects pressure may have on the correlation of intensity ratio to the fuel-air measurement.

Failure Analysis of High Pressure Rupture Discs and Effective Counter Measures

2016 ◽  
Author(s):  
Stefan Rüsenberg ◽  
Georg Vonnahme
Keyword(s):  
High Pressure ◽  
High Pressures ◽  
Influencing Factor ◽  
Applied Pressure ◽  
Life Time ◽  
Burst Pressure ◽  
Counter Measures ◽  
Welding Joint ◽  
Rupture Disc ◽  
Geometrical Change

For the production of LDPE, high process pressures (>1000 bar up to 3500 bar and above) as well as high temperatures (>100 °C up to 300 °C and above) are required. In order to ensure a safe production process the autoclaves and compressors have to be protected against dangerous overpressure. Rupture discs are typically used to protect this high pressure process itself, as well as the employees, and the environment. Traditionally rupture discs for high pressure applications are manufactured by a weld seam which has an influence on the burst pressure. After installation the applied pressure is nearly fully-loaded on the welding joint. Additionally, the welding joint is another unwanted influencing factor. This increases the possibility of an unexpected failure which leads to an unwanted rupture disc response or, in critical cases, to a rupture disc failure recently after initial operation of the process even at lower pressures than the defined burst pressure. This, in turn, leads to a reduced life time of the disc. A special version of a rupture disc, a High Pressure Rupture Disc (HPRD) is developed specifically for this application. This long life version for high pressure applications has a lifetime which is 5–10 times higher than that of a standard rupture disc, that saves money and installation time. The differences are explained in some minor geometrical changes. This safety device allows a protection of high pressures up to 4000 bar and beyond. The HPRD is a forward acting rupture disc and the burst pressure is adjusted by a combination of material thickness, the height of the dome, and, of course, of the chosen material. An easy and simple geometrical change eliminates the welding joint as an influencing factor, thus eliminating any unwanted responding of the rupture disc. The tolerances for high pressure rupture discs are +/−3% and lower and the HPRD can be used for all kind of different high pressure applications.

Effect of organic loading rate on anaerobic digestion of thermally pretreated Scenedesmus sp. biomass

2013 ◽  
Vol 129 ◽  
pp. 219-223 ◽  
Author(s):  
C. González-Fernández ◽  
B. Sialve ◽  
N. Bernet ◽  
J.P. Steyer
Keyword(s):  
Anaerobic Digestion ◽  
Loading Rate ◽  
Organic Loading Rate ◽  
Organic Loading

Thermodynamic Properties of CaSiO3 Perovskite at High Pressure and High Temperature

2009 ◽  
Vol 64 (5-6) ◽  
pp. 399-404 ◽  
Author(s):  
Zi-Jiang Liu ◽  
Xiao-Ming Tan ◽  
Yuan Guo ◽  
Xiao-Ping Zheng ◽  
Wen-Zhao Wu
Keyword(s):  
Thermodynamic Properties ◽  
First Principles ◽  
Density Functional ◽  
High Pressures ◽  
Local Density ◽  
Harmonic Approximation ◽  
Debye Model ◽  
Functional Theory ◽  
Casio3 Perovskite ◽  
First Time

The thermodynamic properties of tetragonal CaSiO3 perovskite are predicted at high pressures and temperatures using the Debye model for the first time. This model combines the ab initio calculations within local density approximation using pseudopotentials and a plane wave basis in the framework of density functional theory, and it takes into account the phononic effects within the quasi-harmonic approximation. It is found that the calculated equation of state is in excellent agreement with the observed values at ambient condition. Based on the first-principles study and the Debye model, the thermal properties including the Debye temperature, the heat capacity, the thermal expansion and the entropy are obtained in the whole pressure range from 0 to 150 GPa and temperature range from 0 to 2000 K.

Liquefaction and methanization of solid and liquid coffee wastes by two phase anaerobic digestion process

2003 ◽  
Vol 48 (6) ◽  
pp. 255-262 ◽  
Author(s):  
E. Houbron ◽  
A. Larrinaga ◽  
E. Rustrian
Keyword(s):  
Anaerobic Digestion ◽  
Wash Water ◽  
Organic Loading Rate ◽  
Two Phase ◽  
Experimental Conditions ◽  
Coffee Pulp ◽  
Anaerobic Digestion Process ◽  
Digestion Process ◽  
Working Volume ◽  
Acidogenic Reactor

This study attempted to investigate the feasibility of volatile fatty acid (VFA) production from coffee pulp hydrolyse, and further to determine the potential of methanization of both the pre-acidified effluent and the coffee wastewater. The experiments were carried out in 2 completely mixed reactors, each one with a working volume of 4 litres. Coffee pulp was used as substrate in the acidogenic reactor and different mixtures of pulper and wash-water and pre-acidified effluent in the methanogenic one. The acidogenic and methanogenic reactors were operated at an organic loading rate of 5 COD g.l-1.d-1 and 0.5 COD g.l-1.d-1. The total, soluble and VFA's effluent COD concentrations of the acidogenic reactor present average values of 57.75, 17.00 and 13.92 g.l-1 respectively. Under these experimental conditions, 23% (COD based) of coffee pulp was hydrolysed with a rate of 1.32 gCOD.l-1.d-1 and the soluble fraction was transformed to VFA's with an acidification efficiency of 82%. Total VFA's concentration reached a value of 13.9 gCOD.l-1, and acetate, propionate, butyrate and valerate represented 52%, 28%, 9% and 11% respectively of the liquid phase COD. In the methanogenic reactor, COD removal and methanization of fresh coffee wastewater, pre-acidified effluent and both combined occur with an efficiency of 85% to 95% respectively, with a characteristic biogas composition of 80% CH4 and 20% CO2. These results show that a humid coffee ‘Beneficio’ processing daily 23 tons of cherry coffee (fresh fruit), equipped with a two stage anaerobic digestion process could generate at least 1,886 CH4 m3.d-1. This represents an increase in methane production by a factor 3 to 5 compared to a ‘Beneficio’ using anaerobic digestion only for the treatment of its wastewater.

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