Impact of recycled effluent on the hydrolysis during anaerobic digestion of vegetable and flower waste

Two trials were established to investigate the effect of recycled effluent on hydrolysis during anaerobic co-digestion of vegetable and flower waste. Trial I evaluated the effect by regulating the flow rate of recycled effluent, while Trial II regulated the ratio of hydrolytic effluent to methanogenic effluent, which were recycled to hydrolysis reactor. Results showed that the recirculation of methanogenic effluent could enhance the buffer capability and operation stability of hydrolysis reactor. Higher recycled flow rate was favourable for microbial anabolism and further promoted hydrolysis. After 9 days of hydrolysis, the cumulative SCOD in the hydrolytic effluent reached 334, 407, 413, 581 mg/g at recycled flow rates of 0.1, 0.5, 1.0, 2.0 m3/(m3·d), respectively. It was feasible to recycling a mixture of hydrolytic and methanogenic effluent to the hydrolysis reactor. This research showed that partially introducing hydrolytic effluent into the recycled liquid could enhance hydrolysis, while excessive recirculation of hydrolytic effluent will inhibit the hydrolysis. The flow ratio 1:3 of hydrolytic to methanogenic effluent was found to provide the highest hydrolysis efficiency and degradation rate of lignocelluloses-type biomass, among four ratios of 0:1, 1:3, 1:1 and 3:1. Under this regime, after 9 days of hydrolysis, the cumulative TOC and TN in the hydrolytic effluent reached 162 mg/g and 15 mg/g, the removal efficiency of TS, VS, C and cellulose in the solid phase were 60.66%, 62.88%, 58.35% and 49.12%, respectively. The flow ratio affected fermentation pathways, i.e. lower ratio favoured propionic acid fermentation and the generation of lactic acid while higher ratio promoted butyric acid fermentation.

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The effect of wilting on butyric acid fermentation in silage.

Netherlands Journal of Agricultural Science ◽

10.18174/njas.v6i3.17706 ◽

1958 ◽

Vol 6 (3) ◽

pp. 204-210 ◽

Cited By ~ 3

Author(s):

G.W. Wieringa

Keyword(s):

Lactic Acid ◽

Osmotic Pressure ◽

Butyric Acid ◽

Ion Concentration ◽

Acid Fermentation ◽

Silage Fermentation ◽

Lactic Acid Content ◽

Vitro Development ◽

Butyric Acid Fermentation

A comparatively slight increase in environmental osmotic pressure inhibited the in vitro development of butyric-acid bacteria [Clostridium spp.], especially with increasing H-ion concentration. Sub-lethal concentrations of salt (NaCl, KCl, Na2SO4) and/or H-ions retarded the start of clostridial development and reduced the quantity of butyric acid produced. In wilted grass silage it was shown that osmotic pressure plays a considerable part in repressing butyric-acid fermentation in the initial stages of silage fermentation. Low temperature (< 20-25 degrees C.), low pH (< 4.2), high lactic-acid content and high osmotic pressure were more harmful to clostridia than to lactic-acid bacteria.-R.B. (Abstract retrieved from CAB Abstracts by CABI’s permission)

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Modeling Pressurized Dense Phase Coal Fluidization and Transport

ASME 2019 Power Conference ◽

10.1115/power2019-1874 ◽

2019 ◽

Cited By ~ 1

Author(s):

Bradley R. Adams ◽

Taylor L. Schroedter

Keyword(s):

Flow Rate ◽

Particle Interaction ◽

Drop Out ◽

Coal Bed ◽

Flow Ratio ◽

Feed System ◽

Horizontal Pipe ◽

Flow Rates ◽

Coal Particles ◽

Coal Flow

Abstract A transient gas-solid model based on CPFD Software’s Barracuda Virtual Reactor was developed for a feed system to a pilot-scale pressurized oxy-coal (POC) reactor. A simplified geometry with a vertical coal hopper feeding into a 0.635-cm diameter horizontal pipe was used to represent key elements of the feed system. Coal particles were transported with 20-atm CO2 gas. The feed system was required to maintain a steady flow of gas and solids at a coal flow rate of approximately 3.8 g/s and a CO2 to coal mass ratio in the range 1–2. Sensitivity of model results to mesh size and particle interaction sub-model settings was assessed. Two design concepts were evaluated. A gravity-fed concept was found to be infeasible due to inadequate coal flow rates even at very high CO2 to coal flow ratios. This was due to gravitational forces being insufficient to move the pressurized coal from the hopper into the CO2 stream at the desired rate. A fluidized bed concept was found to provide the desired coal flow rate and CO2 to coal flow ratio. CO2 injected at the hopper base first fluidized the vertical coal bed before transporting it through a horizontal exit pipe. A second CO2 inlet downstream of the hopper exit pipe was used to dilute the fluidized coal and increase pipe velocities to minimize coal drop out. The amount of coal transported from the hopper was dependent on the net CO2 hopper flow but independent of the CO2 dilution flow. This meant that the coal flow rate and CO2 to coal flow ratio could be controlled independently. Pipe exit coal flow rates were found to fluctuate at levels acceptable for steady burner operation.

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Lactic acid bacteria of the genus Lactobacillus in the formation of sour ales flavor profile

Food Processing Techniques and Technology ◽

10.21603/2074-9414-2018-2-100-108 ◽

2019 ◽

Vol 48 (2) ◽

pp. 100-108 ◽

Cited By ~ 1

Author(s):

Ольга Пономарева ◽

Olga Ponomareva ◽

Екатерина Борисова ◽

Ekaterina Borisova ◽

Игорь Прохорчик ◽

...

Keyword(s):

Lactic Acid ◽

Lactic Acid Bacteria ◽

Dimethyl Sulfide ◽

Solid Phase ◽

Scientific Data ◽

Acid Fermentation ◽

Genus Lactobacillus ◽

The Given ◽

By Products ◽

Flavor Profile

Sour ales have become widely spread in Europe since XVII century. These drinks are still popular in Germany, Belgium, England and other European countries. Interest in sour ales has been growing steadily in Russia. The purpose of this work was to systematize and generalize scientific data and the results of practical use of lactic acid bacteria of the genus Lactobacillus in sour ales production technology and in the formation of the ready beverage flavor profile. The subjects of the research were biochemical and biotechnological properties of lactic acid bacteria of the genus Lactobacillus frequently used in sour ales production, namely, L. delbrueckii, L. brevis, L. buchneri, L. fermentum, L. plantarum. The results of studying sour ales composition by means of gas chromatography, solid phase microextraction, liquid chromatography, and mass spectroscopy show that they have complex compositions. Thus, sour ales of Lambic and Gueuze groups have 64 volatile compounds. Taste and aroma of sour ales are mostly formed by the most important components synthesized during lactic-acid fermentation. They are higher alcohols, complex esters, organic acids, dimethyl sulfide and diacetyl. Concentration of these components is mainly determined by the type of lactic acid bacteria. The article generalizes and systematizes scientific data concerning biochemical and biotechnological properties of different types of lactic acid bacteria of the genus Lactobacillus used for sour ale production. The article reveals concentrations of the main products and by-products synthesized by the given types of lactic acid bacteria during fermentation. The author points out corresponding taste and aroma sensations according to terminology used in European Brewing Convention (EBC).

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High Flow-Rate Sample Loading in Large Volume Whole Water Organic Trace Analysis Using Positive Pressure and Finely Ground Sand as a SPE-Column In-Line Filter

Molecules ◽

10.3390/molecules24071426 ◽

2019 ◽

Vol 24 (7) ◽

pp. 1426

Author(s):

Ola Svahn ◽

Erland Björklund

Keyword(s):

Physicochemical Properties ◽

Flow Rate ◽

Solid Phase ◽

Pure Water ◽

Maximum Flow ◽

Maximum Flow Rate ◽

Positive Pressure ◽

Flow Rates ◽

Relative Standard ◽

Whole Water

By using an innovative, positive pressure sample loading technique in combination with an in-line filter of finely ground sand the bottleneck of solid phase extraction (SPE) can be reduced. Recently published work by us has shown the proof of concept of the technique. In this work, emphasis is put on the SPE flow rate and method validation for 26 compounds of emerging environmental concern, mainly from the 1st and 2nd EU Watch List, with various physicochemical properties. The mean absolute recoveries in % and relative standard deviations (RSD) in % for the investigated compounds from spiked pure water samples at the three investigated flow rates of 10, 20, and 40 mL/min were 63.2% (3.2%), 66.9% (3.3%), and 69.0% (4.0%), respectively. All three flow rates produced highly repeatable results, and this allowed a flow rate increase of up to 40 mL/min for a 200 mg, 6 mL, reversed phase SPE cartridge without compromising the recoveries. This figure is more than four times the maximum flow rate recommended by manufacturers. It was indicated that some compounds, especially pronounced for the investigated macrolide molecules, might suffer when long contact times with the sample glass bottle occurs. A reduced contact time somewhat decreases this complication. A very good repeatability also held true for experiments on both spiked matrix-rich pond water (high and low concentrations) and recipient waters (river and wastewater) applying 40 mL/min. This work has shown that, for a large number of compounds of widely differing physicochemical properties, there is a generous flow rate window from 10 to 40 mL/min where sample loading can be conducted. A sample volume of 0.5 L, which at the recommended maximum flow rate speed of 10 mL/min, would previously take 50 min, can now be processed in 12 min using a flow rate of 40 mL/min. This saves 38 min per processed sample. This low-cost technology allows the sample to be transferred to the SPE-column, closer to the sample location and by the person taking the sample. This further means that only the sample cartridge would need to be sent to the laboratory, instead of the whole water sample, like today’s procedure.

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Effect of flow rate and freezing on cyanocobalamin recovery using a commercial solid phase extraction cartridge

10.1101/538355 ◽

2019 ◽

Author(s):

Lauren Lees ◽

Alison M. Bland ◽

Giacomo R. DiTullio ◽

Michael G. Janech ◽

Peter A. Lee

Keyword(s):

Solid Phase Extraction ◽

Vitamin B12 ◽

Flow Rate ◽

Sea Water ◽

Solid Phase ◽

Negative Impact ◽

Field Studies ◽

Phase Extraction ◽

Flow Rates ◽

Solid Phase Extraction Cartridge

AbstractAnalysis of vitamin B12 in sea water is laborious, time consuming, and often requires storage of relatively large-volume water samples. Alleviating these major limitations will increase the throughput of samples and, as a consequence, improve our understanding of the distribution and role of vitamin B12 in the oceans. Previous studies have indicated that target analyte recovery is negatively affected at flow rates exceeding 1 mL min−1 using home-made C18 Solid Phase Extraction (SPE) cartridges. In this study, the effect of flow rate on recovery of vitamin B12 was tested across a range of flow rates between 1 and 37 mL min−1 using a commercial SPE cartridge containing surface-modified styrene divinylbenzene. Recovery of vitamin B12 at flow rates up to the maximum rate tested did not statistically differ from 1 mL min 1. A second study was conducted to determine whether storage of the SPE cartridges at −20°C had a negative impact on vitamin B12 recovery. Recovery of vitamin B12 from SPE cartridges stored up to 13 days did not differ from unfrozen SPE cartridges. These data suggest that rapid extraction and cold storage of vitamin B12 on commercial SPE cartridges does not negatively affect recovery and offers an economical alternative to field studies.

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Effect of Feed-Flow Rate in a Solid-Liquid Hydrocyclone Based on Total Solid Recovery Equation

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.751.173 ◽

2017 ◽

Vol 751 ◽

pp. 173-179

Author(s):

Pichai Soison ◽

Pakpoom Supachart ◽

Pratarn Wongsarivej

Keyword(s):

Particle Size ◽

Flow Rate ◽

Concentration Ratio ◽

Separation Efficiency ◽

Total Solid ◽

Feed Flow Rate ◽

Solid Concentration ◽

Flow Ratio ◽

Flow Rates ◽

Solid Liquid

Many studies of hydrocyclones have confirmed that increasing the feed-flow rate results in a higher separation efficiency. The purpose of this study was to investigate the separation efficiency for a 100 mm solid–liquid hydrocyclone with 1 and 2 wt% solid concentrations at feed-flow rates of 2, 3, 4, 5 and 6 m3/hr. The solid concentration and particle size distribution were analysed using drying–weighing and a particle-size analyser (Mastersizer 2000), respectively. The experimental results indicated that an increase in feed-flow rate from 2 to 4 m3/hr produced decreased separation efficiency. However, when the feed-flow rates increased from 4 to 6 m3/hr, the separation efficiency increased. Furthermore, the higher the feed-flow rate, the smaller the cut size. A novel separation efficiency equation in terms of the concentration ratio and flow ratio is also proposed.

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Experimental Evaluation of Optimum Water to Air Flow Ratio in an Induced Draft Wet Cooling Tower

FUOYE Journal of Engineering and Technology ◽

10.46792/fuoyejet.v4i2.331 ◽

2019 ◽

Vol 4 (2) ◽

Author(s):

Talib O Ahmadu ◽

Hamisu A Dandajeh

Keyword(s):

Water Flow ◽

Flow Rate ◽

Cooling Tower ◽

Air Flow ◽

Water Flow Rate ◽

Cooling Power ◽

Cooling Efficiency ◽

Flow Ratio ◽

Flow Rates ◽

Optimum Water

Cooling towers are devices used to dissipate waste thermal heat to the ambient environment. Appropriate cooling water and air flow rates are necessary to ensure optimum cooling power and cooling efficiency. Also, a simple design is required for cost effectiveness and minimal maintenance issues. This paper experimentally evaluates the cooling power, cooling efficiency, as well as the optimum water to air flow ratio in a spray type induced draft wet cooling tower. The cooling tower, 6 kW cooling capacity, was developed to operate without packings. The experiments were conducted for three different air flow rates and six different water flow rates. Four different inlet water temperatures of 35, 40, 45 and 50 oC were used. The temperature range is a typical range for inlet water temperature to the cooling tower for an absorption cooling system. For each of the inlet water temperatures, air and water flow rates were varied. The effects of this variation on cooling power and cooling efficiency were studied. Effect of varying water to air flow ratio on cooling power and cooling efficiency were studied. Results showed that the cooling power increased with increasing water flow rate, while the cooling efficiency decreased with increasing water flow rate. Decreasing the air flow rate was seen to cause a decrease in both cooling power and cooling efficiency. Maximum cooling power and cooling efficiency of 5.33 kW and 63% respectively were obtained. An optimum water to air flow ratio of 1.6 was obtained. The cooling tower was seen to have operated satisfactorily without packings. Keywords— cooling tower, cooling power, cooling efficiency, flow ratio, thermal energy

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