A two stage continuous process for the production of thermogelable curdlan-type exopolysaccharide

Biogas production processes from tapioca wastewater have several problems that cause the biogas production is not optimal, such as pH drop at beginning of the process because the rate of acid formation is too fast and the rate of starch wastewater degradation is too slow. Therefore, to obtain optimal biogas production it is required two-stage reactor. The purposes of this research were to (i) study the influence of one stage fermentation and two stage fermentation on biogas production, (ii) study the effect of buffer Na2CO3 on biogas production, and (iii) study the effect of methanogenic bacteria concentration on biogas production from cassava starch effluent. The first method of our research was hydrolysis process by “Saccharomyces cereviceae” as substrate activator. The second is the arrangement of pH and the last is process of methane production. The results showed that the highest biogas production is achieved at concentration of methanogenic bacteria 20% (v/v) that is equal to 2458 ml. At concentration of 8% (v/v) and 15% (v/v), biogas production was 2105 ml and 2117 ml. The addition of Na2CO3 can extend to 16 days with accumulation of 372 ml. While without the addition of buffer, biogas production period was only 9 days with accumulation of 620 ml. In semi continuous process, the analysis carried out every 3 days. Highest biogas production achieved in the variable addition of yeast with the accumulation 9329 ml. Without yeast, accumulation of biogas was 6831 ml. Yeast is use as substrate activator so it can accelerate the hydrolysis process and increased biogas production. The addition of Na2CO3 is increase the alkalinity so the pH drop did not occur early in the process.

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Effect of Effluent Recirculation on Biogas Production Using Two-stage Anaerobic Digestion of Citrus Waste

Molecules ◽

10.3390/molecules23123380 ◽

2018 ◽

Vol 23 (12) ◽

pp. 3380 ◽

Cited By ~ 8

Author(s):

Lukitawesa ◽

Rachma Wikandari ◽

Ria Millati ◽

Mohammad J. Taherzadeh ◽

Claes Niklasson

Keyword(s):

Anaerobic Digestion ◽

Liquid Phase ◽

Biogas Production ◽

Continuous Process ◽

Methane Yield ◽

Organic Loading Rate ◽

Anaerobic Sludge ◽

Two Stage ◽

Effluent Recirculation ◽

Citrus Waste

Citrus waste is a promising potential feedstock for anaerobic digestion, yet the presence of inhibitors such as d-limonene is known to limit the process. Effluent recirculation has been proven to increase methane yield in a semi-continuous process for recalcitrant material, but it has never been applied to toxic materials. This study was aimed to investigate the effect of recirculation on biogas production from citrus waste as toxic feedstock in two-stage anaerobic digestion. The first digestion was carried out in a stirred tank reactor (STR). The effluent from the first-stage was filtered using a rotary drum filter to separate the solid and the liquid phase. The solid phase, rich in hydrophobic D-limonene, was discarded, and the liquid phase containing less D-limonene was fed into the second digester in an up-flow anaerobic sludge bed (UASB) reactor. A high organic loading rate (OLR 5 g VS/(L·day)) of citrus waste was fed into the first-stage reactor every day. The effluent of the first-stage was then fed into the second-stage reactor. This experiment was run for 120 days. A reactor configuration without recirculation was used as control. The result shows that the reactor with effluent recirculation produced a higher methane yield (160–203 NmL/g·VS) compared to that without recirculation (66–113 NmL/g·VS). More stable performance was also observed in the reactor with recirculation as shown by the pH of 5–6, while without recirculation the pH dropped to the range of 3.7–4.7. The VS reduction for the reactor with recirculation was 33–35% higher than that of the control without recirculation. Recirculation might affect the hydrolysis-acidogenesis process by regulating pH in the first-stage and removing most of the D-limonene content from the substrate through filtration.

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Two-stage continuous process development for the production of medium-chain-length poly(3-hydroxyalkanoates)

Biotechnology and Bioengineering ◽

10.1002/1097-0290(20010105)72:1<19::aid-bit3>3.0.co;2-b ◽

2000 ◽

Vol 72 (1) ◽

pp. 19-24 ◽

Cited By ~ 43

Author(s):

Kuno Jung ◽

Wil Hazenberg ◽

Maria Prieto ◽

Bernard Witholt

Keyword(s):

Chain Length ◽

Process Development ◽

Continuous Process ◽

Two Stage ◽

Medium Chain ◽

Medium Chain Length

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Two-Stage Continuous Process for the Extraction of Silica from Rice Husk Using Attrition Ball Milling and Alkaline Leaching Methods

Sustainability ◽

10.3390/su13137350 ◽

2021 ◽

Vol 13 (13) ◽

pp. 7350

Author(s):

Ji Yeon Park ◽

Yang Mo Gu ◽

Seon Young Park ◽

Ee Taek Hwang ◽

Byoung-In Sang ◽

...

Keyword(s):

Ball Milling ◽

Rice Husk ◽

Continuous Process ◽

Solid Content ◽

Emission Spectrometry ◽

Optimum Conditions ◽

Reaction Conditions ◽

Two Stage ◽

Alkaline Leaching ◽

Leaching Methods

A two-stage continuous process was developed for improved silica extraction from rice husk. The two-stage continuous process consists of attrition ball milling and alkaline leaching methods. To find the optimum conditions for the continuous process, the effects of alkaline leaching parameters, such as the alkaline solution type and reaction conditions, on the silica extraction yield were investigated in a batch process. The use of NaOH showed a slightly higher silica yield than KOH. The optimum reaction conditions were found to be 0.2 M, 80 °C, 3 h, and 6% (w/v) for the reaction concentration, temperature, duration time, and solid content, respectively. Attrition ball milling was used to make micron-sized rice husk particles and to improve the fluidity of the rice husk slurry. The two-stage continuous process was performed using optimum conditions as determined based on the results of the batch experiment. The two-stage continuous extraction was stably operated for 80 h with an 89% silica yield. During the operation, the solid content remained consistent at 6% (w/v). The obtained silica was characterized using inductively coupled plasma–optical emission spectrometry (ICP–OES), X-ray diffraction (XRD), and the Brunauer–Emmett–Teller (BET) method.

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Maximization of fructooligosaccharide production by two stage continuous process and its scale up

Journal of Food Engineering ◽

10.1016/j.jfoodeng.2004.05.022 ◽

2005 ◽

Vol 68 (1) ◽

pp. 57-64 ◽

Cited By ~ 45

Author(s):

P.T. Sangeetha ◽

M.N. Ramesh ◽

S.G. Prapulla

Keyword(s):

Continuous Process ◽

Scale Up ◽

Two Stage

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Two-stage self-seeding method for preparation of single crystals of poly(phenylene sulfide)

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100153816 ◽

1989 ◽

Vol 47 ◽

pp. 368-369

Author(s):

Sengshiu Chung ◽

Peggy Cebe

Keyword(s):

Single Crystals ◽

High Performance ◽

Dilute Solution ◽

Two Stage ◽

Annealing Behavior ◽

High Performance Polymers ◽

Seeding Method ◽

Phenylene Sulfide

We are studying the crystallization and annealing behavior of high performance polymers, like poly(p-pheny1ene sulfide) PPS, and poly-(etheretherketone), PEEK. Our purpose is to determine whether PPS, which is similar in many ways to PEEK, undergoes reorganization during annealing. In an effort to address the issue of reorganization, we are studying solution grown single crystals of PPS as model materials.Observation of solution grown PPS crystals has been reported. Even from dilute solution, embrionic spherulites and aggregates were formed. We observe that these morphologies result when solutions containing uncrystallized polymer are cooled. To obtain samples of uniform single crystals, we have used two-stage self seeding and solution replacement techniques.

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