scholarly journals Semi-Continuous Reverse Membrane Bioreactor in Two-Stage Anaerobic Digestion of Citrus Waste

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1341 ◽  
Author(s):  
Tonny Kurniawan ◽  
Lukitawesa ◽  
Ilma Hanifah ◽  
Rachma Wikandari ◽  
Ria Millati ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
H2 Production ◽  
Membrane Bioreactors ◽  
Two Stage ◽  
High Cell Concentration ◽  
Freely Suspended ◽  
Citrus Waste ◽  
System Configurations ◽  
Hydrophilic Membranes ◽  
Better Than

The presence of an antimicrobial compound called D-Limonene in citrus waste inhibits methane production from such waste in anaerobic digestion. In this work, a two-stage anaerobic digestion method is developed using reverse membrane bioreactors (rMBRs) containing cells encased in hydrophilic membranes. The purpose of encasement is to retain a high cell concentration inside the bioreactor. The effectiveness of rMBRs in reducing cell washout is evaluated. Three different system configurations, comprising rMBRs, freely suspended cells (FCs), and a combination of both (abbreviated to rMBR–FCs), are incubated at three different organic loading rates (OLRs) each, namely 0.6, 1.2, and 3.6 g COD/(L cycle). Incubation lasts for eight feeding cycles at 55 °C. Methane yield and biogas composition results show that rMBRs perform better than rMBR–FCs and FCs at all three OLRs. Volatile fatty acid profiles and H2 production show that the reactors are working properly and no upset occurs. Additionally, a short digestion time of 4 days can be achieved using the rMBR configuration in this study.

scholarly journals Anaerobic digestion of citrus waste using two-stage membrane bioreactor

2018 ◽  
Vol 316 ◽  
pp. 012063 ◽  
Author(s):  
Ria Millati ◽  
Lukitawesa ◽  
Ervina Dwi Permanasari ◽  
Kartika Wulan Sari ◽  
Muhammad Nur Cahyanto ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Membrane Bioreactor ◽  
Two Stage ◽  
Citrus Waste

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

Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3380 ◽  
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.

Two-Stage anaerobic digestion in agroindustrial waste treatment: A review

2021 ◽  
Vol 281 ◽  
pp. 111854
Author(s):  
Paulo André Cremonez ◽  
Joel Gustavo Teleken ◽  
Thompson Ricardo Weiser Meier ◽  
Helton José Alves
Keyword(s):  
Anaerobic Digestion ◽  
Waste Treatment ◽  
Two Stage ◽  
Agroindustrial Waste

Increasing 2 -Bio- (H2 and CH4) production from food waste by combining two-stage anaerobic digestion and electrodialysis for continuous volatile fatty acids removal

2021 ◽  
Vol 129 ◽  
pp. 20-25
Author(s):  
Gamal K. Hassan ◽  
Rhys Jon Jones ◽  
Jaime Massanet-Nicolau ◽  
Richard Dinsdale ◽  
M.M. Abo-Aly ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Anaerobic Digestion ◽  
Food Waste ◽  
Volatile Fatty Acids ◽  
Two Stage ◽  
Ch4 Production

scholarly journals Batch and Semi-Continuous Anaerobic Digestion of Industrial Solid Citrus Waste for the Production of Bioenergy

Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 648
Author(s):  
Erik Samuel Rosas-Mendoza ◽  
Andrea Alvarado-Vallejo ◽  
Norma Alejandra Vallejo-Cantú ◽  
Raúl Snell-Castro ◽  
Sergio Martínez-Hernández ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Oxygen Demand ◽  
Continuous Mode ◽  
Citrus Industry ◽  
Batch Mode ◽  
Volatile Solids ◽  
Working Volume ◽  
Plant Level ◽  
Citrus Waste ◽  
Mesophilic Conditions

The aim of this paper is to describe a study of the anaerobic digestion of industrial citrus solid waste (ISCW) in both batch and semi-continuous modes for the production of bioenergy without the elimination of D-limonene. The study was conducted at the pilot plant level in an anaerobic reactor with a working volume of 220 L under mesophilic conditions of 35 ± 2 °C. Cattle manure (CM) was used as the inoculum. Three batches were studied. The first batch had a CM/ISCW ratio of 90/10, and Batches 2 and 3 had CM/ISCW ratios of 80/20 and 70/30, respectively. In the semi-continuous mode an OLR of approximately 8 g total chemical oxygen demand (COD)/Ld (4.43 gVS/Ld) was used. The results showed that 49%, 44%, and 60% of volatile solids were removed in the batch mode, and 35% was removed in the semi-continuous mode. In the batch mode, 0.322, 0.382, and 0.316 LCH4 were obtained at STP/gVSremoved. A total of 24.4 L/d (34% methane) was measured in the semi-continuous mode. Bioenergy potentials of 3.97, 5.66, and 8.79 kWh were obtained for the respective batches, and 0.09 kWh was calculated in the semi-continuous mode. The citrus industry could produce 37 GWh per season. A ton of processed oranges has a bioenergy potential of 162 kWh, which is equivalent to 49 kWh of available electricity ($3.90).

Effect of female executives on Chinese cultural media enterprise efficiency

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ying Li ◽  
Yung-Ho Chiu ◽  
Tai-Yu Lin ◽  
Hongyi Cen
Keyword(s):  
Boards Of Directors ◽  
Company Performance ◽  
Tobit Regression ◽  
Female Executives ◽  
Two Stage ◽  
Content Type ◽  
Female Directors ◽  
The Impact ◽  
Cultural Media ◽  
Better Than

Purpose As more women are now being appointed to senior and top management positions and invited to sit on boards of directors, they are now directly participating in strategic company decision-making. As female directors have been found to provide new ideas, increase company competitiveness, efficiency and performance and bring a greater number of external resources to a company than male directors, this paper aims to put female directors as a variable into the data envelopment analysis (DEA) and statistical models to explore the effect of female directors on operating performances. The DEA first quantified and measured the company efficiencies, after which the statistical model analyzed the correlations between the variables to specifically identify the impact of female decision makers on the operating efficiencies in state-owned and private enterprises. Design/methodology/approach A novel two-stage, meta-hybrid dynamic DEA was developed to explore Chinese cultural media company efficiencies under optimal input and output resource allocations, after which Tobit Regression was applied to determine the effect of female executives on these efficiencies. Findings From 2012 to 2016, the overall efficiencies in Chinese state-owned cultural media enterprises were better than in the private cultural media enterprises. The overall technology gaps (TGs) in the state-owned cultural media enterprises were better than in the private cultural media enterprises. Originality/value Previous research has tended to focus on the causal relationships between female senior executives and business performances; however, there have been few studies on the relationships between female executives and company performance from an efficiency perspective (optimal resource allocation). This paper, therefore, is the first to develop a novel two-stage, meta-hybrid dynamic DEA to examine Chinese cultural media enterprise efficiencies, and the first to apply Tobit Regression to assess the effect of female executives on those efficiencies.

scholarly journals Integration of a Water Scrubbing Technique and Two-Stage Pressurized Anaerobic Digestion in One Process

Energies ◽  
2015 ◽  
Vol 8 (3) ◽  
pp. 2048-2065 ◽  
Author(s):  
Andreas Lemmer ◽  
Yuling Chen ◽  
Anna-Maria Wonneberger ◽  
Frank Graf ◽  
Rainer Reimert
Keyword(s):  
Anaerobic Digestion ◽  
Two Stage
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