Effects of sorghum biomass quality on ensilability and methane yield

The photocatalytic pretreatment of lignocellulosic biomass to oxidize lignin and increase biomass stability has gained attention during the last few years. Conventional pretreatment methods are limited by the fact that they are expensive, non-renewable and contaminate the anaerobic digestate later on. The present study was focused to develop a metal-derived photocatalyst that can work with visible electromagnetic spectra light and oxidize commercial lignin liquor. During this project the advanced photocatalytic oxidation of lignin was achieved by using a quartz cube tungsten T3 Halogen 100 W lamp with a laboratory manufactured TiO2-ZnO nanoparticle (nanocomposite) in a self-designed apparatus. The products of lignin oxidation were confirmed to be vanillic acid (9.71 ± 0.23 mg/L), ferrulic acid (7.34 ± 0.16 mg/L), benzoic acid (6.12 ± 0.17 mg/L) and p-coumaric acid (3.80 ± 0.13 mg/L). These all products corresponded to 85% of the lignin oxidation products that were detectable, which is significantly more than any previously reported lignin pretreatment with even more intensity. Furthermore, all the pretreatment samples were supplemented in the form of feedstock diluent in uniformly operating continuously stirred tank reactors (CSTRs). The results of pretreatment revealed 85% lignin oxidation and later on these products did not hinder the CSTR performance at any stage. Moreover, the synergistic effects of pretreated lignin diluent were seen that resulted in 39% significant increase in the methane yield of the CSTR with constant operation. Finally, the visible light and nanoparticles alone could not pretreat lignin and when used as diluent, halted and reduced the methane yield by 37% during 4th HRT.

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Enhancing methane production from the invasive macroalga Rugulopteryx okamurae through anaerobic co-digestion with olive mill solid waste: process performance and kinetic analysis

Journal of Applied Phycology ◽

10.1007/s10811-021-02548-3 ◽

2021 ◽

Author(s):

D. de la Lama-Calvente ◽

M. J. Fernández-Rodríguez ◽

J. Llanos ◽

J. M. Mancilla-Leytón ◽

R. Borja

Keyword(s):

Anaerobic Digestion ◽

Solid Waste ◽

Methane Production ◽

Methane Yield ◽

Specific Rate ◽

Order Kinetic ◽

Two Phase ◽

First Order ◽

Olive Mill Solid Waste ◽

Olive Mill

AbstractThe biomass valorisation of the invasive brown alga Rugulopteryx okamurae (Dictyotales, Phaeophyceae) is key to curbing the expansion of this invasive macroalga which is generating tonnes of biomass on southern Spain beaches. As a feasible alternative for the biomass management, anaerobic co-digestion is proposed in this study. Although the anaerobic digestion of macroalgae barely produced 177 mL of CH4 g−1 VS, the co-digestion with a C-rich substrate, such as the olive mill solid waste (OMSW, the main waste derived from the two-phase olive oil manufacturing process), improved the anaerobic digestion process. The mixture improved not only the methane yield, but also its biodegradability. The highest biodegradability was found in the mixture 1 R. okamurae—1 OMSW, which improved the biodegradability of the macroalgae by 12.9% and 38.1% for the OMSW. The highest methane yield was observed for the mixture 1 R. okamurae—3 OMSW, improving the methane production of macroalgae alone by 157% and the OMSW methane production by 8.6%. Two mathematical models were used to fit the experimental data of methane production time with the aim of assessing the processes and obtaining the kinetic constants of the anaerobic co-digestion of different combination of R. okamurae and OMSW and both substrates independently. First-order kinetic and the transference function models allowed for appropriately fitting the experimental results of methane production with digestion time. The specific rate constant, k (first-order model) for the mixture 1 R. okamurae- 1.5 OMSW, was 5.1 and 1.3 times higher than that obtained for the mono-digestion of single OMSW and the macroalga, respectively. In the same way, the transference function model revealed that the maximum methane production rate (Rmax) was also found for the mixture 1 R. okamurae—1.5 OMSW (30.4 mL CH4 g−1 VS day−1), which was 1.6 and 2.2 times higher than the corresponding to the mono-digestions of the single OMSW and sole R. okamurae (18.9 and 13.6 mL CH4 g−1 VS day−1), respectively.

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Co-Digestion of Rice Straw with Cow Manure in an Innovative Temperature Phased Anaerobic Digestion Technology: Performance Evaluation and Trace Elements

Energies ◽

10.3390/en14092561 ◽

2021 ◽

Vol 14 (9) ◽

pp. 2561

Author(s):

Furqan Muhayodin ◽

Albrecht Fritze ◽

Oliver Christopher Larsen ◽

Marcel Spahr ◽

Vera Susanne Rotter

Keyword(s):

Trace Elements ◽

Anaerobic Digestion ◽

Greenhouse Gas ◽

Rice Straw ◽

Methane Yield ◽

Methane Formation ◽

Cow Manure ◽

Volatile Solids ◽

Mass Fractions ◽

Cu And Zn

Rice straw is an agricultural residue produced in abundant quantities. Open burning and plowing back the straw to the fields are common practices for its disposal. In-situ incorporation and burning cause emissions of greenhouse gas and particulate matter. Additionally, the energy potential of rice straw is lost. Anaerobic digestion is a technology that can be potentially used to utilize the surplus rice straw, provide renewable energy, circulate nutrients available in the digestate, and reduce greenhouse gas emissions from rice paddies. An innovative temperature phased anaerobic digestion technology was developed and carried out in a continuous circulating mode of mesophilic and hyperthermophilic conditions in a loop digester (F1). The performance of the newly developed digester was compared with the reference digester (F2) working at mesophilic conditions. Co-digestion of rice straw was carried out with cow manure to optimize the carbon to nitrogen ratio and to provide the essential trace elements required by microorganisms in the biochemistry of methane formation. F1 produced a higher specific methane yield (189 ± 37 L/kg volatile solids) from rice straw compared to F2 (148 ± 36 L/kg volatile solids). Anaerobic digestion efficiency was about 90 ± 20% in F1 and 70 ± 20% in F2. Mass fractions of Fe, Ni, Co, Mo, Cu, and Zn were analyzed over time. The mass fractions of Co, Mo, Cu, and Zn were stable in both digesters. While mass fractions of Fe and Ni were reduced at the end of the digestion period. However, no direct relationship between specific methane yield and reduced mass fraction of Fe and Ni was found. Co-digestion of rice straw with cow manure seems to be a good approach to provide trace elements except for Se.

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In vitro five brown algae extracts for efficiency of ruminal fermentation and methane yield

Journal of Applied Phycology ◽

10.1007/s10811-020-02361-4 ◽

2021 ◽

Vol 33 (2) ◽

pp. 1253-1262

Author(s):

You Young Choi ◽

Nyeon Hak Shin ◽

Shin Ja Lee ◽

Ye Jun Lee ◽

Hyun Sang Kim ◽

...

Keyword(s):

Brown Algae ◽

Methane Yield ◽

Ruminal Fermentation

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Effects of granular activated carbon and temperature on the viscosity and methane yield of anaerobically digested of corn straw with different dry matter concentrations

Bioresource Technology ◽

10.1016/j.biortech.2021.125109 ◽

2021 ◽

pp. 125109

Author(s):

Yongdi Liu ◽

Yulei Qian ◽

Xiaoyu Yong ◽

Honghua Jia ◽

Ping Wei ◽

...

Keyword(s):

Activated Carbon ◽

Dry Matter ◽

Granular Activated Carbon ◽

Methane Yield ◽

Corn Straw

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Sugarcane Bagasse as a Co-Substrate with Oil-Refinery Biological Sludge for Biogas Production Using Batch Mesophilic Anaerobic Co-Digestion Technology: Effect of Carbon/Nitrogen Ratio

Water ◽

10.3390/w13050590 ◽

2021 ◽

Vol 13 (5) ◽

pp. 590

Author(s):

Aiban Abdulhakim Saeed Ghaleb ◽

Shamsul Rahman Mohamed Kutty ◽

Gasim Hayder Ahmed Salih ◽

Ahmad Hussaini Jagaba ◽

Azmatullah Noor ◽

...

Keyword(s):

Anaerobic Digestion ◽

Sugarcane Bagasse ◽

Organic Waste ◽

Wastewater Treatment Plants ◽

Biogas Production ◽

Raw Materials ◽

Oil Refinery ◽

Methane Yield ◽

Oil Refineries ◽

Biological Sludge

Man-made organic waste leads to the rapid proliferation of pollution around the globe. Effective bio-waste management can help to reduce the adverse effects of organic waste while contributing to the circular economy at the same time. The toxic oily-biological sludge generated from oil refineries’ wastewater treatment plants is a potential source for biogas energy recovery via anaerobic digestion. However, the oily-biological sludge’s carbon/nitrogen (C/N) ratio is lower than the ideal 20–30 ratio required by anaerobic digestion technology for biogas production. Sugarcane bagasse can be digested as a high C/N co-substrate while the oily-biological sludge acts as a substrate and inoculum to improve biogas production. In this study, the best C/N with co-substrate volatile solids (VS)/inoculum VS ratios for the co-digestion process of mixtures were determined empirically through batch experiments at temperatures of 35–37 °C, pH (6–8) and 60 rpm mixing. The raw materials were pre-treated mechanically and thermo-chemically to further enhance the digestibility. The best condition for the sugarcane bagasse delignification process was 1% (w/v) sodium hydroxide, 1:10 solid-liquid ratio, at 100 °C, and 150 rpm for 1 h. The results from a 33-day batch anaerobic digestion experiment indicate that the production of biogas and methane yield were concurrent with the increasing C/N and co-substrate VS/inoculum VS ratios. The total biogas yields from C/N 20.0 with co-substrate VS/inoculum VS 0.06 and C/N 30.0 with co-substrate VS/inoculum VS 0.18 ratios were 2777.0 and 9268.0 mL, respectively, including a methane yield of 980.0 and 3009.3 mL, respectively. The biogas and methane yield from C/N 30.0 were higher than the biogas and methane yields from C/N 20.0 by 70.04 and 67.44%, respectively. The highest biogas and methane yields corresponded with the highest C/N with co-substrate VS/inoculum VS ratios (30.0 and 0.18), being 200.6 mL/g VSremoved and 65.1 mL CH4/g VSremoved, respectively.

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Enhancement of Thermophilic Biogas Production from Palm Oil Mill Effluent by pH Adjustment and Effluent Recycling

Processes ◽

10.3390/pr9050878 ◽

2021 ◽

Vol 9 (5) ◽

pp. 878

Author(s):

Apinya Singkhala ◽

Chonticha Mamimin ◽

Alissara Reungsang ◽

Sompong O-Thong

Keyword(s):

Palm Oil ◽

Oil Palm ◽

Biogas Production ◽

Optimal Dose ◽

Methane Yield ◽

Ph Adjustment ◽

Oil Palm Ash ◽

Palm Oil Mill ◽

Archaea Community ◽

Effluent Recycling

A sudden pH drops always inhibits the anaerobic digestion (AD) reactor for biogas production from palm oil mill effluent (POME). The pH adjustment of POME by oil palm ash addition and the biogas effluent recycling effect on the preventing of pH drop and change of the archaea community was investigated. The pH adjustment of POME to 7.5 increased the methane yield two times more than raw POME (pH 4.3). The optimal dose for pH adjustment by oil palm ash addition was 5% w/v with a methane yield of 440 mL-CH4/gVS. The optimal dose for pH adjustment by biogas effluent recycling was 20% v/v with a methane yield of 351 mL-CH4/gVS. Methane production from POME in a continuous reactor with pH adjustment by 5% w/v oil palm ash and 20% v/v biogas effluent recycling was 19.1 ± 0.25 and 13.8 ± 0.3 m3 CH4/m3-POME, respectively. The pH adjustment by oil palm ash enhanced methane production for the long-term operation with the stability of pH, alkalinity, and archaea community. Oil palm ash increased the number of Methanosarcina mazei and Methanothermobacter defluvii. Oil palm ash is a cost-effective alkali material as a source of buffer and trace metals for preventing the pH drop and the increased methanogen population in the AD process.

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Anaerobic Degradation of Individual Components from 5-Hydroxymethylfurfural Process-Wastewater in Continuously Operated Fixed Bed Reactors

Processes ◽

10.3390/pr9040677 ◽

2021 ◽

Vol 9 (4) ◽

pp. 677

Author(s):

Muhammad Tahir Khan ◽

Johannes Krümpel ◽

Dominik Wüst ◽

Andreas Lemmer

Keyword(s):

Levulinic Acid ◽

Anaerobic Degradation ◽

Fixed Bed ◽

Methane Yield ◽

Process Stability ◽

Anaerobic Process ◽

Anaerobic Filter ◽

Fixed Bed Reactors ◽

Process Wastewater ◽

By Products

Production of bio-based materials in biorefineries is coupled with the generation of organic-rich process-wastewater that requires further management. Anaerobic technologies can be employed as a tool for the rectification of such hazardous by-products. Therefore, 5-hydroxymethylfurfural process-wastewater and its components were investigated for their biodegradability in a continuous anaerobic process. The test components included 5-hydroxymethylfurfural, furfural, levulinic acid, and the full process-wastewater. Each component was injected individually into a continuously operating anaerobic filter at a concentration of 0.5 gCOD. On the basis of large discrepancies within the replicates for each component, we classified their degradation into the categories of “delayed”, “retarded”, and “inhibitory”. Inhibitory represented the replicates for all the test components that hampered the process. For the retarded degradation, their mean methane yield per 0.5 gCOD was between 21.31 ± 13.04 mL and 28.98 ± 25.38 mL. Delayed digestion was considered adequate for further assessments in which the order of conversion to methane according to specific methane yield for each component from highest to lowest was as follows: levulinic acid > furfural > 5-hydroxymethylfurfural > process-wastewater. Disparities and inconsistencies in the degradation of process-wastewater and its components can compromise process stability as a whole. Hence, the provision of energy with such feedstock is questionable.

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Effect of co-substrate feeding on methane yield of anaerobic digestion of Chlorella vulgaris

Journal of Applied Phycology ◽

10.1007/s10811-016-0796-5 ◽

2016 ◽

Vol 28 (5) ◽

pp. 2741-2752 ◽

Cited By ~ 11

Author(s):

Tamás Rétfalvi ◽

Piroska Szabó ◽

Annamária-Tukacs Hájos ◽

Levente Albert ◽

Attila Kovács ◽

...

Keyword(s):

Anaerobic Digestion ◽

Chlorella Vulgaris ◽

Methane Yield ◽

Substrate Feeding

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Forage brassica: a feed to mitigate enteric methane emissions?

Animal Production Science ◽

10.1071/an15516 ◽

2016 ◽

Vol 56 (3) ◽

pp. 451 ◽

Cited By ~ 16

Author(s):

Xuezhao Sun ◽

David Pacheco ◽

Dongwen Luo

Keyword(s):

Methane Emissions ◽

Methane Yield ◽

Forage Crops ◽

Enteric Methane ◽

Winter Crop ◽

Feeding Trials ◽

Series Of Experiments ◽

Forage Rape ◽

Pastoral Farming ◽

Enteric Methane Emissions

A series of experiments was conducted in New Zealand to evaluate the potential of forage brassicas for mitigation of enteric methane emissions. Experiments involved sheep and cattle fed winter and summer varieties of brassica forage crops. In the sheep-feeding trials, it was demonstrated that several species of forage brassicas can result, to a varying degree, in a lower methane yield (g methane per kg of DM intake) than does ryegrass pasture. Pure forage rape fed as a winter crop resulted in 37% lower methane yields than did pasture. Increasing the proportion of forage rape in the diet of sheep fed pasture linearly decreased methane yield. Feeding forage rape to cattle also resulted in 44% lower methane yield than did feeding pasture. In conclusion, reductions in methane emission are achievable by feeding forage brassicas, especially winter forage rape, to sheep and cattle. Investigating other aspects of these crops is warranted to establish their value as a viable mitigation tool in pastoral farming.

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