Mesophilic condition is more conducive to methane production yield and tylosin removal on tylosin fermentation dreg anaerobic digestion

In this research, sago mill effluent was treated using anaerobic sequencing batch reactor (ASBR). Seven HRT from 10 to 1.5 days were tested to evaluate the methane production from sago mill effluent. The findings revealed the highest methane production rate was found at 1.288 L CH4/L reactor. d under HRT of 2 days The results showed that COD removals decreased from 70% to 47% as HRT was reduced from 10 to 2 days. The HRT 1.5 days was found critical for the studied system, which leads to decreased in methane production, yield and COD removal. Overall, ASBR was capable to treat sago mill effluent in producing methane by means of anaerobic digestion.

Download Full-text

Effect Of Co-Digestion Of Source Separated Organics And Manure On Methane Production

10.32920/ryerson.14645640 ◽

2021 ◽

Author(s):

Devarshi Sevak ◽

Elsayed Elbeshbishy

Keyword(s):

Anaerobic Digestion ◽

Production Rate ◽

Methane Production ◽

Gas Production ◽

Mixture Ratio ◽

Biomethane Potential ◽

Methane Production Rate ◽

Biomethane Production ◽

Mesophilic Condition

Anaerobic co-digestion (AcoD) is more advantageous than conventional mono-digestion, because of higher gas production rate. This study was aimed to study the effect of mixture ratio in codigestion of manure and source separated organics (SSO) in mesophilic condition. Manure and SSO at different mixture ratios of 9:1, 7:3, 5:5, 3:7, and 1:9 on a volumetric basis were used to determine the effect of the mixture ratios on methane production in biomethane potential assay (BMP). Results showed that co-digestion of SSO and manure at the ratio of 1:9 (V/V) resulted in the highest biomethane production rate of 46 mL CH4 /day. In comparison, the maximum methane production rate for anaerobic digestion of manure alone was 43 mL CH4 /day. When manure is mixed with SSO at a ratio of 5:5, about 15% higher cumulative methane production has been achieved. This research also verified the advantages of co-digestion over mono-digestion. Keywords: Anaerobic Digestion, Co-digestion, Source Separated Organics (SSO), Manure

Download Full-text

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.

Download Full-text

Biochar promotes methane production during anaerobic digestion of organic waste

Environmental Chemistry Letters ◽

10.1007/s10311-021-01251-6 ◽

2021 ◽

Author(s):

Leilei Xiao ◽

Eric Lichtfouse ◽

P. Senthil Kumar ◽

Quan Wang ◽

Fanghua Liu

Keyword(s):

Anaerobic Digestion ◽

Methane Production ◽

Organic Waste

Download Full-text

Pretreatment, Anaerobic Codigestion, or Both? Which Is More Suitable for the Enhancement of Methane Production from Agricultural Waste?

Molecules ◽

10.3390/molecules26144175 ◽

2021 ◽

Vol 26 (14) ◽

pp. 4175

Author(s):

Lütfiye Dumlu ◽

Asli Seyhan Ciggin ◽

Stefan Ručman ◽

N. Altınay Perendeci

Keyword(s):

Anaerobic Digestion ◽

Methane Production ◽

Agricultural Waste ◽

Kinetic Studies ◽

Antagonistic Effect ◽

Hydrolysis Rate ◽

Order Kinetic ◽

Maximum Enhancement ◽

Mixing Ratios ◽

Anaerobic Codigestion

Pretreatment and codigestion are proven to be effective strategies for the enhancement of the anaerobic digestion of lignocellulosic residues. The purpose of this study is to evaluate the effects of pretreatment and codigestion on methane production and the hydrolysis rate in the anaerobic digestion of agricultural wastes (AWs). Thermal and different thermochemical pretreatments were applied on AWs. Sewage sludge (SS) was selected as a cosubstrate. Biochemical methane potential tests were performed by mixing SS with raw and pretreated AWs at different mixing ratios. Hydrolysis rates were estimated by the best fit obtained with the first-order kinetic model. As a result of the experimental and kinetic studies, the best strategy was determined to be thermochemical pretreatment with sodium hydroxide (NaOH). This strategy resulted in a maximum enhancement in the anaerobic digestion of AWs, a 56% increase in methane production, an 81.90% increase in the hydrolysis rate and a 79.63% decrease in the technical digestion time compared to raw AWs. On the other hand, anaerobic codigestion (AcoD) with SS was determined to be ineffective when it came to the enhancement of methane production and the hydrolysis rate. The most suitable mixing ratio was determined to be 80:20 (Aws/SS) for the AcoD of the studied AWs with SS in order to obtain the highest possible methane production without any antagonistic effect.

Download Full-text

Efficiency of integrated electrooxidation and anaerobic digestion of waste activated sludge

Biotechnology for Biofuels ◽

10.1186/s13068-021-01929-7 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

J. A. Barrios ◽

A. Cano ◽

F. F. Rivera ◽

M. E. Cisneros ◽

U. Durán

Keyword(s):

Anaerobic Digestion ◽

Current Density ◽

Methane Production ◽

Energy Recovery ◽

Energy Analysis ◽

Mathematical Optimization ◽

Waste Activated Sludge ◽

Bdd Electrode ◽

Vs Removal ◽

Pre Treatment

Abstract Background Most of the organic content of waste activated sludge (WAS) comprises microbial cells hard to degrade, which must be pre-treated for energy recovery by anaerobic digestion (AD). Electrooxidation pre-treatment (EOP) with boron-doped diamond (BDD) electrode have been considered a promising novel technology that increase hydrolysis rate, by the disintegrating cell walls from WAS. Although electrochemical oxidation could efficiently solubilize organic substances of macromolecules, limited reports are available on EOP of WAS for improving AD. In this endeavour, the mathematical optimization study and the energy analysis of the effects of initial total solids concentrations [TS] of WAS and current density (CD) during EOP on the methane production and removal of chemical oxygen demand (COD) and volatile solids (VS) were investigated. Because limited reports are available on EOP of WAS for improving biogas production, it is not well understood; however, it has started to attract interest of scientists and engineers. Results In the present work, the energy recovery as biogas and WAS conversion were comprehensively affected by CD and [TS], in an integrated EOP and AD system. When working with WAS at 3% of [TS] pre-treated at current density of 24.1 mA/cm2, the highest COD and VS removal were achieved, making it possible to obtain the maximum methane (CH4) production of 305 N-L/kg VS and a positive energy balance of 1.67 kWh/kg VS. Therefore, the current densities used in BDD electrode are adequate to produce the strong oxidant (hydroxyl radical, ·OH) on the electrode surface, allow the oxidation of organic compounds that favours the solubilization of particulate matter and VS from WAS. Conclusions The improvement of VS removal and COD solubilization were due to the effects of pre-treatments, which help to break down the microbial cells for faster subsequent degradation; this allows a decomposition reaction that leads to biodegrade more compounds during AD. The balance was positive, suggesting that even without any optimization the energy used as electricity could be recovered from the increased methane production. It is worth noting that this kind of analysis have not been sufficiently studied so far. It is therefore important to understand how operational parameters can influence the pre-treatment and AD performances. The current study highlights that the mathematical optimization and energy analysis can make the whole process more convenient and feasible.

Download Full-text