scholarly journals Improved methane production and energy recovery of post-hydrothermal liquefaction waste water via integration of zeolite adsorption and anaerobic digestion

2019 ◽  
Vol 651 ◽  
pp. 61-69 ◽  
Author(s):  
Ruirui Li ◽  
Dianlei Liu ◽  
Yifeng Zhang ◽  
Jialiang Zhou ◽  
Yiu Fai Tsang ◽  
...  
Keyword(s):  
Waste Water ◽  
Anaerobic Digestion ◽  
Methane Production ◽  
Energy Recovery ◽  
Hydrothermal Liquefaction

scholarly journals Efficiency of integrated electrooxidation and anaerobic digestion of waste activated sludge

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.

scholarly journals Effects of Ultrasonic and Microwave Pretreatment on Lipid Extraction of Microalgae and Methane Production from the Residual Extracted Biomass

2020 ◽  
Author(s):  
Magdalena Rokicka ◽  
Marcin Zieliński ◽  
Magda Dudek ◽  
Marcin Dębowski
Keyword(s):  
Anaerobic Digestion ◽  
Methane Production ◽  
Energy Recovery ◽  
Extraction Efficiency ◽  
Lipid Extraction ◽  
Botryococcus Braunii ◽  
Methane Yield ◽  
Economic Viability ◽  
Ultrasonic Pretreatment ◽  
Microwave Pretreatment

Abstract The extraction of lipids from microalgae cells of Botryococcus braunii and Chlorella vulgaris after ultrasonic and microwave pretreatment was evaluated. Cell disruption increased the lipid extraction efficiency, and microwave pretreatment was more effective compared with ultrasonic pretreatment. The maximum lipid yield from B. braunii was 56.42% using microwave radiation and 39.61% for ultrasonication, while from C. vulgaris, it was respectively 41.31% and 35.28%. The fatty acid composition in the lipid extracts was also analyzed. The methane yield from the residual extracted biomass pretreated by microwaves ranged from 148 to 185 NmL CH4/g VS for C. vulgaris and from 128 to 142 NmL CH4/g VS for B. braunii. In the case of ultrasonic pretreatment, the methane production was between 168 and 208 NmL CH4/g VS for C. vulgaris, while for B. braunii ranging from 150 to 174 NmL CH4/g VS. Anaerobic digestion showed that lipid-extracted biomass presented lower methane yield than non-lipid-extracted feedstock, and higher amount of lipid obtained in the extraction contributed less methane production. Anyway, anaerobic digestion of the residual extracted biomass can be a suitable method to increase economic viability of energy recovery from microalgae.

Contribution of H2 during the Two-Phase Anaerobic Digestion

2014 ◽  
Vol 908 ◽  
pp. 235-238
Author(s):  
Fang Yin ◽  
Wu Di Zhang ◽  
Ling Xu ◽  
Jing Liu ◽  
Hong Yang ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Microbial Community ◽  
Anaerobic Digestion ◽  
Hydrogen Production ◽  
Methane Production ◽  
Energy Recovery ◽  
Fermentation Process ◽  
Energy Conversion Efficiency ◽  
Two Phase ◽  
Technological Support

In the process of anaerobic digestion for methane production, one-third of which is from hydrogen, another two-thirds from acetic acid. From the point of material and energy recovery, the energy conversion efficiency of alone hydrogen or methane production is less than co-generation of hydrogen and methane production. Because hydrogen production is also accompanied by acidification and syntrophic acetogenic fermentation process, it is technically feasible for alone hydrogen or methane production. As the two-phase anaerobic digestion separate the acidifying bacteria and methanogens in different reactors, blocking the synergy of the two different microbial community, we should provide scientific and technological support for two-phase anaerobic application.

scholarly journals Comparative assessment of single-stage and two-stage anaerobic digestion for biogas production from high moisture municipal solid waste

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9693
Author(s):  
Wattananarong Markphan ◽  
Chonticha Mamimin ◽  
Wantanasak Suksong ◽  
Poonsuk Prasertsan ◽  
Sompong O-Thong
Keyword(s):  
Fly Ash ◽  
Anaerobic Digestion ◽  
Methane Production ◽  
Energy Recovery ◽  
Biogas Production ◽  
Single Stage ◽  
Organic Loading ◽  
High Moisture ◽  
Two Stage ◽  
Ph Adjustment

Background Anaerobic digestion (AD) is a suitable process for treating high moisture MSW with biogas and biofertilizer production. However, the low stability of AD performance and low methane production results from high moisture MSW due to the fast acidify of carbohydrate fermentation. The effects of organic loading and incineration fly ash addition as a pH adjustment on methane production from high moisture MSW in the single-stage AD and two-stage AD processes were investigated. Results Suitable initial organic loading of the single-stage AD process was 17 gVS L−1 at incineration fly ash (IFA) addition of 0.5% with methane yield of 287 mL CH4 g−1 VS. Suitable initial organic loading of the two-stage AD process was 43 gVS L−1 at IFA addition of 1% with hydrogen and methane yield of 47.4 ml H2 g−1 VS and 363 mL CH4 g−1 VS, respectively. The highest hydrogen and methane production of 8.7 m3 H2 ton−1 of high moisture MSW and 66.6 m3 CH4 ton−1 of high moisture MSW was achieved at organic loading of 43 gVS L−1 at IFA addition of 1% by two-stage AD process. Biogas production by the two-stage AD process enabled 18.5% higher energy recovery than single-stage AD. The 1% addition of IFA into high moisture MSW was useful for controlling pH of the two-stage AD process with enhanced biogas production between 87–92% when compared to without IFA addition. Electricity production and energy recovery from MSW using the coupled incineration with biogas production by two-stage AD process were 9,874 MJ ton−1 MSW and 89%, respectively. Conclusions The two-stage AD process with IFA addition for pH adjustment could improve biogas production from high moisture MSW, as well as reduce lag phase and enhance biodegradability efficiency. The coupled incineration process with biogas production using the two-stage AD process was suitable for the management of MSW with low area requirement, low greenhouse gas emissions, and high energy recovery.

scholarly journals Evaluation Of Mechanical, Irradiation And Chemical Pretreatment Lignocelulosic Substrate For Enhanced Methane Production

2021 ◽  
Author(s):  
Zeid Amin
Keyword(s):  
Anaerobic Digestion ◽  
Methane Production ◽  
Energy Recovery ◽  
Energy Reserve ◽  
Research Report ◽  
Chemical Pretreatment ◽  
Lignocellulosic Substrate ◽  
Different Types ◽  
Combined Pretreatment ◽  
Pretreatment Processes

Lignocellulosic substrate is a resource that contains a locked energy reserve that is normally lost during anaerobic digestion. Lignocellulosic substrate is one of the most abundant sources of organic matter available and yet its energy recovery has much room for improvement. Lignocellulosic substrate has cellular properties that are deemed extremely difficult to degrade due to complexity which is why this energy reserve is never unlocked during anaerobic digestion. There are several successful pretreatment methods that are used to degrade this lignocellulosic substrate and unlock this energy reserve. This paper will focus on the methods that include mechanical, irradiation, chemical and combined pretreatment processes. Analysis is conducted on all the studies that are obtained to compare the successes of the different types of pretreatment processes used. Each of the different listed pretreatment processes have different energy requirements, treatment times, and solvent requirement and are acting to enhancing methane production. The improvement in methane production varies from process to process and study to study creating a need to compile all of this valuable data into this research report. This will help future researchers in navigating the available studies of pretreatment of lignocellulosic substrate for improving methane production.

Anaerobic digestion of post-hydrothermal liquefaction wastewater for improved energy efficiency of hydrothermal bioenergy processes

2015 ◽  
Vol 72 (12) ◽  
pp. 2139-2147 ◽  
Author(s):  
Yan Zhou ◽  
Lance Schideman ◽  
Mingxia Zheng ◽  
Ana Martin-Ryals ◽  
Peng Li ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Activated Carbon ◽  
Anaerobic Digestion ◽  
Energy Recovery ◽  
Biogas Production ◽  
Inhibitory Effect ◽  
Hydrothermal Liquefaction ◽  
Net Energy ◽  
Recovery Efficiency ◽  
High Concentration

Hydrothermal liquefaction (HTL) is a promising process for converting wet biomass and organic wastes into bio-crude oil. It also produces an aqueous product referred to as post-hydrothermal liquefaction wastewater (PHWW) containing up to 40% of the original feedstock carbon, which reduces the overall energy efficiency of the HTL process. This study investigated the feasibility of using anaerobic digestion (AD) to treat PHWW, with the aid of activated carbon. Results showed that successful AD occurred at relatively low concentrations of PHWW (≤ 6.7%), producing a biogas yield of 0.5 ml/mg CODremoved, and ∼53% energy recovery efficiency. Higher concentrations of PHWW (≥13.3%) had an inhibitory effect on the AD process, as indicated by delayed, slower, or no biogas production. Activated carbon was shown to effectively mitigate this inhibitory effect by enhancing biogas production and allowing digestion to proceed at higher PHWW concentrations (up to 33.3%), likely due to sequestering toxic organic compounds. The addition of activated carbon also increased the net energy recovery efficiency of AD with a relatively high concentration of PHWW (33.3%), taking into account the energy for producing activated carbon. These results suggest that AD is a feasible approach to treat PHWW, and to improve the energy efficiency of the HTL processes.

scholarly journals Evaluation Of Mechanical, Irradiation And Chemical Pretreatment Lignocelulosic Substrate For Enhanced Methane Production

2021 ◽  
Author(s):  
Zeid Amin
Keyword(s):  
Anaerobic Digestion ◽  
Methane Production ◽  
Energy Recovery ◽  
Energy Reserve ◽  
Research Report ◽  
Chemical Pretreatment ◽  
Lignocellulosic Substrate ◽  
Different Types ◽  
Combined Pretreatment ◽  
Pretreatment Processes

Lignocellulosic substrate is a resource that contains a locked energy reserve that is normally lost during anaerobic digestion. Lignocellulosic substrate is one of the most abundant sources of organic matter available and yet its energy recovery has much room for improvement. Lignocellulosic substrate has cellular properties that are deemed extremely difficult to degrade due to complexity which is why this energy reserve is never unlocked during anaerobic digestion. There are several successful pretreatment methods that are used to degrade this lignocellulosic substrate and unlock this energy reserve. This paper will focus on the methods that include mechanical, irradiation, chemical and combined pretreatment processes. Analysis is conducted on all the studies that are obtained to compare the successes of the different types of pretreatment processes used. Each of the different listed pretreatment processes have different energy requirements, treatment times, and solvent requirement and are acting to enhancing methane production. The improvement in methane production varies from process to process and study to study creating a need to compile all of this valuable data into this research report. This will help future researchers in navigating the available studies of pretreatment of lignocellulosic substrate for improving methane production.

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

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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