Effect of feed/inoculum ratio on anaerobic digestion of sonicated sludge

2006 ◽  
Vol 54 (5) ◽  
pp. 77-84 ◽  
Author(s):  
C.M. Braguglia ◽  
G. Mininni ◽  
M.C. Tomei ◽  
E. Rolle
Keyword(s):  
Organic Matter ◽  
Anaerobic Digestion ◽  
Beneficial Effect ◽  
Biogas Production ◽  
Soluble Form ◽  
Excess Sludge ◽  
Experimental Conditions ◽  
Digestion Process ◽  
Anaerobic Reactors ◽  
Kinetics Of

In recent years, relevant interest has been devoted to activated sludge disintegration and solubilisation techniques in order to cope with the biological limitations related to particulate degradation. Mechanical disintegration with ultrasound can efficiently transform insoluble organics into a soluble form: the solubilised organic matter is released from the cells to the bulk phase, thus accelerating the hydrolysis step in the digestion process. Experiments were carried out on bench scale anaerobic reactors fed with either untreated or disintegrated excess sludge, added with a biomass inoculum taken from a full scale anaerobic digester. Digestion tests have been carried out at different feed/inoculum ratios (F/I) in the range of 0.1–2, kinetics of VS reduction has been investigated and a beneficial effect of sonication is observed for all the experimental conditions. Similar beneficial results have also been found for biogas production with a maximum gain of 25% at 0.5 F/I ratio.

Synergistic effect of co-digestion to enhance anaerobic degradation of catering waste and orange peel for biogas production

2017 ◽  
Vol 35 (9) ◽  
pp. 967-977 ◽  
Author(s):  
Muzammil Anjum ◽  
Azeem Khalid ◽  
Samia Qadeer ◽  
Rashid Miandad
Keyword(s):  
Organic Matter ◽  
Anaerobic Digestion ◽  
Antimicrobial Agents ◽  
Biogas Production ◽  
Nutrient Balance ◽  
Oxygen Demand ◽  
Orange Peel ◽  
Soluble Form ◽  
Orange Peel Waste ◽  
Soluble Chemical Oxygen Demand

Catering waste and orange peel were co-digested using an anaerobic digestion process. Orange peel is difficult to degrade anaerobically due to the presence of antimicrobial agents such as limonene. The present study aimed to examine the feasibility of anaerobic co-digestion of catering waste with orange peel to provide the optimum nutrient balance with reduced inhibitory effects of orange peel. Batch experiments were conducted using catering waste as a potential substrate mixed in varying ratios (20–50%) with orange peel. Similar ratios were followed using green vegetable waste as co-substrate. The results showed that the highest organic matter degradation (49%) was achieved with co-digestion of catering waste and orange peel at a 50% mixing ratio (CF4). Similarly, the soluble chemical oxygen demand (sCOD) was increased by 51% and reached its maximum value (9040 mg l-1) due to conversion of organic matter from insoluble to soluble form. Biogas production was increased by 1.5 times in CF4 where accumulative biogas was 89.61 m3 t-1substrate compared with 57.35 m3 t-1substrate in the control after 80 days. The main reason behind the improved biogas production and degradation is the dilution of inhibitory factors (limonene), with subsequent provision of balanced nutrients in the co-digestion system. The tCOD of the final digestate was decreased by 79.9% in CF4, which was quite high as compared with 68.3% for the control. Overall, this study revealed that orange peel waste is a highly feasible co-substrate for anaerobic digestion with catering waste for enhanced biogas production.

Enhanced Biogas Production in the Duckweed Anaerobic Digestion Process

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Hongyan Ren ◽  
Nan Jiang ◽  
Tao Wang ◽  
M. Mubashar Omar ◽  
Wenquan Ruan ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Biogas Production ◽  
Methane Yield ◽  
Mixed Substrates ◽  
Excess Sludge ◽  
Alkali Pretreatment ◽  
Gas Generation ◽  
Digestion Process ◽  
Substrate To Inoculum Ratio ◽  
Group 1

In order to enhance biogas production in the anaerobic digestion of duckweed, and duckweed with excess sludge as single and mixed substrates, the effects of hot alkali pretreatment and variation of the ratio of substrate to inoculum were investigated. The results showed that the delayed stage of anaerobic gas generation could be shortened when the two substrates were mixed during methane production, to give a cumulative gas yield of 2963 mL, which was 11% higher than the calculated value for the complementary substrate. The methane content was 57%, which was 13% higher than that from the duckweed group and 9% higher than from the excess sludge group. Furthermore, the methane yield was improved by 8% after the duckweed was pretreated with hot alkali. When the substrate to inoculum ratio was 1:1, the maximum biogas production of 3309 mL was achieved, with a methane yield of 1883 mL which, respectively, increases of 151 mL and 304 mL compared with the worst group (1:2.5).

Study of thermal hydrolysis as a pretreatment to mesophilic anaerobic digestion of pig slurry

2001 ◽  
Vol 44 (4) ◽  
pp. 109-116 ◽  
Author(s):  
A. Bonmatí ◽  
X. Flotats ◽  
L. Mateu ◽  
E. Campos
Keyword(s):  
Anaerobic Digestion ◽  
Biogas Production ◽  
Limiting Factor ◽  
Pig Slurry ◽  
Thermal Hydrolysis ◽  
Organic Matter Degradation ◽  
Thermal Pretreatment ◽  
Digestion Process ◽  
Degradation Tests ◽  
Thermal Phenomena

Feasibility of anaerobic digestion of pig slurry is dependent, among other factors, on the biogas production rate, which is low compared with other organic wastes, and on the profitable uses of surplus thermal energy produced, a limiting factor in warm geographical areas. The objectives of this work are determining whether low temperature thermal pretreatment (<90°C) improves pig slurry anaerobic digestion, and determining whether organic matter degradation during the thermal pretreatment is due to thermal phenomena (80°C) or to enzymatic ones (60°C). The thermal degradation tests showed that hydrolysis occurring during the thermal pretreatment is due to thermal phenomena. The increase in soluble substances were significantly larger at 80°C than at 60°C (both during 3 h). Two types of slurry were used in the batch anaerobic digestion tests. The effect of thermal pretreatment differed with the type of slurry: it was positive with almost non-degraded slurries containing low NH4+-N concentration, and negative (inhibition of the anaerobic digestion process) when using degraded slurries with high NH4+-N content.

Liquefaction and methanization of solid and liquid coffee wastes by two phase anaerobic digestion process

2003 ◽  
Vol 48 (6) ◽  
pp. 255-262 ◽  
Author(s):  
E. Houbron ◽  
A. Larrinaga ◽  
E. Rustrian
Keyword(s):  
Anaerobic Digestion ◽  
Wash Water ◽  
Organic Loading Rate ◽  
Two Phase ◽  
Experimental Conditions ◽  
Coffee Pulp ◽  
Anaerobic Digestion Process ◽  
Digestion Process ◽  
Working Volume ◽  
Acidogenic Reactor

This study attempted to investigate the feasibility of volatile fatty acid (VFA) production from coffee pulp hydrolyse, and further to determine the potential of methanization of both the pre-acidified effluent and the coffee wastewater. The experiments were carried out in 2 completely mixed reactors, each one with a working volume of 4 litres. Coffee pulp was used as substrate in the acidogenic reactor and different mixtures of pulper and wash-water and pre-acidified effluent in the methanogenic one. The acidogenic and methanogenic reactors were operated at an organic loading rate of 5 COD g.l-1.d-1 and 0.5 COD g.l-1.d-1. The total, soluble and VFA's effluent COD concentrations of the acidogenic reactor present average values of 57.75, 17.00 and 13.92 g.l-1 respectively. Under these experimental conditions, 23% (COD based) of coffee pulp was hydrolysed with a rate of 1.32 gCOD.l-1.d-1 and the soluble fraction was transformed to VFA's with an acidification efficiency of 82%. Total VFA's concentration reached a value of 13.9 gCOD.l-1, and acetate, propionate, butyrate and valerate represented 52%, 28%, 9% and 11% respectively of the liquid phase COD. In the methanogenic reactor, COD removal and methanization of fresh coffee wastewater, pre-acidified effluent and both combined occur with an efficiency of 85% to 95% respectively, with a characteristic biogas composition of 80% CH4 and 20% CO2. These results show that a humid coffee ‘Beneficio’ processing daily 23 tons of cherry coffee (fresh fruit), equipped with a two stage anaerobic digestion process could generate at least 1,886 CH4 m3.d-1. This represents an increase in methane production by a factor 3 to 5 compared to a ‘Beneficio’ using anaerobic digestion only for the treatment of its wastewater.

scholarly journals Historical Perspective of the Addition of Magnetic Nanoparticles Into Anaerobic Digesters (2014-2021)

2021 ◽  
Vol 3 ◽  
Author(s):  
Eudald Casals ◽  
Raquel Barrena ◽  
Edgar Gonzalez ◽  
Xavier Font ◽  
Antoni Sánchez ◽  
...  
Keyword(s):  
Organic Matter ◽  
Magnetic Nanoparticles ◽  
Anaerobic Digestion ◽  
Historical Perspective ◽  
Research Field ◽  
Organic Wastes ◽  
Anaerobic Digesters ◽  
Anaerobic Digestion Process ◽  
Digestion Process ◽  
Iron Based

The addition of magnetic nanoparticles to batch anaerobic digestion was first reported in 2014. Afterwards, the number of works dealing with this subject has been increasing year by year. The discovery of the enhancement of anaerobic digestion by adding iron-based nanoparticles has created a multidisciplinary emerging research field. As a consequence, in the last years, great efforts have been made to understand the enhancement mechanisms by which magnetic nanoparticles (NPs) addition enhances the anaerobic digestion process of numerous organic wastes. Some hypotheses point to the dissolution of iron as essential iron for anaerobic digestion development, and the state of oxidation of iron NPs that can reduce organic matter to methane. The evolution and trends of this novel topic are discussed in this manuscript. Perspectives on the needed works on this topic are also presented.

scholarly journals Operational Parameters of Biogas Plants: A Review and Evaluation Study

Energies ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3761 ◽  
Author(s):  
Abdullah Nsair ◽  
Senem Onen Cinar ◽  
Ayah Alassali ◽  
Hani Abu Qdais ◽  
Kerstin Kuchta
Keyword(s):  
Anaerobic Digestion ◽  
Review Paper ◽  
Biogas Production ◽  
Evaluation Study ◽  
Biogas Plant ◽  
Operational Parameters ◽  
Digestion Process ◽  
Design Considerations ◽  
Biogas Plants ◽  
Main Factors

The biogas production technology has improved over the last years for the aim of reducing the costs of the process, increasing the biogas yields, and minimizing the greenhouse gas emissions. To obtain a stable and efficient biogas production, there are several design considerations and operational parameters to be taken into account. Besides, adapting the process to unanticipated conditions can be achieved by adequate monitoring of various operational parameters. This paper reviews the research that has been conducted over the last years. This review paper summarizes the developments in biogas design and operation, while highlighting the main factors that affect the efficiency of the anaerobic digestion process. The study’s outcomes revealed that the optimum operational values of the main parameters may vary from one biogas plant to another. Additionally, the negative conditions that should be avoided while operating a biogas plant were identified.

scholarly journals Biogas Potential from the Anaerobic Digestion of Potato Peels: Process Performance and Kinetics Evaluation

Energies ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2311 ◽  
Author(s):  
Spyridon Achinas ◽  
Yu Li ◽  
Vasileios Achinas ◽  
Gerrit Jan Willem Euverink
Keyword(s):  
Anaerobic Digestion ◽  
Energy Recovery ◽  
Biogas Production ◽  
Combined Treatment ◽  
Methane Yield ◽  
Cow Manure ◽  
Potato Peel ◽  
Potato Peels ◽  
The Impact ◽  
Kinetics Of

This article intends to promote the usage of potato peels as efficient substrate for the anaerobic digestion process for energy recovery and waste abatement. This study examined the performance of anaerobic digestion of potato peels in different inoculum-to-substrate ratios. In addition, the impact of combined treatment with cow manure and pretreatment of potato peels was examined. It was found that co-digestion of potato peel waste and cow manure yielded up to 237.4 mL CH4/g VSadded, whereas the maximum methane yield from the mono-digestion of potato peels was 217.8 mL CH4/g VSadded. Comparing the co-digestion to mono-digestion of potato peels, co-digestion in PPW/CM ratio of 60:40 increased the methane yield by 10%. In addition, grinding and acid hydrolysis applied to potato peels were positively effective in increasing the methane amount reaching 260.3 and 283.4 mL CH4/g VSadded respectively. Likewise, compared to untreated potato peels, pretreatment led to an elevation of the methane amount by 9% and 17% respectively and alleviated the kinetics of biogas production.

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