The influence of pH in the hydrolytic stage of anaerobic digestion of the organic fraction of urban solid waste

2003 ◽  
Vol 48 (6) ◽  
pp. 249-254 ◽  
Author(s):  
S. Dinamarca ◽  
G. Aroca ◽  
R. Chamy ◽  
L. Guerrero
Keyword(s):  
Anaerobic Digestion ◽  
Solid Waste ◽  
Volatile Fatty Acids ◽  
Organic Fraction ◽  
Buffer Effect ◽  
Two Phase ◽  
Protein Residues ◽  
Working Volume ◽  
Urban Solid Waste ◽  
Influence Of Ph

The influence of the pH in the first stage, the hydrolytic stage, of the anaerobic digestion of the organic fraction of urban solid waste in a two phase anaerobic reactor was studied. The reactor was fed with a solution of the organic fraction of urban solid residues containing 5 to 7% solids. Four reactors with a working volume of 3 L were used, the experiments were done at three controlled pHs; 6, 7, and 8, and one with free pH, the temperature was keep at 37°C in all the experiments. The higher degradation of TSS and VSS was obtained in the reactors operated at pH 7 and 8; 75% degradation of TSS and 85% degradation of VSS. The volatile fatty acids were determined at the different pH conditions, no significant differences were found, and as was expected, the acetic acid was found at the higher value among them (from 25 to 29 g/L). According to the results obtained it is possible to conclude that in the case of the hydrolytic stage of the anaerobic digestion of the organic fraction of urban solid waste it is not necessary to control the pH, the pH is kept stable by the buffer effect of the protein residues and other macromolecules present in the residue.

scholarly journals Improvement of Biomethane Production from Organic Fraction of Municipal Solid Waste (OFMSW) through Alkaline Hydrogen Peroxide (AHP) Pretreatment

Fermentation ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 197
Author(s):  
Alessio Siciliano ◽  
Carlo Limonti ◽  
Giulia Maria Curcio
Keyword(s):  
Hydrogen Peroxide ◽  
Anaerobic Digestion ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Volatile Fatty Acids ◽  
Biofuel Production ◽  
Organic Load ◽  
Organic Substrates ◽  
Organic Fraction ◽  
Alkaline Hydrogen Peroxide

The organic fraction resulting from the separate collection of municipal solid waste (OFMSW) is an abundant residue exploitable for biofuel production. Anaerobic digestion (AD) is one of the most attractive technologies for the treatment of organic wastes thanks to the generation of biogas with a high methane content. However, because of its complex composition, the direct digestion of OFMSW can be less effective. To overcome these difficulties, many pretreatments are under development. In this work, the efficacy of alkaline hydrogen peroxide (AHP) oxidation was assessed for the first time as a pretreatment of OFMSW to enhance its anaerobic biodegradability. In this regard, many AHP batch tests were executed at pH 9 and by changing the peroxide dosages up to 1 gH2O2/gCOD, under room temperature and pressure conditions. Afterwards, biomethane potential tests (BMP) were conducted to evaluate the performance of anaerobic digestion both on raw and pretreated OFMSW. The pretreatment tests demonstrated that AHP induces only a weak reduction in the organic load, reaching a maximum COD removal of about 28%. On the other hand, notable productions of volatile fatty acids (VFA) were found. In fact, by applying a peroxide dose of just 0.025 gH2O2/gCOD, there was a doubling in VFA concentration, which increased by five times with the highest H2O2 amount. These results indicate that AHP mainly causes the conversion of complex organic substrates into easily degradable compounds. This conversion made it possible to achieve much better performance during the BMP tests conducted with the pretreated waste compared to that carried out on fresh OFMSW. Indeed, a low methane production of just 37.06 mLCH4/gTS was detected on raw OFMSW. The cumulated CH4 production in the pretreated samples increased in response to the increase in H2O2 dosage applied during AHP. Maximum specific productions of about 463.7 mLCH4/gTS and 0.31 LCH4/gCODremoved were calculated on mixtures subjected to AHP. On these samples, the satisfactory evolution of AD was confirmed by the process parameters calculated by modeling the cumulated CH4 curves through a new proposed formulation of the Gompertz equation.

scholarly journals Two Phase Anaerobic Digestion System of Municipal Solid Waste by Utilizing Microaeration and Granular Activated Carbon

Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 933
Author(s):  
Fernando Canul Bacab ◽  
Elda España Gamboa ◽  
Juan Enrique Ruiz Espinoza ◽  
Rosa M Leal-Bautista ◽  
Raúl Tapia Tussell ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Anaerobic Digestion ◽  
Solid Waste ◽  
Volatile Fatty Acids ◽  
Granular Activated Carbon ◽  
Aeration Rate ◽  
Packed Bed Reactor ◽  
Anaerobic Sludge ◽  
Hydrolysis Time ◽  
Two Phase

In an anaerobic digestion (AD) process, the hydrolysis phase is often limited when substrates with high concentrations of solids are used. We hypothesized that applying micro-aeration in the hydrolysis phase and the application of granular activated carbon (GAC) in the methanogenesis phase could make the AD process more efficient. A packed bed reactor (PBR) coupled with an up-flow anaerobic sludge blanket (UASB) was conducted, and its effects on methane generation were evaluated. The micro-aeration rate applied in PBR was 254 L-air/kg-Total solids (TS)-d was compared with a control reactor. Micro-aeration showed that it reduced the hydrolysis time and increased the organic matter solubilization as chemical oxygen demand (COD) increasing 200%, with a volatile fatty acids (VFAs) increment higher than 300%, compared to the control reactor (without aeration). Our findings revealed that the implementations of microaeration and GAC in the two-phase AD system could enhance methane production by reducing hydrolysis time, increasing solid waste solubilization.

Methane Generation via Two-Phase Anaerobic Digestion of Organic Fraction of Municipal Solid Wastes

2014 ◽  
Vol 1051 ◽  
pp. 317-321
Author(s):  
Marjorie Baynosa ◽  
Gladys Anne Bondoc ◽  
Leandro Angelo Miguel Sanchez ◽  
Analiza Rollon
Keyword(s):  
Anaerobic Digestion ◽  
Solid Waste ◽  
Solid Wastes ◽  
Small Scale ◽  
Organic Fraction ◽  
Municipal Solid Wastes ◽  
Two Phase ◽  
Methane Generation ◽  
Solids Retention ◽  
Useful Heat

The performance of a small-scale two-phase anaerobic digestion system which processes municipal solid wastes, i.e. vegetable and fruit wastes, was evaluated at mesophilic conditions. An anaerobic digester which required 5 L of fresh cow manure, 5 L of solid waste feed, 5 L each of leachate from the solid waste, and 1 L of anaerobic seeding had been constructed. The volume of the feed solids after digestion has significantly reduced after the operation. The total accumulated methane for a solids retention time (SRT) of 20 days contained useful heat energy amounting to 330.27 KJ.

scholarly journals Anaerobic Digestion of the Organic Fraction of Municipal Solid Waste in Plug-Flow Reactors: Focus on Bacterial Community Metabolic Pathways

Water ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 195
Author(s):  
Elena Rossi ◽  
Simone Becarelli ◽  
Isabella Pecorini ◽  
Simona Di Gregorio ◽  
Renato Iannelli
Keyword(s):  
Anaerobic Digestion ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Volatile Fatty Acids ◽  
Flow Reactor ◽  
Biogas Production ◽  
Plug Flow ◽  
Central Zone ◽  
Bimodal Distribution ◽  
Organic Fraction

The aim of this study is to investigate the performance of a pilot-scale plug-flow reactor (PFR) as a biorefinery system to recover chemicals (i.e., volatile fatty acids (VFAs)), and biogas during the dry thermophilic anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW). The effects of the hydraulic retention time (HRT) on both outputs were studied, reducing the parameter from 22 to 16 days. In addition, VFA variation along the PFR was also evaluated to identify a section for a further valorization of VFA-rich digestate stream. A particular focus was dedicated for characterizing the community responsible for the production of VFAs during hydrolysis and acidogenesis. The VFA concentration reached 4421.8 mg/L in a section located before the end of the PFR when the HRT was set to 16 days. Meanwhile, biogas production achieved 145 NLbiogas/d, increasing 2.7 times when compared to the lowest HRT tested. Defluviitoga sp. was the most abundant bacterial genus, contributing to 72.7% of the overall bacterial population. The genus is responsible for the hydrolysis of complex polysaccharides at the inlet and outlet sections since a bimodal distribution of the genus was found. The central zone of the reactor was distinctly characterized by protein degradation, following the same trend of propionate production.

Influence of hydrothermal pretreatment conditions, typology of anaerobic digestion system, and microbial profile in the production of volatile fatty acids from olive mill solid waste

2021 ◽  
Vol 9 (2) ◽  
pp. 105055
Author(s):  
Yasmim Arantes da Fonseca ◽  
Nayara Clarisse Soares Silva ◽  
Adonai Bruneli de Camargos ◽  
Silvana de Queiroz Silva ◽  
Hector Javier Luna Wandurraga ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Anaerobic Digestion ◽  
Solid Waste ◽  
Volatile Fatty Acids ◽  
Hydrothermal Pretreatment ◽  
Microbial Profile ◽  
Olive Mill Solid Waste ◽  
Pretreatment Conditions ◽  
Olive Mill

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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