The Acidogenic Digestion of the Organic Fraction of Municipal Solid Waste for the Production of Liquid Fuels

1993 ◽  
Vol 27 (2) ◽  
pp. 183-192 ◽  
Author(s):  
E. D'Addario ◽  
R. Pappa ◽  
B. Pietrangeli ◽  
M. Valdiserri
Keyword(s):  
Fatty Acids ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Volatile Fatty Acids ◽  
Flow Reactor ◽  
Methyl Esters ◽  
Stream Processing ◽  
Continuous Stirred Tank Reactor ◽  
Organic Fraction ◽  
Counter Flow

Several reactors were tested for the anaerobic conversion of the organic fraction of municipal solid waste into volatile fatty acids. The reactors examined included Batch, Semi-Continuous Stirred Tank Reactor and Multistage-Counter Flow Reactor. After reasonable retention times (12 days), Batch systems operating at 15% w/v of dry matter and under pH controlled at 6.5, gave better performances both in terms of total Volatile Fatty Acids (VFA) concentration (23-24 g/l) and conversion yield (215 g VFA/kg volatile solids). However, these conditions of reaction caused a high level of liquefaction of the feedstock which resulted in a difficult down-stream processing. On the contrary, the acidogenesis under uncontrolled pH, allowed the production of leachates directly processable for acids recovery. Based on this reason, the Multistage-Counter Flow Reactor, operating under uncontrolled pH, appeared to be the most promising system. The leachate obtained from such a system was processed to obtain mixtures of C2-C7 methyl esters, potentially usable as octane enhancers. The digested solid was intended to be dried and refined to obtain soil amendment. A process for the treatment of municipal solid waste based on the previous steps and including conventional sorting facilities and units for the incineration of all residual solids, was evaluated to be economically comparable with landfilling. The revenues from the sales of esters and fertilizers were highly sensitive to the yield of the acidogenic step and to the value and the amount of the derived fertilizer. Further research is still in progress to improve the economics of the process. The activities are addressed to study proper procedures for the improvement of the down-stream processing of the mixtures originating from acidogenesis under almost neutral pH.

A Mathematical Model of Volatile Fatty Acids (VFA) Production in a Plug-Flow Reactor Treating the Organic Fraction of Municipal Solid Waste (MSW)

1993 ◽  
Vol 27 (2) ◽  
pp. 201-208 ◽  
Author(s):  
E. D. Negri ◽  
J. Mata-Alvarez ◽  
C. Sans ◽  
F. Cecchi
Keyword(s):  
Mathematical Model ◽  
Fatty Acids ◽  
Municipal Solid Waste ◽  
Volatile Fatty Acids ◽  
Flow Reactor ◽  
Plug Flow ◽  
Biomass Concentration ◽  
Organic Fraction ◽  
Initial Biomass Concentration ◽  
Suspended Biomass

A mathematical model of a plug-flow reactor with a fluid recycle has been elaborated to simulate the VFA production process treating the organic fraction of the municipal solid waste. An alternative hydrolytic reaction model (homogeneous - heterogeneous) is proposed. The effect of a possible methanization step is also considered. The effect of process parameters (solid retention time (SRT), pH, recycle ratio) on the reactor performance is analyzed for parameters based on fruit and vegetable waste. The sensitivity of the model to proposed parameters (suspended biomass and initial biomass concentration) is also evaluated. It is found that the reactor production is very sensitive to the system pH. At low SRT, the production of volatile fatty acids (VFA) is proportional to this parameter. As the SRT increases methanization can reduce the VFA production. The effect of the recycle is negligible for the system and operating conditions studied. The effect of suspended biomass and initial biomass concentration was found to be also negligible. For the system analyzed, the pH is a critical parameter and a plug-flow arrangement (without recycle) seems to be the more reasonable election.

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.

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.

Co-digestion of energy crops and the source-sorted organic fraction of municipal solid waste

2005 ◽  
Vol 52 (1-2) ◽  
pp. 217-222 ◽  
Author(s):  
Å. Nordberg ◽  
M. Edström
Keyword(s):  
Municipal Solid Waste ◽  
Solid Waste ◽  
Volatile Fatty Acids ◽  
Pilot Scale ◽  
Nutritional Composition ◽  
Energy Crops ◽  
Full Scale ◽  
Organic Fraction ◽  
Technical Performance ◽  
Reduced Viscosity

The biological and technical performance during co-digestion of energy crops and the source-sorted organic fraction of municipal solid waste has been investigated at laboratory and pilot scale. A 50:50 (TS-based) mixture of energy crops and organic waste reached a loading rate of 6.0 gVS L−1d−1 with a methane yield of 0.33–0.38 L gVS−1, while a 80:20 mixture showed elevated levels of volatile fatty acids at 5.5 gVS L−1d−1 The better performance of the 50:50 mixture can partly be explained by a better nutritional composition. Mincing the ley crop reduced viscosity and reduced problems with fibre floating and scum-blanket formation. The electricity consumed for mincing and stirring at a full-scale plant corresponds to ca 3% of the energy produced. Calculations of the costs for full-scale plants indicate that the price of the up-graded biogas has to be at least 0.078 Euro/kWh in order to balance the costs.

scholarly journals Energy recovery from biowaste: influence of hydraulic retention time on biogas production in dry-anaerobic digestion

2021 ◽  
Vol 238 ◽  
pp. 01007
Author(s):  
Elena Rossi ◽  
Isabella Pecorini ◽  
Renato Iannelli
Keyword(s):  
Anaerobic Digestion ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Retention Time ◽  
Energy Recovery ◽  
Hydraulic Retention Time ◽  
Flow Reactor ◽  
Biogas Production ◽  
Organic Fraction ◽  
Dry Anaerobic Digestion

The hydraulic retention time (HRT) is a key parameter in dry-anaerobic digestion to set during the reactor configuration in order to achieve the optimal biogas production. For this reason, the study compared the results of two experimental tests operating with an HRT of 23 and 14 days. During the tests, the feedstock was organic fraction of municipal solid waste with a solid content of 33% and the digester was a pilot-scale plug-flow reactor operating in thermophilic condition. The highest specific biogas production of 311.91 Nlbiogas kg-1 d-1 was achieved when the HRT was set to 23 days. On the contrary, the highest methane production rate of 1.43 NlCH4 l-1 d-1 was achieved for an HRT of 14 days. In addition, the volatile solids removal (49.15% on average) and the energy content o(4.8 MJ kg-1 on average) were higher for HRT 23 days than for HRT14 days. The results indicated that in dry-anaerobic digestion of organic fraction of municipal solid waste, 23 days is a suitable HRT for energy recovery.

scholarly journals Settlement evaluation of municipal solid waste confined in lysimeters considering the phases of anaerobic biodegradation

2019 ◽  
Author(s):  
Tiago Magalhães Tatagiba ◽  
Miriam Goncalves Miguel
Keyword(s):  
Fatty Acids ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Volatile Fatty Acids ◽  
Physicochemical Characterization ◽  
Oxygen Demand ◽  
Anaerobic Biodegradation ◽  
Total Alkalinity ◽  
Methanogenic Phase

This research evaluated the settlements occurring in the municipal solid waste mass, confined in three lysimeters, considering the influence of the biodegradation of these wastes, by physicochemical characterization of the leachate produced. The physicochemical variables studied were: Chemical Oxygen Demand (COD), Nitrogen-Ammonia, Hydrogen Potential (pH), Volatile Fatty Acids (VFA) and Total Alkalinity. The measured settlements were analyzed based on the biodegradation phases of the confined wastes. Currently, the MSW is in the methanogenic phase of anaerobic biodegradation.

Effect of calcium chloride on abating inhibition due to volatile fatty acids during the start-up period in anaerobic digestion of municipal solid waste

2016 ◽  
Vol 37 (12) ◽  
pp. 1501-1509 ◽  
Author(s):  
Sunil Kumar ◽  
Avijit Das ◽  
G. Lohit Kumar Srinivas ◽  
Hiya Dhar ◽  
Vivek Kumar Ojha ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Anaerobic Digestion ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Calcium Chloride ◽  
Volatile Fatty Acids ◽  
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