scholarly journals Silage of the organic fraction of municipal solid waste to improve methane production

2021 ◽  
Author(s):  
Mario F. Castellón-Zelaya ◽  
Simón González-Martínez
Keyword(s):  
Municipal Solid Waste ◽  
Solid Waste ◽  
Methane Production ◽  
Organic Fraction ◽  
Acid Fermentation ◽  
Fermentation Processes ◽  
Silage Fermentation ◽  
Solids Concentration ◽  
Biogas Plants ◽  
Metabolites Production

Abstract The silage of the organic fraction of municipal solid waste (OFMSW) is a common practice in biogas plants. During silage, fermentation processes take place, affecting the later methanisation stage. There are no studies about how OFMSW silage affects methane production. This work aimed to determine the effects of silage (anaerobic acid fermentation) at different solids concentrations and temperatures on methane production. OFMSW was ensiled at 20, 35, and 55 °C with total solids (TS) concentrations of 10, 20, and 28% for 15 days. The ensiled OFMSW was then tested for methane production at the substrate to inoculum ratios (S/I) of 0.5, 1.0, and 1.5. Independently of the temperature, the production of the metabolites during silage increases with decreasing solids concentration. The highest metabolites production were lactic acid, ethanol, and acetic acid, representing together 95% of the total. Methane production from ensiled OFMSW at 10% solids concentration shows, under every tested condition, better methane production than from fresh OFMSW. Ensiled OFMSW produces more methane than fresh OFMSW, and methane production was highest at 35 °C.

scholarly journals EFFECT OF SOLIDS CONCENTRATION AND SUBSTRATE TO INOCULUM RATIO ON METHANE PRODUCTION FROM ORGANIC MUNICIPAL SOLID WASTE

Detritus ◽  
2021 ◽  
pp. 3-12
Author(s):  
Mario F. Castellón-Zelaya ◽  
Simón González-Martínez
Keyword(s):  
Municipal Solid Waste ◽  
Solid Waste ◽  
Methane Production ◽  
Reaction Times ◽  
Operational Parameters ◽  
Anaerobic Reactors ◽  
Solids Concentration ◽  
Biogas Plants ◽  
Substrate To Inoculum Ratio ◽  
The Times

Organic Fraction of Municipal Solid Waste (OFMSW) is usually stored under variable humidity conditions and long periods before processing them in anaerobic digestion plants. Lately, the fermented OFMSW is mixed with recirculated digestate from the same biogas plants, which is used as methanogenic inoculum. Although both the moisture content during the storage of OFMSW and the inoculum concentration in the feed mixture to the anaerobic reactors are determining factors for the process, to our knowledge, no studies have been done about the combined effect of these operational parameters on methane production. Therefore, this study focused on determining how humidity conditions during OFMSW storage and the substrate to inoculum ratio (S/I) in the methanisation stage can be adjusted to improve methane production. OFMSW was stored at 35°C and 10, 20, and 28%TS for 15 days. In the second stage, methanisation of previously fermented OFMSW was allowed at different S/I ratios of 0.5, 1.0, and 1.5. Ethanol and acetic acid accounted for 90% of all products of fermentation. The lowest solids concentration reached the highest fermentation degree. Compared to fresh OFMSW (without storing), methane from fermented OFMSW increased 32% and, the times to reach the maximum methane production decreased between 11 and 40%. For fermented OFMSW, S/I ratio of 1.0 is the best condition to produce methane. ANOVA shows that, independently of solid concentration during storage, the S/I ratio is the main parameter improving methane production and reducing reaction times.

Anaerobic digestion of co-mingled municipal solid waste and sewage sludge

1998 ◽  
Vol 38 (2) ◽  
pp. 127-132 ◽  
Author(s):  
N. Hamzawi ◽  
K. J. Kennedy ◽  
D. D. McLean
Keyword(s):  
Sewage Sludge ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Biogas Production ◽  
Empirical Models ◽  
Organic Fraction ◽  
Primary Sludge ◽  
Digestion Process ◽  
Solids Concentration ◽  
Anaerobic Biodegradability

This study evaluated the technical feasibility of the anaerobic co-digestion process in the context of typical North American solid waste. Using biological activity tests, an optimal mixture was identified with 25% organic fraction of municipal solid waste (OFMSW) and 75% sewage sludge (65% raw primary sludge (RAW), 35% thickened WAS (TWAS)) based on biogas production. Also, based on the rate of biogas production, the most anaerobically biodegradable components of the OFMSW were paper and grass. The TWAS and the newspaper were found to be the least biodegradable components. Lab-scale testing indicated that alkaline pretreatment increased the biodegradability of the sewage sludge/OFMSW mixture the most, as compared to the untreated control. Thermochemically pretreated feedstocks inhibited anaerobic biodegradability as compared to the control, whereas the anaerobic biodegradability of thermally pretreated feed was not found to be significantly different from that of the control. Empirical models were developed based on alkaline dose, feed total solids concentration and particle size for biogas production and removal of TS and VS. All three experimental factors were found to be significant with respect to the response variables studied.

scholarly journals Use of Inoculum, Water and Percolate as Strategy to Avoid Inhibition on Dry-Batch Anaerobic Digestion of Organic Fraction of Municipal Solid Waste

2021 ◽  
Author(s):  
Ildefonso Rocamora ◽  
Stuart T. Wagland ◽  
Raffaella Villa ◽  
Edmon W. Simpson ◽  
Oliver Fernández ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Methane Production ◽  
Kinetic Modelling ◽  
Methanogenic Archaea ◽  
Methane Formation ◽  
Organic Fraction ◽  
Water Addition ◽  
The Impact

AbstractThe impact of inoculum to substrate ratio (I:S) and the addition of water and percolate on stopping inhibition in dry batch anaerobic digestion of organic fraction municipal solid waste (OFMSW) was investigated. In particular, ratios of I:S from 1:2 to 1:16 and total solid contents from 40 to 25% with water and percolate addition were analysed. Tested I:S did not avoid acidification of the anaerobic digesters (ADs), and the highest biogas and methane production (16.2 and 1.7 L/kg VSadded, respectively) was achieved with the 1:4 ratio. Water addition was also insufficient to avoid acidification, and while biogas increased as TS decreased, 40.9 L/kg VSadded for 25% TS, methane yield remained low at 1.2 L/kg VSadded due to the inhibition of methanogenic archaea. Percolate addition proved a suitable strategy to increase pH buffering, with an increased methane production of 199.4 L/kg VSadded at similar TS ranges (27%). Impact on kinetics of methane formation was assessed by kinetic modelling with logistic model identified as the better fit for most of the ADs. Shorter lag phases were observed as TS were reduced, regardless of the acidification, as mass transfer limitations were reduced at the beginning of the batch, but an increase was observed when percolate was used instead of water. Increases of the maximum methane rate (Rmax) was also achieved with TS reduction, but only when acidification was avoided. This study has highlighted the need to profile percolate composition during batch digestion in order to balance recirculation of nutrients, microbial communities and toxic compounds. Graphic Abstract

scholarly journals Biomethane Production from Anaerobic Co-Digestion of Selected Organic Fraction of Municipal Solid Waste (OFMSW) with Sewage Sludge: Effect of the Inoculum to Substrate Ratio (ISR) and Mixture Composition on Process Performances

2021 ◽  
Vol 18 (24) ◽  
pp. 13048
Author(s):  
Santo Fabio Corsino ◽  
Michele Torregrossa ◽  
Gaspare Viviani
Keyword(s):  
Sewage Sludge ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Production Rate ◽  
Methane Production ◽  
Synergistic Effects ◽  
Methane Yield ◽  
Organic Fraction ◽  
Mixture Ratio ◽  
Substrate Ratio

The aim of this study was to evaluate the effect of the inoculum to substrate ratio (ISR) and the mixture ratio between organic fraction of municipal solid waste (OFMSW) and sewage sludge (SS) on the methane production potential achievable from anaerobic co-digestion (AcoD). Biochemical Methane Potential (BMP) assays at mesophilic temperature were used to determine the best AcoD configuration for maximizing methane yield and production rate, as well as to address possible synergistic effects. The maximum methane yield was observed at ISR of 1 and 60% OFMSW :40% SS as co-digestion mixture, whereas the highest methane production rate was achieved at ISR of 2 with the same mixture ratio (207 mL/gVS/d). Synergistic effects were highlighted in the mixtures having OFMSW below 60%, determining an increase of approximately 40% in methane production than the OFMSW and SS digestion as a sole substrate. The experimental data demonstrated that co-digestion of OFMSW and SS resulted in an increase in the productivity of methane than anaerobic digestion using the sole substrates, producing higher yields or production rates while depending on the ISR and the mixture ratio.

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