Effect of inoculum-substrate ratio on the start-up of solid waste anaerobic digesters

2001 ◽  
Vol 44 (4) ◽  
pp. 103-108 ◽  
Author(s):  
B. Fernández ◽  
P. Porrier ◽  
R. Chamy
Keyword(s):  
Solid Waste ◽  
Methane Production ◽  
Waste Treatment ◽  
Two Phase ◽  
Anaerobic Reactors ◽  
Start Up ◽  
Anaerobic Degradability ◽  
Substrate Ratio ◽  
Two Phases ◽  
Anaerobic System

The anaerobic systems start-up for solid waste treatment is a fundamental step, especially for those with two phases. It is necessary to know both the waste characteristics and the inoculum conditions. The objective of this work was to study the inoculum-substrate ratio (ISR) influence as a previous step of the start-up of an anaerobic system for the solid waste digestion. During this research spent grain was chosen as residue, working at three different concentrations (7; 13 and 20% w/v), studying the ISR effect in terms of anaerobic degradability (AD) and specific methane productivity (SMP). The initial acetoclastic activities (A0) were calculated based on the equation which describes the methane accumulation during each test. The model constants were also calculated and were adjusted to the experimental data. The results showed that in general the ISR variation has less impact on AD than on SMP. While maximum AD were reached in those tests with high ISR, the greatest values of SMP were with the lowest values of ISR ratio. A low ISR caused a slow hydrolysis, although the methane production was fast. So, during the start-up of a two-phase anaerobic system an elevated ISR would not be necessary in order to reach a good AD and a good intermediate products production, because the hydrolysis and the VFA production must be optimised in the first phase of these systems. While in conventional systems, where phases are together, it is much better to optimise the methane production. The ISR and the SMP indicated which inoculum percentage would be interesting based on the objective of the whole system: methane or intermediate compounds (VFA) production. All this information is important during the conventional anaerobic reactors operation because these tests would show which ISRs avoid inhibition.

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.

scholarly journals New Strategy for a Suitable Fast Stabilization of the Biomethanization Performance

Archaea ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
L. A. Fernández-Güelfo ◽  
C. J. Álvarez-Gallego ◽  
D. Sales Márquez ◽  
L. I. Romero García
Keyword(s):  
Solid Waste ◽  
Anaerobic Sludge ◽  
Continuous Stirred Tank Reactor ◽  
Operational Conditions ◽  
Anaerobic Reactors ◽  
Organic Solid ◽  
Start Up ◽  
New Strategy ◽  
Thermophilic Conditions ◽  
Dry Conditions

The start-up strategies for thermophilic anaerobic reactors usually consist of an initial mesophilic stage (35°C), with an approximate duration of 185 days, and a subsequent thermophilic stage (55°C), which normally requires around 60 days to achieve the system stabilizatio. During the first 8–10 days of the mesophilic stage, the reactor is not fed so that the inoculum, which is generally a mesophilic anaerobic sludge, may be adapted to the organic solid waste. Between mesophilic and thermophilic conditions the reactor is still not fed in an effort to prevent possible imbalances in the proces. As a consequence, the start-up and stabilization of the biomethanization performance described in the literature require, at least, around 245 days. In this sense, a new strategy for the start-up and stabilization phases is presented in this study. This approach allows an important reduction in the overall time necessary for these stages in an anaerobic continuous stirred tank reactor (CSTR) operated at thermophilic-dry conditions for treating the organic fraction of the municipal solid waste (OFMSW): 60 days versus 245 days of conventional strategies. The new strategy uses modified SEBAC technology to adapt an inoculum to the OFMSW and the operational conditions prior to seeding the CSTR.

scholarly journals Measurement of Biochemical Methane Potential of Heterogeneous Solid Substrates: Results of a Two-Phase French Inter-Laboratory Study

Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2814 ◽  
Author(s):  
Thierry Ribeiro ◽  
Romain Cresson ◽  
Sébastien Pommier ◽  
Sébastien Preys ◽  
Laura André ◽  
...  
Keyword(s):  
Biochemical Methane Potential ◽  
Two Phase ◽  
Bicarbonate Buffer ◽  
Solid Substrates ◽  
Methane Potential ◽  
Repeatability And Reproducibility ◽  
Substrate Ratio ◽  
Two Phases ◽  
Heterogeneous Solid ◽  
Previous Step

Biochemical methane potential (BMP) is essential to determine the production of methane for various substrates; literature shows important discrepancies for the same substrates. In this paper, a harmonized BMP protocol was developed and tested with two phases of BMP tests carried out by eleven French laboratories. Surprisingly, for the three same solid tested substrates (straw; raw mix and dried-shredded mix of potatoes, maize, beef meat and straw; and mayonnaise), the standard deviations of the repeatability and reproducibility inter-laboratory were not enhanced by the harmonized protocol (average of about 25% depending on the substrate), as compared to a previous step where all laboratories used their own protocols. Moreover, statistical analyses of all the results, after removal of the outliers (about 15% of all observations), did not highlight significant effect of the operational effect on BMP (stirring, automatic or manual gas quantification, use of trace metal, uses a bicarbonate buffer, inoculum to substrate ratio) at least for the tested ranges. On the other hand, the average intra-laboratory repeatability was low, about 7%, whatever the protocol, the substrate and the laboratory. It also appears that drying the SA substrate, which contained proteins, carbohydrates, lipids and fibers, does not impact its BMP.

scholarly journals Progressive Two-Stage Efficient Codigestion of Food Waste and Petrochemical Wastewater for Higher Methane and Hydrogen Production

2019 ◽  
Vol 31 (11) ◽  
pp. 2575-2578
Author(s):  
M.N.I. Siddique ◽  
B.K. Zaied ◽  
M.N. Kabir ◽  
M.F. Ahmad
Keyword(s):  
Food Waste ◽  
Waste Treatment ◽  
Phase System ◽  
Petrochemical Wastewater ◽  
Two Phase ◽  
Methane Generation ◽  
Anaerobic Codigestion ◽  
Continuous Feeding ◽  
Anaerobic System ◽  
The Ideal

The valorization of agro-modern waste through anaerobic codigestion signifies a remarkable prospect for waste treatment and sustainable energy source generation. This study intended to improve the codigestion of food waste and petrochemical wastewater by an advanced two-phase process. In view of concentric acidogenic and methanogenic stages, intended for upgrading execution and diminishing pollution. The ideal food waste to petrochemical wastewater proportion was assessed under batch operations. From that point, codigestion was carried out by continuous feeding operations weighting single-and two-phase digestions. The outcomes exhibited that the supplementation of petrochemical wastewater in codigestion with food waste incredibly improved the anaerobic system. The maximum methane generation was acquired codigesting the two wastes at equivalent proportion by utilizing the creative two-phase system. The proposed framework achieved the highest methane production of 259 mL/g volatile solid, which is more than double than the single-phase system and 11 % greater than that of conventional two-phase system.

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.

Start-up of a multi-stage system for biogas production and solid waste treatment in low-tech countries

2003 ◽  
Vol 48 (4) ◽  
pp. 239-243 ◽  
Author(s):  
E.M. Biey ◽  
E.D. Musibono ◽  
W. Verstraete
Keyword(s):  
Solid Waste ◽  
Waste Treatment ◽  
Biogas Production ◽  
Daily Basis ◽  
Methanogenic Activity ◽  
Multi Stage ◽  
Start Up ◽  
Solid Waste Treatment ◽  
Stage System ◽  
Biowaste Treatment

Vegetable fruit garden wastes were treated anaerobically using a multistage Dranco system. The digesters were composed of three 50 L vessels kept in mesophilic conditions. They were operating at 14.5-17% TS. By controlling the pH in the system, the start-up for biogas production was shortened to 60 days. The pH correction was a buffering which enhanced methanogenic activity in the digesters. With a loading rate of 4.1 kg VS/m3reactor.day, the production of biogas was 5 m3/m3reactor.day, and 60-70% methane content. This allowed making a multisystem by starting every 3 weeks with new vessels in order to maintain biogas production, to be used in industries or in local communities in low-tech countries. The designed model was started in Kinshasa (Congo) where a project is expected to treat one ton of solid waste on a daily basis, for a production of 100 m3 biogas. This cost effectiveness of the system is demonstrated and presents the opportunity for biowaste treatment coupled with environmental protection and substantial energy recovery.

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.

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