Theoretical Methane Yield Research Articles

Process performance of in-situ bio-methanation for co-digestion of sewage sludge and lactic acid, aiming to utilize waste poly-lactic acid as methane

This study examined hydrogen conversion efficiency and operational stability in pilot-scale in-situ bio-methanation during the co-digestion of sewage sludge and lactic acid (partially derived from waste poly-lactic acid). Parallel laboratory-scale experiments were also conducted. In the pilot, hydrogen conversion efficiency decreased from 98.9 % to 84.4 % as the hydrogen feed rate increased from 240 to 1,200 mL/LR/d. Conversely, laboratory experiments maintained efficiencies above 95 % at a feed rate of 3,600 mL/LR/d, suggesting that hydrogen gas–liquid transfer limited hydrogen conversion efficiency in the pilot. Lactic acid degradation was observed both with and without hydrogen injection in the pilot. Methane yields from the acid were 310 ± 30 and 300 ± 30 mL/g (chemical oxygen demand (COD))-added, close to the theoretical methane yield (350 mL/gCOD). These results demonstrate the importance of hydrogen gas–liquid transfer when scaling up bio-methanation processes. Moreover, they showed the potential of waste poly-lactic acid as a methane source.

The design of bidirectional selective hydrolases for lignin, cellulose and hemicellulose through in silico methods

The production of methane from straw lignocellulose is limited by its structure. It is necessary to break the complex structure and prevent the loss of cellulose/hemicellulose by lignin-removing pretreatment. This paper designed bidirectional selective hydrolases based on laccase of Pleurotus ostreatus (Q6RYA4) and Bacillus subtilis (E7EDN4), established Scenario 1 (6 % H2SO4 and E7EDN4–2) and Scenario 2 (5 % NaOH and E7EDN4–12), significantly enhancing lignin hydrolysis while minimizing cellulose/hemicellulose hydrolysis using homology modeling, molecular docking and molecular dynamics. The suitable environmental conditions for the scenarios were determined through L9 Taguchi orthogonal. Resveratrol was found to enhance enzyme activity in an acidic environment, while rhamnolipid in an alkaline environment. The enhanced mechanism of lignin hydrolysis was elucidated through the hotspots amino acids, root mean square fluctuation, and enzyme adsorption-desorption process. Subsequently, the deep learning algorithm was employed to conduct the enzyme turnover numbers of new hydrolases, quantifying lignin hydrolysis rate and theoretical methane yield. Compared with E7EDN4, the lignin hydrolysis rate in Scenario 1 and 2 increased by 208.16 % and 272.49 %, while the theoretical methane yields were increased by 98.23 % and 97.96 % under suitable environmental condition of appropriate concentration of exogenous substances (rhamnolipid or resveratrol). This study constituted an advanced technology for the high-efficiency utilization of cellulose/hemicellulose, which offered novel insights and approaches for the biological enhancement of the pretreatment of lignocellulose.

Methane Generation Potential of the Easily Degradable Group of Landfilled Municipal Solid Waste

Municipal solid waste (MSW) remains in sanitary landfills for many years. To maintain a circular economy, assessing the feasibility of reinserting MSW excavated from sanitary landfills into the production chain is important. This reduces environmental impacts, helping to minimize soil, water, and air pollution resulting from the decomposition of waste in landfills. In addition, it promotes economic benefits from the energy recovery of waste, such as biomass, which can generate electricity and heat, contributing to a sustainable energy matrix. The present study aimed to evaluate the easily degradable MSW group with 24 years of landfilling (ED-24) regarding its potential for methane generation. The ED group consisted of putrescible organic matter, wood, paper, cardboard, and pruning landfilled at a sanitary landfill in Southeastern Brazil. The feasibility of valuing ED-24 as a substrate for anaerobic digestion was assessed by analyzing its physical, chemical, and biochemical characterization and calculating its theoretical methane yield (TMY). The total volatile solids (TVS) and holo-cellulose contents of ED-24 were 73.45% and 61.39%, respectively, on a dry-weight basis. These values were in the range of those determined for non-landfilled lignocellulosic materials. Thus, 24 years of landfilling partially degraded the anaerobically lignocellulosic materials. The TMY of ED-24 was 233.41 mL CH4/g TVS, indicating a potential to generate methane. Despite the high lignin value, ED-24 can be valued as a substrate for anaerobic digestion.

Determining biomethane potential from animal-source industry wastes by anaerobic digestion: A case study from La rioja, Spain

The animal-source food industry (ASFI) is currently facing important challenges derived from sustainability policies and market requirements. In this respect, the ecological footprint resulting from emissions, management of residues, effluents, and by-products has become a key factor not only due to the laws in force, but also from the point of view of operation efficiency and market requirements. This paper assesses the potential use of the organic wastes generated by the ASFI as a source of biofuel generation (i.e., biomethane) in the region of La Rioja (Spain). To this end, primary data were directly collected from factories and the so-produced wastes were sampled and characterized. Statistical inference from collected data leads to theoretically estimate that the region might produce up to 118.46 GWh per year, mainly provided from piggeries, which would replace 12.4 % of the natural gas used by the regional industry. Besides, this strategy also reduces the environmental footprint and the generation of added value for companies and rural localities. However, the analytics show that an excess of nitrogen content may hinder the calculated theoretical methane yields and lead to operational issues. Looking for biowaste from vegetable sources more optimal admixtures may be designed to address these concerns.

Novel insights into the estimation of theoretical methane yield from lignocellulosic waste based on formula modification

Novel insights into the estimation of theoretical methane yield from lignocellulosic waste based on formula modification

Fertilisation of permanent grasslands with digestate and its effect on soil properties and sustainable biomass production

BackgroundDigestate may be used instead of mineral fertilisers for both arable soil or pastures and grasslands. Broadcast or splash spreading of digestate on soil surface may decrease utilisation efficiency of nutrients – available forms of nitrogen (e.g. ammonia) – due to losses by emission. This research aimed to evaluate if the novel approach of split application of digestate deeper into the soil profile of permanent grassland by injection improves multiple soil and plant quality indicators. MethodsBetween 2019 and 2021, a small-scale-plot field experiment on permanent grassland with three experimental treatments: (1) control (unamended), (2) injector (20 m3·ha-1 of digestate, applied to the soil by injection after the first and the second cut), and (3) hose (20 m3·ha-1 of digestate, applied to the soil by hose spreading device after the first and the second cut). Cumulative plant biomass yield and quality were determined throughout the experiment. In October 2021, soil samples were obtained and analysed. ResultsThe injector application of digestate to soil improved long-termed total carbon sequestration, respirations induced by L-alanine and N-acetyl-β-D-glucosamine, nitrate content and urease activity. Compared to the control, soil pH was significantly decreased due to both approaches of digestate application. Although total nitrogen content did not vary significantly between experimental treatments, the nitrification rate was assumed as moderate in the injector experimental treatment and primarily high in the hose experimental treatment. This led to increased acidification; despite high ammonium content, it hindered further nitrification and lowered urease activity at suboptimal pH. The digestate amendment improved grass biomass yield and its nutritional value, contributing to the increased theoretical methane yield from the grass feedstock of the injector experimental treatment. This is the first report to benefit from this possible agriculture management practice for digestate-based fertilisation of permanent grassland.

Predicting Maize Theoretical Methane Yield in Combination with Ground and UAV Remote Data Using Machine Learning.

The accurate, timely, and non-destructive estimation of maize total-above ground biomass (TAB) and theoretical biochemical methane potential (TBMP) under different phenological stages is a substantial part of agricultural remote sensing. The assimilation of UAV and machine learning (ML) data may be successfully applied in predicting maize TAB and TBMP; however, in the Nordic-Baltic region, these technologies are not fully exploited. Therefore, in this study, during the maize growing period, we tracked unmanned aerial vehicle (UAV) based multispectral bands (blue, red, green, red edge, and infrared) at the main phenological stages. In the next step, we calculated UAV-based vegetation indices, which were combined with field measurements and different ML models, including generalized linear, random forest, as well as support vector machines. The results showed that the best ML predictions were obtained during the maize blister (R2)-Dough (R4) growth period when the prediction models managed to explain 88-95% of TAB and 88-97% TBMP variation. However, for the practical usage of farmers, the earliest suitable timing for adequate TAB and TBMP prediction in the Nordic-Baltic area is stage V7-V10. We conclude that UAV techniques in combination with ML models were successfully applied for maize TAB and TBMP estimation, but similar research should be continued for further improvements.

Multi-faceted analysis of thermophilic anaerobic biodegradation of poly(lactic acid)-based material

Currently, the production of bio-based polymeric materials, of which poly(lactic acid) (PLA) is the most popular, has been increasing, causing the growth of PLA waste in municipal waste. Thus, it is necessary to develop sustainable methods for treating it. Methane production, resulting from anaerobic digestion (AD), is a potential end-of-life scenario for PLA waste that needs to be investigated. To obtain high efficiency of AD, thermophilic fermentation was applied, and to overcome low rates of biodegradation, hydrothermal (HT) and alkaline (A) pretreatments were used. For a deep insight into the process, differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR), and microscopic and microbial analyses (based on 16S rDNA) were applied. For both untreated (PLA) and pretreated (PLAHT, PLAA) samples a high maximal methane production (MP) of 453 L/kg volatile solids (VS) was obtained, almost 100 % of the theoretical methane yield from PLA. The use of pretreatment allowed shortening of the time for obtaining maximal MP, especially the hydrothermal pretreatment, which shortened the overall time of MP 1.3-fold, and methane was produced at an almost 10 % higher rate (8.35 vs 7.79 L/(kg VS·d)). However, DSC and microscopic analyses revealed that, in all cases, methane was intensively produced i) after the reduction of the molecular mass of the PLA material and ii) also when PLA pieces were not visible. This should be considered when designing the operational time for the AD process. Parallel to the gradual biodegradation of PLA, the abundances of Firmicutes, Thermotogae, and Euryarcheota increased. With PLAHT, Syntrophobacteraceae, Thermoanaerobacteraceae, and methanogens were identified as potential key thermophilic PLA biodegraders.

In-situ production of magnetic char via rapid subcritical hydrothermal carbonisation of paunch waste

The conventional hydrothermal carbonisation (HTC) is mainly tied to the high capital investment of the reactor and low product quality. In a novel approach, the rapid subcritical HTC of paunch waste (at 240 °C for only 5 min) was proposed to enhance the quality of products and their utilisation via in-situ production of magnetic hydrochar. Magnetite nanoparticles were found on the surface of hydrochar with size of 10–20 nm and crystal lattice spacing of 0.25 nm, XRD characteristic peaks of magnetite, and strong FTIR peak at 580 cm−1 assigned to Fe-O stretching in the crystalline lattice of magnetite. Magnetic hydrochar could adsorb Congo Red at a capacity of 59.9 mg g−1. An organic-rich process water with a high COD of 43 g L−1 was co-generated along with magnetic hydrochar and assumed to be anaerobically digested. The estimated theoretical methane yield was found sufficient to run the HTC plant in an energy-neutral mode. After developing a process model in Aspen plus, the discounted cash flow analysis revealed a net present value of US$13.04 MM for 30 years of operation, which can increase to $34.79 MM if the iron precursors are sourced from locally available iron-rich sludge.

Cultivation of Navicula sp. on rice straw hydrolysate for the production of biogenic silica

Rice straw hydrolysate (RSH) prepared at room temperature was found to be rich in silica (140 ± 4.1 mg L-1) and other nutrients (nitrate-N: 160 ± 4.3 mg L−1, total dissolve phosphate: 164 ± 6.7 mg L−1, ammoniacal-N: 439.8 ± 17 mg L−1). The aim of this work was to study four RSH dilutions (10, 30, 50, 70% v/v) to cultivate Navicula sp. with modified ASN-III as a control. The best result was achieved in 30% RSH in terms ofdoubling time (d = 1.49 days) and growth rate (µmax = 0.46 day−1). Compared to control, specific growth rate and biomass productivity were increased by 2.93 folds and 1.85 folds, respectively. Cultivation in 5 L reactor with optimized 30% RSH yielded frustule (54.2 ± 1.9%), carbohydrate (12.4 ± 1.2%), lipid (18.9 ± 1.4%), and protein (8.2 ± 0.6%). The residual solid fraction showed 18.99% increased theoretical methane yield than raw rice straw. Overall, the present process offers a sustainable solution to manage rice straw residue and recover nanoporous silica.

Investigation of the Theoretically Potential for Biogas Production from Mucilage in the Marmara Sea

This research is about the disposal and evaluation of mucilage, which threatens human health, marine ecosystem, social life and economy. For this purpose, the idea of providing benefits by creating an alternative to meet the energy need, which is one of the world's priority problems, has been adopted. It has been determined that mucilage can be used in the production of biogas, which is a popular energy type in recent times, in line with its structural properties and content. Biogas, which has the potential to be an alternative to fossil fuels thanks to its numerous advantages, is a versatile renewable energy source that can be used in many different areas. In this study, the biogas production potential of mucilage was investigated theoretically with two different methods. One of the methods is to calculate the methane yield based on the protein, lipid and carbohydrate content of the organic matter. In the other method, according to the results of elemental analysis, the methane yield was calculated using the stoichiometric equation. According to the analysis and calculations, the theoretical methane yield of the mucilage was found to be 528.68 mL CH4/g VS according to the organic matter content and 526.15 mL CH4/g VS according to the elemental content. Theoretical calculation of the methane yield before the experimental study saves material and time. In this direction, it has been concluded that the biogas production potential of the mucilage is high and suitable for experimental work, since the methane yield values calculated using different methods are high and close to each other. It is believed that this study, which investigates the disposal of mucilage, which is a harmful formation, and its usability in the production of biogas, which is an efficient energy type, makes a multi-faceted contribution to the literature for humanity

Effects of organic loading rate on methane production from switchgrass in batch and semi-continuous stirred tank reactor system

Long-term anaerobic digestion of switchgrass (SG) was investigated in batch and semi-continuous reactors operating at different Substrate to Inoculum (S:I) ratios and organic loading rates (OLRs) by monitoring process stability, microbial community structure, and investigating kinetic modeling. The highest methane yield of 204 mLCH4/gVS was observed when the batch system was operated at the S:I ratio of 1.1. Methane yields in the semi-continuous configuration were around 148, 157, and 60 mLCH4/gVS at OLRs of 0.75, 1.0, and 1.5 gVS/(L.d), respectively. A drastic decrease in methane yields was observed at the highest OLR value of 1.5 gVS/(L.d). The optimum OLR in the semi-continuous configuration was decided as 1.0 gVS/(L.d) where 35% of the SG theoretical methane yield and 38% energy recovery were attained. Several methanogenic archaea, Methanosarcina, Methanosaeta, Methanothrix, and Methanomethylovorans, together with bacteria species, Chloroflexi, Firmicutes, Spirochaetes, and Actinobacteria were observed in the semi-continuous configuration after 270 days of operation. The dominant bacterial phyla of s-CSTR were mostly members of Spirochaetes phylum, which plays a considerable role in acetate oxidation under either mesophilic or thermophilic conditions.

Study on the process wastewater reuse and valorisation during hydrothermal co-carbonization of food and yard waste

The commercial success of hydrothermal carbonization (HTC) is contingent on seeking solutions for the downstream wastewater (process water) generated during the process which is still regarded largely as a nuisance. In the present study, the reusability and valorization strategy of process wastewater generated during co-HTC of organic fraction of municipal solid waste (food and yard waste) at 220 °C for 1 h was established. The process wastewater was anaerobically digested in the first part to determine its methane-generating capacity; and in the second part, it was recirculated up to five times to understand the evolution of physicochemical and fuel characteristics of hydrochar. The process water was characterized by the presence of high total organic carbon (up to 40 g/L) and chemical oxygen demand (up to 96 g/L). The decreasing trend of heavy metals with increasing recirculation suggested possible adsorption/immobilization mechanism taking place to the hydrochar surface. The process water generated from co-HTC condition has anaerobic biodegradability of 72% while experimental and theoretical methane yield observed were 224 mL/g COD and 308 mL/g COD, respectively. The presence of high organic and ionic species in recirculated process water promoted the overall carbonization process which was evident from the increased energy yield (86 to 92%), carbon content (68 to 71%) and calorific value (20 to 27 MJ/kg). The recirculation also enhanced overall combustion characteristics of hydrochar as analyzed by thermogravimetric analysis. The recirculation strategy enhanced fuel properties of hydrochar while making sure upstream and downstream water related burden is reduced (as illustrated by life cycle analysis) to create a cleaner production system for renewable solid biofuels production.

Enhancement of lignocellulosic biomass anaerobic digestion by optimized mild alkaline hydrogen peroxide pretreatment for biorefinery applications

Lignocellulosic energy crops are promising feedstocks for producing renewable fuels, such as methane, that can replace diminishing fossil fuels. However, there is a major handicap in using lignocellulosic sources to produce biofuels, which is their low biodegradability. In this study, the application and the optimization of a lignocellulose pretreatment process, named alkaline hydrogen peroxide, was investigated for the enhancement of methane production from the energy crop switchgrass. Four independent process variables, solid content (3–7%), reaction temperature (50–100 °C), H2O2 concentration (1–3%), and reaction time (6–24 h), and three response variables, soluble reducing sugar, soluble chemical oxygen demand, and biochemical methane potential were used in process optimization and modeling. The optimization was performed by two different approaches as maximum methane production and cost minimization. The optimum conditions for the highest methane production were found as 6.65 wt% solid content, 50.6 °C reaction temperature, 2.94 wt% H2O2 concentration, and 16.05 h reaction time. The conditions providing the lowest cost were 6.43 wt% solid content, 50 °C reaction temperature, 1.83 wt% H2O2 concentration, and 6.78 h reaction time. For maximum methane production and cost minimization, specific methane yields of 338.52 mL CH4/g VS and 291.34 mL CH4/g VS were predicted with 62.4 % and 39.8 % enhancements compared to untreated switchgrass, respectively. Finally, it was found that the predicted methane production for the maximum methane production represents 77 % of the theoretical methane yield and 82.22 % energy recovery.

Diversity of dimethylsulfide-degrading methanogens and sulfate-reducing bacteria in anoxic sediments along the Medway Estuary, UK.

Methane is a powerful greenhouse gas but the microbial diversity mediating methylotrophic methanogenesis is not well-characterized. One overlooked route to methane is via the degradation of dimethylsulfide (DMS), an abundant organosulfur compound in the environment. Methanogens and sulfate-reducing bacteria (SRB) can degrade DMS in anoxic sediments depending on sulfate availability. However, we know little about the underlying microbial community and how sulfate availability affects DMS degradation in anoxic sediments. We studied DMS-dependent methane production along the salinity gradient of the Medway Estuary (UK) and characterized, for the first time, the DMS-degrading methanogens and SRB using cultivation-independent tools. DMS metabolism resulted in high methane yield (39%-42% of the theoretical methane yield) in anoxic sediments regardless of their sulfate content. Methanomethylovorans, Methanolobus and Methanococcoides were dominant methanogens in freshwater, brackish and marine incubations respectively, suggesting niche-partitioning of the methanogens likely driven by DMS amendment and sulfate concentrations. Adding DMS also led to significant changes in SRB composition and abundance in the sediments. Increases in the abundance of Sulfurimonas and SRB suggest cryptic sulfur cycling coupled to DMS degradation. Our study highlights a potentially important pathway to methane production in sediments with contrasting sulfate content and sheds light on the diversity of DMS degraders.

Effect of Biochar Addition on the Microbial Community and Methane Production in the Rapid Degradation Process of Corn Straw

Anaerobic digestion with corn straw faces the problems of difficult degradation, long fermentation time and acid accumulation in the high concentration of feedstocks. In order to speed up the process of methane production, corn straw treated with sodium hydroxide was used in thermophilic (50 °C) anaerobic digestion, and the effects of biochar addition on the performance of methane production and the microbial community were analyzed. The results showed that the cumulative methane production of all treatment groups reached over 75% of the theoretical methane yield in 7 days and the addition of 4% biochar increased the cumulative methane production by 6.75% compared to the control group. The addition of biochar also decreased the number of biogas and methane production peaks from 2 to 1, and had a positive effect on shortening the digestion start-up period and reducing the fluctuation of biogas production during the digestion process. The addition of 4% biochar increased the abundance of the bacterial family Peptococcaceae throughout the digestion period, promoting the hydrolysis rate of corn straw. The dominant archaeal genus Methanosarcina was significantly more abundant at the peak stage and the end of methane production with 4% biochar added compared to the control group.

Forecasting the potential and economic feasibility of power generation using biogas from food waste in Ghana: Evidence from Accra and Kumasi

Global environmental change is driven by food production. Biogas from food waste is a better source of clean energy. Ghana’s energy strategy targets a 10% increase in renewable energy and modern biomass in the national electricity generation mix. Studies on the assessment of electricity generation potential and economic feasibility of biogas to electricity projects in Ghana’s major cities are scarcely available. This study assesses the electricity generation potential of biogas from food waste through anaerobic digestion technology. The municipal solid waste generation potential of Accra and Kumasi was estimated from 2020 to 2039. The potential theoretical methane yield from food waste was calculated using Buswell’s equation. The study analyzed anaerobic digestion projects’ economic feasibility using the total life cycle cost, net present value, investment payback period, levelized cost of energy, and internal rate of return methods. A sensitivity analysis based on two scenarios (optimistic and pessimistic) was performed to analyze the influence of changes in the composition of food waste, per capita waste generation rate, population growth rate, per capita GDP growth rate, discount rate, capacity factor, electricity generation efficiency, waste collection efficiency, and methane production potential on the economic feasibility of the projects. The main findings indicate that the amount of waste generation in Accra during the project life cycle is 899,000 t/y to 3,359,000 t/y, while that of Kumasi is 915,000 t/y to 3,159,000 t/y. The power generation potential of the project in Accra ranges from 80.43 to 300.49 GWh/y, and in Kumasi ranges from 60.63 to 209.31 GWh/y. Economically, the project is feasible in Accra and Kumasi. The net present value of the project in Accra and Kumasi is $217,800,000 and $156,100,000. The sensitivity analysis shows that the project is infeasible in all the cities with a discount rate exceeding 20%. When the discount rate exceeds 20%, the project becomes highly infeasible in Accra compared to Kumasi. This study will offer itself as scientific guidance for investment in biogas to electricity projects in Ghana’s cities.

Valorization of palm oil mill wastewater for integrated production of microbial oil and biogas in a biorefinery approach

This work presents an integrated biorefinery concept combining two biological platforms for the valorization of palm oil mill effluents and for simultaneous production of high market value products, such as microbial oils and bioenergy. Palm oil mill effluents were aerobically fermented to produce lipids and subsequently the effluent from the fermentation was used as influent feedstock in an anaerobic digester for biogas production. It was found that pasteurization of the wastewater before fermentation by Yarrowia lipolytica TISTR 5151 was mandatory for efficient lipid production yielding 159.2 mg lipids/g-COD. In contrast, fermentation with untreated wastewater failed to produce lipids (3.10–43.51 mg lipids/g-COD), but instead supported the growth of several indigenous bacteria (e.g., Asaia sp., Lactobacillus brevis and Acetobacter sp.) with 6.57%–65.24% of relative abundance. Regarding biogas production, a maximum of 74% of the theoretical methane yield (280 mL/g-COD) in continuous reactor operation was achieved. The dominant bacteria, Synergistales sp. (18.19%) and Bacteroidetes sp. (15.96%), found at steady state period in the biogas reactor are known for acetate, butyrate, and hydrogen production. Moreover, within archaeal population, Methanosarcina thermophila (2.27%) and Methanoculleus thermophilus (1.38%) were identified as responsible for biomethane production.

BIOMETHANE POTENTIAL OF INVASIVE AQUATIC WEED WATER PRIMROSE

This study aims to examine the perspective of feedstock for producing biomethane from invasive aquatic weed water primroses (Ludwigia Hyssopifolia). The methane yield and methane content of biogas were analyzed and studied. The calculating methods of theoretical methane yield based on the elemental application or the theoretical chemical oxygen demand (COD) number were showed. The percentage of element chemicals, carbon (C), hydrogen (H), oxygen (O), nitrogen (N), and sulfur (S) of raw materials were analyzed, and results were 40.2%, 5.03%, 22.13%, 1.8% and 0.24%, respectively. The plant biomass was contained moisture content, volatile carbon, fixed carbon and ash were 7.28%, 63.07%, 1.28% and 28.37%, respectively. From the water primroses calculated yield of methane (CH4), carbon dioxide (CO2) and ammonia (NH3) results were 54.90%, 41.40% and 3.70%, respectively. Therefore, the aquatic weed water primroses biomass are suitable feedstock for biogas production as well as future scale-up studies.

Solid-state anaerobic co-digestion of food waste and cardboard in a pilot-scale auto-fed continuous stirred tank reactor system

Abstract Increasing volume of Food waste (FW) and cardboard (CB) which are the two major fractions of municipal solid waste increases environmental concerns. This study evaluated the performance of a pilot-scale auto-fed continuous stirred tank reactor (CSTR) system for the solid-state anaerobic co-digestion (ACoD) of acetic acid rich food waste (FW) and cardboard (CB). The objective to co-digest acids rich FW and CB originates from the fact that acetic acid can act as a pre-treatment agent. Can the frequency of feeding and feeding pattern assists the system to withstand an organic loading rate >4 g volatile solids (VS)/(L.d) without addition of any pH boosting chemicals? Four mixing ratios of 100:0, 80:20, 60:40, 50:50 (v/v %) of FW and CB on biogas yield and process stability at an OLR > 4 g VS/(L.d) at a hydraulic residence time (HRT) of 40 d was investigated. Results revealed that the reactor R1 operated with FW:CB in the ratio of 100:0 achieved 76% biodegradability (the ratio of experimental to theoretical methane yield) while it was 39%, 32% and 22% for FW:CB ratios of 80:20, 60:40 and 50:50, respectively. This study concludes that exposing the CB to acetic acid-rich FW assisted the disintegration and depolymerization of CB without any pre-treatment step. Micro-feeding the reactor on an hourly basis assisted to overcome the susceptible failure of the system. The outcomes of this study provides new insight into the potential of implementing decentralized AD units for the treatment of FW and CB at source, which not only diverts waste from landfills but creates a revenue model through bioenergy generation and digestate sales.