Biogas Production Rate Research Articles

Mass Transfer Enhancement in High-Solids Anaerobic Digestion of Organic Fraction of Municipal Solid Wastes: A Review.

The increasing global population and urbanization have led to a pressing need for effective solutions to manage the organic fraction of municipal solid waste (OFMSW). High-solids anaerobic digestion (HS-AD) has garnered attention as a sustainable technology that offers reduced water demand and energy consumption, and an increased biogas production rate. However, challenges such as rheology complexities and slow mass transfer hinder its widespread application. To address these limitations, this review emphasizes the importance of process optimization and the mass transfer enhancement of HS-AD, and summarizes various strategies for enhancing mass transfer in the field of HS-AD for the OFMSW, including substrate pretreatments, mixing strategies, and the addition of biochar. Additionally, the incorporation of innovative reactor designs, substrate pretreatment, the use of advanced modeling and simulation techniques, and the novel conductive materials need to be investigated in future studies to promote a better coupling between mass transfer and methane production. This review provides support and guidance to promote HS-AD technology as a more viable solution for sustainable waste management and resource recovery.

Evaluation of activated pyrochar for boosting anaerobic digestion: Performances and microbial community

In this study, the effects of CO2-activated/non-activated pyrochars (PCs) from cornstalk, cotton straw, and rice straw on anaerobic digestion (AD) performances and microbial characteristics were investigated. The maximum biogas production rate (2.2 L/L/d) with a methane content of 73% was obtained from the AD with CO2-activated cotton straw PC. The activated PC mainly played a strengthening role in the early and middle stages of AD. Specifically, the cornstalk PC could greatly relieve acid inhibition, and cotton straw PC had a significantly positive effect on the regulation of ammonia nitrogen concentration. The rare genera like Verrucomicrobia had obvious differences among groups of AD with PCs. Regarding differential metabolites, cornstalk PC-N2 displayed a positive correlation with isoleucyl-alanine, while exhibiting a negative correlation with deoxyinosine, and the corresponding relative expression levels were + 3.0 and −2.4, respectively. Overall, gas-activated PCs could promote methane production and affect the composition of microbial community.

Biogas Production from Tofu Processing Waste and Rice Straw with the Addition of Beef Bone Lime

The waste processing of tofu and rice straw can be used as the basic material for making biogas. The acidic pH of the waste will cause a non-optimal biogas production. This research was conducted using NaOH and the variations of beef bone lime 3 replications. The purpose of this study was to obtain the value of volume, pressure, biogas production rate and flame quality. The result showed the best quality of flame with a blue color (for 64.48 seconds) and 962 ml/day of biogas production rate was obtained by adding 3% of beef bone. The highest volume was obtained by adding 3% of beef bone lime (2210.33 ml) and the highest pressure was obtained by adding 2% and 3% of beef bone lime (1.0159 bar).

Predicting steady-state biogas production from waste using advanced machine learning-metaheuristic approaches

This research offers a fast and accurate method for measuring the biogas production rate throughout biogas production. An agricultural biogas plant's measurement of eight process variables served as the source of experimental data used to create the models. Biomass type, reactor/feeding, volatile solids, pH, organic load rate, hydraulic retention time, temperature, and reactor volume were utilized in this context. Artificial neural networks (ANN) were developed to evaluate the biogas production rate. The variable selection was carried out using the cuckoo optimization algorithm (COA), multi-verse optimization algorithm (MVO), leagues championship algorithm (LCA), evaporation-rate water cycle algorithm (ERWCA), stochastic fractal search (SFS), and teaching–learning-based optimization (TLBO). In this study, the model's size decreased, the important process variables were highlighted, and the ANN models' potential was enhanced for prediction. The proposed COA, MVO, LCA, ERWCA, SFS, and TLBO and ensembles are the outcome of using the abovementioned approaches to synthesize the multi-layer perceptron (MLP). To evaluate the effectiveness of the used models, we have developed a scoring system in addition to employing mean absolute error, mean square error, and coefficient of determination as accuracy criteria. Implementing the COA, MVO, LCA, ERWCA, SFS, and TLBO algorithms enhances the accuracy of the MLP. It is found that some of the used hybrid techniques could provide better prediction outputs than traditional MLP rankings. Additional investigation indicated that the ERWCA is better than the three other algorithms. The biogas production rate was estimated with the greatest precision with R2 = 0.9314 and 0.9302, RMSE of 0.1969 and 0.24925, and MAE of 0.1307 and 0.19591.

The Design and Performance Prediction Model of an Integrated Scheme of a Membrane Bioreactor and Anaerobic Digester for the Treatment of Domestic Wastewater and Biowaste

An innovative and integrated scheme that encompasses two well-established waste treatment technologies, the aerobic biological degradation of organic matter bioprocess via membranes and anaerobic digestion, was demonstrated as a zero-waste approach that may effectively treat wastewater and biowaste in an integrated and symbiotic manner. Aiming to create a tool for the design, monitoring, and control of the scheme, prediction models were developed, validated, and implemented for the process simulation of the integrated scheme. The minimization of selected objective functions led to the estimation of the models’ parameters. The activated sludge model no. 1 (ASM1) was adopted for the simulation of the aerobic membrane bioreactor. The kinetic parameters were calibrated using volatile suspended solids and total nitrogen as the objective functions permitting the model to simulate the bioprocess satisfactorily (Nash–Sutcliffe efficiency > 0.86) and to calculate the concentration of the active biomass. The predominance of heterotrophic bacteria (4300 to 9770 mg COD/L) over autotrophic biomass (508 to 1422 mg COD/L) was showcased. For the anaerobic process unit, a simplified anaerobic digestion model 1 ADM1-R4 was used, and the first-order hydrolysis constants (kch 0.41 d−1, kpr 0.25 d−1, kli 0.09 d−1) and microbial decay rate (kdec 0.02 d−1) were evaluated, enabling an accurate prediction of biogas production rates. A full-scale implementation of the integrated scheme was conducted for a decentralized waste treatment plant in a small community. Preliminary design calculations were performed in order to estimate the values related to certain process and technical parameters. The performance of this full-scale plant was simulated by the developed model, presenting clear benefits for practical applications in waste treatment plants.

Comparison of prediction of biogas yield in a batch mode underground fixed dome digester with cow dung

The study aimed to compare the development of an artificial neural network (ANN) and multilinear regression (MLR) model used to predict the performance of biogas in a batch-mode underground fixed dome biogas digester. In this study, 50 experimental datasets were used to assess the rate of biogas production with developed ANN and MLR models. The six variables, including solar irradiance, relative humidity, slurry temperature, biogas temperature, pH, and ambient temperature, were selected as the input parameters or predictors of the model. Therefore, the developed ANN and MLR models were used to describe the rate of biogas yield. The study found that the determination coefficient (R2) and root mean square error (RMSE) for ANN and MLR were 0.999/0.968 and 8.33 × 10−6/1.84 × 10−4, respectively. Both models were significant because of their high correlation between measured and predicted values of the biogas yield. However, the ANN performs better because of the smaller RMSE and higher R2 derived compared to the corresponding values of the MLR. The study proved that both the ANN and MLR can accurately predict the rate of biogas production but with better predictions obtained from ANN.

Multi-Parametric Analysis Based on Physico-Chemical Characterization and Biochemical Methane Potential Estimation for the Selection of Industrial Wastes as Co-Substrates in Anaerobic Digestion

Anaerobic digestion is considered as one of the most feasible waste-to-energy technologies for the valorization of organic wastes. It can be applied to many different substrates but the mono-digestion of a single substrate usually has some important drawbacks due to the physico-chemical characteristics of the substrate. A feasible solution is the simultaneous co-digestion of several substrates with different composition and characteristics, so that synergetic effects may be generated and physico-chemical characteristics may be compensated, thus reaching higher process efficiencies and biogas production rates. In this work, a multi-parametric analysis for the objective comparison of industrial wastes was developed in order to help with decision making about their suitability as a co-substrate in anaerobic co-digestion. Criteria considered for this analysis included sample composition, C/N ratios, theoretical biochemical methane potential (BMP), and other important issues such as production rates, seasonality, and the distance to the WWTP or pre-treatment requirements. Results showed that, among the 13 evaluated wastes, 2 of them showed a higher potential for being used in anaerobic co-digestion: 1. Fried corn from the snack food industry and 2. Wet fatty pomace from the olive oil industry. Both wastes showed high estimated BMP values, high lipid and carbohydrate content, and C/N ratios in a proper range to improve the low C/N ratio of sewage sludge. Other wastes such as olive pomace (dry), skinless corn (not fried), and grape pomace from the winery industry may also be used as co-substrates. As a conclusion, this procedure based on a selection matrix can be considered as a useful tool to help both producers and WWTP operators to make decisions about the potential applicability of specific industrial wastes as co-substrates in anaerobic co-digestion.

Two-stage (liquid-solid) anaerobic mono-digestion of ammonia-rich chicken manure at low-temperature: Operational strategy and techno-economic assessment

This study investigated mono-digestion of ammonia-rich chicken manure (CM) in a high-solids anaerobic-digester (HSAD) at low-temperature (20±1°C) adopting the recirculation-percolation mode of operation using liquid-inoculum. HSAD was operated for about 282 days in batch-runs under different organic loading rates (4.3-8.7 gVS/L.d), total solids (65-70%) and total kjeldahl nitrogen (TKN) (23.3- 32.8 g/L) concentrations. It was noted that acclimation of the liquid inoculum to a high concentration of TKN (6.9 g/L) facilitated CM digestion, thereby reducing the start-up phase. The maximum cumulative biogas production rate and specific methane yield were found to be 20 L/d and 0.80±0.12 LCH4g/VSfed, respectively with a methane content over 60% without any signs of inhibition. Operating HSAD at low temperature prevented the accumulation of free-ammonia, which is toxic to methanogens. A techno-economic analysis was also conducted as part of this study to determine the profitability of the system and a 9-year tentative payback period was estimated.

Valorisation of eyewear bioplastics through HTC and anaerobic digestion: Preliminary results

Bioplastics are increasingly replacing traditional plastics in many sectors, but the legislative and operative frameworks for their disposal remain unclear: they should be collected and treated together with the organic fraction of municipal solid waste (OFMSW), but often do not biodegrade satisfactorily in the plants that treat OFMSW. This work focuses on a type of cellulose diacetate employed in the eyewear industry to analyse hydrothermal carbonization (HTC) as a pre-treatment before anaerobic digestion (AD). The results show that HTC can hydrolyse this bioplastic even at moderate temperatures, reaching an almost total dissolution in the liquid phase at 210 °C and, at higher temperatures, producing hydrochar. When the HTC slurry obtained at 210 °C is fed to mesophilic or thermophilic AD, both the amount and the production rate of biogas are enhanced compared to the raw bioplastic. In particular, in thermophilic conditions, the amount of produced biogas undergoes at least a threefold increase compared to the untreated cellulose diacetate. Thus, this work confirms that a prior HTC step may be a suitable approach to enhance the disposal and energy recovery of bioplastics through AD.

PH and Heat Pretreatments with Zero-Valent Iron Addition to Enhance Biogas Production from Cassava Pulp Wastewater: Optimization and Comparison of Mathematical Models

Pretreatments of pH and heat with zero-valent iron (ZVI) additions enhance anaerobic digestion and increase reducing sugar availability for optimum biogas production. This study aimed to optimize the conditions of different pH and heat pretreatment with additional ZVI to yield higher biogas amounts from the anaerobic digestion (AD) of cassava wastewater. Thirteen pH conditions, ten ZVI concentrations, and eleven heating periods were varied and measured to optimize the standard conditions. Four mathematical models that are widely used to evaluate the cumulative biogas production were employed, namely, the Modified Gompertz, Logistic, Transference, and Exponential models. The pretreatment of pH 10 and 35 min of boiling time with a ZVI concentration of 60 g·kg·TVS−1 produced the highest cumulative biogas at the end of the AD process. The Logistic and Modified Gompertz models were better fitted with the experimental data than the other models. Interestingly, the optimized conditions altered the biogas production rate but prolonged the lag phase. A reasonably positive correlation was also found between the FeOOH amount and biogas production rate in the LF and MG models. These optimal fitted models, kinetics parameters, and possible correlations are novel findings that can help develop extensive scale developments for biogas generation from cassava wastewater.

Evaluation of biogas production rate and leachate treatment in Landfill through a water-energy nexus framework for integrated waste management

The aim of this study was to investigate the simultaneous biogas generation and leachate treatment using municipal waste and its polluted leachate at Mashhad landfill in northeast Iran. The research focused on examining the kinetic model of CH4, CO2, CO, H2S and O2 production with and without leachate recirculation (LR) through control/test wells. The findings from both wells showed an increase in logarithmic CH4 production rate, with the coefficient related to the rate of increase in methane concentration ranging from 0/52-0/64 in the control well and 0/47-0/55 in the test well, respectively. Under LR conditions, it was observed that the CH4 production rate was slower, taking an average of 120 minutes to reach 50% concentration, compared to just 15 minutes without LR. Using first-order equations, the CH4 production coefficients were measured to be 2/17 h−1 and 0/9 h−1 for the control and test wells, respectively. The analysis of recirculated leachate revealed a significant decrease (∼30%) in the total volume of leachate with 72% COD removal, which could help manage overloaded leachate problems in the landfill. The COD removal coefficient was found to be 0/036 day−1 in the control well, whereas the test well with leachate recirculation showed a more rapid decrease from 50 g.l−1 to about 14 g.l−1 with a removal coefficient of 0/012 day−1, three times higher than the control well. Additionally, nitrogen content analysis indicated that although the amount of ammonia content increased with LR, the increase was relatively low in comparison to conditions without LR, equivalent to 1394 ppm and 1000 ppm in control and test wells, respectively. This study aligns with the water-energy-nexus concept by offering a sustainable solution for waste management and energy generation, while also addressing water management challenges associated with landfill operations.

Demand-driven biogas production from Upflow Anaerobic Sludge Blanket (UASB) reactors to balance the power grid

Future energy systems necessitate dispatchable renewable energy to balance electrical grids with high shares of intermittent renewables. Biogas from anaerobic digestion (AD) can generate electricity on-demand. High-rate methanogenic reactors, such as the Upflow Anaerobic Sludge Blanket (UASB), can react quicker to variations in feeding as compared to traditional AD systems. In this study, experimental trials validated the feasibility of operating the UASB in a demand-driven manner. The UASB was operated with leachate produced from a hydrolysis reactor treating grass silage. The UASB demonstrated a high degree of flexibility in responding to variable feeding regimes. The intra-day biogas production rate could be increased by up to 123% under 4 hours in demand-driven operation, without significant deterioration in performance. A model based on kinetic analysis was developed to help align demand-driven operation with the grid. The findings suggest significant opportunities for UASBs to provide positive and negative balance to the power grid.

ANAEROBIC DIGESTION OF BREWER’S SPENT GRAIN WITH BIOCHAR – BIOGAS PRODUCTION KINETICS AND PROCESS EFFICIENCY

Biochars made from brewer’s spent grain were added to the anaerobic digestion of brewer’s spent grain to enhance the methane fermentation process and improve biogas production. In research, the effect of biochars made at 300, 450, and 600 °C and doses of 1-8% added to anaerobic digestion was tested. The biochemical biogas potential tests in mesophilic conditions were performed. The tests took 28 days, the biogas yield for each reactor varied from 500-650 ml×gVS-1, and around 60% substrate degradation was obtained. For each test, the kinetics parameters using the first-order model were determined. The constant biogas production rate (k), and the biogas production rate (r) varied from 0.05-0.08 d−1, and 42-60 ml×(gVS×d)−1 respectively. Though the differences in biogas production turned out to be statistically insignificant (p<0.05) due to the high disappearance in obtained data and conflicting effects, the response surface area analysis showed that biochar made at 450 °C at the share of 1-4% could be used to maximize biogas production. Nevertheless, supplementation with biochar needs to be done carefully since in many cases, a reduction in biogas production was observed

Evaluation of bioenergy production and material flow in treating Japanese concentrated Johkasou sludge using high-solid anaerobic membrane bioreactor based on one-year operation

The treatment of waste sludge generated from on-site wastewater treatment facilities (Johkasou) applied extensively in Japan is a key concern. In this study, a high-solid anaerobic membrane bioreactor (AnMBR) was continuously operated throughout a year to investigate the bioenergy production, material flow and seasonal impacts of concentrated Johkasou sludge (CJoS). The CJoS has higher carbon-to-nitrogen ratio and lipid fraction, but less proteins than waste activated sludge (WAS). The biogas yield of CJoS by AnMBR ranged from 0.47 to 0.52 L/g-VSfed, which was higher than the anaerobic digestion of WAS and lower than mixed sewage sludge from centralized wastewater treatment facilities. The greatest biogas production rate was observed during summer (0.63 L/L/d), owing to the high total organic and solid content. However, winter CJoS had the highest biogas yield and carbon conversion rate owing to the conservation of soluble organic matter in low temperature and high digestibility. The material flow results revealed that 46.5–52.4% total COD and 50.2–58.0% carbon was converted to biogas. The energy recovery rates ranged from 8.69 to 9.96 kJ/g-VSfed and the system energy self-sufficiency rates ranged from 1.92 to 3.02. The optimal dewaterability of digested sludge was achieved when polyamidine flocculant dosage was 30 mg/g-MLSS and the corresponding sludge specific resistance to filtration was 2.26 × 1012 m/kg. The results demonstrated that AnMBR yielded high energy conversion efficiency without co-digestion and pretreatment processing.

Dynamic modelling the effects of ionic strength and ion complexation on trace metal speciation during anaerobic digestion

Dosing trace metals into anaerobic digestors is proven to improve biogas production rate and yield by stimulating microorganisms involved in the metabolic pathways. Trace metal effects are governed by metal speciation and bioavailability. Though chemical equilibrium speciation models are well-established and widely used to understand metal speciation, the development of kinetic models considering biological and physicochemical processes has recently gained attention. This work proposes a dynamic model for metal speciation during anaerobic digestion which is based on a system of ordinary differential equations aimed to describe the kinetics of biological, precipitation/dissolution, gas transfer processes and, a system of algebraic equations to define fast ion complexation processes. The model also considers ion activity corrections to define effects of ionic strength. Results from this study shows the inaccuracy in predicting trace metal effects on anaerobic digestion by typical metal speciation models and the significance of considering non-ideal aqueous phase chemistry (ionic strength and ion pairing/complexation) to define speciation and metal labile fractions. Model results show a decrease in metal precipitation and increase in metal dissolved fraction and methane production yield with increase in ionic strength. Capability of the model to dynamically predict trace metal effects on anaerobic digestion under different conditions, like changing dosing conditions and initial iron to sulphide ratio, was also tested and verified. Dosing iron increases methane production and decreases hydrogen sulphide production. However, when iron to sulphide ratio is greater than 1, methane production decreases due to increase in dissolved iron which reaches inhibitory concentration levels.

Enhanced biomethane production with a low carbon footprint via anaerobic co-digestion of swine wastewater with rice husk

An electricity-assisted anaerobic co-digestion (EAAD) process was developed and compared with conventional anaerobic co-digestion (AD) using piggery wastewater and rice husk as feedstocks. Various methodologies, including kinetic models, microbial community analyses, life-cycle carbon footprints, and preliminary economic analysis, were integrated to comprehensively evaluate the performance of the two processes. The results demonstrated that EAAD exhibited a positive improvement of 2.6 % to 14.5 % in biogas production compared to AD. The suitable wastewater-to-husk ratio for EAAD was found to be 3:1, which corresponded to a carbon-to‑nitrogen ratio of approximately 14. This ratio demonstrated positive co-digestion effects and electrical enhancements in the process. According to the modified Gompertz kinetics, the biogas production rate in EAAD ranged from 1.87 to 5.23 mL/g-VS/d, significantly higher than the range of 1.19 to 3.74 mL/g-VS/d observed in AD. The study also investigated the contributions of acetoclastic and hydrogenotrophic methanogens to biomethane formation, revealing that acetoclastic methanogens accounted for 56.6 % ± 0.6 % of the methane production, while hydrogenotrophic methanogens contributed to 43.4 % ± 0.6 %. No significant difference in the methanogenic reaction pathways was observed between AD and EAAD, indicating that the introduction of an external electric field did not alter the predominant pathways (p > 0.05, two-sample t-test). Furthermore, retrofitting existing AD plants with EAAD units can reduce the carbon intensity of piggery wastewater treatment by 17.6 % to 21.7 %. The preliminary economic analysis indicated a benefit-cost ratio of 1.33 for EAAD, confirming the feasibility of implementing EAAD for wastewater treatment while simultaneously producing bioenergy. Overall, this study provides valuable insights into upgrading the performance of existing AD plants by introducing an external electric field. It demonstrates that EAAD can achieve higher and cost-effective biogas production with a lower life-cycle carbon footprint, thus enhancing the sustainability and efficiency of the biogas production process.

Enzymatic-Based Hydrolysis of Digested Potato Peel Wastes by Amylase Producing Fungi to Improve Biogas Generation

Potato peel wastes are generated in high quantities from potato processing industries. They are pollutants to the environment, and they release greenhouse gases into the atmosphere. The present study assessed the potentiality of hydrolyzing potato wastes by amylase-producing fungi to improve biogas generation from potato peels through the anaerobic digestion process. Different fungal isolates were screened for amylase production on potato wastes, and the highest amylase producer was selected for optimizing the efficacy of producing amylases in high quantities to efficiently allow the conversion of potato organic matter into fermentable sugars that are utilized for the anaerobic digestion process. The best amylase producers were those derived from Rhizopus stolonifer (32.61 ± 0.89 U/mL). The highest cumulative methane yield from hydrolyzed potato peel was 65.23 ± 3.9 mL CH4/g and the methane production rate was 0.39 mL CH4/h, whereas the highest biogas yield from unhydrolyzed potato wastes was 41.32 ± 2.15 mL CH4/g and the biogas production rate was 0.25 mL CH4/h. Furthermore, it was found that the two combined sequential stages of anaerobic digestion (biogas production) followed by biodiesel production (enzymatic esterification) were the most effective, recording 72.36 ± 1.85 mL CH4/g and 64.82% biodiesel of the total analytes. However, one-pot fermentation revealed that biogas yield was 22.83 ± 2.8 mL CH4/g and the biodiesel extracted was 23.67% of the total analytes. The insights of the current paper may increase the feasibility of potato peel-based biorefinery through the biological hydrolysis strategy of potato wastes using eco-friendly enzymes.

Characteristics of instability and suitable early-warning indicators for cornstalk-fed anaerobic digestion subjected to various sudden changes

In the process of anaerobic digestion (AD), the poor buffer capacity of the system could lead to the imbalance of the supply and demand of methanogens for organic matters, which may subsequently result in the decrease of biogas production, and even the instability of the whole AD system. In this study, key factors of sudden change were simulated based on the frequent instability problems in biogas projects, and subsequent instability properties, early-warning indicators, and microbial community characteristics were investigated. On the whole, the stable early-warning indicators were biogas production rate and content, pH, total alkalinity, bicarbonate alkalinity, and the sum of volatile fatty acids (VFAs). The threshold value of VFAs for AD instability was 10,000 mg/L, under which the biogas production rate reduced from 0.377 to 0.038 L/L/d, CH4 content decreased from 62.8% to 33.6%, and the proportion of Methanosaeta dropped from 74% to 51.6%. Furthermore, Methanosaeta abundance was greatly sensitive to the sudden variation of VFAs, therefore this kind of archaea could be considered as a warning microbial indicator for acid inhibition. There has been an obvious difference in the functional abundances between bacteria and archaea. This study could provide theoretical guidance for stable operation of biogas projects.

Efficient methane production from anaerobic co-digestion of poultry litter with wheat straw in sequencing batch reactor: Effects of carbon-to-nitrogen ratio, total solids, and hydraulic retention time

This study performed co-digestion of poultry litter (PL) with wheat straw in the daily anaerobic sequencing batch reactor considering operation parameters of carbon-to-nitrogen ratio (C/N, 11.6 to 28.4), total solids (TS, 2.6 to 9.4%), and hydraulic retention time (HRT, 7.6 to 24.4d). The inoculum with a diverse microbial community structure included 2% of methanogens (Methanosaeta) was chosen. Experimental performance by central composite design showed continuous methane production with the highest biogas production rate (BPR) obtained at C/N = 20, TS = 6%, and HRT = 7.6d, being (1.18 ± 0.14 L/LR/d). A significant modified quadratic model (p < 0.0001) for predicting BPR was built (R2 = 0.9724). The operation parameters and process stability both affected the release of nitrogen, phosphorus, and magnesium in the effluent. The results provided new support for the novel reactor operations for efficient bioenergy production from PL and agricultural wastes.

Kinetic modeling and interrelationship aspects of biogas production from waste activated sludge solubilized by enzymatic and thermal pre-treatment

Monte Carlo Simulation (MCS) and kinetic models were applied using data from the biogas production test of waste activated sludge (WAS) pre-treated samples. Indeed, eleven different pre-treatments were applied, combining enzymatic and thermals technologies of sludge solubilization. The main study was proposed to understand the kinetic dynamics of the anaerobic digestion (AD) process and its biogas production potential as a renewable energy source, optimized by distinct solubilization techniques that can be applied to enhance biogas production. As a result, most of the evaluated scenarios significantly improved the biogas production, when compared to the control scenario. Among those, the scenario with thermal solubilization and enzymatic solubilization associated in series, obtained the greatest biogas production potential, reaching 291 ± 3 NmL.gVSS-1, corresponding to a production increase of about 71%. The maximum rate of biogas production obtained was 33.5 ± 0.7 NmL.gVSS-1.day−1. The average lag phase duration (λ) was 0.56 days, and the hydrolysis coefficient (kh) varied between the minimum value of 0.08 ± 0.002 and the maximum of 0.15 ± 0.003 days−1. The two-way ANOVA indicated that there is an interrelationship between the solubilization techniques applied. The confidence interval obtained through MCS allowed us to conclude that the adjustments of the models and the obtention of its parameters to all the scenarios, with exception of the control one, do not have significant differences between them. Therefore, more than a single application of kinetic models to biogas production test results, the statistical approaches supported to elucidate and measure the influence of solubilization techniques in the bioconversion of WAS to biogas as renewable energy source.