Kinetics Of Anaerobic Digestion Research Articles

Impacts of material characteristics on the anaerobic digestion kinetics and biomethane potential of American bourbon and whiskey stillage

Stillage of American whiskey (e.g., bourbon) manufacturing is an abundant byproduct that is distinguished from fuel ethanol and malt whisky stillage materials by its highly inconsistent nature due to variability in mash bill composition. The impact of stillage physicochemical characteristics on biomethane production through anaerobic digestion was assessed by characterizing American whiskey stillage samples before batch biochemical methane potential tests of whole stillage. A maximum methane yield of 419 Nml CH4/g VS was obtained under food to microbe ratio (F: M) of 0.5 and organic loading rate (OLR) of 10 g VS/L while digester instability was noted under F: M ratios exceeding 0.5 under batch production. Methane production was significantly influenced by the mash bill composition with lowest methane yields obtained with higher rye content (rye whiskey) and highest methane yields obtained with higher corn content (bourbon or corn whiskey). A multiple linear regression model including C, P, N, and Na was able to accurately describe the methane yield (R2 = 0.93). This study provides valuable insights to aid the design of anaerobic digesters generating renewable natural gas from heterogeneous American whiskey stillage.

Use of Cacao Pod Husks Under Different Pretreatments for Bioenergy Production

Abstract The current study sought to determine the potential of cacao pod husks for energy use. Biogas potential, the kinetics of anaerobic digestion at bench scale, and physicochemical characterisation of materials were evaluated for cacao pod husks (CPH), depectinised cacao pod husks (CPH-D), and cacao pod husks treated by Pleurotus spp. (CPH-DF). These materials showed accumulated biogas productions of 314.86 ±4.45 l·kg−1 VS−1, 369.49 ±15.98 l·kg−1 VS−1, and 342.52 ±10.98 l·kg−1 VS−1, respectively. The calorific values in CPH-DF, CPH, and CHP-DF were 17.65 MJ·kg−1, 15.43 MJ·kg−1, and 17.21 MJ·kg−1, respectively. These values indicate that the evaluated materials have a high potential to be used as biofuels.

Biogas Production from Plantain and Yam Peels: Modelling using Response Surface Methodology

The world’s growing demand for energy and our concern to preserve the environment have prompted research into alternative sources of energy. Renewable energy from biomass is one such opportunity. The aim of this study is to model the production of biogas from the anaerobic digestion of plantain and yam peelings and cattle dung. A characterisation of these residues showed their good suitability for methanisation with good moisture contents (˃70%), high volatile solids contents (˃75%) and C/N ratios of between 20 and 30. In addition, methanisation trials under mesophilic conditions following a mixing plan generated quantities of biogas ranging from 128 to 565 mL with CH4 contents of between 54.03 and 72.98%. The digester made up of 1/6 plantain peels + 2/3 yam peels + 1/6 cattle dung gave the best biogas yield with 565 mL for 67.52% CH4. The model established from these results is highly significant with an F value (1268.01) having a probability significantly lower than 0.05. In addition to the coefficients R2 (0.9994) and R2 (0.9986) which adjust are very close to unity, there is a good correlation between the experimental results and those predicted. This prediction model is therefore reliable for explaining biogas production. However, further study of the kinetics of anaerobic digestion and biogas treatment remains important.

An integrated energy recovery system for productive biogas applications: Continuous mode operation and assessment

The application of biogas as a renewable energy source continues to face competition from conventional energy sources, which are readily available and seemingly cheap. In addition, productive biogas system deployments in Uganda are currently facing challenges related to sustainability of biogas production, which has led to massive dis-adoption in recent years. These systems have failed to utilize alternatives during scarcity of primary feedstock due to lack technical data for energy recovery, which could be linked to insufficient R&D in the biogas sector. Relatedly, global scientific research has placed focus mostly on methane yield improvements through optimization of anaerobic digestion kinetics on lab-scale, with little focus on the enabling environment for these kinetics to thrive in continuously operated systems.This study therefore aimed to develop an integrated energy recovery system that enables alteration of feedstock and control of digester operating parameters for sustainable biogas production in continuously fed digesters. An array of system components was developed and integrated into a state-of-art energy recovery system, which was prototyped and deployed in real working environment for pilot studies. The system was configured to measure the moisture content of the feedstock and then determine and display to the operator the amount of water to be added to optimize the quality of the substrate. The system also monitors the digester operating parameters and prompts corrective action to prevent possible inhibition of biogas production process. Results show that the system is about 33% more efficient than the conventional one, allows alteration of feedstocks, and can be deployed to replace conventional energy usage for productive applications. For instance, a poultry farm with 10,000 commercial layers may have its energy needs be met 100% by the proposed system with a pay-back period of 4.5 years for deep liter system and 3.7 years for battery cage system.

Application of Terebralia palustris shell extract for bio-coagulation treatment of produced water and digestion of generated sludge into enriched biomethane

In this study, produced water (PW) was decontaminated using the coag-flocculation method, and generated sludge after treatment (GSAT) was transformed into methane-rich gas. The origin of the active coagulant was a novel extract from the green Terebralia palustris shell (TPS). The Terebralia palustris shell extract (TPSE) was created by processing the TPS using a modified Fernadez-Kim method into a protein-based active coagulant. To increase the output of bio-methane, the GSAT and cow dung (CD) were co-digested. Anaerobic digestion process kinetics were examined. The physicochemical characterization of TPS revealed the active component, which contains 16.67% protein. The optimal dosage, pH, and settling time for the coag-flocculation process were 2 g/L, pH 2, and 20 min, respectively, which produced the best turbidity removal efficiency of 94.2%. A total of 36 mL, 490 mL, and 641 mL of biogas were recovered from the anaerobic production of biogas, respectively. With a determination coefficient of 0.9291 for the GSAT and 0.9717 for the GSAT + CD, the anaerobic digestion kinetics followed exponential and logistic models, respectively. In conclusion, coagulation and anaerobic digestion were combined to effectively decontaminate PW and convert coagulation by-products into biogas.

Gamma distribution function to understand anaerobic digestion kinetics: Kinetic constants are not constant

The Gamma model is a novel approach to characterise the complex degradation dynamics taking place during anaerobic digestion. This three parameters model results from combining the first-order kinetic model and the Gamma distribution function. In contrast to conventional models, where the kinetic constant is considered invariant, the Gamma model allows analysing the variability of the kinetic constant using a probability density function. The kinetic constant of mono-digestion and co-digestion batch tests of different wastes were modelled using the Gamma model and two common first-order models: one-step one-fraction model and one-step two-fraction model. The Gamma distribution function approximates three distinct probability density functions, i.e. exponential, log-normal, and delta Dirac. Specifically, (i) cattle paunch and pig manure approximated a log-normal distribution; (ii) cattle manure and microalgae approximated an exponential distribution, and (iii) primary sludge and cellulose approximated a delta Dirac distribution. The Gamma model was able to characterise two distinct waste activated sludge, one approximated to a log-normal distribution and the other to an exponential distribution. The same cellulose was tested with two different inocula; in both tests, the Gamma distribution function approximated a delta Dirac function but with a different kinetic value. The potential and consistency of Gamma model were also evident when analysing pig manure and microalgae co-digestion batch tests since (i) the mean k of the co-digestion tests were within the values of the mono-digestion tests, and (ii) the profile of the density function transitioned from log-normal to exponential distribution as the percentage of microalgae in the mixture increased.

Kinetic prediction of biochemical methane potential of pig slurry

Empirical Kinetic Models have been used to describe and establish the Anaerobic Digestion kinetics of pig slurry’s (8% TS) Biochemical Chemical Potential. A wide selection of Empirical Kinetic Models were fitted to the experimental data collected in batch assays of different Substrate to Inoculum ratios, 0.65 (BMP1) and 1 (BMP2). For the selection of the most suitable model for each BMP assay, the statistical tools R2 and the RMSE, along with the Information Criterion AIC and BIC, were taken into consideration. From all the studied models, the Weibull model proved to be the most suitable for kinetic parameter prediction for both BMP1 and BMP2 assays. This model presented the lowest values of AIC and BIC, along with the highest value of R2 and the lowest RMSE. In this regard, a R2=0.998, and a RMSE=0.004, was obtained for BMP1, and a R2=0.999 and a RMSE=0.008 for BMP2.

Performance and Kinetic Evaluation of Palm Oil Mill Effluent (POME) Digestion in a Continuous High Rate Up-Flow Anaerobic Sludge Blanket (UASB) Bioreactor

In this study, we operated a 10 litre upflow anaerobic sludge blanket (UASB) reactor continuosly at mesophilic temperature (38 °C). UASB reactor performance was evaluated based on the impact of the hydraulic retention time (HRT) ranged between 1 and 5 days and influent COD concentration in the range of 4540 mgL-1 and 20,820 mgL-1. The pH of the UASB was maintained in the range of 6.5 to 7.2 by adding buffering solution containing of 5 gL-1 of calcium oxide (CaO) derived from waste cockle shells. A simplified Monod’s model was employed to describe kinetics of anaerobic digestion of POME by using UASB reactor at organic loading rates (OLR) in the range between 1.17 g.CODL-1d-1 and 17.22 g.CODL-1d-1. A high COD degradation rate of 93.26 % was recorded at OLR of 3.92 g.COD L-1d-1 and HRT of 4 days. The UASB reactor generated the maximum biogas production at 34.95 L/d when operated at HRT 1 day and OLR 7.70 g.CODL-1. The proposed kinetic equations are applicable to describe anaerobic treatment of palm oil mill effluent with the UASB reactor. Biokinetic coefficients evaluated were, the growth yield (YG), 3.906 g VSS/g CODremoved.d-1; the specific biomass decay (b), 0.233 d-1; the specific biomass growth rate (μmax), 1.861 d-1; and the saturation constant (Ks), 3.459 g-CODL-1.

Kinetic Study on Biogas Production from Cabbage (Brassica oleracea) Waste and Its Blend with Animal Manure Using Logistic Function Model

This research paper aimed to evaluate the kinetics of anaerobic digestion (AD) of mixtures of cabbage waste (CW) with (Poultry dropping (PD) and Cow dung (CD). The study was conducted in 10L bio-digesters for 35 days under mesophilic conditions (25 - 35OC). Logistic function equation was used to simulate the experimental data to test for its goodness of fit and kinetic parameters namely: maximum biogas potential (Pb), the maximum biogas production rate (Rm), and the lag phase duration (λ) were estimated in each treatment. Chemical analysis showed that individual substrates possess characteristics that could support microbial activities in biogas production. The biogas yield in terms of added volatile solids (VS) in decreasing order was as follows: 0.022, 0.018, 0.017, 0.014, 0.014 and 0.013 dm3/g VS for CW/CD 2:1, CW/PD3:1, CW/CD 1:1, CW alone, CW/PD1:1 and CW/PD 2:1, respectively. A significant difference (P ≤ 0.05) in biogas yield was recorded in CW/CD 2:1 with 7.19 dm3 (53.29% increase). The kinetic parameters (Pb, Rm, and λ) for CW/CD 2:1 was 7.01 dm3, 1.58 dm3.d, and 2.29 days, respectively. This was followed by CW/PD 3:1 (5.84 dm3); with 24.92% increase in gas production and CW/CD 1:1 (5.42 dm3) with 15.53% increase relative to CW alone, 4.69 dm3. The digesters fed with CW/PD 1:1 and CW/PD 2:1 exhibited inhibitory effects on biogas production, with 7.51 and 2.05% decrease in gas yield, respectively. The logistic function model demonstrated a strong relationship between the experimental and model-predicted data. The high correlation coefficient (R2) ranging between 0.978 - 0.993 is evident. The model proved to be a useful tool in predicting anaerobic digestion and biogas production process.

Surface-Related Kinetic Models for Anaerobic Digestion of Mi-crocrystalline Cellulose: The Role of Particle Size.

In this work, for modelling the anaerobic digestion of microcrystalline cellulose, two surface-related models based on cylindrical and spherical particles were developed and compared with the first-order kinetics model. A unique dataset consisting of particles with different sizes, the same crystallinity and polymerisation degree was used to validate the models. Both newly developed models outperformed the first-order kinetics model. Analysis of the kinetic constant data revealed that particle size is a key factor determining the anaerobic digestion kinetics of crystalline cellulose. Hence, crystalline cellulose particle size should be considered in the development and optimization of lignocellulose pre-treatment methods. Further research is necessary for the assessment of impact of the crystalline cellulose particle size and surface properties on the microbial cellulose hydrolysis rate.

Kinetics of Anaerobic Digestion of Unripe Plantain Peels

This study was carried out to investigate the biogas production obtained from anaerobic digestion of unripe plantain peels (PP) and the kinetics of the digestion process. 400 g of dried and shredded unripe plantain peels were mixed with 200 ml of water and put into 1 L digester and observed for biogas for hydraulic retention time (HRT) of 15 days by the method of downwards displacement. The cumulative biogas volume obtained after digestion was 285 ml. The COD removal efficiency of 72.5% was achieved. The kinetics of PP digestion was evaluated using first order, Monod, Contois and, Grau second-order models. Results showed that the kinetics of anaerobic digestion of PP followed the first-order model with a constant (K) of 0.095 day-1. Monod kinetics was evaluated and the maximum rate of substrate utilization (K), the half velocity constant (KS), endogenous decay coefficient (Kd), biomass growth yield (Y) and, maximum specific microorganism growth rate (µmax) obtained were 0.7615 day-1, 16.20 mg/l, 0.0047 day-1, 0.0112 mgVSS mgCOD-1 and, 0.009 day-1 respectively. These results revealed that inoculation would be required to increase the rate and volume of biogas production. Both first-order and Monod models gave a high coefficient of determination indicating that first order and Monod models can be used to model the digestion of PP. Contois model gave values of µmax and β as 0.011 day-1 and 0.644 mgCOD mgVSS-1 respectively. The result obtained has shown that the digestion of PP did not follow second-order kinetics.

Biogas production using coagulation sludge obtained from paint wastewater decontamination: Characterization and anaerobic digestion kinetics"

This work focuses on the characterization and conversion of post coagulation sludge (PCS) from paint wastewater coagulation using nano Konki-De into biogas. Paint wastewater, snail shell flour (SSF) and PCS were used as raw materials. The nano konki-De (crude protein) extracted from SSF sometimes referred to as coincholin was used as the coagulants, while the PCS recovered after coagulation process was used for the biogas production. Modified Fernadez-Kim method, Jar test experiment and anaerobic digestion were used for bio-coagulant extraction, wastewater treatment and biogas production, respectively. SEM-EDX, FTIR and XRD studies were undertaken, to understand the structure, composition and crystalline nature of nano Konki-De and PCS. The biogas was characterized using gas chromatography (GC). Premised on experimental and instrumental analysis, the active ingredient in SSF was found to be Nano Konki-De, a chitno protein. Paint wastewater contains 2598 ​mg/L total suspended particles and 110 ​mg/L total dissolved solids in excess of NERS standard. The post coagulation sludge contains total solid of 222 ​g/L, high volatile solid content (76% total solid) and carbon to nitrogen ratio of 25:1. The actual gas production started after the lag period of 4 days. Maximum daily yield of 80 ​mL was obtained at the 20th day while the cumulative yield of 250 ​mL was recovered within the retention time. The kinetics of bio-fermentation process followed logistic models amidst the five kinetic models investigated.

Kinetics of Anaerobic Digestion of Dairy Fat Waste with Saponification Pre-Treatment

Anaerobic digestion has been an attractive field of research in the era of energy crisis. Biogas, which is the product of anaerobic digestion, provides alternative energy, while at the same time it also prevents pollution due to organic waste accumulation. Among various organic wastes, dairy fat waste is a potential substrate for anaerobic digestion. Fat waste has high theoretical biogas potential because of its high lipid content. However, anaerobic digestion of organic waste with high lipid content is quite challenging. The main obstacle in anaerobic digestion of fat waste is its tendency to form insoluble floating layer on top of the liquid phase. This phenomenon hinders the access of hydrolytic bacteria to the substrate. Saponification is one of the methods to increase the solubility of the floating layer and hence to improve the availability of substrate for the bacteria. Saponification changes the lipid content into soap which has both polar and non-polar functional groups and the polar side will increase the solubility of the substrate in water. This study evaluated the effect of different dosage of base added as the reactant during saponification pre-treatment on the productivity of anaerobic digestion of dairy fat waste. The kinetics of the anaerobic digestion process was analyzed by mean of mathematical model. The variations of the alkaline dosages studied for saponification pre-treatment were 0.04 mol base/g sCOD; 0.02 mol base/g sCOD; and no pre-treatment for control reactor. This study proved that saponification increased the solubility of dairy fat waste. This result was confirmed by the hydrolysis constant value (kH) of 0.00782/day for reactor with saponification, which was twenty times of magnitude higher than the kH value of 0.00032/day in the reactor without saponification. However, the exposure to high pH during the saponification pre-treatment might somewhat inhibit indigenous acidogenic bacteria in the waste which results in lower methane yield in the reactors with saponification to be compared to the control reactor. A B S T R A KPeruraian anaerobik merupakan salah satu bidang riset yang sangat menarik perhatian dalam era krisis energi. Biogas tidak hanya menyediakan energi alternatif, tetapi juga dapat mencegah pencemaran akibat limbah organik. Limbah lemak susu adalah substrat yang potensial untuk proses peruraian anaerobik karena memiliki potensi biogas teoritis yang tinggi akibat kandungan lemaknya yang tinggi. Namun, peruraian anaerobik dari limbah organik dengan kandungan lemak yang tinggi memiliki tantangan tersendiri. Hambatan utama dalam peruraian anaerobik dari limbah lemak susu adalah kecenderungan untuk membentuk lapisan padatan yang tidak larut dan mengapung di bagian atas fase cair. Fenomena ini menghambat akses bakteri hidrolisis terhadap substrat. Saponifikasi adalah salah satu cara untuk meningkatkan kelarutan lapisan padatan tersebut, sehingga meningkatkan ketersediaan substrat untuk bakteri. Saponifikasi akan mengubah kandungan lemak menjadi sabun yang memiliki gugus fungsi polar maupun non-polar. Gugus fungsi yang bersifat polar akan meningkatkan kelarutan substrat dalam air. Studi ini mengevaluasi pengaruh dari berbagai dosis larutan basa yang ditambahkan sebagai reaktan selama perlakuan awal saponifikasi terhadap peruraian anaerobik limbah lemak susu. Kinetika proses peruraian anaerobik dianalisis dengan menggunakan model matematika. Variasi dosis yang diamati pengaruhnya untuk perlakuan awal saponifikasi adalah 0,04 mol basa/g sCOD; 0,02 mol basa/g sCOD; dan nol (tanpa perlakuan awal saponifikasi). Dari penelitian ini, terbukti bahwa saponifikasi berhasil meningkatkan kelarutan limbah lemak susu dan juga ditunjukkan oleh nilai konstanta hidrolisis (kH) 0,00782/hari lebih tinggi dua puluh kali lipat dibandingkan dengan nilai kH 0,00032/hari pada reaktor tanpa saponifikasi. Akan tetapi, penelitian ini juga mengindikasikan bahwa bakteri asidogenik bawaan substrat terhambat kinerjanya oleh paparan pH yang tinggi selama perlakuan awal saponifikasi berlangsung sehingga hasil gas metan yang diperoleh lebih rendah daripada reaktor kontrol.

A Cyanobacterial Sidestream Nutrient Removal Process and Its Life Cycle Implications

This study proposes a novel integration of a municipal wastewater treatment facility (WWTF) with a cyanobacterial nutrient removal process for sidestream wastewater treatment. A life cycle assessment (LCA) approach was used to determine the effectiveness and environmental performances of the integrated system. The LCA is populated by models of wastewater process engineering, material balance, cyanobacterial growth, and kinetics of anaerobic digestion. The cyanobacteria growth model incorporates chlorophyll synthesis, nitrogen uptake, photosynthesis, centrate inhibition, and competition for nitrogen between cyanobacteria and nitrifiers. Modeling results are validated against experiments with Synechocystis sp. PCC6803 grown in sludge centrate. With a maximum specific growth rate of 1.09 day−1, the nitrogen removal rate of the proposed WWTF would be increased by 15% when compared to the baseline wastewater treatment facility with a biological nutrient removal process. Incorporating the cyanobacterial nutrient removal process as the sidestream wastewater treatment of a conventional activated sludge process reduces the total nitrogen concentrations discharged from the WWTF from 25.9 to 15.2 mg 1−1. Methane yield was found to be increased by 4% of the baseline value when cyanobacterial biomass was co-digested with the activated sludge. Life cycle energy use and greenhouse gas emissions were found to be reduced by 8% and 17%, respectively, relative to a baseline wastewater treatment facility. Overall, a cyanobacteria-based sidestream municipal wastewater treatment process could be an effective and environmentally sustainable biological nutrient removal process in the future addressing the water-energy-food nexus.

Effect of Mechanical Pre-Treatment of the Agricultural Substrates on Yield of Biogas and Kinetics of Anaerobic Digestion

The effect of mechanical pre-treatment of nine different agricultural substrates minced to particle sizes of 1.5 mm, 5 mm and 10 mm on biogas and methane yields and fermentation kinetics was investigated. The results showed, that for five of the nine tested substrates (grass, Progas rye, Palazzo rye, tall wheatgrass, beet), a higher biogas production was obtained for the degree of fragmentation of 10 mm compared to fragmentation of 5 mm and 1.5 mm. For fragmentation of 5 mm, the highest biogas production was achieved for sorghum silage, Atletico maize and Cannavaro maize—649.80, 735.59 and 671.83 Nm3/Mg VS, respectively. However, for the degree of fragmentation of 1.5 mm, the highest biogas production (510.43 Nm3/Mg volatile solid (VS)) was obtained with Topinambur silage. The modified Gompertz model fitted well the kinetics of anaerobic digestion of substrates and show a significant dependence of the model parameters Hmax (biogas production potential) and Rmax (maximum rate of biogas production) on the degree of substrate fragmentation.

Kinetics of Anaerobic Digestion of Palm Oil Mill Effluent (POME) in Double-Stage Batch Bioreactor with Recirculation and Fluidization of Microbial Immobilization Media

Palm Oil Mill Effluent (POME) becomes big problem for palm oil industries, especially for Crude Palm Oil (CPO) industry since it produces 3 tons of POME for every ton of CPO production.The high amount of organic loading in POME makes it potential as a substrate in anaerobic digestion to generate biogas as renewable energy source. The most common but conventional method by using open lagoon is still preferred for most CPO industry in Indonesia to treat POME because of its simplicity and easiness. However, this method creates new major problem for the water bodies since it has no significant chemical oxygen demand (COD) removal and needs wide area. Besides, greenhouse gas (CH4) is also released during the process. An innovation was made in this study by designing vertical column process equipment to run an anaerobic digestion of POME. The vertical column was functioned as anaerobic fluidized bed reactor (AFBR). To enhance the digestion rate in AFBR, natural zeolite was used as the immobilization media and the inoculum was taken from digested biodiesel waste. This research aimed to determine the kinetic constants of double-stage anaerobic POME digestion for COD removal and biogas production. To get close to the real condition, the POME used in this experiment had 8,000 mg/L of sCOD (the real sCOD was ±16,000 mg/L). The experiment was conducted under room temperature with up-flow velocity between 1.75 and 2.3 cm/s for optimum fluidization of immobilization media.

Microbial electrochemical cells as an alternative to biochemical methane potential tests for analyzing batch anaerobic digestion kinetics

Microbial electrochemical cells as an alternative to biochemical methane potential tests for analyzing batch anaerobic digestion kinetics

Improved characterization of anaerobic digestion kinetics of mixed sludges with and without thermally pretreated WAS.

Improved characterization of anaerobic digestion kinetics of mixed sludges with and without thermally pretreated WAS.

Enhancement of microalgae anaerobic digestion by thermo-alkaline pretreatment with lime (CaO)

The aim of this study was to evaluate for the first time the effect of a thermo-alkaline pretreatment with lime (CaO) on microalgae anaerobic digestion. The pretreatment was carried out by adding different CaO doses (4 and 10%) at different temperatures (room temperature (25°C), 55 and 72°C). The exposure time was 4days for pretreatments at 25°C, and 24h for pretreatments at 55 and 72°C. Following, a biochemical methane potential test was conducted with pretreated and untreated microalgae. According to the results, the pretreatment enhanced proteins solubilisation by 32.4% and carbohydrates solubilisation by 31.4% with the highest lime dose and temperature (10% CaO and 72°C). Furthermore, anaerobic digestion kinetics were improved in all cases (from 0.08 to 0.14day−1 for untreated and pretreated microalgae, respectively). The maximum biochemical methane potential increase (25%) was achieved with 10% CaO at 72°C, in accordance with the highest biomass solubilisation. Thus, lime pretreatment appears as a potential strategy to improve microalgae anaerobic digestion.

Application of the Initial Rate Method in Anaerobic Digestion of Kitchen Waste.

This article proposes a methane production approach through sequenced anaerobic digestion of kitchen waste, determines the hydrolysis constants and reaction orders at both low total solid (TS) concentrations and high TS concentrations using the initial rate method, and examines the population growth model and first-order hydrolysis model. The findings indicate that the first-order hydrolysis model better reflects the kinetic process of gas production. During the experiment, all the influential factors of anaerobic fermentation retained their optimal values. The hydrolysis constants and reaction orders at low TS concentrations are then employed to demonstrate that the first-order gas production model can describe the kinetics of the gas production process. At low TS concentrations, the hydrolysis constants and reaction orders demonstrated opposite trends, with both stabilizing after 24 days at 0.99 and 1.1252, respectively. At high TS concentrations, the hydrolysis constants and the reaction orders stabilized at 0.98 (after 18 days) and 0.3507 (after 14 days), respectively. Given sufficient reaction time, the hydrolysis involved in anaerobic fermentation of kitchen waste can be regarded as a first-order reaction in terms of reaction kinetics. This study serves as a good reference for future studies regarding the kinetics of anaerobic digestion of kitchen waste.