High Organic Loading Research Articles

Simulation models of microbial community, pH, and volatile fatty acids of anaerobic digestion developed by machine learning

Anaerobic digestion (AD) is a promising method for treating high-content organic waste via the microbiome in an anaerobic environment. However, because AD is a complex process involving microbial community (MC), it is essential to determine the relationship between the MC, pH, and volatile fatty acids (VFAs). This study employed five machine learning models: artificial neural network, convolutional neural network, extra trees, extreme gradient boost, and support vector machine to estimate the relationship between MC, pH, and VFAs. Methanoregulaceae, Methanomicrobiaceae, Spirochaetes, pH, acetic acid, isobutyric acid, and isovaleric acid were estimated with high accuracy, with R2 >0.800. The variable importance of the models with the highest accuracy was calculated based on the shapley additive explanations analysis. As a result, the MC estimation models suggested syntrophic acetate oxidation by Spirochaetes, and VFAs-pH estimation models suggested that the high organic loading rate during the start-up phase can lead to isovaleric acid accumulation. In an in-silico test using the machine learning simulator, the change of MC resulted in the critical effects on the acetate accumulation from 500 to 1500 mg/L. The optimal relative abundance of Mehtanoregulaceae and Methanomicrobiaceae for the stable operation was suggested as 15–37 % and 3–15 %, respectively, resulting in the acetic acid concentration below 1000 mg/L.

Performance optimization of novel multi-unit green wall system for blackwater treatment and reuse on-site

Blackwater constitutes a primary component of environmental pollution posing serious risk to human health; however, reusing the nutrients found in blackwater diminishes the associated pollution and promotes resource recycling. Conventional green-wall systems are not suitable for in situ treatment of high-concentration wastewater. Thereby, a novel multi-unit green-wall system with six independent treatment units was designed to achieve a cost-effective and eco-friendly in situ treatment of blackwater with high organic load. Zeolite carriers were selected for the matrix with carrier depth of 14.5 cm, ivy and chlorophytum were selected as the greening plants. Various pollutants were rapidly reduced at the initial stage and the concentration of the pollutants decreased as the number of treatment units increased. Overall, the green-wall system was more effective in removing COD and NH4+–N with the removal rates of 98.5% and 98%, which may be due to the good buffering capacity of the media and the roles of Firmicutes and Bacteroidetes in COD degradation and ammoniated nitrification reactions. In addition, the maximum TP and TN removal rates were observed with a value of 85% and 42%, respectively. Consequently, the novel multi-unit green-wall system is an effective method for in situ blackwater reuse.Graphical

Synergistic effects of biochar addition and filtration mode optimization on mitigating membrane fouling in high-solid anaerobic membrane bioreactors

In this study, a high-solid anaerobic membrane bioreactor was established for treating food waste, and membrane fouling rates were regulated through multivariate modulation. The anaerobic membrane bioreactor operated stably at a high organic loading rate of 28.75 gCOD/L/d achieved a methane production rate of 8.03 ± 0.61 L/L/d. Experimental findings revealed that the most effective control of membrane fouling was achieved at a filtration– relaxation ratio (F/R) of 10/90 s. This indicates that a higher relaxation frequency provided improved the mitigation of membrane fouling. Compared with single F/R modulation, the combined modulation of biochar and F/R provided enhanced control over membrane fouling. Moreover, the addition of biochar altered the sludge properties of the reactor, thereby preventing the formation of a dense cake layer. Additionally, biochar enhanced the sheer force of the fluid on the membrane surface and facilitated the separation of pollutants during the relaxation stage, thereby contributing to improved control of membrane fouling.

Evaluating the environmental and economic performance of biological and advanced biological wastewater treatment plants by life cycle assessment and life cycle costing.

The primary objective of this study is to assess and establish benchmarks for environmental and economic sustainability of biological and advanced biological wastewater treatment plants (WWTPs) with different treatment technologies and characteristics. Furthermore, the study aims to determine the beneficial role of WWTPs to reduction of eutrophication potential. Environmental and economic sustainability of ten municipal WWTPs was assessed using life cycle assessment (LCA) and life cycle costing (LCC). In the first section of the study, LCA was performed to determine the environmental performance of the WWTPs. Furthermore, net environmental benefit (NEB) approach was implemented to reveal the beneficial role of WWTPs to eutrophication potential. In the subsequent section, LCA-based LCC was conducted by integrating the results of LCA. The most significant environmental impact was determined as marine aquatic ecotoxicity, which is highly affected from the generation and transmission of electricity consumed in the WWTPs. Wastewater recovery and co-incineration of sewage sludge in cement kiln ensure significant environmental savings on ozone layer depletion, human toxicity, acidification, photochemical oxidation, and abiotic depletion (fossil fuel) potential. Considering NEB approach, the highest NEB values were found for the WWTPs with the higher organic load and nutrient concentration in the influent. The results of LCC in WWTPs varied between 0.21 and 0.53 €/m3. External (environmental) costs were evaluated higher than internal (operational) costs for all selected WWTPs. While eutrophication was the highest among environmental costs, electricity cost was the highest among operational costs for almost all WWTPs.

Oxidation of Abattoir Wastewater Using Cobalt-Catalyzed Potassium Persulfate

Abattoir wastewater (AWW) contains a high level of organic pollutants due to the presence of toxic contaminants such as blood, feces from animals, and detergents from cleaning activities. In this study, the wastewater from the slaughterhouse was treated with a cobalt-catalyzed persulfate oxidation reaction to determine how well persulfate works as an oxidant to get rid of and break down organic materials. The water tested had a high organic load (COD = 2100mg/L), a pH of 7.7, and a BOD of 800mg/L. Time (10–90min), temperature (25–75°C), acid content (0.5–2.5M), persulfate (0.025–0.1g), and cobalt catalyst (50–150 mg/L) were all evaluated as operational conditions. Temperature and acid content was found to have a positive effect on COD elimination while increasing the residence time. The reaction conditions were optimized at a constant dose of 0.3 g of potassium persulfate, 1 M acid concentration in 30 minutes, and a maximum temperature of 60°C. At optimum conditions, approximately 98.46% of the COD was removed. The COD elimination rate was 92.85% at a low amount of potassium persulfate (0.075g). The study concludes that the developed approach could be used to efficiently treat abattoir wastewater.

Investigating the efficiency of a two-stage anaerobic-aerobic process for the treatment of confectionery industry wastewaters with simultaneous production of biohydrogen and polyhydroxyalkanoates.

The scope of the current study was to investigate the efficiency of a two-stage anaerobic-aerobic process for the simultaneous treatment and valorization of selective wastewater streams from a confectionary industry. The specific wastewater (confectionary industry wastewater, CIW) was a mixture of the rinsing eluting during washing of the cauldrons in which jellies and syrups were produced, and contained mainly readily fermentable sugars, being thus of high organic load. The first stage of the process was the dark fermentation (DF) of the CIW in continuous, attached-biomass systems, in which the effect on hydrogen yields and distribution of metabolites were studied for different packing materials (ceramic or plastic), hydraulic retention times, HRTs (12 h–30 h) and feed substrate concentration (20 g COD/L- 50 g COD/L). In the second stage, the effectiveness of the aerobic treatment of the DF effluents was evaluated in terms of the reduction of the organic load and the production of polyhydroxyalkanoates (PHAs) through an enriched mixed microbial culture (MMC). The MMC was developed in a continuous draw and fill system, in which the accumulation potential of PHAs was studied. It was shown that the hydrogen production rates decreased for increasing substrate concentration and HRTs, with a maximum of 12.70 ± 0.35 m3 H2/m3 initial CIW achieved for the lowest HRT and feed concentration and using ceramic beads as packing material. Butyrate, acetate and lactate were the main metabolites generated in all cases, in different ratios. The distribution of metabolites during DF was shown to highly affect the efficiency of the second process in terms of both the reduction of organic load and the PHAs yields. The highest removal of organic load achieved after 48 h of aerobic treatment was 84.0 ± 0.9 %, whereas the maximum PHAs yield was 21.46 ± 0.13 kg PHAs/m3 initial CIW.

Aqueous Phase Reforming of Dairy Wastewater for Hydrogen Production: An Experimental and Energetic Assessment

The treatment of dairy industry effluents poses a significant challenge from the environmental point of view because of its high organic load. In this work, the aqueous phase reforming of lactose was investigated as a representative model compound for the production of renewable hydrogen. The tests were conducted using two different scenarios: the first one is referred to as direct aqueous phase reforming (APR); the second one proposed a pre-hydrogenation step, followed by APR. The implementation of this reactive pretreatment allowed for minimizing the solid by-product formation with respect to the direct APR, where most of the initial carbon ended up as solid residue. The pre-hydrogenation was investigated in the range of 180–220 °C, using Ru-based catalysts. In the best scenario (using 5% Ru/C), the carbon to solid was reduced by 95%, and up to 70% of the initial carbon was converted into gaseous compounds, hence contributing to the removal of the organic content of the wastewater while producing an energy carrier. Moreover, the hydrogen selectivity increased up to 70% (with respect to 2.5% for direct APR), thanks to hindering homogeneous reaction pathways that do not lead to hydrogen production. Finally, an energetic analysis was conducted to assess the possibility of coupling the APR with the dairy industry and quantifying the percentage of energy which may be produced in situ to satisfy industrial duties.

EFFICIENCY OF AN UPFLOW ANAEROBIC FILTER FOR POULTRY EFFLUENT TREATMENT

Poultry slaughterhouses discharge large quantities of effluents that can be treated biologically. The objective of this study was to evaluate the chemical oxygen demand (COD) removal efficiency of an upflow anaerobic filter (UAF) with effluents from a poultry slaughterhouse, using volcanic stone (tezontle) as a support medium. Effluent characterization was carried out in accordance with Mexican official standards and standard methods. The support medium was inoculated with activated sludge from an urban wastewater treatment plant. The filter was operated in continuous flow with applied volumetric loads (AVL) of 1, 1.5, 2, 2.5, and 3 kg COD m-3 d-1 and hydraulic retention times (HRT) of 5.8, 3.8, 2.9, 2.3, and 1.9 days. An analysis of variance (ANOVA) was performed, and significant differences were determined for each AVL using the Krustall-Wallis method. The results obtained in the gradually applied AVL were 26.1, 53.2, 40.1, 17, and 49.7 % COD removal. However, in the AVL of 2 and 2.5 kg COD m-3 d-1, there was a decrease in the removal, which is attributed to the destabilization of the system due to the increase in loads. The maximum methane production was 125 mL at an AVL of 3 kg COD m-3 d-1, with a methane yield (YCH4) of 0.082 LCH4 g-1 COD-1rem. With no increase in methane production at each AVL, the theoretical yield of 0.328 LCH4 g-1 COD-1rem. was not met. The upflow anaerobic filter demonstrated its efficiency with a poultry effluent, with maximum COD removal greater than 50 %; however, more acclimatization time is required for the formation of biofilm in the support medium, a pretreatment that removes the high organic load and allows for gradual biogas production.

Optimization of Initial Cell Density and Usage Efficiency of Seed Culture Medium During Lipid Production from Distillery Wastewater by Rhodosporidium toruloides

For the environmentally sustainable development, the recovery of resource or energy from wastes has attracted worldwide attention in recent years. The wastewater produced from distillery is more difficult to treat than the domestic wastewater due to the high organic loads. This study explores the possibility of developing a process, which could produce microbial lipid convertible to biodiesel by recovering nutrients from non-sterile wastewater while simultaneously removing part of organic matters through cultivating oleaginous microorganisms. Especially, it is intended to further optimize the initial cell density and the usage efficiency of seed culture medium. The lipid productivity by oleaginous yeast Rhodosporidium toruloides was studied using wastewater from rice wine distillery, at 30ºC under different initial cell densities (2 x 107, 1 x 107, 0.8 x 107, and 0.5 x 107 cells/mL) and incubation periods (2-5 days). Chemical oxygen demand (COD) removal efficiency, cell yield, and lipid yield were analyzed and the potential for bioenergy recovery from wastewater was assessed. The seed culture medium was found reusable for the second time without the addition of extra nutrient and possible for the third time with the addition of glucose.

Assessing lab-scale hybrid wetland performance for pollutant and pathogen removal from high organic loading septage

A laboratory-scale three-staged hybrid constructed wetland (CW) system was operated for the treatment of septage. The Hybrid-CW, covering an area of 1.92 m2, consisted of a sludge drying bed (SDB) of 0.41 m2, a vertical sub-surface flow bed (VSSF) of 0.58 m2, and a horizontal sub-surface flow bed (HSSF) of 0.93 m2. The SDB, VSSF and HSSF beds were operated at an average hydraulic loading rate (HLR) 22.2, 5.2 and 3.2 cm d−1. With an average organic loading rate (OLR) of 28.8 g d−1 the Hybrid-CW confirmed effective removal of BOD5, COD, TS, and TSS by 99.2 ± 0.3% and 99.4 ± 0.2%, 96.4 ± 0.8% and 86.9 ± 2.4%, respectively. The correlation between effluent TS and TSS concentrations with influent concentrations indicated a dependence of TS and TSS removal on influent concentration. Average total coliform count in influent and effluent was observed as 6.3 × 107 and 1.6 × 103 CFU L−1respectively. Average helminthes eggs count in the influent and effluent was recorded as 5 × 107 and 2 × 104 eggs L−1 respectively. With an inlet TS loading of 177.5 g d−1, the hybrid CW system attained 96.4% TS removal and 87% TSS removal. The sludge drying bed, operating with a remarkably high TS loading of 861.9 ± 77.1 g m−2 d−1, avoided clogging and achieved >90% removal rates for total coliform and helminthes eggs along with around 60% for TS and BOD. Furthermore, the system exhibited excellent removal rates of over 99% for both total coliform (TC) and helminthes eggs (HE). Treated septage meets the Indian wastewater discharge criteria for BOD, COD, TS and TN.

Composting of distillery spent wash

Distillery spent wash, a by-product of the alcoholic beverage industry, is an organic waste whose management poses significant challenges due to its acidity, high organic load, notable content of polyphenols, macronutrients, micronutrients and heavy metals. In Europe, billions of liters of distillery waste are generated annually and its eco-unfriendly disposal can cause severe environmental and health impacts. Composting is a viable management strategy to treat and manage distillery slop promoting the recycling and stabilization of organic matter and nutrients in the material. The review examines different composting methods, such as single composting, co-composting and vermicomposting, along with their benefits and drawbacks. To optimize composting effectiveness, various materials, such as sewage sludge, vinasse, green and animal manure, inorganic amendments, bagasse, filter cake and municipal solid waste, among other agro-food and animal bio-wastes, can be used as a source of nitrogen and microorganisms. Also, the usage of different materials and mixtures aims to enhance the composting process increasing the degradation rate and the quality of the compost. The challenges of distillery spent wash composting are also covered in the paper which are mainly due to its characteristics, including high salt content, low carbon-to-nitrogen ratio, low pH and potential phytotoxicity. The paper concludes that composting distillery spent wash is an effective and sustainable waste management solution for recovering valuable nutrient resources and producing a stable nutrient-rich organic soil amendment. The produced compost can improve crop yields, nutrient absorption by plants and plant biomass and contribute to soil properties and restoration. The review provides insights into the current state of distillery spent wash composting and recommends future research directions to improve efficiency and expand potential applications.

Biodegradation of olive mill wastewater by two bacterial strains

Wastewater from olive mill is a by-product of olive oil production, that is a serious environmental problem in many Mediterranean countries. The production of large quantities of waste in a short period of time together with the high organic load and high toxicity of the waste make it difficult to deal with the problem. Phenolic compounds are one of the main factors responsible for the toxicity of olive mill wastewater (OMW). In the present work, two selectively anaerobic bacteria, Sporolactobacillus spp. and Rhodopseudomonas spp. isolated from compost tea were used. These two strains were tested for their ability to reduce the BOD5 and COD levels and to degrade polyphenols responsible for the toxicity of OMW. The two strains were able to grow on a dilution of a natural OMW and largely degrade the polyphenols. The dilution depended on the initial COD value of the waste. After 90 days of treatment reduction over 70% was observed in all three parameters which were measured while in an additional sampling that carried out in the 150th day, the reduction of BOD5, COD and total phenols concentration, reached to 96.1%, 81.8% and 75.1% respectively. Additionally, an increase in the pH was observed, moving from acidic to slightly alkaline. All these features make the two strains attractive candidates for the development of a biotechnological process for the biodegradation of OMW.

Determination of the level of chromium (III) and comparison of chemical precipitating agents to recover and reuse it from tannery waste water

Most tannery wastes are discharged into the natural environment without any treatment system and pose a potential negative impact on living things due to their high organic loading and chromium content. In this study, a comparison of chemical precipitating agents to recover and reuse chromium (III) from tannery waste water was done. The study was conducted by performing physicochemical characterization and chemical precipitation. The Cr concentration was determined using the flame atomic absorption spectroscopy (FAAS) method. Statistical analysis was performed using the SPSS program through one-way analysis of variance (ANOVA). In terms of sludge volume, magnesium oxide produced 25%, calcium hydroxide 31%, and sodium hydroxide 44%. The findings have implications for global sustainability, as the use of magnesium oxide as a precipitating agent results in a smaller sludge volume and potentially less environmental impact.

TRATAMENTO DE EFLUENTE DE LATICÍNIO POR PROCESSO OXIDATIVO AVANÇADO TIPO FENTON‑FOTOCATALISADO

TREATMENT DAIRY INDUSTRY WASTE WATER BY ADVANCED OXIDATION PROCESSES PHOTOCATALYSIS-SELF-FENTON SYSTEM. With the increase in industrial production, there is a direct increase in waste generation. Milk processing industries are one of these cases that results in a complex effluent with a high organic load. If the effluent is discarded without proper treatment, it can compromise the survival of biota in water courses. Advanced oxidation processes (AOP) are one of the main technologies used in the treatment of effluents, especially the Photocatalysis-Self-Fenton System (PF) type. The present study aimed to evaluate the efficiency of the PF process and to optimize the parameters of dairy effluent treatment. The raw effluent was characterized considering the parameters: conductivity, pH, chemical oxygen demand (COD), solids, and oils and greases. Through an experimental design, the variation of the concentrations of Fe2+, H2O2 and the reaction time were optimized, and the influence of these three variables on the removal of COD was evaluated. Statistical analysis showed that all variables were statistically significant, and the model used had a coefficient of determination of 0.97, confirming that the model was well adjusted. The ideal conditions for COD removal, reaching 79%, were obtained in 60 min, 0.625 g L-1 of Fe²+ and 0.829 mL L-1 of H2O2.

Microalgae: A Biological Tool for Removal and Recovery of Potentially Toxic Elements in Wastewater Treatment Photobioreactors.

Potentially toxic elements (PTE) pollution in water bodies is an emerging problem in recent decades due to uncontrolled discharges from human activities. Copper, zinc, arsenic, cadmium, lead, mercury, and uranium are considered potentially toxic and carcinogenic elements that threaten human health. Microalgae-based technologies for the wastewater treatment have gained importance in recent years due to their biomass high growth rates and effectiveness. Also, these microalgae-bacteria systems are cost-effective and environmentally friendly, utilize sunlight and CO2, and simultaneously address multiple environmental challenges, such as carbon mitigation, bioremediation, and generation of valuable biomass useful for biofuel production. Additionally, microalgae possess a diverse array of extracellular and intracellular mechanisms that enable them to remove and mitigate the toxicity of PTE present in wastewater. Therefore, photobioreactors are promising candidates for practical applications in bioremediation of wastewater containing toxic elements. Despite the increasing amount of research in this field in recent years, most studies are conducted in laboratory scale and there is a scarcity of large-scale studies under real and variable environmental conditions. Besides, the limited understanding of the multiple mechanisms controlling PTE biosorption in wastewater containing high organic matter loads and potentially toxic elements requires further studies. This chapter provides a schematic representation of the mechanisms and factors involved in the remediation of potentially toxic elements by microalgae, as well as the main results obtained in recent years.

A remarkable step in the aerobic biological treatment of Olive Mill Wastewater (OMW): A combination of selected microbial strains that enhance their decolorization and depollution

The olive industry extracts oil from olives but also generates solid co-products called pomace and liquid wastes known as Olive Mill Wastewater (OMW). With global annual production exceeding 30 million tons and approximately 685,000 tons in Morocco alone, these wastes pose environmental challenges due to their high acidity, organic load, and phenolic compounds. Our research aims to depollute and recycle OMW using aerobic biological treatment methods. Samples were collected from various ecological sites across four Moroccan regions. We isolated and purified several strains of molds, yeasts, and bacteria capable of decolorizing OMW. Decolorization experiments revealed promising results, with a combination of seven selected molds showing significant reductions in chemical oxygen demand (COD) by 71.44%, biochemical oxygen demand (BOD5) by 69.91%, and polyphenols content by 84.22%. Encouraged by these findings, we propose further treatment using sourdoughs composed of combinations of different pure strains, including yeasts and selected bacteria such as Bacillus subtilis and Pseudomonas aeruginosa. This approach demonstrates a practical and cost-effective method for depolluting and recycling OMW, contributing to environmental protection and human health preservation. By mitigating the risks associated with untreated OMW discharge, this study offers a viable solution to the environmental challenges posed by olive processing industries globally, particularly in regions like Morocco where olive cultivation is significant.

Electronic regulation to achieve efficient anaerobic digestion of organic fraction of municipal solid waste (OFMSW): strategies, challenges and potential solutions

Anaerobic digestion (AD) of organic fraction of municipal solid waste (OFMSW) is prone to system breakdown under high organic loading rates (OLRs) condition, which subsequently reduces the efficiency of digestion process and results in substantial economic losses. In this perspective paper, the substances metabolisms, electrons flow, as well as microbial interaction mechanisms within AD process are comprehensively discussed, and the underlying bottleneck that causes inefficient methane production is identified, which is “electrons surplus”. Systems encountering severe electron surplus are at risk of process failure, making it crucial to proactively prevent this phenomenon through appropriate approaches. On this basis, the present perspective proposes three potential electronic regulation strategies to prevent electrons surplus, namely, electron shunt, accelerating electron transfer and regulating methanogenic metabolism pathway, and presents specific methodologies for each strategy. Furthermore, the potential solutions to challenges that may occur during the electronic regulation process are also presented in this paper. This perspective aims to provide innovative approaches to achieve the efficient and stable operation of OFMSW anaerobic digestion, especially under high OLRs condition.

Mathematical modeling to size anaerobic stabilization ponds intended for slaughterhouse wastewater treatment – the role of temperature and hydraulic retention time

A new mathematical model for constructing anaerobic stabilization pond treatment systems for high organic load wastewater, based on biochemical oxygen demand, temperature and hydraulic retention time, is discussed.

Inorganic carbon as a key factor governing competition between methanogens and acetogens in high-rate anaerobic treatment of methanol wastewater

The anaerobic treatment of methanolic wastewater has become a crucial issue. Sodium bicarbonate (NaHCO3), as a typical representative of inorganic carbon substances, not only provides alkalinity in the anaerobic treatment of methanol but also governs the competition between methanogens and acetogens. However, a suitable dosage has rarely been mentioned. In this study, we demonstrate the crucial role of NaHCO3 in the anaerobic treatment of methanol using a long-term operated up-flow anaerobic sludge blanket (UASB) reactor and batch tests. The UASB results revealed that by adding 3 to 5 g/L of NaHCO3 to the influent at a high organic loading rate of 50 gCOD/L/d, a significant accumulation of acetic acid was detected, with a maximum value of up to 1400 mg/L. In the context of microbial community evolution, this study profiled substrate competition between the acetogens Acetobacterium and Methanomethylovorans, which directly utilize methanol, as well as the synergistic effects of Acetobacterium and acetoclastic Methanosaeta. Abundance analysis of genes encoding relevant pathway enzymes also revealed that the acetic acid production pathway was significantly enhanced when more NaHCO3 was added. According to the dose–response mechanism in the batch test based on kinetic analysis, an acceptable threshold prediction scheme was beneficial in reasonably adding NaHCO3 to improve acid production capacity and rapid methanol degradation, and ensuring that the generated acetate could be rapidly degraded without inhibition, in the high-rate anaerobic treatment of methanolic wastewater.

Improving the Anaerobic Digestion Process of Wine Lees by the Addition of Microparticles

Wine lee generation, a by-product of the wine industry, implies economic challenges for producers in terms of management due to its high organic load and low pH value. Biological treatment based on controlled anaerobic digestion may emerge as a viable management alternative given its promising potential for biogas production thanks to the organic content of the substrate. However, the complex properties of wine lees may lead to microbial activity inhibition and process kinetics failure. Various solutions have already been explored, including co-digestion with other substrates, or the application of different pretreatments, to mitigate the effects of the accumulation of phenolic compounds, volatile fatty acids, antioxidants, or the acidic pH value of the medium. In this study, laboratory-scale batch reactors were established, adding iron- (magnetite) or carbon (graphite)-based microparticles to assess their impact on the kinetics of the process. The results demonstrate a significant improvement of 35% in the potential production of biomethane after four days of operation with graphite particles and 42% after five days using magnetite particles. Methane production rates, as determined by the Gompertz model, were 45.38 and 46.54 mL CH4∙gVS−1∙d−1 for the application of graphite and magnetite microparticles to the medium, respectively, compared to the value of 33.46 mL CH4∙gVS−1∙d−1 for the control trial, confirming kinetic process improvements of 36% and 39%, respectively. Evidences of the acceleration of the methanogenesis phase were detected along the essays; however, the strong inhibition mediated by the carboxylate accumulation was not avoided in any of the tested conditions.