RESUMEN
Antimony, extensively used in energy applications, poses toxicity and contamination concerns, especially in anaerobic environments where its impact on microbial activity is poorly understood. Emerging remedies, like biochar, show promise in soil and water treatment. This study investigates biochar's influence on methanogenic activity under Sb(V) and Sb(III) stress using anaerobic sludge as inoculum and lactate as the carbon source. Sb(III) and Sb(V) were introduced at varied concentrations (5-80 mg/L), with or without biochar, monitoring changes in biogas production, pH, Sb, and lactate levels over time. Experiments with Sb(V) also involved calculating mass balance and electron distribution. Results showcased the following significant enhancements: biochar notably improved COD removal and biogas production in Sb(III) spiked conditions, up to 5-fold and 2-fold increases, respectively. Sb(III) removal reached up to 99% with biochar, while in high Sb(V) concentrations, biochar reduced the adverse effect on biogas production by 96%. Adsorption capacities favored biomass (60.96 mg Sb(III)/gVSS, and 22.4 mg Sb(V)/gVSS) over biochar (3.33 mg Sb(III)/g, and 1.61 mg Sb(V)/g) for both Sb species. This study underscores biochar's potential to mitigate metalloid impact on methanogenic activity while aiding Sb removal from liquid phase, suggesting promising implications for remediation and methane production enhancement strategies.
Asunto(s)
Antimonio , Carbón Orgánico , Euryarchaeota , Biocombustibles , Ácido Láctico , MetanoRESUMEN
OBJECTIVES: This study evaluated the effect of particle size and dosage of granular activated carbon (GAC) on methane production from the anaerobic digestion of raw effluent (RE) of swine wastewater, and the solid (SF) and liquid (LF) fractions. The effect of temperature using the selected size and dosage of GAC was also evaluated. METHODS: 60 mL of swine wastewater were inoculated with anaerobic granular sludge and GAC at different dosages and particle size. The cultures were incubated at different temperatures at 130 rpm. The kinetic parameters from experimental data were obtained using the Gompertz model. RESULTS: The cultures with the LF and GAC (75-150 µm, 15 g/L) increased 1.87-fold the methane production compared to the control without GAC. The GAC at 75-150 µm showed lower lag phases and higher Rmax than the cultures with GAC at 590-600 µm. The cumulative methane production at 45 °C with the RE + GAC was 7.4-fold higher than the control. Moreover, methane production at 45 °C significantly increased with the cultures LF + GAC (6.0-fold) and SF + GAC (2.0-fold). The highest production of volatile fatty acids and ammonium was obtained at 45 °C regardless of the substrate and the addition of GAC contributed to a higher extent than the cultures lacking GAC. In most cases, the kinetic parameters at 30 °C and 37 °C were also higher with GAC. CONCLUSIONS: GAC contributed to improving the fermentative and methanogenesis stages during the anaerobic digestion of fractions, evidenced by an improvement in the kinetic parameters.
Asunto(s)
Carbón Orgánico , Aguas Residuales , Animales , Porcinos , Anaerobiosis , Temperatura , Reactores Biológicos , MetanoRESUMEN
Biocatalytic degradation of recalcitrant pollutants employing ligninolytic enzymes is a promising approach for wastewater treatment. However, enzymes production must be improved to make biodegradation a more cost-effective treatment. In this research, laccase production from Trametes versicolor using lignocellulosic residues (agave bagasse, coconut fibers and wheat bran) as cosubstrates was improved using a central composite face-centered design, and the application of the enzymes-rich culture supernatant was evaluated for blue wastewater biodegradation. Findings revealed that the optimal conditions for laccase production were found at 35 °C and 5 g/L of wheat bran as cosubstrate, reaching about 200 U/mL in 11 days in a batch submerged fermentation. These conditions were scaled up for a submerged fermentation using an airlift reactor, and a maximum enzymatic activity of 1200 U/mL was achieved in 9 days at 30 °C. This enzymes-rich culture supernatant was tested for the degradation of blue wastewater from aircraft in an airlift reactor. Results showed a COD removal efficiency of 43% and an increase of the biodegradability index from 0.64 to 1.36, both results applying an enzymatic activity of supernatant of 300 U/mL. In conclusion, the enzymatic biodegradation becomes a viable strategy for the pretreatment of a real effluent such as the blue wastewater collected in public transportation.
Asunto(s)
Lacasa , Trametes , Biodegradación Ambiental , Lignina , Aguas ResidualesRESUMEN
In this work, lawsone (LQ) and anthraquinone 2-sulphonate (AQS) (dissolved and covalently immobilized on activated carbon) were evaluated as redox mediators during the dark fermentation of glucose by a pretreated anaerobic sludge. Findings revealed that the use of dissolved LQ increased H2 production (10%), and dissolved AQS improved H2 production rate (11.4%). Furthermore, the total production of liquid byproducts (acetate, butyrate, ethanol, and butanol) was enhanced using dissolved (17%) and immobilized (36%) redox mediators. The established redox standard potentials of LQ and AQS suggested a possible interaction through electron transfer in cytochromes complexes for hydrogen production and the Bcd/EtfAB complex for volatile fatty acid formation.