RESUMO
This research aimed at evaluating optimal conditions to obtain value-added metabolites, such as bio-CH4, by co-digesting swine manure and food waste diluted in domestic sewage. The assays were carried out in batches using the statistical methods of Rotational Central Composite Design (RCCD) and Surface Response to evaluate the ranges of food waste (1.30-9.70 gTS.L-1), pH (6.16-7.84) and granular Upflow Anaerobic Sludge Blanket sludge as inoculum (2.32-5.68 gTS.L-1), besides about 250 mL of swine manure in 500 mL Duran flasks. According to the RCCD matrix, bio-CH4 yields among 600.6 ± 60.1 and 2790.0 ± 112.0 mL CH4 gTS.L-1 were observed, besides the maximum CH4 production rate between 0.4 ± 0.5 and 49.7 ± 2.0 mL CH4 h-1 and λ between ≤0.0 and 299.3 ± 4.5 h. In the validation assay, the optimal conditions of 9.98 gTS.L-1 of food waste, pH adjusted to 8.0 and 2.20 gTS.L-1 of inoculum were considered, and the bio-CH4 yield obtained (5640.79 ± 242.98 mL CH4 gTS.L-1 or also 5201.83 ± 224.07 mL CH4 gTVS.L-1) was 11.3 times higher than in assays before optimization (499.3 ± 16.0 mL CH4 gTS.L-1) with 5 gTS.L-1 of food waste, 3 gTS.L-1 of inoculum and pH 7.0. Besides, the results observed about the energetic balance of the control and validation assays highlight the importance of process optimization, as this condition was the only one with energy supply higher than the energy required for its operation, exceeding max consumption sevenfold. Based on the most dominant microorganisms (Methanosaeta, 31.06%) and the metabolic inference of the validation assay, it could be inferred that the acetoclastic methanogenesis was the predominant pathway to CH4 production.
Assuntos
Eliminação de Resíduos , Esgotos , Animais , Suínos , Esgotos/química , Anaerobiose , Eliminação de Resíduos/métodos , Esterco , Alimentos , Reatores Biológicos , Concentração de Íons de Hidrogênio , Metano , Biocombustíveis/análiseRESUMO
An alternative to improve the production of biorefinery products, such as biohydrogen (H2) and volatile fatty acids (VFA), is the combination of nanotechnology and biological processes. In order to compare the use of both processes in two different reactor configurations, batch reactors and continuous anaerobic fluidized bed reactors (AFBR) were studied under the same conditions (37°C, pH 6.8, Clostridium butyricum as an inoculum and glucose as a substrate) to evaluate the influence of zero valence iron and nickel nanoparticles (NPs) on H2 and VFA production. There was a shift in the production of acetic and butyric acids to produce mainly valeric acid when NPs were added in batch reactors. Meanwhile, in AFBR the change was from lactic acid to butyric and acetic acids with the addition of NPs. It showed that the effect of NPs on the fermentation process was different when the configuration of batch and continuous reactors was compared. The H2 yield in both reactor configurations increased with the addition of NPs. In batch reactors from 6.6 to 8.0â mmol H2 g-1 of COD and in AFBR from 4.9 to 6.2â mmol of H2 g-1 of COD. Therefore, given the simplicity and low cost of the synthesis of metallic NPs, it is a promising additive to optimize the fermentation process in different reactor configurations.
RESUMO
Diclofenac (DCF), ibuprofen (IBU), propranolol (PRO), triclosan (TCS) and linear alkylbenzene sulfonate (LAS) can be recalcitrant in Wastewater Treatment Plants (WWTP). The removal of these compounds was investigated in scale-up (69 L) Expanded Granular Sludge Bed (EGSB) reactor, fed with sanitary sewage from the São Carlos-SP (Brazil) WWTP and 200 mg L-1 of ethanol. The EGSB was operated in three phases: (I) hydraulic retention time (HRT) of 36±4 h; (II) HRT of 20±2 h and (III) HRT of 20±2 h with ethanol. Phases I and II showed no significant difference in the removal of LAS (63 ± 11-65 ± 12 %), DCF (37 ± 18-35 ± 11 %), IBU (43 ± 18-44 ± 16 %) and PRO (46 ± 25-51 ± 23 %) for 13±2-15 ± 2 mg L-1, 106 ± 32-462 ± 294 µg L-1, 166 ± 55-462 ± 213 µg L-1 and 201 ± 113-250 ± 141 µg L-1 influent, respectively. Higher TCS removal was obtained in phase I (72 ± 17 % for 127 ± 120 µg L-1 influent) when compared to phase II (51 ± 13 % for 135 ± 119 µg L-1 influent). This was due to its greater adsorption (40 %) in the initial phase. Phase III had higher removal of DCF (42 ± 10 % for 107 ± 26 µg L-1 influent), IBU (50 ± 15 % for 164 ± 47 µg L-1 influent) and TCS (85 ± 15 % for 185 ± 148 µg L-1 influent) and lower removal of LAS (35 ± 14 % for 12 ± 3 mg L-1 influent) and PRO (-142 ± 177 % for 188 ± 88 µg L-1 influent). Bacteria similar to Syntrophobacter, Smithella, Macellibacteroides, Syntrophus, Blvii28_wastewater-sludge_group and Bacteroides were identified in phase I with relative abundance of 3.1 %-4.7 %. Syntrophobacter was more abundant (15.4 %) in phase II, while in phase III, it was Smithella (12.7 %) and Caldisericum (15.1 %). Regarding the Archaea Domain, Methanosaeta was more abundant in phases I (84 %) and II (67 %), while in phase III it was Methanobacterium (86 %).
Assuntos
Preparações Farmacêuticas , Esgotos , Anaerobiose , Brasil , HigieneRESUMO
The influence of ethanol on the degradation kinetics of linear alkyl benzene sulfonate (LAS) and organic matter was investigated using batch experiments with different initial LAS concentrations (8.3 mg L-1 to 66.9 mg L-1) and biomass immobilized on sand. Data were fitted with a substrate inhibition model. Concentrations of 2.4 mg LAS L-1 and 18.9 mg LAS L-1 (without and with ethanol) provided the maximum LAS utilization rate by the biomass (Sbm). For LAS degradation, ethanol addition favored a lower decrease in the specific substrate utilization rate (robs), even at the LAS concentration usually reported as inhibitory (> 14.4 mg L-1). For organic matter degradation, robs was higher with ethanol. Higher biomass differentiation was observed at higher LAS concentrations. With ethanol, microbial selection occurred at LAS concentrations near Sbm. At higher LAS concentrations, the dominance and diversity values did not change significantly with ethanol, whereas without ethanol, their behaviors were irregular.
Assuntos
Ácidos Alcanossulfônicos/metabolismo , Biomassa , Etanol/metabolismo , Esgotos , Eliminação de Resíduos Líquidos , Purificação da Água , Biodegradação AmbientalRESUMO
The 16S rRNA gene amplicon and whole-genome shotgun metagenomic (WGSM) sequencing approaches were used to investigate wide-spectrum profiles of microbial composition and metabolic diversity from a full-scale UASB reactor applied to poultry slaughterhouse wastewater treatment. The data were generated by using MiSeq 2 × 250 bp and HiSeq 2 × 150 bp Illumina sequencing platforms for 16S amplicon and WGSM sequencing, respectively. Each approach revealed a distinct microbial community profile, with Pseudomonas and Psychrobacter as predominant genus for the WGSM dataset and Clostridium and Methanosaeta for the 16S rRNA gene amplicon dataset. The virome characterization revealed the presence of two viral families with Bacteria and Archaea as host, Myoviridae, and Siphoviridae. A wide functional diversity was found with predominance of genes involved in the metabolism of acetone, butanol, and ethanol synthesis; and one-carbon metabolism (e.g., methanogenesis). Genes related to the acetotrophic methanogenesis pathways were more abundant than methylotrophic and hydrogenotrophic, corroborating the taxonomic results that showed the prevalence of the acetotrophic genus Methanosaeta. Moreover, the dataset indicated a variety of metabolic genes involved in sulfur, nitrogen, iron, and phosphorus cycles, with many genera able to act in all cycles. BLAST analysis against Antibiotic Resistance Genes Database (ARDB) revealed that microbial community contained 43 different types of antibiotic resistance genes, some of them were associated with growth chicken promotion (e.g., bacitracin, tetracycline, and polymyxin).
Assuntos
Matadouros , Reatores Biológicos/microbiologia , Biota , Águas Residuárias , Purificação da Água , Animais , Archaea/classificação , Archaea/genética , Bactérias/classificação , Bactérias/genética , Bacteriófagos/classificação , Bacteriófagos/genética , Galinhas , Análise por Conglomerados , DNA Arqueal/química , DNA Arqueal/genética , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Metagenômica , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNARESUMO
This study evaluates the kinetics of methane production and degradation of standard linear alkylbenzene sulfonate (LAS) (50 ± 3.5 mg/L) and LAS from laundry wastewater (85 ± 2.1 mg/L) in anaerobic batch reactors at 30°C with different sources of inoculum. The inocula were obtained by auto-fermentation (AFM) and UASB reactors from wastewater treatment of poultry slaughterhouse (SGH), swine production (SWT) and wastewater treatment thermophilic of sugarcane industry (THR). The study was divided into three phases: synthetic substrate (Phase I), standard LAS (Phase II) and LAS from laundry wastewater (Phase III). For SGH, the highest values for cumulative methane productions (1,844.8 ± 149 µmol-Phase II), methane production rate (70.8 ± 88 µmol/h-Phase II and 4.01 ± 07 µmol/h-Phase III) were observed. The use of thermophilic biomass (THR) incubated at 30°C was not favorable for methane production and LAS biodegradation, but the highest kinetic coefficient degradation (k1app) was obtained for LAS (0.33 ± 0.3 h) compared with mesophilic biomass (SGH and SWT) (0.13 ± 0.02 h). Therefore, both LAS sources influenced the kinetics of methane production and organic matter degradation. For SGH, inoculum obtained the highest LAS degradation. In the SGH inoculum sequenced by MiSeq-Illumina was identified genera (VadinCA02, Candidatus Cloacamonas, VadinHB04, PD-UASB-13) related to degrade toxic compounds. Therefore, it recommended the reactor mesophilic inoculum UASB (SGH) for the LAS degradation.
Assuntos
Ácidos Alcanossulfônicos/metabolismo , Metano/metabolismo , Tensoativos/metabolismo , Poluentes Químicos da Água/metabolismo , Anaerobiose , Animais , Bactérias/metabolismo , Biodegradação Ambiental , Biomassa , Reatores Biológicos , Resíduos Industriais , Cinética , Saccharum , Suínos , Águas ResiduáriasRESUMO
The biodegradation of linear alkylbenzene sulfonate (LAS) from commercial laundry wastewater was evaluated in an anaerobic fluidized bed reactor (FBR) fed with synthetic substrate (598 mg L(-1) to 723 mg L(-1) of organic matter) supplemented with 9.5±3.1 mg L(-1) to 27.9±9.6 mg L(-1) of LAS. The average chemical oxygen demand (COD) removal efficiency was 89% and the biodegradation of LAS was 57% during the 489 days of anaerobic FBR. Higher levels of volatile fatty acids (VFA) were observed in the effluent at the stage with the best LAS removal performance. Increasing the surfactant concentration did not increase the VFA production in the effluent. The predominant VFAs after the addition of LAS were as follows: isovaleric acid and valeric acid, followed by propionic acid, caproic acid and formic acid. The similarities of 64% and 45% to Archaea and Bacteria domains were observed in the samples taken in the operating period of anaerobic FBR fed with 23.6±10 mg L(-1) and 27.9±10 mg L(-1) of LAS. During the operation stages in the reactor, Gemmatimonas, Desulfobulbus and Zoogloea were determined as the most abundant genera related to surfactant degradation using 454-Pyrosequencing.
Assuntos
Ácidos Alcanossulfônicos/metabolismo , Archaea/metabolismo , Bactérias Anaeróbias/metabolismo , Reatores Biológicos/microbiologia , Lavanderia , Águas Residuárias/química , Águas Residuárias/microbiologia , Anaerobiose , Biodegradação Ambiental , Ácidos Graxos Voláteis/metabolismo , Tensoativos/metabolismo , Poluentes Químicos da Água/metabolismoRESUMO
In this paper, the microbial characteristics of the granular sludge in the presence of oxygen (3.0+/-0.7 mg O2 l(-1)) were analyzed using molecular biology techniques. The granules were provided by an upflow anaerobic sludge blanket (UASB) operated over 469 days and fed with synthetic substrate. Ethanol and sulfate were added to obtain different COD/SO4(2-) ratios (3.0, 2.0, and 1.6). The results of fluorescent in situ hybridization (FISH) analyses showed that archaeal cells, detected by the ARC915 probe, accounted for 77%, 84%, and 75% in the COD/SO(4)(2-) ratios (3.0, 2.0, and 1.6, respectively). Methanosaeta sp. was the predominant acetoclastic archaea observed by optical microscopy and FISH analyses, and confirmed by sequencing of the excised bands of the DGGE gel with a similarity of 96%. The sulfate-reducing bacterium Desulfovibrio vulgaris subsp. vulgaris (similarity of 99%) was verified by sequencing of the DGGE band. Others identified microorganism were similar to Shewanella sp. and Desulfitobacterium hafniense, with similarities of 95% and 99%, respectively. These results confirmed that the presence of oxygen did not severely affect the metabolism of microorganisms that are commonly considered strictly anaerobic. We obtained mean efficiencies of organic matter conversion and sulfate reducing higher than 74%.