Optimization of methane production from solid tuna waste: Thermal pretreatment and co-digestion.

Fish canning industries generate large amounts of solid waste during their processing operations, creating a significant environmental challenge. Nonetheless, this waste can be efficiently and sustainably treated through anaerobic digestion. In this study, the potential of biogas production from anaerobic digestion of thermally pretreated and co-digested solid tuna waste was investigated. The thermal pretreatment of raw fish viscera resulted in a 50 % increase in methane yield, with a production of 0.27 g COD-CH4/g COD added. However, this pretreatment did not lead to a significant increase in biogas production for cooked tuna viscera. When non-thermally pretreated raw viscera was tested, a large accumulation of volatile fatty acids and long chain fatty acids was observed, with levels reaching 21 and 6 g COD/L, respectively. On the other hand, anaerobic co-digestion of cooked tuna viscera with fat waste significantly enhanced methane production, achieving 0.87 g COD-CH4/g COD added. In contrast, co-digestion of cooked tuna viscera with dairy waste and sewage sludge resulted in notably lower yields of 0.36 and 0.46 g COD-CH4/g COD added, respectively. These results may be related to the C/N ratio, which was found to be within the optimal range for anaerobic digestion only in the tuna and fat waste co-digestion assay.

Impact of Sports Education Model in Physical Education on Students' Motivation: A Systematic Review.

BACKGROUND: Research has suggested that applying the Sport Education Model (SEM) in Physical Education (PE) increases students' motivation. However, it is important to systematize this evidence to have a clearer idea. Therefore, this study aimed to analyze the impact of the SEM on the students' motivation. METHODS: A systematic review with a narrative synthesis was performed. In March 2021, an articles search was conducted in PubMed, Scopus, and Web of Science. Eligibility criteria were: longitudinal or experimental study design; outcomes included PE settings; results reported the relationship between the SEM and students' motivation. RESULTS: Fourteen studies were included, totaling 2146 students. The majority of the studies indicated a significant association between the SEM and motivation, particularly in autonomy and more enjoyment toward PE. CONCLUSIONS: This review supports that the SEM has a positive impact on motivation. The SEM offers a wide range of opportunities for students to develop more self-determined motivated behavior in PE classes. Therefore, the SEM should be considered when developing or adapting existing PE programs to promote students' intrinsic motivation to engage in physical activity.

Towards a standardization of biomethane potential tests.

Production of biogas from different organic materials is a most interesting source of renewable energy. The biomethane potential (BMP) of these materials has to be determined to get insight in design parameters for anaerobic digesters. Although several norms and guidelines for BMP tests exist, inter-laboratory tests regularly show high variability of BMPs for the same substrate. A workshop was held in June 2015, in Leysin, Switzerland, with over 40 attendees from 30 laboratories around the world, to agree on common solutions to the conundrum of inconsistent BMP test results. This paper presents the consensus of the intense roundtable discussions and cross-comparison of methodologies used in respective laboratories. Compulsory elements for the validation of BMP results were defined. They include the minimal number of replicates, the request to carry out blank and positive control assays, a criterion for the test duration, details on BMP calculation, and last but not least criteria for rejection of the BMP tests. Finally, recommendations on items that strongly influence the outcome of BMP tests such as inoculum characteristics, substrate preparation, test setup, and data analysis are presented to increase the probability of obtaining validated and reproducible results.

Continuous fungal treatment of non-sterile veterinary hospital effluent: pharmaceuticals removal and microbial community assessment.

Source point treatment of effluents with a high load of pharmaceutical active compounds (PhACs), such as hospital wastewater, is a matter of discussion among the scientific community. Fungal treatments have been reported to be successful in degrading this type of pollutants and, therefore, the white-rot fungus Trametes versicolor was applied for the removal of PhACs from veterinary hospital wastewater. Sixty-six percent removal was achieved in a non-sterile batch bioreactor inoculated with T. versicolor pellets. On the other hand, the study of microbial communities by means of DGGE and phylogenetic analyses led us to identify some microbial interactions and helped us moving to a continuous process. PhAC removal efficiency achieved in the fungal treatment operated in non-sterile continuous mode was 44 % after adjusting the C/N ratio with respect to the previously calculated one for sterile treatments. Fungal and bacterial communities in the continuous bioreactors were monitored as well.

Effect of different carbon materials as electron shuttles in the anaerobic biotransformation of nitroanilines.

Aromatic amines resulted from azo dyes biotransformation under anaerobic conditions are generally recalcitrant to further anaerobic degradation. The catalytic effect of carbon materials (CM) on the reduction of azo dyes is known and has been confirmed in this work by increasing threefold the biological reduction rate of Mordant Yellow 1 (MY1). The resulting m-nitroaniline (m-NoA) was further degraded to m-phenylenediamine (m-Phe) only in the presence of CM. The use of CM to degraded anaerobically aromatic amines resulted from azo dye reduction was never reported before. In the sequence, we studied the effect of different CM on the bioreduction of o-, m-, and p-NoA. Three microporous activated carbons with different surface chemistry, original (AC0 ), chemical oxidized with HNO3 (ACHNO3 ), and thermal treated (ACH2 ), and three mesoporous carbons, xerogels (CXA and CXB) and nanotubes (CNT) were assessed. In the absence of CM, NoA were only partially reduced to the corresponding Phe, whereas in the presence of CM, more than 90% was converted to the corresponding Phe. ACH2 and AC0 were the best electron shuttles, increasing the rates up to eightfold. In 24 h, the biological treatment of NoA and MY1 with AC0 , decreased up to 88% the toxicity towards a methanogenic consortium, as compared to the non-treated solutions. Biotechnol. Bioeng. 2016;113: 1194-1202. © 2015 Wiley Periodicals, Inc.

A methodology for a quantitative interpretation of DGGE with the help of mathematical modelling: application in biohydrogen production.

Molecular biology techniques provide valuable insights in the investigation of microbial dynamics and evolution. Denaturing gradient gel electrophoresis (DGGE) analysis is one of the most popular methods which have been used in bioprocess assessment. Most of the anaerobic digestion models consider several microbial populations as state variables. However, the difficulty of measuring individual species concentrations may cause inaccurate model predictions. The integration of microbial data and ecosystem modelling is currently a challenging issue for improved system control. A novel procedure that combines common experimental measurements, DGGE, and image analysis is presented in this study in order to provide a preliminary estimation of the actual concentration of the dominant bacterial ribotypes in a bioreactor, for further use as a variable in mathematical modelling of the bioprocess. This approach was applied during the start-up of a continuous anaerobic bioreactor for hydrogen production. The experimental concentration data were used for determining the kinetic parameters of each species, by using a multi-species chemostat-model. The model was able to reproduce the global trend of substrate and biomass concentrations during the reactor start-up, and predicted in an acceptable way the evolution of each ribotype concentration, depicting properly specific ribotype selection and extinction.

Kinetic and stoichiometric characterization of a fixed biofilm reactor by pulse respirometry.

An in situ respirometric technique was applied to a sequential biofilm batch reactor treating a synthetic wastewater containing acetate. In this reactor, inoculated with mixed liquor from a wastewater plant, unglazed ceramic tiles were used as support media while maintaining complete mixing regime. A total of 8 kinetic and stoichiometric parameters were determined by in situ pulse respirometry; namely substrate oxidation yield, biomass growth yield, storage yield, storage growth yield, substrate affinity constant, storage affinity constant, storage kinetic constant and maximum oxygen uptake rate. Additionally, biofilm growth was determined from support media sampling showing that the colonization process occurred during the first 40 days, reaching an apparent steady-state afterward. Similarly, most of the stoichiometric and kinetic parameters were changing over time but reached steady values after day 40. During the experiment, the respirometric method allowed to quantify the amount of substrate directed to storage, which was significant, especially at substrate concentration superior to 30mg CODL(-1). The Activated Sludge Model 3 (ASM3), which is a model that takes into account substrate storage mechanisms, fitted well experimental data and allowed confirming that feast and famine cycles in SBR favor storage. These results also show that in situ pulse respirometry can be used for fixed-bed reactors characterization.

Quantitative monitoring of an activated sludge reactor using on-line UV-visible and near-infrared spectroscopy.

The performance of an activated sludge reactor can be significantly enhanced through use of continuous and real-time process-state monitoring, which avoids the need to sample for off-line analysis and to use chemicals. Despite the complexity associated with wastewater treatment systems, spectroscopic methods coupled with chemometric tools have been shown to be powerful tools for bioprocess monitoring and control. Once implemented and optimized, these methods are fast, nondestructive, user friendly, and most importantly, they can be implemented in situ, permitting rapid inference of the process state at any moment. In this work, UV-visible and NIR spectroscopy were used to monitor an activated sludge reactor using in situ immersion probes connected to the respective analyzers by optical fibers. During the monitoring period, disturbances to the biological system were induced to test the ability of each spectroscopic method to detect the changes in the system. Calibration models based on partial least squares (PLS) regression were developed for three key process parameters, namely chemical oxygen demand (COD), nitrate concentration (N-NO(3)(-)), and total suspended solids (TSS). For NIR, the best results were achieved for TSS, with a relative error of 14.1% and a correlation coefficient of 0.91. The UV-visible technique gave similar results for the three parameters: an error of approximately 25% and correlation coefficients of approximately 0.82 for COD and TSS and 0.87 for N-NO(3)(-) . The results obtained demonstrate that both techniques are suitable for consideration as alternative methods for monitoring and controlling wastewater treatment processes, presenting clear advantages when compared with the reference methods for wastewater treatment process qualification.

Continuous high rate anaerobic treatment of oleic acid based wastewater is possible after a step feeding start-up.

Mineralization of a synthetic effluent containing 50% COD as oleic acid was achieved in a continuous anaerobic reactor at organic loading rates up to 21 kg COD m(-3) day(-1), HRT of 9 h, attaining 99% of COD removal efficiency and a methane yield higher than 70%. A maximum specific methane production rate of 1170 +/- 170 mg COD-CH4 g VS(-1) day(-1) was measured during the reactor's operation. A start-up strategy combining feeding phases and batch degradation phases was applied to promote the development of an anaerobic community efficient for long chain fatty acids (LCFA) mineralization. Through the start-up period, the methane yield increased gradually from 67% to 91%, and LCFA accumulated onto the sludge only during the first 60 days of operation. For the first time, it is demonstrated that a step feeding start-up is required to produce a specialized and efficient anaerobic community for continuous high rate anaerobic treatment of LCFA-rich wastewater.

Kinetic and stoichiometric parameters estimation in a nitrifying bubble column through "in-situ" pulse respirometry.

This article proposes a simple "in-situ" pulse respirometric method for the estimation of four important kinetic and stoichiometric parameters. The method is validated in a suspended biomass nitrifying reactor for the determination of (i) maximum oxygen uptake rate (OUR(ex)max), (ii) oxidation yield (f(E)), (iii) biomass growth yield (f(S)), and (iv) affinity constant (K(S)). OUR(ex)max and f(E) were directly obtained from respirograms. In the presented case study, a minimum substrate pulse of 10 mgNH(4) (+)-N L(-1) was necessary to determine OUR(ex)max which was 61.15 +/- 4.09 mgO(2) L(-1) h(-1) (5 repetitions). A linear correlation (r(2) = 0.93) obtained between OUR(ex)max and the biomass concentration in the reactor suggests that biomass concentration can be estimated from respirometric experiments. The substrate oxidation yield, f(E), was determined along 60 days of continuous operation with an average error of 5.6%. The biomass growth yield was indirectly estimated from the substrate oxidation yield f(E). The average obtained value (0.10 +/- 0.04 mgCOD mg(-1)COD) was in accordance with the f(S) estimation by the traditional COD mass balance method under steady-state conditions (0.09 +/- 0.01). The affinity constant K(S) was indirectly estimated after fitting the ascending part of the respirogram to a theoretical model. An average value of 0.48 +/- 0.08 mgNH(4) (+)-N L(-1) was obtained, which is in the range of affinity constants reported in the literature for the nitrification process (0.16-2 mgNH(4) (+)-N L(-1)).

[Etiology of urinary tract infections and antimicrobial susceptibility of urinary pathogens]. / Etiologia das infecções do tracto urinário e sua susceptibilidade aos antimicrobianos.

With the objective of knowing the common etiological agents in urinary infection and comparing its antimicrobial susceptibility in nosocomial and community-acquired urinary infections, we analyse all the urine bacteriological exams from the Serviço de Patologia Clínica do Centro Hospitalar do Nordeste, EPE - Unidade Hospitalar de Bragança, during a two years period (April 2004 to March 2006). During this period, 4018 urine bacteriological exams were made. The cultural exam was positive in 572 samples (144 from nosocomial infections and 428 from community-acquired urinary infections). The Escherichia coli was the more isolated strain (68,4 %), followed by Klebsiella spp (7,9%), Pseudomonas aeruginosa (6,1%) and Proteus mirabilis (5,2%). Concerning to antimicrobial susceptibility, Escherichia coli and Klebsiella spp showed a high resistance to the antimicrobials Amoxicillin, Piperacillin, Cephalothin, Ceftazidim and Quinolones. For Enterobacteriaceae Imipenem, Amikacin and Netilmicin were the antimicrobials with more level of susceptibility. Imipenem and Amikacin were the more efficient antimicrobials against Pseudomonas aeruginosa. Concerning to the susceptibility for the same etiological agent, in nosocomial and community-acquired urinary infections, we founded statistical significant differences in the antimicrobials Ticarcillin-clavulanic acid and Collistin for Pseudomonas aeruginosa and in the group of antimicrobials from Quinolones for the Proteus mirabilis. In the other identified agents there were no statistical significant differences for antimicrobials. This study it allows making use of data necessary for the knowledge of etiologic urinary infection agents in Bragança and provides the information about the antimicrobials resistance, which were necessary to initiate an adequate empirical treatment and to elaborate treatment guides.

Molecular monitoring of microbial diversity in expanded granular sludge bed (EGSB) reactors treating oleic acid.

Abstract A molecular approach was used to evaluate the microbial diversity of bacteria and archaea in two expanded granular sludge bed (EGSB) reactors fed with increasing oleic acid loading rates up to 8 kg of chemical oxygen demand (COD) m(-3) day(-1) as the sole carbon source. One of the reactors was inoculated with granular sludge (RI) and the other with suspended sludge (RII). During operation, the sludge in both reactors was segregated in two layers: a bottom settled one and a top floating one. The composition of the bacterial community, based on 16S rDNA sequence diversity, was affected most during the oleate loading process in the two reactors. The archaeal consortium remained rather stable over operation in RI, whereas in RII the relative abundance of Methanosaeta-like organisms became gradually weaker, starting in the bottom layer. In the range of oleate loads evaluated, 6 kg of COD m(-3) day(-1) was found as the maximum value that could be applied to the system. A further increase to 8 kg of oleate-COD m(-3) day(-1) induced a maximal shift on the microbial structure of the sludges. At this time point, methanogenic acetoclastic activity was not detected and only very low methanogenic activity on H(2)/CO(2) was exhibited by the sludges.