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1.
Chemosphere ; 283: 131309, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34467946

RESUMO

Omics longitudinal studies are effective experimental designs to inform on the stability and dynamics of microbial communities in response to perturbations, but time-course analytical frameworks are required to fully exploit the temporal information acquired in this context. In this study we investigate the influence of ammonia on the stability of anaerobic digestion (AD) microbiome with a new statistical framework. Ammonia can severely reduce AD performance. Understanding how it affects microbial communities development and the degradation progress is a key operational issue to propose more stable processes. Thirty batch digesters were set-up with different levels of ammonia. Microbial community structure and metabolomic profiles were monitored with 16 S-metabarcoding and GCMS (gas-chromatography-mass-spectrometry). Digesters were first grouped according to similar degradation performances. Within each group, time profiles of OTUs and metabolites were modelled, then clustered into similar time trajectories, evidencing for example a syntrophic interaction between Syntrophomonas and Methanoculleus that was maintained up to 387 mg FAN/L. Metabolites resulting from organic matter fermentation, such as dehydroabietic or phytanic acid, decreased with increasing ammonia levels. Our analytical framework enabled to fully account for time variability and integrate this parameter in data analysis.


Assuntos
Amônia , Microbiota , Anaerobiose , Reatores Biológicos , Metano
2.
Sci Total Environ ; 792: 148446, 2021 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-34465036

RESUMO

A double-chamber microbial fuel cell (MFC) with Ru/Fe-modified-biocathode was constructed for simultaneous mineralization of 2-anilinophenylacetate (APA) and denitrification. The factors on performance of simultaneous APA degradation and denitrification were explored. The contributions of ROS to APA degradation were evaluated by EPR and quenching experiments. The microbial community of Ru/Fe-modified-biocathode was determined by high-throughput sequencing. Results showed that low resistance accelerated APA degradation by Ru/Fe-modified-biocathode, while higher initial APA concentration inhibited microbial activity of the biocathode. The optimum ammonia concentration was 50 mg L-1, while too high or too low ammonia concentration did not favor APA degradation. The APA degradation efficiency of Ru/Fe-modified-biocathode-MFC was higher than that of other modified-cathode-MFCs. The APA degradation process confirmed to the pseudo-first-order kinetic model, and APA degradation kinetic constant, the maximum removal efficiency of TOC, ammonia and TN were 2.15d-1, 59.70%, 99.20% and 44.56% respectively, signifying a simultaneous APA mineralization and denitrification performance of Ru/Fe-modified-biocathode-MFC. The coulombic efficiency decreased with APA concentration increase. OH was the primary radical in APA degradation progress. Eight kinds of intermediates were measured, and two APA degradation pathways were proposed, among which APA hydroxylation was the main pathway. The microbial community of Ru/Fe-modified-biocathode was dominated with Nitrosomonas at genus level, and enriched with various APA-degraders, nitrifiers, and denitrifiers such as Pseudomonas, Nitrospira, Nitrobacter, Paracoccus, Thermomonas, Dechloromonas, and Clostridium_Sutra_stricto_1. COG analysis showed the redox reaction of Ru/Fe might affect signal transduction and environment adaptation, while FAPROTAX analysis suggested that Ru/Fe-modified-biocathode exhibited higher nitrification activity than that of carbon-felt-biocathode. The synergistic mechanism of simultaneous APA mineralization and denitrification was mainly redox reaction of Ru/Fe and supplemented by aerobic biodegradation.


Assuntos
Fontes de Energia Bioelétrica , Reatores Biológicos , Desnitrificação , Eletrodos , Nitrificação , Nitrogênio/análise , Águas Residuárias
3.
J Environ Sci (China) ; 108: 145-151, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34465428

RESUMO

This study investigated a combined low-thermal and CaO2 pretreatment to enhance the volatile fatty acid (VFA) production from waste activated sludge (WAS). The fermentative product was added to a sequencing batch reactor (SBR) as an external carbon source to enhance nitrogen removal. The results showed that the combined pretreatment improved WAS solubilization, releasing more biodegradable substrates, such as proteins and polysaccharides, from TB-EPS to LB-EPS and S-EPS. The maximum VFA production of 3529 ± 188 mg COD/L was obtained in the combined pretreatment (0.2 g CaO2/g VS + 70 °C for 60 min), which was 2.1 and 1.4-fold of that obtained from the sole low-thermal pretreatment and the control test, respectively. Consequently, when the fermentative liquid was added as an external denitrification carbon source, the effluent total nitrogen decreased to Class A of the discharge standard for pollutants in rural wastewater treatment plants in most areas of China.


Assuntos
Nitrogênio , Esgotos , Reatores Biológicos , Desnitrificação , Ácidos Graxos Voláteis , Fermentação , Peróxidos
4.
J Hazard Mater ; 416: 125833, 2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-34492791

RESUMO

Aerosol emissions from wastewater treatment plants (WWTPs) have been associated with health reverberation but studies about characteristics of size-segregated aerosol particulate matter (PM) are scarce. In this study, the measurement of particulate number size distribution in the range of < 10 µm, and the collection of PM10-2.5, PM2.5-1.0 and PM1.0, were conducted from an aerobic moving bed biofilm reactor (MBBR) at a full-scale WWTP. MBBR aerosols showed a unimodal number size distribution, with the majority of particles (>94%) in the ultrafine size range (<100 nm). For toxic metal(loid)s or potential pathogens, significant differences were found within MBBR aerosols (PM10-2.5, PM2.5-1.0, and PM1.0), and also between MBBR aerosols and wastewater. Both wastewater and ambient air had important source contributions for MBBR aerosols. The compositions of toxic metal(loid)s in PM1.0, and the populations of potential bacterial or fungal pathogens in PM10-2.5 and PM2.5-1.0, were dominated by that from wastewater. Compared to PM10-2.5 and PM2.5-1.0, PM1.0 had the highest aerosolization potential for the toxic metal(loid)s of As, Cd, Co, Cr, Li, Mn, Ni, U, and Zn, and the genera of Acinetobacter, Pseudomonas and Fusarium. Due to the size-segregated specialty, targeted measures should be employed to reduce the health risks. CAPSULE: The compositions of toxic metal(loid)s in PM1.0, and the populations of potential pathogens in PM10-2.5 and PM2.5-1.0, were dominated by that from wastewater.


Assuntos
Biofilmes , Purificação da Água , Aerossóis/análise , Reatores Biológicos , Material Particulado
5.
J Hazard Mater ; 416: 125865, 2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-34492813

RESUMO

Anaerobic biological treatment technologies are one of the major hotspots of antibiotic resistance genes (ARGs). Previous studies have applied the electrochemical process to improve biogas production, however, it was challenged that high voltages might promote membrane permeability and reactive oxygen species overproduction to promote ARGs proliferation. Herein, the biogas production and ARGs proliferation in an anaerobic electrochemical membrane bioreactor (AnEMBR) were investigated at the gradient voltages of 0-0.9 V. Results show the reactor performances (average CH4 production and current generation) were distinctly improved with the increase of applied voltage, and reached the optimum at 0.9 V. However, long-term application (>30 day) of 0.9 V deteriorated the reactor performances. Meanwhile, the relative abundances of most target ARGs in the supernatant and effluent of AnEMBR at 0.9 V increased by 0.68-1.55 and 0.42-1.26 logs compared to those before applying voltage, respectively. After disconnecting the circuit, these ARGs abundances all decreased to the original level. Significant correlations between intlI and ARGs (e.g., tetA, tetQ, sulI, and sulII) were observed, indicating horizontal gene transfer may contribute to the increased ARGs. Moreover, the shift of microbial communities caused by the applied voltage enriched potential ARGs-hosts (e.g., Tolumonas), contributing to the proliferation of ARGs.


Assuntos
Antibacterianos , Biocombustíveis , Anaerobiose , Antibacterianos/farmacologia , Reatores Biológicos , Proliferação de Células , Resistência Microbiana a Medicamentos/genética , Genes Bacterianos
6.
Chemosphere ; 282: 131136, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34470172

RESUMO

Organic fraction of municipal solid waste (OFMSW) is an ideal substrate for biogas production; however, complex chemical structure and being heterogeneous obstruct its biotransformation in anaerobic digestion (AD) process. Thermal pre-treatment of OFMSW has been suggested to enhance the solubilization and improve the anaerobic digestibility of OFMSW. This paper critically and comprehensively reviews the characterization of OFMSW (physical, chemical, bromatological) and enlightens the valuable properties of OFMSW for waste valorization. In following sections, the advantages and limitations of AD of OFMSW are discussed, followed by the application of temperature phased AD, and various thermal pre-treatments, i.e., conventional thermal, microwave, and thermo-chemical for high rate bioenergy transformation. Effects of pre-treatment on COD, proteins, sugars and VS solubilization, and biogas yield are discussed. Formation of recalcitrant during thermal pre-treatment and the effect on anaerobic digestibility are considered. Full scale application, and techno-economic and environmental feasibility of thermal pre-treatment methods are also revealed. This review concluded that thermophilic (55 °C) and temperature phased anaerobic digestion, temperature phased anaerobic digestion, TPAD (55 + 37 °C) processes shows effective and stable performance at low HRTs and high OLRs and achieved higher methane yield than mesophilic digestion. The thermal pre-treatment at a lower temperature (120 °C) improves the net energy yield. However, high-temperature pre-treatment (>150 °C) result in decreased biogas yield and even lower than the non-pre-treated OFMSW, although a high degree of COD solubilization. The OFMSW solubilization in terms of COD, proteins, and sugars cannot accurately reflect thermal/hybrid pre-treatments' potential. Thus, substrate pre-treatment followed by anaerobic digestibility of pretreated substrate together can evaluate the actual effectiveness of thermal pre-treatment of OFMSW.


Assuntos
Eliminação de Resíduos , Resíduos Sólidos , Anaerobiose , Reatores Biológicos , Metano , Resíduos Sólidos/análise
7.
Chemosphere ; 282: 131137, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34470173

RESUMO

This study investigated biological treatment for two kinds of volatile organic compounds (VOCs)-containing wastewaters collected from wet scrubbers in a semiconductor industry. Batch test results indicated that one wastewater containing highly volatile organic compounds was not suitable for aerated treatment conditions while the other containing much lower volatile organic compounds was suitable for aerobic treatment. Accordingly, two moving bed bioreactors, by adding commercial biocarrier BioNET, were operated under aerobic and anoxic conditions for treating low volatility wastewater (LVW) and high volatility wastewater (HVW), respectively. During 280 days of operation, the aerobic LVW bioreactor attained the highest chemical oxygen demand (COD) removal rate of 98.9 mg-COD/L/h with 81% of COD removal efficiency at hydraulic retention time (HRT) of 1 day. The anoxic HVW bioreactor performed above 80% of COD removal efficiency with the highest COD removal rate of 16.5 mg-COD/L/h at HRT of 2 days after 380 days of operation. The specific COD removal rates at different initial substrate-to-biomass (S0/X0) ratios, using either suspended sludge or microorganisms attached onto BioNET from both bioreactors, followed the Monod-type kinetics, while the half-saturation coefficients were generally higher for the microorganisms onto BioNET due presumably to relatively poor mass transfer efficiency. Based on the results of microbial community analysis using the next generation sequencing technique, the dominant communities of suspended sludge and BioNET, including nitrifiers, denitrifiers, and degraders for polycyclic aromatic hydrocarbons, were similar in the corresponded bioreactors, but microbial community shifts were observed with increased organic loadings.


Assuntos
Compostos Orgânicos Voláteis , Águas Residuárias , Reatores Biológicos , Semicondutores , Esgotos
8.
Nat Commun ; 12(1): 4975, 2021 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-34404791

RESUMO

Plant cell wall hydrolysates contain not only sugars but also substantial amounts of acetate, a fermentation inhibitor that hinders bioconversion of lignocellulose. Despite the toxic and non-consumable nature of acetate during glucose metabolism, we demonstrate that acetate can be rapidly co-consumed with xylose by engineered Saccharomyces cerevisiae. The co-consumption leads to a metabolic re-configuration that boosts the synthesis of acetyl-CoA derived bioproducts, including triacetic acid lactone (TAL) and vitamin A, in engineered strains. Notably, by co-feeding xylose and acetate, an enginered strain produces 23.91 g/L TAL with a productivity of 0.29 g/L/h in bioreactor fermentation. This strain also completely converts a hemicellulose hydrolysate of switchgrass into 3.55 g/L TAL. These findings establish a versatile strategy that not only transforms an inhibitor into a valuable substrate but also expands the capacity of acetyl-CoA supply in S. cerevisiae for efficient bioconversion of cellulosic biomass.


Assuntos
Parede Celular/metabolismo , Engenharia Metabólica , Polissacarídeos/metabolismo , Saccharomyces cerevisiae/metabolismo , Acetilcoenzima A/metabolismo , Biomassa , Reatores Biológicos , Fermentação , Lignina , Pironas/metabolismo , Saccharomyces cerevisiae/genética , Vitamina A/metabolismo , Xilose/metabolismo
9.
Environ Res ; 200: 111777, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34333016

RESUMO

The presence of antibiotics in the wastewater is one of the important issues related to environmental management. In this study, antibiotics-degrading bacteria were screened from the enriched sewage sludge sample. Among the isolated bacterial strains, Bacillus subtilis AQ03 showed maximum antibiotic tolerance (>2000 ppm). The characterized strain B. subtilis AQ03 degraded sulfamethaoxazole and sulfamethoxine and the optimum nutrient and physical-factors were analyzed. B. subtilis AQ03 degraded 99.8 ± 1.3 % sulfamethaoxazole, and 93.3 ± 6.2 % sulfamethoxine. Sodium nitrate and ammonium chloride were improved antibiotics degradation (<90 %). The optimized conditions were maintained in a moving bed bioreactor for the removal of antibiotics and nutrients from the wastewater. The selected strain considerably produced proteases (109.4 U/mL), amylases (55.1 U/mL), cellulase (9.6 U/mL) and laccases (15.2). In moving bed reactor, sulfamethaoxazole degradation was maximum after 8 days (100 ± 1.5 %) and sulfamethoxazole (100 ± 0) was removed completely from wastewater after 10 days. In moving bed reactor, biological oxygen demand (92.1 ± 2.8 %), chemical oxygen demand (79.6 ± 1.2 %), nitrate (89.4 ± 3.9 %) and phosphate (91.8 ± 1.2) were removed from the wastewater along with antibiotics after 10 days of treatment. The findings indicate that the indigenous bacterial communities and the ability to survive in the presence of high antibiotic concentrations and xenobiotics. Moving bed bioreactor is useful for the removal of nutrients and antibiotics from wastewater.


Assuntos
Preparações Farmacêuticas , Águas Residuárias , Reatores Biológicos , Nutrientes , Esgotos , Eliminação de Resíduos Líquidos
10.
Water Res ; 202: 117441, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34343873

RESUMO

The suspended sludge and carrier-attached biofilms of three different hybrid moving bed biofilm reactor (MBBR) systems were investigated with respect to their transformation potential for a broad range of micropollutants (MPs) as well as their microbial community composition. For this purpose, laboratory-scale batch experiments were conducted with the separated suspended sludge and the carrier-attached biofilm of every system in triplicate. For all batches the removal of 31 MPs as well as the composition of the microbial community were analyzed. The carrier-attached biofilms from two hybrid MBBR systems showed a significant higher overall transformation potential in comparison to the respective suspended sludge. Especially for the MPs trimethoprim, diclofenac, mecoprop, climbazole and the human metabolite 10,11-dihydro-10-hydroxycarbamazepine consistently higher pseudo-first-order transformation rates could be observed in all three systems. The analysis of the taxonomic composition revealed taxa showing higher relative abundances in the carrier-attached biofilms (e. g. Nitrospirae and Chloroflexi) and in the suspended biomasses (e. g. Bacteroidetes and Betaproteobacteria). Correlations of the biodiversity indices and the MP biotransformation rates resulted in significant positive associations for 11 compounds in suspended sludge, but mostly negative associations for the carrier-attached biofilms. The distinct differences in MP removal between suspended sludge and carrier-attached biofilm of the three different MBBR systems were also reflected by a statistically significant link between the occurrence of specific bacterial taxa (Acidibacter, Nitrospira and Rhizomicrobium) and MP transformation rates of certain MPs. Even though the identified correlations might not necessarily be of causal nature, some of the identified taxa might serve as suitable indicators for the transformation potential of suspended sludge or carrier-attached biofilms.


Assuntos
Microbiota , Esgotos , Biofilmes , Biomassa , Reatores Biológicos , Humanos , Águas Residuárias
11.
Water Res ; 202: 117481, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34358904

RESUMO

Our previous work has reported the pretreatment of secondary sludge with free ammonia (NH3, FA) enhanced the methane production in batch biochemical methane potential tests. However, the batch biochemical methane potential test could only provide conservative results compared to continuous/semi-continuous anaerobic digestion. Also, the impacts of FA pretreatment on the key anaerobic digestion parameters, including volatile solids (VS) destruction, sludge dewaterability and pathogen removal, are still unknown. This study for the first time investigated these impacts using semi-continuous anaerobic digestion systems for 130 days. Pretreatment of secondary sludge for 24 h at an FA concentration of 560 mg NH3-N/L improved VS destruction by 26.4% (from 22.0 to 27.8%), supported by a similar increase of 28.6% in methane production (from 126.7 to 162.9 ml CH4/g VSfed). Model based analysis revealed that FA pretreatment improved the sludge degradability extent, which may be the reason for the enhanced VS destruction. Equally importantly, the dewaterability of the digested sludge with FA pretreatment was also enhanced by 9.2% (from 12.0 to 13.1% in solids content of the dewatered digested sludge), which could be partly attributed to the increased zeta potential from -16.7 to -14.5 mV. Anaerobic digestion with FA pretreatment enhanced the removals of Fecal Coliform and E. Coli by 1.3 and 1.4 log MPN/g TS (MPN: Most Probable Number; TS: Total Solids), indicating FA pretreatment was effective in enhancing pathogen removal. With inorganic solids representing 21% of the sludge used, the volume of dewatered sludge to be disposed of was reduced by 14.5% via FA pretreatment. This will substantially decrease the cost as evaluated by economic analysis. In brief, this study provides a promising strategy to enhance sludge reduction in anaerobic digestion and is of great significance in promoting the application of FA pretreatment strategy in the real world.


Assuntos
Amônia , Esgotos , Anaerobiose , Reatores Biológicos , Escherichia coli
12.
Water Res ; 202: 117491, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34358911

RESUMO

The addition of nano zero-valent iron (nZVI) has been proven to improve the efficiency of the anammox process, however, the mechnism is not clear. Here, the effect of nZVI on anammox microbial community was studied by metagenomic sequencing methods. It was found that 50 mg/L nZVI indeed promoted the removal of NH4+ and NO2- of the anammox reactor and significantly improved the relative abundance of AnAOB (Ca. Brocadia) from 42.1% to 52.5%. What's more, 50 mg/L nZVI increased the abundance of c-di-GMP synthesized protein from 148 rpmr to 252 rpmr in the microbial community and decreased the abundance of c-di-GMP degradation protein from 238 rpmr to 204 rpmr, which indirectly led to the enrichment of c-di-GMP in the microbial community. The enrichment of c-di-GMP reduced the motility of microorganisms in the reactor and promoted the secretion of extracellular polymers by bacteria, which is beneficial to the formation of sludge particles in the anammox reactor. In conclusion, this research clarified the mechanism of nZVI promoting the anammox process and provided theoretical guidance for the engineering application of anammox.


Assuntos
Reatores Biológicos , Ferro , Bactérias/genética , Nitrogênio , Oxirredução , Percepção de Quorum , Esgotos
13.
Huan Jing Ke Xue ; 42(9): 4374-4382, 2021 Sep 08.
Artigo em Chinês | MEDLINE | ID: mdl-34414736

RESUMO

To explore the effects of dissolved oxygen (DO) on the treatment of low carbon/nitrogen municipal wastewater, this study examined the characteristics of the microbial community in a low carbon source environment. The treatment process was conducted with the aeration area having DO concentrations of 2-3, 1-2, and lower than 1 mg·L-1. The results demonstrated that reduced DO concentration in the aeration area increased the efficiency of the nitrogen removal process by 20.23% and 80.54%, for external and internal carbon sources, respectively. Similarly, the efficiency of internal carbon source utilization in the phosphorus removal process increased by 13.89%, thus enhancing the nutrient removal efficiency of the low carbon/nitrogen wastewater treatment system. High-throughput sequencing and RDA analysis showed that reduced oxygen concentration motivated an adjustment in microbial community structure, causing functional microorganisms (i.e., Dechloromonas) to become dominant. In addition, the upregulation of genes associated with energy production and conversion, signal transduction, substrate transport, and metabolism provided favourable nutritional conditions for the proliferation of functional microorganisms in low carbon source conditions. This study provides a theoretical basis for improving the growth of microorganisms involved in the nutrient removal process when treating low carbon/nitrogen municipal wastewater.


Assuntos
Microbiota , Purificação da Água , Reatores Biológicos , Carbono , Desnitrificação , Nitrogênio , Nutrientes , Oxigênio
14.
Huan Jing Ke Xue ; 42(9): 4383-4389, 2021 Sep 08.
Artigo em Chinês | MEDLINE | ID: mdl-34414737

RESUMO

This study explored the effect of sludge retention time (SRT) on ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) under intermittent gradient aeration, as well as the effect of the short-range nitrification endogenous denitrification phosphorus removal system on the treatment of low C/N ratio domestic sewage. In this study, an SBR reactor was used to cultivate aerobic granular sludge, using actual domestic sewage as the influent substrate. As the SRT decreased from 50 d to 30 d, the specific ammonia oxidation rate increased from 3.16 mg·(g·h)-1to 4.38 mg·(g·h)-1, and the specific nitrite oxidation rate decreased from 3.4 mg·(g·h)-1to 1.8 mg·(g·h)-1. The activity of NOB decreased by about 44%, resulting in short-range nitrification within the system. With an SRT of 30 d, the maximum nitrite accumulation was 6.93 mg·L-1. Because the reduced SRT led to a slight decrease in sludge concentration within the system, an aeration reduction strategy was adopted after 40 d, according to the DO curve. When the final SRT was 30 d, the effluent COD concentration was 40.76 mg·L-1, the TN concentration was 12.4 mg·L-1, the TP concentration was 0.31 mg·L-1, and the simultaneous removal of C, N and P was realized. Thus, a stable short-range nitrification endogenous denitrification phosphorus removal system was finally obtained. At the same time, the EPS content of aerobic granular sludge was negatively correlated with SRT, the protein content increased from 66.7 mg·g-1 to 95.1 mg·g-1, and the polysaccharide content remained in the range of 12.1-17.2 mg·g-1, indicating that the decreased SRT had a great effect on the protein content. With an SRT of 30 d, the PN/PS value was maintained at approximately 6.2, and the structural stability of aerobic granular sludge can be maintained under such conditions.


Assuntos
Nitrogênio , Esgotos , Reatores Biológicos , Nitrificação , Fósforo
15.
Huan Jing Ke Xue ; 42(9): 4390-4398, 2021 Sep 08.
Artigo em Chinês | MEDLINE | ID: mdl-34414738

RESUMO

As an intermediate form of microbial denitrification, nitrite serves as a key substrate for anaerobic ammonium oxidation (ANAMMOX). This study investigated the partial dentification (PD) characteristics and the coupling feasibility of PD+ANAMMOX in the biofilm system, using a moving bed biofilm reactor which was operated for 120 days. After 40 days of operation with a C/N ratio of 3.0 and filling fraction of 20%, the nitrate-to-nitrite transformation ratio (NTR) reached (69.38±3.53)%, and enzymatic assays indicated that the activities of nitrate reductase (NAR) had increased from 0.03 to 0.45 µmol·(min·mg)-1 while the activities of nitrite reductase (NIR) had decreased from 0.18 to 0.02 µmol·(min·mg)-1. Illumina high-throughput sequencing analysis revealed that the proportion of genus of Thauera bacteria to total microorganism increased from 0.3% (d1) to 37.27% (d64). Finally, the effluent had a total nitrogen (TN) concentration of (6.41±1.50) mg·L-1, indicating a total nitrogen removal ratio of (88.16±2.71)% and confirming the feasibility of PD+ANAMMOX in the biofilm system.


Assuntos
Reatores Biológicos , Desnitrificação , Biofilmes , Nitrogênio , Oxirredução
16.
Huan Jing Ke Xue ; 42(9): 4399-4405, 2021 Sep 08.
Artigo em Chinês | MEDLINE | ID: mdl-34414739

RESUMO

Actual domestic sewage has a complex composition and relatively low carbon and nitrogen content. Anaerobic plug-flow influent can enhance the utilization of COD by aerobic granular sludge by providing a locally high concentration of substrate. In this study, intermittent aeration was used to cultivate aerobic granular sludge in a sequencing batch reactor (SBR), and actual domestic sewage was used as the feed water to inoculate the sewage plant sludge. In the R1 experiment, rapid anaerobic feeding was adopted, while in R2, anaerobic plug-flow feeding was adopted, to explore the impact of different feeding modes on the aerobic granular sludge system of domestic sewage. Under rapid anaerobic feeding in R1, the particle structure appeared earlier, but particle breakage occurred after 71 days of operation; the particle structure generated in R2 was denser than that of R1, the particle surfaces were smoother, and the denitrifying phosphorous accumulating organisms (DPAO) had a more enriching effect. In the final R1 and R2 reactors, the proportion of DPAO to phosphorous accumulating organisms (PAO) was 14.17% and 22.07%, respectively. The results show that the anaerobic plug-flow feeding mode can enhance the use of influent COD by granular sludge, which is conducive to enriching DPAO, generating denser and more stable particles, realizing "one carbon dual purpose" operation, and removing more nitrogen and phosphorus.


Assuntos
Nitrificação , Esgotos , Anaerobiose , Reatores Biológicos , Fósforo
17.
Huan Jing Ke Xue ; 42(9): 4406-4413, 2021 Sep 08.
Artigo em Chinês | MEDLINE | ID: mdl-34414740

RESUMO

In this study, domestic sewage was used to inoculate mature short-cut nitrification denitrifying phosphorus removal particles, which were cultivated and matured under artificial water. The operation of the short-cut nitrification denitrifying phosphorus removal system was optimized using different aerobic/anoxic durations combined with zoned sludge discharge. The results showed that regulating the aerobic/anoxic duration, in combination with zoned sludge discharge, can realize the stable operation of the system. In the later stable period, the effluent COD concentration was below 50 mg·L-1, the effluent TN concentration was below 15 mg·L-1, the TN removal rate reached about 83% and remained stable, the effluent P concentration was below 0.5 mg·L-1, and the average P removal rate was 93.72%. At the same time, zoned sludge discharge (70% top sludge and 30% bottom sludge) can be used to screen out microorganisms, maintain good nitrosation and phosphorus removal performance, limit the particle size distribution, and ensure the growth advantages of AOB and DPAOs. Increases in the anoxic duration improved the growth rate of anoxic heterotrophic bacteria, causing them to secrete more EPS and ensuring granular sludge improvements and continued stability.


Assuntos
Fósforo , Esgotos , Reatores Biológicos , Nitrificação , Nitrogênio , Eliminação de Resíduos Líquidos
18.
Stem Cell Res Ther ; 12(1): 455, 2021 08 12.
Artigo em Inglês | MEDLINE | ID: mdl-34384480

RESUMO

BACKGROUND: Culturing cells as cell spheres results in a tissue-like environment that drives unique cell phenotypes, making it useful for generating cell populations intended for therapeutic use. Unfortunately, common methods that utilize static suspension culture have limited scalability, making commercialization of such cell therapies challenging. Our team is developing an allogeneic cell therapy for the treatment of lumbar disc degeneration comprised of discogenic cells, which are progenitor cells expanded from human nucleus pulposus cells that are grown in a sphere configuration. METHODS: We evaluate sphere production in Erlenmeyer, horizontal axis wheel, stirred tank bioreactor, and rocking bag format. We then explore the use of ramped agitation profiles and computational fluid dynamics to overcome obstacles related to cell settling and the undesired impact of mechanical forces on cell characteristics. Finally, we grow discogenic cells in stirred tank reactors (STRs) and test outcomes in vitro (potency via aggrecan production and identity) and in vivo (rabbit model of disc degeneration). RESULTS: Computation fluid dynamics were used to model hydrodynamic conditions in STR systems and develop statistically significant correlations to cell attributes including potency (measured by aggrecan production), cell doublings, cell settling, and sphere size. Subsequent model-based optimization and testing resulted in growth of cells with comparable attributes to the original static process, as measured using both in vitro and in vivo models. Maximum shear rate (1/s) was maintained between scales to demonstrate feasibility in a 50 L STR (200-fold scale-up). CONCLUSIONS: Transition of discogenic cell production from static culture to a stirred-tank bioreactor enables cell sphere production in a scalable format. This work shows significant progress towards establishing a large-scale bioprocess methodology for this novel cell therapy that can be used for other, similar cell therapies.


Assuntos
Reatores Biológicos , Transplante de Células-Tronco Hematopoéticas , Animais , Técnicas de Cultura de Células , Células Cultivadas , Coelhos
19.
Waste Manag ; 133: 110-118, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34390961

RESUMO

The methane and digestate production from biowaste (BW, 95% food waste and 5% garden waste based on fresh mass) and grease trap sludge (GTS) co-digestion at the Grossache-Nord WWTP (Austria) as a basis for a cost-benefit analysis was determined using two approaches: The first one was to determine the specific methane yields (SMY) and total solids (TS) removals (%) of the used substrates in biomethane potential (BMP) tests. In the second, the full-scale process data from a supervisory control and data acquisition (SCADA) system were analyzed. From these data, the SMY of the sewage sludge (SS) was calculated for a period without co-digestion and applied to the study period. Thus, it was possible to calculate the methane and digestate production from the co-substrates. Both approaches produced different co-substrate SMYs and TS degradation results. In the approach using the BMP, the SMY was 518 m3/t TSadded and the TS degradation was 77%. For the full-scale method, these values were found to be 620 m3/t TSadded and 66%, respectively. However, the cost-benefit analysis of both approaches indicated that electricity generation from co-digestion can cover the associated costs. The benefit to cost ratio was 1.14 and 1.08 for the BMP and full-scale approach, respectively. The application of the respective approach depends on the availability and quality of full-scale process SCADA data.


Assuntos
Reatores Biológicos , Eliminação de Resíduos , Anaerobiose , Digestão , Alimentos , Metano , Esgotos
20.
Waste Manag ; 133: 119-126, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34391987

RESUMO

The effect of fat saponification and the inclusion or exclusion of blood in slaughterhouse mixtures were assessed in terms of anaerobic digestion performance. Mixtures of animal by-products (ABP) were collected for 1 year, whereby following the daily activity and waste generation at a slaughterhouse facility, seasonal fluctuations were found. The blood content of ABP mixtures was variable, affecting both the methane yield and the production rate (287.8-320.5 NLCH4 kgCOD-1 and 80.3-94.7 and NLCH4 kgCOD-1 d-1, respectively). The saponification of fatty ABP materials was studied to assess the methane production rate, singularly or combined, with and without the addition of blood. Data showed that saponification significantly reduced the lag phase, from 2.2 to 1.5 days in winter mixtures and from 1.5 to 0.9 days in summer mixtures (all with blood), and from 0.3 to 0.1 days in summer mixtures without blood. Finally, the percentage of energy demand at the slaughterhouse potentially covered by net biogas energy was estimated, finding that the facility could be 100% energy self-sufficient in winter, whereas this would be reduced to 85% in the summer due to different methane yields of ABP mixtures based on season.


Assuntos
Matadouros , Biocombustíveis , Anaerobiose , Animais , Biocombustíveis/análise , Reatores Biológicos , Metano/análise
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