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1.
Chemosphere ; 259: 127426, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32634721

RESUMO

For eight months, a sequencing batch reactor (SBR) with integrated fixed-film activated sludge (IFAS) was operated in ambient temperature to study engineering and practical aspects of application of deammonification for mainstream conditions. For biofilm formation, K3 Kaldnes carriers were used, where the anaerobic ammonium oxidation (anammox) process can occur in deep layers of biofilm, while partial nitritation occurs in oxygen-rich outer layers. After the initial running phase of the reactor (Phase 1) to provide time for microorganisms to adapt, the COD: N ratio increased to around 2.6 in Phase 2 through reducing the ammonium concentration and increasing COD in synthetic wastewater to get closer to mainstream conditions. The total reaction time in each half-day batch cycle was kept 625 min throughout various phases, but the duration of intermittent aeration was regulated at 4 ± 1 min. While final nitrogen removal efficiency (NRE) for Phase 1 was 43%, at the end of Phase 2, it decreased to 37%. However, a maximum NRE at 90% was achieved during Phase 2. The identification of the responsible microorganisms was made through Fluorescence in situ hybridization (FISH), while Mixed Liquor Suspended Solid (MLSS) and Mixed Liquor Volatile Suspended Solid (MLVSS) was used to estimate the physical presence of bacteria. Ammonium oxidizing bacteria (AOB) and anaerobic ammonia-oxidizing bacteria (AnAOB) were dominant bacteria, respectively. The adverse effects of a gradual increase of COD: N ratio from 0.17 to more than 2.0 caused a decline in NRE to around 15%.


Assuntos
Compostos de Amônio , Análise da Demanda Biológica de Oxigênio , Reatores Biológicos , Desnitrificação , Nitrogênio , Eliminação de Resíduos Líquidos , Bactérias , Betaproteobacteria , Biofilmes , Hibridização in Situ Fluorescente , Oxirredução , Esgotos/microbiologia , Águas Residuárias
2.
Chemosphere ; 259: 127444, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32640378

RESUMO

In this study, we assessed and optimized a low-dissolved-oxygen oxic-anoxic (low-DO OA) process to achieve a low-cost and sustainable solution for wastewater treatment systems in the developing tropical countries treating low chemical oxygen demand-to-nitrogen ratio (COD/N) wastewater. The low-DO OA process attained complete ammonia removal and the effluent nitrate nitrogen (NO3-N) was below 0.3 mg/L. The recommended hydraulic retention time and sludge retention time (SRT) were 16 h and 20 days, respectively. The 16S rRNA sequencing data revealed that long SRT (20 days) encouraged the growth of nitrite-oxidizing bacteria (NOB) affiliated with "Candidatus Nitrospira defluvii". Comammox made up 10-20% of the Nitrospira community. NOB and comammox related to Nitrospira were enriched at long SRT (20 days) to achieve good low-DO nitrification performance. The low-DO OA process was efficient and has simpler design than conventional processes, which are keys for sustainable wastewater treatment systems in the developing countries treating low COD/N wastewater.


Assuntos
Eliminação de Resíduos Líquidos/métodos , Amônia , Bactérias , Análise da Demanda Biológica de Oxigênio , Reatores Biológicos , Nitratos , Nitrificação , Nitrogênio , Oxigênio , RNA Ribossômico 16S , Esgotos/microbiologia , Águas Residuárias/química
3.
Chemosphere ; 260: 127544, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32673869

RESUMO

Aerobic granular sludge sequencing batch reactor (AGSBR) is a promising approach for wastewater treatment. In the paper, the effects of methanol, starch and sucrose as carbon sources on the treatment of swine wastewater (SW) containing antibiotics by aerobic granular sludge (AGS) were studied. The results revealed that the carbon sources could affect the morphology, biomass, and settleability of AGS, and AGS could maintain a better sludge performance when sucrose was used as carbon source. The pollutants (ammonium nitrogen (NH+ 4-N), organic matter and total phosphorus (TP)) in SW also had a good removal effect, and the removal rates reached 81.14%, 96.83% and 97.37% respectively. The removal efficiencies of tetracycline (TC) and oxytetracycline (OTC) from SW were the best when sucrose as co-metabolic matrix by microorganisms. The analysis of miseq pyrosequencing demonstrated that carbon sources with methanol, starch and sucrose improved the diversity of microbial community in AGS, and the dominant bacteria also changed. The dominant groups involved in TC and OTC, removal at different classification levels suggested that the formation of bacterial communities was determined by carbon sources.


Assuntos
Antibacterianos/metabolismo , Eliminação de Resíduos Líquidos/métodos , Aerobiose , Compostos de Amônio , Animais , Bactérias , Biomassa , Reatores Biológicos , Carbono , Poluentes Ambientais , Microbiota , Nitrogênio , Oxitetraciclina , Fósforo , Esgotos/microbiologia , Suínos , Águas Residuárias
4.
PLoS One ; 15(7): e0235508, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32614917

RESUMO

This study examined the influence of bioaugmentation on metal concentrations (aluminum, cadmium, chromium, cobalt, copper, iron, lead, manganese, molybdenum, nickel and zinc) in anaerobically digested sewage sludge. To improve the digestion efficiency, bioaugmentation with a mixture of wild-living Archaea and Bacteria (MAB) from Yellowstone National Park, USA, was used. The total concentration of all metals was higher in the digestate than in the feedstock. During anaerobic digestion, the percent increase in the concentration of most of metals was slightly higher in the bioaugmented runs than in the un-augmented runs, but these differences were not statistically significant. However, the percent increase in cadmium and cobalt concentration was significantly higher in the bioaugmented runs than in the un-augmented runs. At MAB doses of 9 and 13% v/v, cadmium concentration in the digestate was 211 and 308% higher than in the feedstock, respectively, and cobalt concentration was 138 and 165%, respectively. Bioaugmentation increased over 4 times the percentage of Pseudomonas sp. in the biomass that are able to efficiently accumulate metals by both extracellular adsorption and intracellular uptake. Biogas production was not affected by the increased metal concentrations. In conclusion, bioaugmentation increased the concentration of metals in dry sludge, which means that it could potentially have negative effects on the environment.


Assuntos
Metais/metabolismo , Esgotos/química , Adsorção , Anaerobiose , Archaea/genética , Archaea/crescimento & desenvolvimento , Archaea/metabolismo , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Bactérias/metabolismo , Biomassa , Cádmio/análise , Cádmio/metabolismo , Cobalto/análise , Cobalto/metabolismo , Metais/química , Pseudomonas/genética , Pseudomonas/crescimento & desenvolvimento , Pseudomonas/metabolismo , Esgotos/microbiologia , Eliminação de Resíduos Líquidos
5.
Artigo em Inglês | MEDLINE | ID: mdl-32475216

RESUMO

Zinc oxide nanoparticles (ZnO NPs) production and usage might lead to a large discharge of ZnO NPs into the natural environment, raising concerns of pollution and ecological security. The effects of ZnO NPs on waste activated sludge hydrolytic acidification and microbial communities were studied in semi-continuous fermentation systems. The fermentation performance of eight ZnO NPs concentrations including ZnO NPs normal [0.01, 0.1, 1 and 10 mg/g mixed liquor suspended solids (MLSS)] and ZnO NPs shock (10, 1000, 1000 and 10,000 mg/g MLSS) were discussed, and their biodegradability was also analyzed. The experimental results showed that proteins, polysaccharides and short-chain fatty acids were enhanced by ZnO NPs, particularly by ZnO NPs shock. Low ZnO NPs concentrations inhibited coenzyme 420 (F420) and dehydrogenase activities but enhanced α-glucosidase and protease activities. Illumina MiSeq sequencing revealed that ZnO NPs addition enriched Azospira, Ottowia and Hyphomicrobium but not Anaerolineaceae.


Assuntos
Fermentação , Microbiota/efeitos dos fármacos , Nanopartículas/toxicidade , Esgotos/microbiologia , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/toxicidade , Óxido de Zinco/toxicidade , Anaerobiose , Biodegradação Ambiental , Hidrólise , Nanopartículas/análise , Esgotos/química , Poluentes Químicos da Água/análise , Óxido de Zinco/análise
6.
Chemosphere ; 259: 127397, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32599380

RESUMO

A hybrid wastewater treatment process with combined attached biofilm (moving bed biofilm reactor) and activated sludge, named as Hybas™, was implemented for the treatment of municipal wastewater. The system consisted of six staged reactors in series including pre-denitrification and nitrification in the Hybas™ line and post-denitrification in a pure MBBR. In addition to the significant removal of nutrients and organic matter from municipal wastewater, Hybas™ also showed removal capacity for pharmaceuticals. Of particular interest was the enhanced removal for pharmaceuticals (i.e. X-ray contrast media) compared to other biological systems. Spiking experiments showed that the maximum removal rate constants (k, h-1) for 10 out of the 21 investigated pharmaceuticals (including diclofenac) were observed to occur within the two aerobic Hybas ™ reactors, operated in a flow-shifting mode that allows even biofilm growth of nitrifying bacteria. In total, 14 out of the 21 pharmaceuticals were removed by more than 50% during continuous flow operation in the all Hybas™ line and post-denitrification MBBR. The calculated and estimated removal contributions of pharmaceuticals by each individual reactor were also assessed.


Assuntos
Preparações Farmacêuticas , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água , Biofilmes/crescimento & desenvolvimento , Reatores Biológicos , Nitrificação , Esgotos/microbiologia , Águas Residuárias
7.
Chemosphere ; 258: 127271, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32535444

RESUMO

Water and soil contamination by industrial wastes is a global concern. Biological treatment of industrial wastewater using bioreactors allows the removal of organic matter and nutrients and enables either reuse or safe discharge. Wastewater bioremediation depends in part on the microbial communities present in the bioreactor. To ascertain which communities may play a role in the remediation process, the present study investigates the microbial community structure and diversity of microorganisms found in a full-scale membrane bioreactor (MBR) for industrial wastewater treatment. The study was carried out using high-throughput data observations following a failure (crash) of the MBR and during the extended recovery of the process. Results revealed a positive correlation between the MBR's ability to remove organic matter and its microbial community richness. The significant changes in relative microbial abundance between crash and recovery periods of the MBR revealed the important role of specific bacterial genera in wastewater treatment processes. A whole-genome metagenomics based comparison showed a clear difference in microbial makeup between two functional periods of MBR activity. The crash period was characterized by abundance in bacteria belonging to Achromobacter, Acinetobacter, Halomonas, Pseudomonas and an uncultured MBAE14. The recovery period on the other hand was characterized by Aquamicrobium and by Wenzhouxiangella marina. Our study also revealed some interesting functional pathways characterizing the microbial communities from the two periods of bioreactor function, such as Nitrate and Sulfate reduction pathways. These differences indicate the connection between the bacterial diversity of the MBR and its efficiency to remove TOC.


Assuntos
Reatores Biológicos/microbiologia , Microbiota/efeitos dos fármacos , Águas Residuárias , Purificação da Água/métodos , Biodegradação Ambiental , Gammaproteobacteria/efeitos dos fármacos , Gammaproteobacteria/genética , Resíduos Industriais/análise , Membranas Artificiais , Metagenômica , Microbiota/genética , Esgotos/microbiologia , Águas Residuárias/química , Águas Residuárias/microbiologia
8.
Chemosphere ; 258: 127230, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32535439

RESUMO

The design of new wastewater treatment plants with the aim of capturing organic matter for energy recovery is a current focus of research. Operating with low sludge residence time (SRT) appears to be a key factor in maximizing organic matter recovery. In these new configurations, it is assumed that phosphorus is chemically removed in a tertiary step, but the integration of enhanced biological phosphorus removal (EBPR) into these short-SRT systems seems to be an alternative worth studying. A key point of this integration is to prevent the washout of polyphosphate accumulating organisms (PAO) despite the low SRT applied. However, the minimum SRT required to avoid PAO washout depends on temperature, due to its effects on reaction kinetics, gas transfer rates, biomass growth and decay rates. This work includes a wide range of short and long-term experiments to understand these interactions and shows which combinations of SRT and temperature are detrimental to PAO growth. For example, an EBPR system operating at 20 °C and SRT = 5 d showed good performance, but EBPR activity was lost at 10 °C. EBPR operated at SRT = 10 d had 86% P removal at 20 °C but decreased to 71% at 15 °C and progressively lost its activity at lower temperature. The temperature coefficient obtained for PAO show a low degree of temperature dependence (θ = 1.047 ± 0.014), and should be considered when designing short-SRT systems with EBPR.


Assuntos
Fósforo/análise , Polifosfatos/análise , Esgotos/microbiologia , Águas Residuárias/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Anaerobiose , Reatores Biológicos , Cinética , Temperatura , Fatores de Tempo
9.
Ecotoxicol Environ Saf ; 201: 110739, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32505047

RESUMO

In the study, antibiotic resistance genes (ARGs) were examined in wastewater and sludge samples to explore the effect of cephalexin (CFX) on the spreading and removal of ARGs in the Expanded Granular Sludge Bed (EGSB) reactor treating antibiotics wastewater. The result showed that the addition of CFX in the wastewater affected the removal amount of ß-lactam ARGs and other types ARGs. Besides, the addition of CFX in the wastewater had no obviously effect on total concentration of targeted ARGs in the sludge, but it was related to the accumulation of some typical ARGs. Based on gene cassette array libraries analysis, the diversity of gene cassettes carried by intI1 gene was increased by the addition of CFX in the wastewater. Furthermore, the co-occurrence patterns between ARGs and bacterial genus were also investigated. The results showed the CFX in the wastewater not only affected the number of potential host bacteria of ARGs, but also changed the types of potential host bacteria of ARGs. The correlation analysis of ARG in influent, effluent and sludge showed that, for blaCTX-M, sul2, qnrS and AmpC genes, their removal amount in EGSB reactor treating antibiotic wastewater system might be enhanced by reducing their concentration in the sludge.


Assuntos
Antibacterianos/farmacologia , Cefalexina/farmacologia , Resistência Microbiana a Medicamentos/efeitos dos fármacos , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/microbiologia , Antibacterianos/análise , Bactérias/efeitos dos fármacos , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Bactérias/isolamento & purificação , Cefalexina/análise , Resistência Microbiana a Medicamentos/genética , Genes Bacterianos/efeitos dos fármacos , Esgotos/química , Esgotos/microbiologia , Águas Residuárias/química
10.
Chemosphere ; 256: 127092, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32559887

RESUMO

Although nitrogen removal from wastewater is essential to prevent eutrophication, the biological processes employed to this end are characterized by several disadvantages, including high energy consumption and the production of large quantities of sludge. Thus, in this study, the organic matter and nitrogen removal efficiencies of the new sulfate reduction, denitrification/anammox and partial nitrification (SRDAPN) process were examined using an anaerobic-anoxic-oxic biofilter reactor. The results showed that the organic matter removal efficiency of the new process at loading rate 1.0 kg COD/m3 per day was 97%. With a circulation flow from the oxic to the anoxic column that was 3 times influent, the nitrogen removal efficiency of the sulfur denitrification and nitrification (SRDN) process without anammox, was 66%, while that of the SRDAPN process with anammox was 76%. Additionally, nitrogen consumption by the anammox reaction in the anoxic column was 13.8% for nitrite-nitrogen and 10.5% for ammonium-nitrogen, and the withdrawal of excess sludge was not required throughout the 170 days of operation. Microbial community analysis showed that acetogenic sulfate reducing bacteria and acetoclastic methanogens coexisted in the anaerobic column, and in the anoxic column, the total relative abundance of anammox bacteria, including Candidatus Brocadia, which coexisted with heterotrophic denitrifying bacteria and sulfur denitrifying bacteria, was 17-18%. Thus, this study established the SRDAPN process as an energy saving and high removal efficiency process.


Assuntos
Sulfatos/química , Eliminação de Resíduos Líquidos/métodos , Compostos de Amônio , Bactérias , Reatores Biológicos/microbiologia , Desnitrificação , Nitrificação , Nitritos , Nitrogênio , Oxirredução , Esgotos/microbiologia , Enxofre , Águas Residuárias/química , Águas Residuárias/microbiologia
11.
Int J Syst Evol Microbiol ; 70(7): 4199-4203, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32553047

RESUMO

A novel Gram-negative, obligate aerobic, mobile, rod-shaped and non-spore-forming bacterial strain, WCHP16T, was isolated from the wastewater treatment plant at West China Hospital in Chengdu, PR China. It was characterized using a polyphasic approach. Analysis of its 16S rRNA gene sequence showed that strain WCHP16T belonged to the genus Pseudomonas with the highest similarity to Pseudomonas qingdaonensis JJ3T (99.34 %), Pseudomonas shirazica VM14T (99.0 %), Pseudomonas plecoglossicida NBRC 103162T (99.0 %) and Pseudomonas asiatica RYU5T (99.0 %). Phylogenomic analysis based on 107 core gene sequences demonstrated that WCHP16T was a member of the Pseudomonas putida group but was distant from all closely related species. Whole-genome comparisons, using average nucleotide identity based on blast (ANIb) and in silico DNA-DNA hybridization (isDDH), confirmed low genome relatedness to all the known Pseudomonas species (below the recommended thresholds of 95 % [ANIb] and 70 % [isDDH] for species delineation). Phenotypic characterization tests showed that the utilization of phenylacetic acid and capric acid, but not d-arabitol, and inability to produce fluorescent (King B medium) in combination could distinguish this strain from other related species of the genus Pseudomonas. Therefore, based on genetic and phenotypic evidence, it is clear that strain WCHP16T represents a novel species, for which the name Pseudomonas defluvii sp. nov. is proposed. The type strain is WCHP16T (GDMCC1.1215T=CCTCC AB 2017103T=KCTC 52991T).


Assuntos
Hospitais , Filogenia , Pseudomonas/classificação , Esgotos/microbiologia , Técnicas de Tipagem Bacteriana , Composição de Bases , China , DNA Bacteriano/genética , Ácidos Graxos/química , Hibridização de Ácido Nucleico , Pseudomonas/isolamento & purificação , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Águas Residuárias
12.
J Biosci Bioeng ; 130(3): 319-326, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32439285

RESUMO

An up-flow anaerobic sludge blanket (UASB) reactor was operated to investigate the performance, sludge granulation, and microbial community dynamics of the simultaneous anammox and denitrification (SAD) process at different C/N ratios by inducing a shift from the anammox process. The nitrogen removal efficiency (NRE) increased with an increase in the C/N ratio at lower C/N ratios (≤ 0.5). The NRE and nitrogen removal rate (NRR) were 90.81% and 1.75 kgN m-3d-1, respectively, at a C/N ratio of 0.5. The contribution of the anammox process to nitrogen removal (Eanammox) decreased sharply to 51% from 81% as a result of the decreased activity of the anaerobic ammonia-oxidizing bacteria (AnAOB) at a C/N ratio of 0.9. The EPS production and the ratio of the protein fraction of EPS (EPSp) to the carbohydrate fraction of EPS (EPSc) increased with the increase in the C/N ratio (0.0-0.9), which induced sludge aggregation and resulted in larger particle size. The enrichment of denitrifying bacteria (DNB) on the surface of the AnAOB due to EPS bridging further enhanced sludge granulation. The Illumina sequencing results showed that the dominant genus of AnAOB (Candidatus Jettenia) initially increased with an increase in the C/N ratio at lower levels and then decreased sharply at a C/N ratio of 0.9. The relative abundance of Candidatus Jettenia was promoted by decreasing the C/N ratio, which supported the recovery of the AnAOB activity. Denitratisoma, Bacillus, Acinetobacter, and Pseudomonas were responsible for denitrification throughout the entire operational period.


Assuntos
Compostos de Amônio/metabolismo , Bactérias/metabolismo , Carbono/metabolismo , Desnitrificação , Nitrogênio/metabolismo , Esgotos/microbiologia , Anaerobiose , Reatores Biológicos/microbiologia , Nitrogênio/isolamento & purificação , Oxirredução
13.
World J Microbiol Biotechnol ; 36(5): 75, 2020 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-32390104

RESUMO

Biofilm reactors retain microbial cells in the form of biofilm which is attached to free moving or fixed carrying materials, thus providing a high active biomass concentration and automatic liquid and solid separation. Nowadays, microbial biofilm reactors have been widely used in high-strength wastewater treatment where very high pollutant removal efficiency is required, which usually requires excessive space and aeration energy for conventional activated sludge-based treatment. This paper provides an overview of microbial biofilm reactors developed over the last half-century, including moving bed biofilm reactor (MBBR), trickling filter (TF) reactor, rotating biological contactor (RBC), membrane biofilm reactor (MBfR), passive aeration simultaneous nitrification and denitrification (PASND) biofilm reactor, for their applications in high-strength wastewater treatment of not only removing carbon, nitrogen, sulphur but also a variety of oxidized contaminants including perchlorate and bromate. Despite the advance of biofilm reactor that exhibits high resistance to excessive pollutants loading, its drawbacks both from engineering and microbiological point of view are reviewed. The future prospects of biofilm reactor are also discussed in this review paper.


Assuntos
Biofilmes , Reatores Biológicos/microbiologia , Águas Residuárias/microbiologia , Purificação da Água/métodos , Biomassa , Bromatos/metabolismo , Carbono/metabolismo , Desnitrificação , Microbiologia Industrial , Membranas , Nitrificação , Nitrogênio , Percloratos/metabolismo , Esgotos/microbiologia
14.
Artigo em Inglês | MEDLINE | ID: mdl-32458727

RESUMO

Waste-activated sludge (WAS) with trace organic pollutants, e.g., polycyclic aromatic hydrocarbons (PAHs), has become an environmental concern. Anaerobic technology is a feasible option for WAS treatment due to its advantages of low-energy consumption and high-energy recovery compared to aerobic technology, but it still has many shortcomings, such as low biogas production and a low organic pollutant removal efficiency. Thus, this study investigated the effects of cellulose on PAHs degradation and microbial community structure variation during anaerobic digestion of sewage sludge. Four semicontinuous experiments were set by adding cellulose to sewage sludge based on the volatile solids (VS) concentration. The proportions of sludge VS to cellulose VS were 1:0 (CK), 1:0.2, 1:0.5 and 1:1. The results showed the following: (1) The biodegradation of 2-ring, 3-ring and 4-ring PAHs was enhanced by cellulose addition, with total PAHs removal efficiencies of 14.82%, 20.75% and 19.35%, respectively. (2) The abundance of bacteria that could degrade PAHs, such as Chloroflexi, Bacteroidetes, Aminicenantes, Planctomycetes and Spirochaeta, was obviously increased by cellulose addition. (3) The abundance of Methanosaeta during sludge anaerobic digestion was apparently increased by cellulose addition. Methanobacterium and Methanolinea appeared after cellulose addition, while they were not observed in the blank experiment.


Assuntos
Celulose/farmacologia , Microbiota/efeitos dos fármacos , Hidrocarbonetos Policíclicos Aromáticos/análise , Esgotos , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/análise , Anaerobiose , Biodegradação Ambiental , Biocombustíveis/análise , Celulose/metabolismo , Esgotos/química , Esgotos/microbiologia
15.
Chemosphere ; 255: 127010, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32416397

RESUMO

The present work demonstrated the invention of synergistically strengthen of chemical and biological removal of phosphorus (P) in biological wastewater treatment, which was achieved by exposure the bioreactors to different levels of La-based-adsorbents. We fabricated a high-performance La2O2CO3 micro-adsorbent (H-La2O2CO3) and added it into sequencing batch reactors. When activated sludge was exposed to 40 mg/L H-La2O2CO3 for 40 d, effluent total phosphorus (TP) concentration significantly decreased to approximately 0.18 mg/L, with the steady removal efficiency of 96.4%, which is superior to the biological phosphorus removal (BPR). The effect of H-La2O2CO3 dosages on P removal in biological wastewater treatment was also detailedly investigated. The H-La2O2CO3 adsorbent could not only capture P by chemical bonding itself, but also increased protein (PN) contents of extracellular polymeric substances (EPS) and changed the functional group of EPS to chemically adsorb P. Additionally, the results of 16s rDNA molecular analysis revealed that the species richness and microbial diversity varied with the different dosages of adsorbent. Sequence analyses showed that the appropriate concentration of H-La2O2CO3 addition increased the contents of several polyphosphate accumulating organisms (PAOs) at genus level in sludge.


Assuntos
Reatores Biológicos/microbiologia , Carbonatos/química , Lantânio/química , Fósforo/análise , Esgotos/química , Águas Residuárias/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Adsorção , Microbiota/efeitos dos fármacos , Polifosfatos/análise , RNA Ribossômico 16S , Esgotos/microbiologia , Águas Residuárias/microbiologia
16.
Int J Syst Evol Microbiol ; 70(6): 3718-3723, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32427091

RESUMO

Two novel actinobacteria, designated NBRC 107696T and NBRC 107697T, were isolated from sludge samples from a wastewater treatment plant and their taxonomic positions were investigated by a polyphasic approach. The cells of the strains were aerobic, rod-shaped, non-motile and non-endospore-forming. The strains contained glutamic acid, alanine and meso-diaminopimelic acid in the peptidoglycan. Galactose and arabinose were detected as cell-wall sugars. The predominant menaquinone was identified as MK-9(H2) and the major fatty acids were C16  :  0, C18 : 1ω9c and C16 : 1ω7c. The DNA G+C contents of NBRC 107696T and NBRC 107697T were 68.07 and 68.99 mol%, respectively. Phylogenetic analyses based on 16S rRNA gene sequence comparisons revealed that NBRC 107696T and NBRC 107697T were a clade with members of the genus Gordonia. The highest 16S rRNA gene sequence similarity values were obtained with Gordonia araii IFM 10211T (98.9 %) for NBRC 107697T, and Gordonia malaquae IMMIB WWCC-22T, Gordonia neofelifaecis AD-6T and Gordonia humi CC-12301T (98.1 %) for NBRC 107696T, respectively. The digital DNA-DNA relatedness data coupled with the combination of genotypic and phenotypic data indicated that the two strains are representatives of two novel separate species. The names proposed to accommodate these two strains are Gordonia spumicola sp. nov. and Gordonia crocea sp. nov., and the type strains are NBRC 107696T (=IFM 10067T=TBRC 11239T) and NBRC 107697T (=IFM 10881T=TBRC 11240T), respectively.


Assuntos
Gordonia (Bactéria)/classificação , Filogenia , Esgotos/microbiologia , Águas Residuárias/microbiologia , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Gordonia (Bactéria)/isolamento & purificação , Japão , Hibridização de Ácido Nucleico , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Vitamina K 2/análogos & derivados , Vitamina K 2/química
17.
PLoS One ; 15(5): e0232324, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32357180

RESUMO

Anaerobic digestion (AD) is used to minimize solid waste while producing biogas by the action of microorganisms. To give an insight into the underlying microbial dynamics in anaerobic digesters, we investigated two different AD systems (wastewater sludge mixed with either fish or grass waste). The microbial activity was characterized by 16S RNA sequencing. 16S data is sparse and dispersed, and existent data analysis methods do not take into account this complexity nor the potential microbial interactions. In this line, we proposed a data pre-processing pipeline addressing these issues while not restricting only to the most abundant microorganisms. The data were analyzed by Common Components Analysis (CCA) to decipher the effect of substrate composition on the microorganisms. CCA results hinted the relationships between the microorganisms responding similarly to the AD physicochemical parameters. Thus, in overall, CCA allowed a better understanding of the inter-species interactions within microbial communities.


Assuntos
Archaea/metabolismo , Bactérias/metabolismo , Esgotos/microbiologia , Anaerobiose , Archaea/isolamento & purificação , Bactérias/isolamento & purificação , Biodiversidade , Análise de Dados , Pesqueiros , Interações Microbianas , RNA Bacteriano , RNA Ribossômico 16S , Estatística como Assunto
18.
Arch Microbiol ; 202(7): 1907-1913, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32448962

RESUMO

In this work, volatile fatty acids (VFAs) were used as a carbon source to assess the ability of bacteria present in waste activated sludge (WAS), as indigenous flora, to accumulate polyhydroxyalkanoates (PHA). Acetic acid and propionic acid were used both separately and in combination as feedstock, producing either homopolymer poly(3-hydroxybutyrate) (3PHB) and/or the co-polymer, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) P(3HB-co-3HV). The overall potential to use waste activated sludge as biomass for production of valuable polymers was assessed, and a quality assessment of the as-produced polymers was run, with the extracted polymer being analyzed for properties such as thermal, microstructure and molecular weight. It was found that a blend of copolymers was typically produced, with thermal properties being similar to those reported elsewhere. The overall PHA cell content obtained was 0.29 gPHA gVSS-1.


Assuntos
Biomassa , Microbiologia Industrial , Poli-Hidroxialcanoatos/metabolismo , Esgotos/microbiologia , Carbono/metabolismo , Ácidos Graxos Voláteis , Peso Molecular , Poli-Hidroxialcanoatos/biossíntese , Poli-Hidroxialcanoatos/química
19.
Ecotoxicol Environ Saf ; 199: 110639, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32408033

RESUMO

Graphene Oxide (GO) has wide applications in many fields which has caused a large expected quantity of the graphene-based wastes. It is necessary to understand the toxic effects of the GO on the activated sludge (AS) considering its inevitable discharge to the wastewater treatment plants as the ultimate repositories for these wastes. In this study, the acute exposures of the multilayer Nano-graphene oxide (MNGO) at different dosages were conducted in order to investigate its integrated effects on the formation of the biofilm, mature biofilm and the microbial activity of the activated sludge. Raman spectroscopy and laser scanning confocal microscopy (LSCM) were adopted for the in-situ characterization of the biofilm with the exposure of the MNGO. The results showed that the activated sludge was tolerable to the acute exposure of the less than 100 mg/L of the MNGO, especially for the mature biofilm, and only a subtle decrease was found in the size and thickness during the formation of the biofilm, while the amount of 300 mg/L of the MNGO caused the sever deterioration on the activated sludge system. The microbial metabolic activity, viability, and the biological removal of the nutrients were significantly affected with the more than 100 mg/L of the MNGO. It was also demonstrated by the microbial cytotoxicity tests that the increase in the exposure of the MNGO was related to the increase in the reactive oxygen species (ROS) and the damaging degree of the cell membrane.


Assuntos
Biofilmes/efeitos dos fármacos , Grafite/toxicidade , Viabilidade Microbiana/efeitos dos fármacos , Esgotos/microbiologia , Águas Residuárias/microbiologia , Poluentes Químicos da Água/toxicidade , China , Espécies Reativas de Oxigênio/metabolismo , Esgotos/química , Águas Residuárias/química , Purificação da Água/métodos
20.
Ecotoxicol Environ Saf ; 199: 110755, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32446099

RESUMO

To increase the degree of immobilization of heavy metals subjected to sludge pyrolysis, we investigated the effects of pretreating sludge with Ochrobactrum supplementation on the immobilization of chromium (Cr) and copper (Cu) during sludge pyrolysis. The sequential extraction procedure was used to test the metallic forms of Cr and Cu. The immobilization of Cr and Cu was characterized with X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, etc. Results show that: 1) the addition of Ochrobactrum (1-8%) can accelerate the mineralization process in blank sludge and can accelerate the conversion of the oxidizable forms of Cr and Cu into the residual forms subjected to pyrolysis; 2) pretreatment with Ochrobactrum supplementation can inhibit the volatilization of Cr and Cu during sludge pyrolysis, particularly in the case of a high concentration of Cu. Notably, the pretreatment with Ochrobactrum can reduce 20.38-85.09% of the potential ecological risk of Cr and Cu. The pretreatment with Ochrobactrum contributes to the immobilization of Cr and Cu subjected to sludge pyrolysis and thus can prevent pollution of the environment. The results of this study can be used for harmless disposal of municipal sludge.


Assuntos
Cromo/análise , Cobre/análise , Ochrobactrum/química , Pirólise , Esgotos , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/análise , Adsorção , China , Microscopia Eletrônica de Varredura , Ochrobactrum/metabolismo , Oxirredução , Esgotos/química , Esgotos/microbiologia
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