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1.
J Environ Sci (China) ; 87: 205-212, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31791493

RESUMO

This study aims to investigate the effect of a magnetic field on nitrous oxide (N2O) emission from a sequencing batch reactor treating low-strength domestic wastewater at low temperature (10°C). After running for 124 days in parallel, results indicated that the conversion rate of N2O for a magnetic field-sequencing batch reactor (MF-SBR) decreased by 34.3% compared to that of a conventional SBR (C-SBR). Meanwhile, the removal efficiencies for total nitrogen (TN) and ammonia nitrogen (NH4-N) of the MF-SBR were 22.4% and 39.5% higher than those of the C-SBR. High-throughput sequencing revealed that the abundances of AOB (Nitrosomonas), NOB (Nitrospira) and denitrifiers (Zoogloea), which could reduce N2O to N2, were promoted significantly in the MF-SBR. Enzyme activities (Nir) and gene abundances (nosZ nirS and nirK) for denitrification in the MF-SBR were also notably higher compared to C-SBR. Our study shows that application of a magnetic field is a useful approach for inhibiting the generation of N2O and promoting the nitrogen removal efficiency by affecting the microbial characteristics of sludge in an SBR treating domestic wastewater at low temperature.


Assuntos
Reatores Biológicos , Campos Magnéticos , Óxido Nitroso/análise , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias , Temperatura Baixa , Desnitrificação , Nitrificação , Nitrogênio , Nitrosomonas
2.
Water Res ; 167: 115102, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31574346

RESUMO

Artificial sweeteners (ASs) have been frequently detected in aquatic environment and are of emerging concern due to their environmental persistence, acesulfame (ACE) and sucralose (SUC) are two ASs that are difficult to remove. The ultraviolet/persulfate (UV/PS) advanced oxidation process has been proven to remove ASs in real wastewater effectively. In this study, radical-based degradation kinetic model, pathways and toxicity evaluation of ASs by UV/PS process were explored. ACE and SUC were effectively removed by UV/PS process, and UV photolysis, hydroxyl radicals (HO∙) and sulfate radicals (SO4∙-) contributes the degradation of ASs. A kinetic prediction model for ASs degradation was established based on the second-order rate constants with HO∙ and SO4∙-, and the steady state concentrations of HO∙ and SO4∙- were calculated through the degradations of two reference compounds. The kinetic model could predict the degradation process of ASs in five real wastewaters effluents. Furthermore, two models based on the kinetic and the water matrices parameters for ASs degradation in wastewater were compared. Finally, the tentative pathways of ASs degradations by UV/PS were proposed. Also, toxicity evaluation showed that ASs after UV/PS treatment enhanced the toxicity on C. carpio liver, and prolongation of treatment time and recovery in fresh water can reduce the toxicity on C. carpio.


Assuntos
Poluentes Químicos da Água , Purificação da Água , Peróxido de Hidrogênio , Cinética , Oxirredução , Fotólise , Edulcorantes , Raios Ultravioleta , Águas Residuárias
3.
Chemosphere ; 237: 124371, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31369902

RESUMO

Public concerns about potential ecological risks of androgens discharged to the environment through wastewater treatment plants (WWTPs) has resulted in an increased interest regarding the occurrence and fate of androgens in WWTPs. In this study, the occurrence and removal of eight androgens from 12 municipal WWTPs distributed in eleven cities in China were investigated. The composition profiles of eight androgens in influent, effluent, and excess sludge were studied. Multiple factor analyses were performed to reveal the factors affecting the distribution of androgens in WWTP influent. Results showed similar composition profiles of androgens in the studied WWTPs, with androsterone and dehydroepiandrosterone confirmed as the dominant androgens. The distributions of androgens in WWTP influent were related to the chemical oxygen demand in influent and the gross domestic product (GDP) of WWTP-associated cities. The target androgens have high aqueous removal rates, with a mean removal rate of >90%. Additionally, the behaviors of androgens were evaluated by mass balance along anaerobic-anoxic-oxic (AAO) processes in a WWTP, in which many of the androgens were eliminated mainly in the anaerobic tank. Further, 15 biotransformation products of testosterone were identified under anaerobic, anoxic, and aerobic sludge, respectively. Based on these metabolites, a general biotransformation pathway of testosterone under anaerobic, anoxic, and aerobic sludge is presented.


Assuntos
Androgênios/análise , Águas Residuárias/química , Poluentes Químicos da Água/análise , Androgênios/metabolismo , Androsterona/análise , China , Cidades , Esgotos/química , Testosterona/metabolismo , Instalações de Eliminação de Resíduos , Eliminação de Resíduos Líquidos , Poluentes Químicos da Água/metabolismo , Purificação da Água
4.
Sci Total Environ ; 683: 80-88, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31136967

RESUMO

Diclofenac (DCF), as an emerging contaminant in aquatic environments, has sparked increasing concerns about its impact on the environment. Nitrification in wastewater treatment processing has removed DCF to a large extent. However, the removal characteristics and mechanisms of DCF in the nitrification process are still poorly understood. In this study, enriched nitrifying sludge was used to investigate the transformation of DCF during the nitrification process. Elimination of DCF caused by volatilization, hydrolyzation and adsorption was limited. Abiotic nitration removal was confirmed as significant in enriched nitrifying sludge at a low pH and high nitrite concentration. Free nitrite acid was proposed as the reaction species participating in the DCF transformation process, and a regression equation was developed to predict the contribution of abiotic nitration on DCF removal in enriched nitrifying sludge. By slowly and continuously adding an ammonia stock solution and controlling the pH, we avoided the effect of abiotic nitration removal, and DCF biodegradation was positively correlated to specific ammonium oxidation rates (SAORs). The removal of DCF fit the first order kinetic model (R2 = 0.8285, p < 0.05) with an SAOR of 0.25 mg NH4+-N/(gMLSS·min). The high removal rate constant of k (0.1286 L/(gMLSS·h)) and short half-life (2.48 h) revealed the strong capability of nitrifying bacteria to transform DCF. Nine DCF transformation products were identified and three of them were quantified in the transformation process. The formation of kinetic profile 4-OH-DCF, 5-OH-DCF and DCF-Benzoic acid (DCF-BA) implied that hydroxylation may be the first reaction of DCF and DCF-BA may be a terminal product that resists further degradation. The postulated reactions concerning the transformation of DCF were hydroxylation, lactam formation and oxidation. Accordingly, a detailed degradation pathway was presented.


Assuntos
Compostos de Amônio/metabolismo , Diclofenaco/metabolismo , Nitrificação , Eliminação de Resíduos Líquidos , Poluentes Químicos da Água/metabolismo , Biotransformação , Cinética , Oxirredução , Esgotos/análise
5.
Sci Total Environ ; 668: 1191-1199, 2019 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-31018459

RESUMO

Progestagens discharged from municipal wastewater treatment plants (WWTPs) have increasingly gained attention due to their potential risks to the aquatic organisms. However, limited information is available on the occurrence and removal of various progestagens in WWTPs in different cities of China. This work investigated the occurrence and removal of 11 progestagens in 21 WWTPs from 19 Chinese cities. Results showed that progestagens are widely distributed in the investigated WWTPs, with higher influent concentrations of total progestagens in northern WWTPs. The concentration of progestagens in WWTP influent were closely correlated with influent quality, service population and daily service volume of the WWTPs. Additionally, progesterone (PGT) and dydrogesterone (DDT) were two predominant progestagens in influent, effluent and excess sludge. Up to 5 of 11 progestagens showed high aqueous removal efficiencies (median removal efficiency >90%), whereas megestrol acetate (MTA), chlormadinone acetate (CMA), drospirenone (DSP) and levonorgestrel (LNG) had a removal efficiency of below 50%. Specially, the behaviors of progestagens along the anaerobic-anoxic-oxic of a WWTP were further explored and the aerobic tank is the main contributor to the removal of progestagens. Finally, in the effluent of these 21 WWTPs, daily mass loadings of the total progestagens ranged from 0.51 to 10.4 g d-1. Notably, LNG exhibited high potential risk to the fish base on risk quotient.


Assuntos
Progestinas/análise , Águas Residuárias/química , Poluentes Químicos da Água/análise , Purificação da Água , China , Monitoramento Ambiental , Progestinas/química , Medição de Risco , Poluentes Químicos da Água/química
6.
Sci Rep ; 9(1): 6019, 2019 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-30962457

RESUMO

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.

7.
Bioresour Technol ; 272: 599-605, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30509729

RESUMO

Deficiency of researches on biotic community-driven biofilm activity makes biofilm regulation lack of quantitative response for decades. Based on three full-scale aerobic bioreactors in wastewater treatment plants, this study for the first time linked microbial respiratory activity with phospholipid fatty acid (PLFA) of biofilm developed on fixed and suspended carriers. Results showed that C16:00, C18:00, C16:1, ω7c, C18:1, ω7c, C12:00 and C18:1ω9c were top six biomarkers of PLFA among different sources of samples and Gram-negative bacteria (G-) was more abundant than Gram-positive bacteria (G+) with average G-/G+ of 2.98. It's interesting to find defective revealing of PLFA-based biofilm activity by specific oxygen uptake rate (SOUR). Further modeling indicated that C16:00 achieved the optimal quantitative response to STOUR with the best model of composite, growth, or exponential curve (R2 = 0.416, p = 0.005). This research was promising to provide important reference for biofilm regulation and accurate control of biofilm-based process.


Assuntos
Biofilmes , Reatores Biológicos/microbiologia , Ácidos Graxos/metabolismo , Fosfolipídeos/metabolismo
8.
Water Res ; 150: 12-20, 2019 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-30503870

RESUMO

The frequent detection of artificial sweeteners (ASs) in wastewater and surface water gives rise to concerns about their removal, Acesulfame (ACE) and sucralose (SUC) are two ASs that are difficult to remove. The ultraviolet/persulfate (UV/PS) advanced oxidation technology (AOT) is being considered as an effective process for the degradation of micropollutants in wastewater. However, the study of the degradation of ASs in real wastewater by the UV/PS is minimal. This study investigated the kinetics and modeling of ACE and SUC degradation in wastewater by the UV/PS process. Both ACE and SUC could be degraded effectively using this process. The degradation of ACE was mainly attributed to UV photolysis (51%), HO∙ (26%) and SO4∙- (16%), while that of SUC was mainly attributed to HO∙ (68%) and SO4∙- (27%). The second-order rate constants of ASs with SO4∙- were significantly lower than that with HO∙. Three major transformation products (TPs) of ACE and four major TPs of SUC were identified. Additionally, the effects and mechanisms of the water matrices, such as HCO3-, Cl-, NO3- and natural organic matter (NOM), on ASs degradation were investigated through response surface methodology (RSM). NOM and Cl- significantly inhibited the degradation of ACE in the UV/PS system, whereas NOM and HCO3- played a main inhibition role on the degradation of SUC. A water matrices parameter model for predicting ASs degradation in real wastewater was established by RSM for the first time, and the removal of ACE and SUC was well predicted by the model.


Assuntos
Poluentes Químicos da Água , Purificação da Água , Cinética , Oxirredução , Fotólise , Edulcorantes , Raios Ultravioleta , Águas Residuárias
9.
Sci Rep ; 8(1): 13512, 2018 09 10.
Artigo em Inglês | MEDLINE | ID: mdl-30202028

RESUMO

The efficiency of advanced oxidation processes (AOPs) for disposing of non-steroidal anti-inflammatory drugs (NSAIDs) has been widely studied, but the environmental fates and effects of the NSAIDs and their degradation products (DPs) are poorly understood. In this study, the efficiency of ultraviolet light/Na2S2O8 (UV/PS) in degrading three NSAIDs-diclofenac, naproxen, and ibuprofen-and the toxicity of their DPs on Cyprinus carpio (C. carpio) was investigated. Results showed that the three NSAIDs can be completely removed (removal rate > 99.9%) by UV/PS, while the mineralization rate of the NSAIDs was only 28%. When C. carpio were exposed to 0.1 µM NSAIDs, 10 µM persulfate (PS), and 0.1 µM DPs of the NSAIDs for 96 h, respectively, the toxicity effects are as the NSAID DPs > PS > NSAIDs. Research results into the time-dependent effect of NSAID DPs on C. carpio demonstrated that obvious toxicity effects were observed in the first 48 hours, and the toxicity effects strengthened over time. NSAID DPs may have more severe toxicity effects than NSAIDs on C. carpio; therefore, the operating conditions of UV/PS must be optimized to eliminate the ecotoxicity of DPs.


Assuntos
Anti-Inflamatórios não Esteroides/toxicidade , Carpas , Poluentes Ambientais/toxicidade , Doenças dos Peixes/prevenção & controle , Purificação da Água/métodos , Animais , Anti-Inflamatórios não Esteroides/química , Diclofenaco/química , Diclofenaco/efeitos da radiação , Diclofenaco/toxicidade , Monitorização de Parâmetros Ecológicos , Poluentes Ambientais/química , Poluentes Ambientais/efeitos da radiação , Poluição Ambiental/prevenção & controle , Doenças dos Peixes/induzido quimicamente , Ibuprofeno/química , Ibuprofeno/efeitos da radiação , Ibuprofeno/toxicidade , Eliminação de Resíduos de Serviços de Saúde , Naproxeno/química , Naproxeno/efeitos da radiação , Naproxeno/toxicidade , Oxirredução , Fotólise/efeitos dos fármacos , Fotólise/efeitos da radiação , Compostos de Sódio/química , Sulfatos/química , Testes de Toxicidade Aguda , Raios Ultravioleta , Águas Residuárias/química , Águas Residuárias/toxicidade
10.
Huan Jing Ke Xue ; 39(3): 1151-1158, 2018 Mar 08.
Artigo em Chinês | MEDLINE | ID: mdl-29965459

RESUMO

In order to investigate the characteristics of bacterioplankton in the spring in Zhushan Bay, Lake Taihu, the 16S rRNA gene of the bacterioplankton at four sampling sites in Zhushan Bay was sequenced by high-throughput sequencing using water samples collected from Yapugang, Shatanggang, Zhushanhunan, and Jiaoshan. The results showed that the coverage of the sequencing library was very high and could accurately represent the bacterioplankton community in the samples. The species richness of Jiaoshan was the highest, but the species evenness was lower. Cyanobacteria, Actinobacteria, Proteobacteria, and Bacteroidetes were the dominant phylum in Zhushan Bay. The average abundance of Cyanobacteria was as high as 64.73%, which indicated an outbreak of cyanobacteria bloom in the water. At the genus level, Anabaena, hgcI_clade, CL 500-29 _marine_group, Microcystis, Synechococcus, and Mycobacterium were predominant. The results of redundancy analysis (RDA) for the relationship between bacterioplankton and environmental factors showed that water temperature, chlorophyll a (Chl-a), ammonia nitrogen(NH4+-N), dissolved oxygen (DO), and phosphate (PO43--P)were the main environmental factors affecting the bacterioplankton community. Dissolved oxygen could significantly affect Microcystis; nutrient and water temperature also had an effect.


Assuntos
Bactérias/classificação , Lagos/microbiologia , Plâncton/classificação , Amônia/análise , Bactérias/crescimento & desenvolvimento , Baías , China , Clorofila A/análise , Monitoramento Ambiental , Oxigênio/análise , Fosfatos/análise , Plâncton/crescimento & desenvolvimento , RNA Ribossômico 16S/genética , Temperatura Ambiente
11.
Sci Rep ; 8(1): 10298, 2018 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-29967416

RESUMO

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.

12.
Bioresour Technol ; 265: 17-24, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29864733

RESUMO

This paper investigated the influences of different dissolved oxygen (DO) concentration (0.71-1.32, 2.13-3.02 and 4.31-5.16 mg/L) on cell membrane characteristics and microbial population distribution of moving biofilm reactors. Two representative reactors, i.e., moving bed biofilm reactors and integrated fixed-film activated sludge were operated. Results indicated that both DO concentration of 0.71-1.32 mg/L and 4.31-5.16 mg/L could increase membrane lipid mobile fraction (49.4%-67.4%) of the microbes, however, through prompting the synthesis of branched fatty acids and unsaturated fatty acids, respectively. For the biofilms, the abundance of Bacteroidetes decreased and Actinobacteria increased with the increase of DO levels. The lowest EfOM content and the highest microbial diversities (1.14-1.52) was observed at DO of 2.13-3.02 mg/L. Redundancy analysis showed that changes of DO levels could alter cell membrane properties and bacterial community structures, and subsequently significantly influenced effluent organic matter composition of moving biofilm reactors.


Assuntos
Reatores Biológicos , Membrana Celular , Oxigênio/análise , Bactérias , Biofilmes , Esgotos , Eliminação de Resíduos Líquidos
13.
Sci Total Environ ; 624: 1013-1022, 2018 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-29929218

RESUMO

Startup of biofilm process triggered by initial adhesion of bacteria is difficult in high ammonia nitrogen wastewater treatment. In this study, the influence of two commonly used N-acyl homoserine lactones (AHLs), N-Hexanoyl-l-homoserine lactone (C6-HSL) and N-Octanoyl-l-homoserine lactone (C8-HSL), on the adhesion of soluble macromolecules and bacteria in four types of high ammonia nitrogen wastewater to surfaces of model biocarriers (i.e. polystyrene, polyamide and polyethylene terephthalate) was investigated by using a quartz crystal microbalance with dissipation (QCM-D) monitoring technology. Results showed that the adhesion was enhanced by the addition of exogenous AHLs and there was more microbial retention attributed by C8-HSL. Greater deposition amount was generally found on PS and better enhanced performances of the adhesion were found on PA surface. Furthermore, viscoelastic film formed under synchronous high-low salinity and organic content and dominant bacteria of real wastewater determined the role of exogenous AHLs. The method of adding moderate amount of exogenous AHLs into bioreactors has important implications for accelerating the startup process treating high ammonia nitrogen wastewater by biofilm process.


Assuntos
Amônia/análise , Biofilmes , Reatores Biológicos/microbiologia , Águas Residuárias/química , Poluentes Químicos da Água/análise , 4-Butirolactona/análogos & derivados , 4-Butirolactona/metabolismo , Amônia/metabolismo , Homosserina/análogos & derivados , Homosserina/metabolismo , Lactonas/metabolismo , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/metabolismo
14.
PLoS One ; 13(6): e0198958, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29879232

RESUMO

[This corrects the article DOI: 10.1371/journal.pone.0189867.].

15.
Water Res ; 137: 281-289, 2018 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-29554532

RESUMO

Phosphite (P+III) is of emerging chemical interest due to its importance within the global phosphorus cycle. Yet, to date, precise/accurate measurements of P+III are still lacking due to the inherent analytical challenges linked to its instability/ease of oxidation and ultra-trace concentration. Here, we present the first in-situ sampling and speciation analysis method, for dissolved P+III, using the diffusive-gradients-in-thin-films (DGT) technique, combined with capillary-column-configured-dual-ion-chromatography (CC-DIC). Method optimization of the DGT elution regime, to simultaneously maximize desorption efficiency and CC-DIC sensitivity, along with the characterization of diffusion coefficients for P+III, were undertaken before full method validation. Laboratory-performance testing confirmed DGT-P+III acquisition to be independent of pH (3.0-10.0) and ionic strength (0-500 mM). The capacity for P+III was 45.8 µg cm-2, while neither P+V (up to 10 mg L-1) nor As+V (up to 1 mg L-1) impacted the DGT-P+III measurement. This novel method's functionality stems from the herein confirmed speciation preservation and double pre-concentration of P+III, resulting in quantification limits as low as 7.44 ng L-1 for a 3-day deployment. Applications of this method in various terrestrial/aquatic environments were demonstrated and simultaneous profiles of P+III and P+V across a sediment-water interface were captured at mm resolution in two contrasting redox-mesocosm systems.


Assuntos
Poluentes Ambientais/análise , Fosfitos/análise , Monitoramento Ambiental/métodos , Água Doce/análise , Concentração Osmolar , Solo/química , Águas Residuárias/análise
16.
Sci Rep ; 8(1): 3399, 2018 02 21.
Artigo em Inglês | MEDLINE | ID: mdl-29467367

RESUMO

Concern is growing over contamination of the environment with artificial sweeteners (ASWs) because of their widespread existence in wastewater treatment plants (WWTPs). To evaluate ASWs removal and the effect on activated sludge, acesulfame (ACE), sucralose (SUC), cyclamate (CYC) and saccharin (SAC) were introduced individually or in mixture to sequencing batch reactors (SBRs) in environmentally relevant concentrations (100 ppb) for 100 days. Comparisons between ACE removal in a full-scale WWTP and in lab-scale SBRs were conducted. Results showed that CYC and SAC were completely removed, whereas SUC was persistent. However, ACE removal in lab-scale SBRs was significantly greater than in the full-scale WWTP. In SBRs, chemical oxygen demand (COD), ammonia nitrogen (NH4+-N) and total nitrogen (TN) removal appeared unchanged after adding ASWs (p > 0.05). Adenosine triphosphate (ATP) concentrations and triphenyl tetrazolium chloride-dehydrogenase activity (TTC-DHA) declined significantly (p < 0.05). The mixed ASWs had more evident effects than the individual ASWs. Microbial community analyses revealed that Proteobacteria decreased obviously, while Bacteroidetes, Chloroflexi and Actinobacteria were enriched with the addition of ASWs. Redundancy Analysis (RDA) indicated ACE had a greater impact on activated sludge than the other ASWs.

17.
Water Res ; 133: 37-46, 2018 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-29407713

RESUMO

Start-up of biofilm process initiated by the deposition of soluble matters on biocarriers is a very important yet time-consuming procedure. However, rapid start-up methods especially in the enhancement of soluble matters deposition have been rarely addressed. In this study, a quartz crystal microbalance with dissipation monitoring (QCM-D) was applied to investigate the influences of calcium ion and rhamnolipid (RL) on the deposition of soluble matters from real and synthetic industrial wastewaters with different configurations of organics (bovine serum albumin and sodium alginate) and ionic strength on the model biocarriers polystyrene and polyamide. Results showed that deposition was effectively promoted by the addition of Ca2+ and along with the increase in Ca2+ content. However, RL enhanced the deposition effectively only in hyperhaline wastewater through breaking hydration repulsion and decreased the deposition in low-salinity wastewater, and its influence to the deposited layer property exhibited characteristics of negative feedback. The combined use of Ca2+ and RL had a better enhancement effect than that of separate use and the mechanism involved can not be soundly explained only by Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. The strategy of mediating the deposition of soluble matters on different biocarriers by adding Ca2+ and RL has important implications for regulating biofilm formation to accelerate the start-up process in attached-growth bioreactors.


Assuntos
Reatores Biológicos , Cálcio/química , Glicolipídeos/química , Nylons/química , Poliestirenos/química , Alginatos/química , Biofilmes/crescimento & desenvolvimento , Ácido Glucurônico/química , Ácidos Hexurônicos/química , Resíduos Industriais , Concentração Osmolar , Técnicas de Microbalança de Cristal de Quartzo , Soroalbumina Bovina/química , Águas Residuárias
18.
PLoS One ; 13(1): e0189867, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29293534

RESUMO

Five full-scale wastewater treatment plants (WWTPs) in China using typical biodegradation processes (SBR, oxidation ditch, A2/O) were selected to assess the removal of four popular artificial sweeteners (ASs). All four ASs (acesulfame (ACE), sucralose (SUC), cyclamate (CYC) and saccharin (SAC)) were detected, ranging from 0.43 to 27.34µg/L in the influent. Higher concentrations of ASs were measured in winter. ACE could be partly removed by 7.11-50.76% through biodegradation and especially through the denitrifying process. The A2/O process was the most efficient at biodegrading ASs. Adsorption (by granular activated carbon (GAC) and magnetic resin) and ultraviolet radiation-based advanced oxidation processes (UV/AOPs) were evaluated to remove ASs in laboratory-scale tests. The amounts of resin adsorbed were 3.33-18.51 times more than those of GAC except for SUC. The adsorption ability of resin decreased in the order of SAC > ACE > CYC > SUC in accordance with the pKa. Degradation of ASs followed pseudo-first-order kinetics in UV/H2O2 and UV/PDS. When applied to the secondary effluent, ASs could be degraded from 30.87 to 99.93% using UV/PDS in 30 minutes and UV/PDS was more efficient and economic.


Assuntos
Edulcorantes/química , Águas Residuárias/química , Purificação da Água/métodos
19.
Bioresour Technol ; 247: 319-326, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28950141

RESUMO

In order to explore physicochemical and biological effects on detachment and activity recovery of aging biofilm by enzyme and surfactant treatments, two kinds of biofilm processes, i.e. biological aeration filter (BAF) and moving bed biofilm reactor (MBBR), and multiple indicators including water quality, biofilm morphology, activity and microbial community structure, were employed. Results showed that detachment of aging biofilm was mainly attributed by extracellular polymeric substance (EPS) solubilization and dispersion, and activity recovery of aging biofilm mainly depended on biological effects of dominant bacteria. Phosphorus metabolism related bacteria, such as Microbacterium and Micropruina, were responsible for BAF biofilm regeneration. More abundant microbial community structure of MBBR regenerated biofilm was found, and biofilm activity was not only related to phosphorus metabolism related bacteria, but also to denitrifying bacteria. Rhamnolipid performed best on aging biofilm detachment and regeneration, giving a clue for effective activation of aging biofilm in wastewater treatment systems.


Assuntos
Reatores Biológicos , Bactérias , Biofilmes , Tensoativos , Águas Residuárias
20.
Bioresour Technol ; 247: 116-124, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28946084

RESUMO

Although AHL-mediated quorum sensing (QS) signaling has been proved to be ecologically important in biofilm formation and aerobic granulation process, the biological role of AHL in anaerobic granule has not been experimentally investigated. In this paper, we explored the AHL level in 10 full-scale industrial anaerobic granular bioreactors and detected a total of 4 kinds of AHLs. C8-HSL and C10-HSL were indicated to be the potentially universal QS signal molecules in anaerobic granules and involved in extracellular polymeric substance (EPS) production and granulation process. The add-back experiments further supported the hypothesis that C8-HSL and C10-HSL might play an important role in facilitating anaerobic granulation through regulation of EPS synthesis. 12 Microorganisms might be regulated by AHL to play an important role in EPS production. This study provides a foundation for exploring the function of AHL in anaerobic granular systems, which may shed light on advanced AHL-based anaerobic granulation strategy.


Assuntos
Acil-Butirolactonas , Esgotos , 4-Butirolactona , Reatores Biológicos , Indústrias , Percepção de Quorum
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