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1.
Bioresour Technol ; 295: 122241, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31627067

RESUMO

An anoxic-aerobic membrane bioreactor (AO-MBR), an anaerobic side-stream reactor (ASSR) coupled MBR (A-MBR), and an MBR with ASSR packed with carriers (AP-MBR) were operated parallelly to investigate biological nutrient removal, microbial community structure and mass balance of nutrients in sludge reduction systems. Compared to AO-MBR, A-MBR and AP-MBR were both efficient in COD and NH4+-N removal, had significantly higher nitrogen removal, reduced sludge production by 35.0% and 45.9%, but deteriorated biological phosphorus removal. Nitrosomonadaceae and Nitrospira were major bacteria responsible for ammonium and nitrite oxidation in the three systems. Inserting ASSR and packing carriers both favored denitrifying bacteria enrichment and organic substances release, and thus resulted in higher nitrate uptake rate (NUR) in the anoxic tank. Higher endogenous NUR in ASSR than in anoxic tank also indicated that ASSR and carriers both accelerated sludge decay. Denitrification and sludge reduction occurred in ASSR played important roles in biological nutrient removal.


Assuntos
Rios , Esgotos , Anaerobiose , Reatores Biológicos , Nitrogênio , Nutrientes , Fósforo , Eliminação de Resíduos Líquidos
2.
Bioresour Technol ; 295: 122225, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31629283

RESUMO

Recently, upflow microaerobic sludge blanket (UMSB) system has been developed to remove ammonium and organic matter simultaneously. This study aims to establish influent and operational conditions promoting anammox-based nitrogen removal process in the UMSB reactor by using a modified Activated Sludge Model. Experiments were performed on a laboratory-scale UMSB reactor treated piggery wastewater for over two years. With the experimentally determined model parameters, the established model well simulated the UMSB reactor performance. The maximum anammox growth rate was calibrated to be 0.41 d-1 at 35 °C. Further simulations showed that UMSB reactor operated with high influent organics or nitrogen loading rates at temperature above 15 °C can achieve efficient nitrogen removal (>70%). The nitrogen loading over 0.6 kg N/(m3·d)) significantly favors anammox activity. UMSB could also be a promising system for nitrogen removal from low-strength ammonium wastewater with fluctuated COD influence. These results provide support to UMSB design and operational optimization.


Assuntos
Nitrogênio , Esgotos , Reatores Biológicos , Desnitrificação , Eliminação de Resíduos Líquidos , Águas Residuárias
3.
Bioresour Technol ; 295: 122284, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31669869

RESUMO

The application of MBR in high saline wastewater treatment is mainly constrained by poor nitrogen removal and severe membrane fouling caused by high salinity stress. A novel carriers-enhanced MBR system was successfully developed for treating saline mariculture wastewater, which showed efficient TN removal (93.2%) and fouling control. High-throughput sequencing revealed the enhancement mechanism of bio-carriers under high saline condition. Bio-carriers substantially improved the community structure, representatively, nitrifiers abundance (Nitrosomonas, Nitrospira) increased from 2.18% to 9.57%, abundance of denitrifiers (Sulfurimonas, Thermogutta, etc.) also rose from 3.81% to 14.82%. Thereby, the nitrogen removal process was enhanced. Noteworthy, ammonia oxidizer (Nitrosomonas, 8.26%) was the absolute dominant nitrifiers compared with nitrite oxidizer (Nitrospira, 1.13%). This supported the finding of shortcut nitrification-denitrification process in hybrid system. Moreover, a series of biomacromolecule degraders (Lutibacterium, Cycloclasticus, etc.) were detected in bio-carriers, which could account for the mitigation of membrane fouling as result of EPS and SMP degradation.


Assuntos
Microbiota , Águas Residuárias , Reatores Biológicos , Desnitrificação , Membranas Artificiais , Nitrificação , Nitrogênio , Eliminação de Resíduos Líquidos
4.
Bioresour Technol ; 295: 122300, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31669872

RESUMO

Current high-rate activated sludge (HRAS) process is an aerobic A-stage process that would cause significant organic loss resulted from the mineralization. In this study, the feasibility of operating a high rate A-stage without aeration (HRNS) was carried out in a demo-scale plant (275 m3/h). The organics transformation and energy production potential in A-stage were explored. The developed A-stage process was demonstrated to be more effective for organics recovery compared to that operated with aeration (53.82% versus 40.94%), despite its relatively low total COD removal efficiency (54.3% versus 63.5% with aeration). Minor organics (accounted for 1.75% of incoming COD) was found to be lost in HRNS process. Moreover, sludge generated from HRNS had higher degradability and higher methane compared to that from HRAS. Overall, this study documented the feasibility of high rate A-stage without aeration, and acted as a guide in achieving energy neutrality or even energy-positive wastewater treatment.


Assuntos
Reatores Biológicos , Esgotos , Metano , Eliminação de Resíduos Líquidos , Águas Residuárias
5.
Bioresour Technol ; 295: 122287, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31669873

RESUMO

Johannesburg-Sulfur autotrophic denitrification (JHB-SAD) system was investigated for the combined treatment of leachate and municipal wastewater with low strength and low COD/TN ratio. The average removal efficiencies for chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) were 85.2%, 96.2% and 75.8%, respectively. The municipal wastewater and leachate (dosing of 2.1‰, v/v) can be treated via the JHB-SAD system to achieve efficient nutrients removal. The mass balance calculations suggested that 58.1-69.8% TN was removed in JHB unit and 32.9-41.2% TN in SAD unit. Further, the denitrifying phosphorus removal process occurred in the anoxic zone. EEM-PARAFAC analysis found that the protein-like materials were more efficiently removed than fulvic-like materials in JHB-SAD system. The tryptophan-like materials had the most positive linear relationship with the COD concentrations. The bacterial community was difference between JHB and SAD unit. Furthermore, bacteria abundance relating to nitrogen removal increased with additional leachate.


Assuntos
Águas Residuárias , Poluentes Químicos da Água , Análise da Demanda Biológica de Oxigênio , Reatores Biológicos , Desnitrificação , Nitrogênio , África do Sul , Enxofre , Eliminação de Resíduos Líquidos
6.
Bioresour Technol ; 295: 122313, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31670203

RESUMO

Sludge rheology is an essential factor for anaerobic digestion (AD) processes to control the agitation energy consumption. In this study, the sludge rheology was characterized for an osmotic membrane bioreactor and a conventional sludge anaerobic digestion reactor as the solid content being increased from 3.5-3.7% to 7.5-7.7%. The flow curves were fitted using different rheological models and the mechanism was discussed. The sludge from the osmotic membrane bioreactor exhibited obviously better rheological properties than that of the conventional reactor at a solid content of 7.5-7.7%. Larger particles induced by less negative zeta potential and higher extracellular polymeric substances, together with the higher conductivity resulted by reverse salt flux in the osmotic membrane bioreactor, improved the sludge rheology due to reduced interactions between particles. As a result, the agitation energy consumption of the osmotic membrane bioreactor can save up to 34-39% compared with the conventional one at total solid content of 7.5-7.7%.


Assuntos
Reatores Biológicos , Esgotos , Anaerobiose , Membranas Artificiais , Osmose , Reologia , Eliminação de Resíduos Líquidos
7.
Bioresour Technol ; 295: 122291, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31670206

RESUMO

In this study a continuous flow reactor (CFR) was employed to compare the feasibility of bacterial aerobic granular sludge (AGS-CFR) and algal-bacterial granular sludge (ABGS-CFR) for treating 1-4% saline wastewater. High salinity was found to enhance algae growth in ABGS-CFR, which exhibited slightly higher total nitrogen and phosphorus removal efficiencies at 1-3% salinity. ABGS-CFR maintained good granular stability at 1-4% salinity, while AGS-CFR gradually disintegrated at 4% salinity with 39.3% less accumulation of alginate-like exopolysaccharides in the extracellular polymeric substances. Indole-3-acetic acid (IAA) and superoxide dismutase (SOD) analysis suggested that bacteria and algae (Nitzschia) in ABGS-CFR formed a good symbiotic relationship under high salinity conditions, achieving rapid algae growth and 2 times lipid production. High salinity was conducive to enriching Halomonas and Nitzschia but unfavorable for Nitrosomonas and Flavobacterium. Results from this study could provide useful information on interactions between bacteria and algae in ABGS-CFR for its future practical application.


Assuntos
Reatores Biológicos , Águas Residuárias , Aerobiose , Bactérias , Lipídeos , Nitrogênio , Esgotos , Eliminação de Resíduos Líquidos
8.
Bioresour Technol ; 295: 122298, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31675521

RESUMO

Four lab-scale moving bed biofilm reactors (MBBRs) were built to treat simulated wastewater containing typical pharmaceuticals and personal care products (PPCPs). The efficiency in removing different PPCPs at different concentrations (1, 2 and 5 mg/L) and their effects on the performance of MBBRs were investigated. Results showed that the average removal efficiencies of sulfadiazine, ibuprofen and carbamazepine were 61.1 ±â€¯8.8%, 74.9 ±â€¯8.8% and 28.3 ±â€¯7.4%, respectively. Compared to the reactor without PPCPs, the total nitrogen (TN) removal efficiency of the reactors containing sulfadiazine, ibuprofen and carbamazepine declined by 21%, 30% and 42%, respectively. Based on the microbial community analysis, increasing the PPCPs concentration within a certain range (<2 mg/L) could stimulate microbial growth and increase microbial diversity yet the diversity reduced when the concentration (5 mg/L) exceeded the tolerance of microorganisms. Furthermore the presence and degradation of different PPCPs resulted in a different kind of microbial community structure in the MBBRs.


Assuntos
Reatores Biológicos , Microbiota , Biofilmes , Nitrogênio , Eliminação de Resíduos Líquidos , Águas Residuárias
9.
Bioresour Technol ; 295: 122302, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31678888

RESUMO

The performance of pollutant removals, activated sludge characteristics, and microbial communities of two biofilm membrane bioreactors coupled with pre-anoxic tanks (BF-AO-MBRs) (one using fiber bundle bio-carriers (FB-MBR) and the other using suspended bio-carriers (MB-MBR)) were compared at the salinity between zero and 60 g/L. At all salinities, three bioreactors showed good COD average removal efficiencies (>94.1%), and FB-MBR showed the best TN removal efficiency (90.4% at 30 g/L salinity). Moreover, FB-MBR had the faster process start-up time and better salt shock resistance. At high salinities (30-60 g/L), more extracellular polymeric substances were produced by the BF-AO-MBRs to avoid the penetration of salt and protect the bacterial community. Because of the different attachment patterns of biofilms, the microbial community structure in the FB-MBR exposed to 30 g/L salinity had higher nitrite-oxidizing/ammonia-oxidizing bacteria ratio (6.44) with more abundance of denitrifiers, which contribute to higher TN removal efficiency and lower nitrite accumulation.


Assuntos
Microbiota , Águas Residuárias , Biofilmes , Reatores Biológicos , Membranas Artificiais , Esgotos , Eliminação de Resíduos Líquidos
10.
J Environ Manage ; 253: 109691, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31630062

RESUMO

To investigate the effect of the organic loading rate (OLR) on anaerobic treatment of monosodium glutamate (MSG) wastewater, a lab-scale up-flow anaerobic blanket (UASB) reactor was continuously operated over a 222-day period. The overall performances of COD removal and methane recovery initially exhibited an increase and subsequently decreased when the OLR was increased from 1 g-COD/L/d to 24 g-COD/L/d. At the optimal OLR of 8 g-COD/L/d, superior performance was obtained with a maximum COD removal efficiency of 97%, a methane production rate of 2.3 L/L/d, and specific methanogenic activity of 86 mg-CH4/g-VSS/d (feeding on glutamate), with superior characteristics of sludge in VSS concentration, average diameter of granules, and settling velocity. According to the results of the specific methanogenic activity, the methanogenic pathway was more inclined to pass through acetate than through hydrogen. Methanosarcina instead of Methanosaeta, with Methanobacterium and greatly increased Firmicutes, dominated in the UASB reactor after long term operation. These results support that the OLR had a substantial effect on both the treatment and energy recovery efficiency of MSG wastewater as well as on microbial community variations in the UASB reactor.


Assuntos
Microbiota , Esgotos , Anaerobiose , Reatores Biológicos , Metano , Glutamato de Sódio , Eliminação de Resíduos Líquidos , Águas Residuárias
11.
J Environ Manage ; 253: 109648, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31634741

RESUMO

Two laboratory-scale up-flow anaerobic sludge granules reactors were operated as control reactor (R1) and chitosan (CTS) addition reactor (R2) to investigate the effect of the addition of CTS on the granulation process of sulfate-reducing bacteria (SRB) anaerobic sludge. Granular sludge with the diameter greater than 0.5 mm was selected to calculate the granulation percentage, and the remaining sludge was considered as flocculent sludge in this paper. The results showed that the granulation percentage in the two reactors were stabilized to 47.3% and 64.2%, respectively. The sizes of sludge granules in R2 were mainly between 0.5 and 1.5 mm with the average pore diameter of 91.6 nm and the porosity of 57.1% while the granules in the same particle size in R1 were 41.5 nm and 46.1%, respectively. It demonstrated that CTS was an appropriate additive which can enhance the formation of SRB granule sludge with better pore structure. The granular sludge with CTS exhibited excellent physical performance and more extracellular polymeric substances, especially for protein (PN). In addition, computational fluid dynamics (CFD) simulation was conducted to illustrate the hydrodynamic characteristics of granules with Kozeny-Carman model. With a higher porosity, the permeability of the granules fed with CTS was considerably increased. Moreover, the model also indicated that the permeability and convection changed significantly with Reynolds numbers (Re) of the external flow field for a given type of the porous structure.


Assuntos
Quitosana , Esgotos , Anaerobiose , Bactérias Anaeróbias , Reatores Biológicos , Sulfatos , Eliminação de Resíduos Líquidos
12.
Water Res ; 168: 115151, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31630019

RESUMO

This study investigated nutrient removal characteristics and the related pathways in aerobic granular reactors using three pilot-scale granular sequencing batch reactors (GSBRs) treating wastewaters of diverse carbon and nutrient strength. The GSBRs were operated with alternating (AN/O/AX/O_SBR and AN/O_SBR) and purely-aerobic (O_SBR) operation modes. Mineral-rich aerobic granules with hydroxyapatite (HAp) core were cultivated in all the three GSBRs. The highest nitrogen removal efficiency (75%) was achieved in AN/O/AX/O_SBR and O_SBR and the lowest (22%) in AN/O_SBR, establishing a quasi-linear relationship with organic loading rate (OLR). Phosphorus removal efficiencies of 55-63% were achieved in the GSBRs despite different influent PO4-P concentrations. Heterotrophic nitrification and biologically-induced phosphate precipitation (BIPP) became the dominant nutrient depletion pathways, contributing 61-84% and 39-96% to overall ammonium nitrogen and phosphorus removal, respectively. A direct relation was noted between heterotrophic nitrification efficiency (ηHeterotrophic nitrification) and nutrient availability, as nitrification efficiencies of 18 and 64% were observed for COD:Ninf of 5 and 20, respectively. Whereas, BIPP efficiency (ηBIPP) established inverse relation with (COD:P)inf and (Ca:P)inf and direct relation with phosphorus concentration beyond microbial growth requirement. Core heterotrophic nitrifiers and bio-calcifying species were identified as {Thauera and Flavobacterium} and {Flavobacterium, Acinetobacter, Pseudomonas, and Corynebacterium}, respectively. Ca-P crystallization was proposed to be via phosphate precipitation on calcite surfaces. Granulation mechanism was proposed as crystallization on bio-aggregates' periphery and then crystal growth toward the core.


Assuntos
Nutrientes , Esgotos , Aerobiose , Reatores Biológicos , Minerais , Nitrificação , Nitrogênio , Fósforo , Eliminação de Resíduos Líquidos
13.
Water Res ; 168: 115154, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31630020

RESUMO

Pyrrhotite is often considered as a gangue mineral, and discarded in mine wastes and tailings. Glyphosate and fertilizer, often excessively used in agriculture, flow into water bodies with agriculture runoff, and cause pollution of water bodies. In this study, the pyrrhotite was used as a substrate in a pilot constructed wetland (CW) to remove the glyphosate and nutrients from simulated agriculture runoff. In nearly one year, the pilot pyrrhotite constructed wetland (Pyrr-CW) removed 90.3 ±â€¯6.1% of glyphosate, 88.2 ±â€¯5.1 of total phosphorus (TP) and 60.40 ±â€¯5.60% of total nitrogen (TN) on average, much higher than the control CW. The abundances of sulfur-oxidizing bacteria, such as Sulfurifustis, Sulfuriferula and Thiobacillus, were much higher in the Pyrr-CW than those in the control CW. In the Pyrr-CW goethite was produced by pyrrhotite aerobic oxidation (PAO) and pyrrhotite autotrophic denitrification (PAD) continuously and spontaneously. Higher glyphosate and TP removals were resulted from adsorption on the goethite produced, and higher TN removal was attributed to the PAD. High glyphosate and nutrients removal could keep a long term until the pyrrhotite in the Pyrr-CW was used up. The phosphorus (P) sequestered in the Pyrr-CW existed mainly in organic P, (Fe + Al)P and (Ca + Mg)P, and their order was (Fe + Al)P > organic P > (Ca + Mg)P. No heavy metal ions released from the Pyrr-CW. With higher and lasting removal rate, and lower cost, the Pyrr-CW is a promising technology for simultaneous glyphosate and nutrients removal from agricultural runoff and wastewater.


Assuntos
Nutrientes , Áreas Alagadas , Agricultura , Glicina/análogos & derivados , Nitrogênio , Fósforo , Eliminação de Resíduos Líquidos , Águas Residuárias
14.
Water Res ; 168: 115195, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31639590

RESUMO

Membrane fouling or flux limitation is the major bottleneck that hinders anaerobic membrane bioreactor (AnMBR) application. An AnMBR with a working volume of 15 L was operated for 180 days to investigate the maximum sustainable flux at different high solid concentrations during the anaerobic treatment of food waste. A total of eight filtration-to-relaxation (F/R) ratios were incorporated, with a fixed filtration time of 3 min and varied relaxation times (decreased from 12 to 1 min). Besides, a total of five instantaneous fluxes were applied: 12, 14, 16, 18 and 20 L/m2/h (LMH). Results showed that sustainable flux was greatly enhanced by filtration mode optimization. The optimal F/R ratios were 3:1, 3:1, 3:1 and 3:6 at mixed liquor total solid (MLTS) concentrations of 10, 15, 20 and 25 g/L, respectively. The corresponding sustainable flux values were 13.2 ±â€¯0.3, 10.1 ±â€¯0.4, 9.3 ±â€¯0.2 and 4.0 ±â€¯0.3 LMH, respectively. These values were 29%, 35%, 52% and 21% higher than the critical flux determined by the flux-stepping technique. The results of this study were used to perform a mathematical simulation. The obtained regression equation between the maximum sustainable flux and MLTS concentration can be used to predict the sustainable flux at other MLTS concentrations. This work provides valuable insight into the design and operation of high-solid AnMBRs, and is expected to contribute to further advances in the application of AnMBRs in industry.


Assuntos
Eliminação de Resíduos , Eliminação de Resíduos Líquidos , Anaerobiose , Reatores Biológicos , Filtração , Alimentos , Membranas Artificiais , Águas Residuárias
15.
Water Sci Technol ; 80(5): 892-901, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31746796

RESUMO

Characteristics of Chlorella sorokiniana treating wastewater with consideration of HRT (6 d, 16 h, 8 h), hydraulic conditions, light or dark culture were evaluated and compared with activated sludge. Results showed that optimal HRT was 8 h; if longer, effluent chemical oxygen demand (COD) and NH4+-N in the dark began to rebound. Mixing was beneficial to COD removal of algae, while aeration was suitable for nutrient removal. Growth of C. sorokiniana in the light was mixotrophic growth and 1.3-1.7 times more than that of dark heterotrophic growth. The maximum specific growth rate (µmax), productivity, and biomass yields on COD (YCOD), N (YNH4), P (YP) of algae were higher in the light than that in the dark. COD assimilation capacity of algae was similar to activated sludge but with different dynamics. N and P assimilation capacity of algae was 1.4, 1.2-2.5 times more than activated sludge; N and P removal efficiency of algae was 5%-10%, 10%-55% respectively higher than activated sludge. This study confirmed the advantage of algae over activated sludge and reveal why algae could assist the activated sludge process.


Assuntos
Chlorella , Águas Residuárias , Análise da Demanda Biológica de Oxigênio , Reatores Biológicos , Processos Heterotróficos , Esgotos , Eliminação de Resíduos Líquidos
16.
Water Sci Technol ; 80(5): 920-928, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31746799

RESUMO

A novel Fenton-SBR-microwave pyrolysis integrated process is developed to treat liquid crystal wastewater possessing complex components, high toxicity and strong stability. In this integrated process, Fenton-SBR and microwave pyrolysis are for the removal of chemical oxygen demand (COD) and disposal of iron mud generated in the Fenton process respectively. The effects of H2O2:Fe2+ molar ratio and Fenton dosage on COD removal were optimized. The experimental results revealed that the removal efficiencies for COD and total organic carbon (TOC) were 99.8% and 99.2%, and the values for MLSS and SVI were stable at 4,500 mg L-1 and 65%, respectively. Microscopic examination proved that there were rotifer, Epistylis galea, Opercularia coarctata, vorticella and mormon genus which are indicative microbes for good water quality. Iron mud waste produced in the Fenton reaction was handled with microwave pyrolysis, producing ɑ-Fe2O3 commercial byproduct. The estimated cost including chemical reagents and electricity for this integrated process is about $320 T-1, without consideration of the added value of the ɑ-Fe2O3 byproduct. TOC removals in the Fenton and SBR processes both fit well with pseudo-first-order kinetics and the corresponding half-life times are 0.15 and 7 h, respectively.


Assuntos
Cristais Líquidos , Poluentes Químicos da Água , Purificação da Água , Peróxido de Hidrogênio , Micro-Ondas , Oxirredução , Pirólise , Eliminação de Resíduos Líquidos , Águas Residuárias
17.
Water Sci Technol ; 80(5): 961-969, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31746803

RESUMO

The efficiency of electrolysis (EC/Cl2) and photo-assisted electrolysis (EC/UV/Cl2) methods, in the presence of chloride, for the abatement of real dairy waste from a producer in the Triangulo Mineiro region of Brazil, was evaluated. A complete 23 factorial design was performed for the variables time, pH and current. After determining the ideal pH, a Central Compound Design (CCD) was performed, where the applied current (533.42 mA) and treatment time (60.45 minutes) were maximized. The effluent was subsequently submitted to prolonged EC/Cl2 and EC/UV/Cl2 treatment in order to evaluate the behaviour of specific environmental parameters over time. The EC/UV/Cl2 method was more efficient than simple EC/Cl2 treatment. The EC/UV/Cl2 method resulted in a reduction of all environmental parameters investigated to levels within legal standards for effluent discharge. A relatively low cost of treatment is obtained with Energy per Order (EEO) values of 0.89 and 1.22 kWh m-3 order-1 for the EC/UV/Cl2 and EC/Cl2 treatments, respectively. The electrochemical production of free chlorine species followed by subsequent photolysis and production of radical species can convert a simple electrochemical process into an advanced oxidation process (AOP).


Assuntos
Poluentes Químicos da Água , Purificação da Água , Brasil , Cloretos , Eletrólise , Oxirredução , Eliminação de Resíduos Líquidos , Águas Residuárias
18.
Water Sci Technol ; 80(5): 979-988, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31746805

RESUMO

The aim of this study was to assess the efficiency of mucilage extracted from the fruit of Dillenia indica for enhancing coagulation in the treatment of textile effluent. The mucilage extraction was carried out in water at room temperature. The pH, concentration of coagulant FeCl3.6H2O, and concentration of mucilage solution were optimized with star-type central composite design (CCD). We were able to analyze the synergistic effects between the FeCl3.6H2O and mucilage concentrations: the process of coagulation/flocculation (CF) for chemical oxygen demand (COD) removal was more efficient at a low chemical coagulant concentration (8.00 mg L-1) and a higher natural coagulant (NC) concentration (15.00 mg L-1). This demonstrated the potential of this mucilage to treat textile effluents, with 67.66%% COD removal, 96.86% turbidity removal and 91.12% apparent color reduction. The characterization of the mucilage of Dillenia indica was done using Fourier transform infrared spectroscopy (FTIR) and solid-state cross-polarization magic angle spinning carbon-13 nuclear magnetic resonance (CP/MAS 13C NMR), and the signals obtained indicated the presence of polysaccharides, which are responsible for enhancing the CF process.


Assuntos
Dilleniaceae , Poluentes Químicos da Água , Purificação da Água , Floculação , Resíduos Industriais , Indústria Têxtil , Têxteis , Eliminação de Resíduos Líquidos
19.
J Water Health ; 17(5): 670-682, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31638019

RESUMO

In Ontario, Canada, information is lacking on chlorine and ultraviolet (UV) light disinfection performance against enteric viruses in wastewater. We enumerated enteroviruses and noroviruses, coliphages, and Escherichia coli per USEPA methods 1615, 1602, and membrane filtration, respectively, in pre- and post-disinfection effluent at five wastewater treatment plants (WWTPs), with full-year monthly sampling, and calculated log10 reductions (LRs) while WWTPs complied with their monthly geometric mean limit of 200 E. coli/100 mL. Modeling of densities by left-censored estimation and Bayesian inference gave very similar results. Polymerase chain reaction (PCR)-detected enteroviruses and noroviruses were abundant in post-disinfection effluent (mean concentrations of 2.1 × 10+4-7.2 × 10+5 and 2.7 × 10+4-3.6 × 10+5 gene copies (GC)/L, respectively). Chlorine or UV disinfection produced modest LRs for culture- (0.3-0.9) and PCR-detected enteroviruses (0.3-1.3), as well as noroviruses GI + GII (0.5-0.8). Coliphages and E. coli were more susceptible, with LRs of 0.8-3.0 and 2.5, respectively. Sand-filtered effluent produced significantly higher enteric virus LRs (except cultured enteroviruses). Coliphage and human enteric virus densities gave significantly positive correlations using Kendall's Tau test. Enteric viruses are abundant in wastewater effluent following routine chlorine or UV disinfection processes that target E. coli. Coliphages appear to be good indicators for evaluating wastewater disinfection of enteric viruses.


Assuntos
Desinfecção , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/virologia , Teorema de Bayes , Cloro , Escherichia coli , Humanos , Ontário , Raios Ultravioleta
20.
J Water Health ; 17(5): 701-716, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31638022

RESUMO

The variability of fecal microorganisms and wastewater micropollutants (WWMPs) loads in relation to influent flow rates was evaluated for a water resource recovery facility (WRRF) in support of a vulnerability assessment of a drinking water source. Incomplete treatment and bypass discharges often occur following intense precipitation events that represent conditions that deviate from normal operation. Parasites, fecal indicator bacteria, and WWMPs concentrations and flow rate were measured at the WRRF influent and effluent during dry and wet weather periods. Influent concentrations were measured to characterize potential bypass concentrations that occur during wet weather. Maximum influent Giardia and C. perfringens loads and maximum effluent Escherichia coli and C. perfringens loads were observed during wet weather. Influent median loads of Cryptosporidium and Giardia were 6.8 log oocysts/day and 7.9 log cysts/day per 1,000 people. Effluent median loads were 3.9 log oocysts/day and 6.3 log cysts/day per 1,000 people. High loads of microbial contaminants can occur during WRRF bypasses following wet weather and increase with increasing flow rates; thus, short-term infrequent events such as bypasses should be considered in vulnerability assessments of drinking water sources in addition to the increased effluent loads during normal operation following wet weather.


Assuntos
Eliminação de Resíduos Líquidos , Águas Residuárias/química , Purificação da Água , Animais , Bactérias , Cryptosporidium , Giardia , Parasitos , Águas Residuárias/microbiologia , Águas Residuárias/parasitologia , Recursos Hídricos
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