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1.
Food Environ Virol ; 13(3): 303-315, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34296387

RESUMO

Wastewater surveillance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an emerging public health tool to understand the spread of Coronavirus Disease 2019 (COVID-19) in communities. The performance of different virus concentration methods and PCR methods needs to be evaluated to ascertain their suitability for use in the detection of SARS-CoV-2 in wastewater. We evaluated ultrafiltration and polyethylene glycol (PEG) precipitation methods to concentrate SARS-CoV-2 from sewage in wastewater treatment plants and upstream in the wastewater network (e.g., manholes, lift stations). Recovery of viruses by different concentration methods was determined using Phi6 bacteriophage as a surrogate for enveloped viruses. Additionally, the presence of SARS-CoV-2 in all wastewater samples was determined using reverse transcription quantitative PCR (RT-qPCR) and reverse transcription droplet digital PCR (RT-ddPCR), targeting three genetic markers (N1, N2 and E). Using spiked samples, the Phi6 recoveries were estimated at 2.6-11.6% using ultrafiltration-based methods and 22.2-51.5% using PEG precipitation. There was no significant difference in recovery efficiencies (p < 0.05) between the PEG procedure with and without a 16 h overnight incubation, demonstrating the feasibility of obtaining same day results. The SARS-CoV-2 genetic markers were more often detected by RT-ddPCR than RT-qPCR with higher sensitivity and precision. While all three SARS-CoV-2 genetic markers were detected using RT-ddPCR, the levels of E gene were almost below the limit of detection using RT-qPCR. Collectively, our study suggested PEG precipitation is an effective low-cost procedure which allows a large number of samples to be processed simultaneously in a routine wastewater monitoring for SARS-CoV-2. RT-ddPCR can be implemented for the absolute quantification of SARS-CoV-2 genetic markers in different wastewater matrices.


Assuntos
Fracionamento Químico/métodos , SARS-CoV-2/isolamento & purificação , Ultrafiltração/métodos , Águas Residuárias/química , Águas Residuárias/virologia , Precipitação Química , Monitoramento Ambiental , Polietilenoglicóis/química , Saúde Pública , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , SARS-CoV-2/genética , Esgotos/química , Esgotos/virologia , Proteínas Virais/genética , Poluição da Água/análise
2.
Molecules ; 26(11)2021 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-34067394

RESUMO

Pharmaceuticals are found in waterbodies worldwide. Conventional sewage treatment plants are often not able to eliminate these micropollutants. Hence, Advanced Oxidation Processes (AOPs) have been heavily investigated. Here, metoprolol is exposed to UV irradiation, hydrogen peroxide, and ozonation. Degradation was analyzed using chemical kinetics both for initial and secondary products. Photo-induced irradiation enhanced by hydrogen peroxide addition accelerated degradation more than ozonation, leading to complete elimination. Degradation and transformation products were identified by high-performance liquid-chromatography coupled to high-resolution higher-order mass spectrometry. The proposed structures allowed to apply Quantitative Structure-Activity Relationship (QSAR) analysis to predict ecotoxicity. Degradation products were generally associated with a lower ecotoxicological hazard to the aquatic environment according to OECD QSAR toolbox and VEGA. Comparison of potential structural isomers suggested forecasts may become more reliable with larger databases in the future.


Assuntos
Ecotoxicologia , Metoprolol/análise , Ozônio/química , Relação Quantitativa Estrutura-Atividade , Esgotos/química , Águas Residuárias/química , Poluentes Químicos da Água/análise , Algoritmos , Reatores Biológicos , Cromatografia Líquida de Alta Pressão , Ecotoxicologia/métodos , Monitoramento Ambiental/métodos , Peróxido de Hidrogênio/química , Concentração de Íons de Hidrogênio , Cinética , Metoprolol/química , Oxigênio/química , Fotoquímica , Fotólise , Software , Raios Ultravioleta , Poluentes Químicos da Água/química
3.
Bioelectrochemistry ; 140: 107821, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33915342

RESUMO

Hydrodynamics has received considerable attention for application in improving microbial fuel cell (MFC) performance. In this study, a method is proposed to calculate the effect of fluid flow on MFC current production from sewage wastewater. First, the effect of flow velocity in an up-flow channel was evaluated, where an air-core MFC was polarized with external resistance (Rext). When tested at a flow velocity ranging from 0 to 20 cm s-1, the MFC with the higher flow velocity produced more current. In sewage wastewater with a chemical oxygen demand (COD) of 76 mg L-1, the MFC polarized with 3 Ω of Rext, and a flow velocity of 20 cm s-1 had 5.4 times more current than the MFC operating in a no-flow environment. This magnitude decreased with higher Rext and COD values. The Michaelis-Menten equation, modified herein by integrating COD and flow velocity, demonstrated the production of current by MFC operating under different conditions of flow. Calculation of current by MFC in a virtual fluid suggested that the flow surrounding the MFC varied with the configuration and affected the current production.


Assuntos
Fontes de Energia Bioelétrica , Esgotos/microbiologia , Análise da Demanda Biológica de Oxigênio , Eletrodos , Esgotos/química
4.
Molecules ; 26(4)2021 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-33672924

RESUMO

Presently, water quantity and quality problems persist both in developed and developing countries, and concerns have been raised about the presence of emerging pollutants (EPs) in water. The circular economy provides ways of achieving sustainable resource management that can be implemented in the water sector, such as the reuse of drinking water treatment sludges (WTSs). This study evaluated the potential of WTS containing a high concentration of activated carbon for the removal of two EPs: the steroid hormones 17ß-estradiol (E2) and 17α-ethinylestradiol (EE2). To this end, WTSs from two Portuguese water treatment plants (WTPs) were characterised and tested for their hormone adsorbance potential. Both WTSs showed a promising adsorption potential for the two hormones studied due to their textural and chemical properties. For WTS1, the final concentration for both hormones was lower than the limit of quantification (LOQ). As for WTS2, the results for E2 removal were similar to WTS1, although for EE2, the removal efficiency was lower (around 50%). The overall results indicate that this method may lead to new ways of using this erstwhile residue as a possible adsorbent material for the removal of several EPs present in wastewaters or other matrixes, and as such contributing to the achievement of Sustainable Development Goals (SDG) targets.


Assuntos
Esgotos/química , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água , Elementos Químicos , Concentração de Íons de Hidrogênio , Minerais/análise , Termogravimetria
5.
Ecotoxicol Environ Saf ; 214: 112070, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33652361

RESUMO

In line with sustainable development principles and in order to combat climate change, which contributes to progressive soil depletion, various solutions are being sought to use treated sewage sludge as a soil amendment to improve soil quality and enrich arable soils with adequate amounts of biogenic compounds. This review article focuses on the effects of the agricultural use of biosolids on the environment. The article reviews the existing knowledge on selected emerging contaminants in treated sewage sludge and describes the impact of these pollutants on the environment and living organisms based on 183 publications selected from over 16,000 papers on related topics published over the last ten years. This study deals not only with chemical contaminants but also genetic determinants of resistance to these compounds. Current research has questioned the agricultural use of biosolids due to the presence of mutual interactions between antibiotics, heavy metals, the genetic determinants of resistance (antibiotic resistance genes - ARGs and heavy metal resistance genes - HMRGs) and non-steroidal anti-inflammatory drugs as well as the risks associated with their transfer to the environment. This study emphasizes the need for more extensive legal regulations that account for other pollutants of environmental concern (PEC), particularly in countries where sewage sludge is applied in agriculture most extensively. Future research should focus on more effective methods of eliminating PEC from sewage sludge, especially from the sludge that is used to fertilize agricultural land, because even small amounts of these micropollutants can have serious implications for the health and life of humans and animals.


Assuntos
Agricultura , Esgotos/química , Poluentes do Solo/análise , Eliminação de Resíduos Líquidos/métodos , Animais , Antibacterianos , Produtos Agrícolas , Resistência Microbiana a Medicamentos/genética , Poluentes Ambientais , Humanos , Metais Pesados/análise , Solo/química
6.
Artigo em Inglês | MEDLINE | ID: mdl-33617393

RESUMO

This study evaluated the level of the contaminant of the heavy metals in sludge from different sources and the ecological risk criteria associated with it was also analyzed to establish its reuse in agriculture. The sludge samples were collected from the water plant (WTP), wastewater treatment plant (WWTP), and industrial water treatment plant (IPT) in Taiwan. The inductively coupled plasma mass spectrometry was used to measure the trace metals in sludge. The pollution level and ecological risk criteria for heavy metals in sludge were also used to evaluate its reuse in agriculture. The result shows the average concentrations of trace metals in sludge for three groups (WTP, WWTP, and ITP). Significant correlations were found between concentrations of Zn-Ag (p < 0.001). The higher values of Igeo showed in ITP, indicated Hg to be a major pollutant. In Taiwan, the regulations did not establish the reuse of sludge in agriculture. However, the concentration level of trace metals in sludge was particularly lower than the regular levels in most groups, like WTP and WWTP groups. The industrial sludge was not recommended for the use in agriculture. The results of this study can be used for regular monitoring to establish a reference for sludge management and application to agriculture.


Assuntos
Metais Pesados/análise , Esgotos/química , Oligoelementos/análise , Poluentes Químicos da Água/análise , Irrigação Agrícola/normas , Monitoramento Ambiental , Medição de Risco , Taiwan , Purificação da Água/normas
7.
Ecotoxicol Environ Saf ; 208: 111574, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396100

RESUMO

Endocrine disrupting chemicals (EDC) are exogenous substances that can potentially mimic hormonal substances and cause adverse effects on the endocrine system of living beings. The behavior and fate of these compounds in the environment is directly related to their physical-chemical properties, which indicate great affinity for solid and organic particles and suggest an inherent mechanism of fractionation between dissolved and particulate phases of aqueous matrices. However, few studies have been considering this fact when quantifying these pollutants and their effects through bioassays. In this study, the fractionation of estrogenic substances between dissolved and particulate phases in an urban stream was investigated via estrogenic activity evaluation by the YES assay. Two fractions of suspended solids (< 0.7 µm and between 0.45 and 0.7 µm) and the dissolved phase were considered and two approaches of SPE percolations were applied. Total estradiol equivalent (E2-Eq) values were observed in the 29-65 ng L-1 range, of which 35-62% were associated with the particulate phase. Most of the estrogenicity was associated with particles between 0.45 and 0.7 µm, whereas cytotoxicity was induced by extracts of particles greater than 0.7 µm. Results demonstrated the importance of solid fractions analysis towards the quantification of total estrogenic activity from aqueous environmental matrices and highlights the relevance of controlling fine suspended solids in sewage treatment plant effluents, regarding the control of endocrine disrupters in the environment.


Assuntos
Bioensaio/métodos , Disruptores Endócrinos/toxicidade , Poluentes Químicos da Água/toxicidade , Sistema Endócrino , Monitoramento Ambiental/métodos , Estrogênios/toxicidade , Rios/química , Esgotos/química , Ativação Transcricional
8.
PLoS One ; 16(1): e0245430, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33444389

RESUMO

Reducing the water content of oily sludge is essential for the disposal of it. Despite conditioning and solid-liquid separation, the water content of oily sludge generally exceeds 65%. A large amount of this water exists in the form of emulsified and bound water, reducing the efficiency of water removal during the natural semi-drying process of oily sludge. To shorten the time required for natural semi-drying, this study applied an orthogonal test to screen an oily sludge modified material (OSM). The effect and mechanism of OSM on the natural semi-drying of oily sludge were studied using a thermal gravimetric analyzer (TGA), scanning electron microscope (SEM), surface tension measurement, and microscopic observations. The results show that when the ambient temperature exceeded 10°C, the OSM increased in mass by 8-10%, and the time required for the natural semi-drying of oily sludge was shortened from 15 days to less than 5 days. OSM can rupture the emulsion, reduce the surface tension, convert the emulsion and bound water in the oily sludge into free water, and accelerate the rate of water migration, diffusion, and natural evaporation from the inside of the oily sludge to the surface and air. The research results show that changing the form of water can speed up the drying of oily sludge, creating positive economic benefits in the process of oily sludge reduction and recycling.


Assuntos
Óleos/química , Esgotos/química , Eliminação de Resíduos Líquidos/métodos , Água/química , Dessecação , Emulsões/química
9.
World J Microbiol Biotechnol ; 37(2): 33, 2021 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-33469843

RESUMO

Among the various pharmaceutical pollutants, diclofenac sodium (DFS), a widely prescribed non-steroid anti-inflammatory drug is detected in the aquatic environment at concentrations which can be harmful to living organisms. Present study illustrates the isolation and characterization of strain Klebsiella pneumoniae WAH1 from activated sludge and its ability to degrade DFS as sole source of carbon and energy. The growth and degradation capacity of K. pneumoniae WAH1 under different conditions of pH, temperature, rotation speed, and inoculum age were evaluated using optical density and liquid chromatography-mass spectroscopy (LCMS). The results show that K. pneumoniae WAH1 can grow well with DFS as its sole source of carbon and degrade 79.14% of DFS (10 mg L-1) within 72 h. Based on chemical structure of intermediates detected through LCMS, it is inferred that degradation pathway advanced by hydroxylation, decarboxylation, and dechlorination reactions. Toxicity studies revealed the non-toxic nature of the end-products of DFS degradation after 72 h. The findings suggest that K. pneumoniae WAH1 has an excellent potential for bioremediation of DFS in industrial wastewaters.


Assuntos
Diclofenaco/química , Klebsiella pneumoniae/isolamento & purificação , Esgotos/microbiologia , Biodegradação Ambiental , Carbono/química , Cromatografia Líquida , Descarboxilação , Concentração de Íons de Hidrogênio , Hidroxilação , Klebsiella pneumoniae/classificação , Klebsiella pneumoniae/crescimento & desenvolvimento , Espectrometria de Massas , Esgotos/química , Temperatura
10.
Ecotoxicol Environ Saf ; 208: 111673, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396005

RESUMO

In the present research, a bioremediation process was developed using solid complex bacterial agents (SCBA) through a combined two-step biodegradation process. Four isolated strains showed high efficiency for the degradation of total petroleum hydrocarbons (TPH) and the reduction of COD of the oily sludge, at 96.6% and 92.6%, respectively. The mixed strains together with bran prepared in form of SCBA exhibited improved performance compared to individual strains, all of which had an optimal temperature of around 35 °C. The use of SCBA provided advantages over commonly used liquid media for storage and transportation. The two-step process, consisting of firstly biosurfactant-assisted oil recovery and secondly biodegradation of the remaining TPH with SCBA, demonstrated the capability for treating oily sludge with high TPH content (>10 wt%) and short process period (60 days). The large-scale (5 tons oily sludge) field test, achieving a TPH removal efficiency of 93.8% and COD reduction of 91.5%, respectively, confirmed the feasibility and superiority of the technology for industrial applications.


Assuntos
Microbiota , Poluição por Petróleo/prevenção & controle , Petróleo/análise , Esgotos , Biodegradação Ambiental , Meios de Cultura , Hidrocarbonetos/análise , Hidrocarbonetos/metabolismo , Petróleo/metabolismo , Poluição por Petróleo/análise , Esgotos/química , Esgotos/microbiologia , Temperatura
11.
J Appl Microbiol ; 130(5): 1582-1591, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-32544271

RESUMO

AIMS: Oily sludge is a kind of mixture that is extremely harmful to the environment. Anaerobic digestion (AD) is a commonly used method for biodegrading oily sludge. However, the AD treatment cycle is usually long and inefficient. Here, we developed an approach to improve the degradation rate of oily sludge by integrating subcritical hydrothermal pretreatment (SHP) and AD. METHODS AND RESULTS: First, using SHP, the hydrocarbon compounds with long carbon chains that make up oil sludge were decomposed into hydrocarbons with short carbon chains, which are conducive to microbial decomposition and transformation. Then, AD was performed using a variety of temperature and solid-liquid ratio parameters. The results showed that the degradation ratio of oily sludge was higher when SHP was combined with AD than when no pre-treatment was performed. Optimal degradation was reached by performing SHP to obtain CHS8, then performing AD at 30°C using a 1:5 solid-liquid ratio. Under these conditions, maximum degradation ratios of 69·00% of TOC, 59·02% of COD, 44·68% of ammonia and 54·24% of oil content were reached. CONCLUSIONS: In conclusion, after SHP with 8% dilute sulphuric acid, most of the macromolecular hydrocarbons in the oily sludge were converted into smaller molecules, which facilitated subsequent microbial decomposition. The results showed that this combination of SHP and AD processes promotes more efficient degradation than a conventional single AD process without any hydrothermal pretreatment. SIGNIFICANCE AND IMPACT OF THE STUDY: Our experiments provide technical support for enhancing the rapid degradation of oily sludge.


Assuntos
Petróleo/metabolismo , Esgotos , Eliminação de Resíduos Líquidos/métodos , Anaerobiose , Biodegradação Ambiental , Hidrocarbonetos/química , Hidrocarbonetos/metabolismo , Esgotos/química , Temperatura
12.
J Agric Food Chem ; 69(1): 67-77, 2021 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-33205963

RESUMO

Animal husbandry is the second largest source of steroid estrogen (SE) pollutants in the environment, and it is significant to investigate the occurrence and fate of SEs discharged from concentrated animal feeding operations. In this research, with a Chinese typical concentrated dairy farm as the object, the concentrations of SEs (E1, 17α-E2, 17ß-E2, E3, and E1-S3) in slurry, lagoon water, and slurry-irrigated soil samples in summer, autumn, and winter were determined. The total concentrations of SEs (mainly E1, 17α-E2, and 17ß-E2) in slurry were very high in the range of 263.1-2475.08 ng·L-1. In the lagoon water, the removal efficiencies of the aerobic tank could reach up to 89.53%, with significant fluctuation in different seasons. In the slurry-irrigated soil, the maximum concentrations of SEs in the topsoil and subsoil were 21.54 ng·g-1 to 6.82 g·g-1, respectively. Most of the SEs tended to transport downward and accumulate in the soil accompanied with the complex mutual conversion. Correlations and hierarchical clustering analysis showed a variety of intertransformation among SEs, and the concentrations of SEs were correlated with various physicochemical indexes, such as TN and NO3--N of the slurry, chemical oxygen demand of the lagoon water, and the heavy metals of soil. In addition, 17ß-estradiol equivalency assessment and risk quotients indicated that the slurry irrigation and discharge of the lagoon water would cause potential estrogenic risks to the environment. Consequently, reasonable slurry irrigation and lagoon water discharge are essential to efficiently control SE pollution in the environment.


Assuntos
Estrogênios/química , Poluentes do Solo/química , Esteroides/química , Poluentes Químicos da Água/química , Criação de Animais Domésticos , Animais , Bovinos , Queixo , Monitoramento Ambiental , Esgotos/química
13.
Ecotoxicol Environ Saf ; 208: 111498, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33091768

RESUMO

Biomonitoring of heavy metal pollution through the use of biomarkers could be a difficult task since the organisms' physiological changes could shift regarding natural factors (i.e., the season of the year) and due to the anthropogenic pressures of the environment. In the Southwest Atlantic Ocean, where most industrial and developing countries are settled, it is essential to address these concerns to generate information for the stakeholders and monitoring programs that aim to use biochemical biomarkers as early warning signals to detect heavy metal pollution. The present study intended to determinate the heavy metal concentrations in sediments and the hepatopancreas of the crab species Neohelice granulata as well as the ecological risk through the use of biomarkers and geochemical indices in sites with different anthropogenic pressures of the Bahía Blanca estuary (SW Atlantic Ocean) during the warm and cold season. The results showed low to moderate heavy metal pollution in the sediments by Cu with possible effects on the biota in a site with sewage waters' discharges. Except for GST that was explained by Cd, the biomarkers employed were not useful to assess spatial heavy metal pollution, and they might be ruled out by physiological seasonal variations rather than anthropogenic constraints, or another type of pollutants in the area.


Assuntos
Monitorização de Parâmetros Ecológicos , Estuários , Metais Pesados/análise , Poluentes Químicos da Água/análise , Animais , Oceano Atlântico , Braquiúros/metabolismo , Monitorização de Parâmetros Ecológicos/métodos , Biomarcadores Ambientais , Sedimentos Geológicos/química , Humanos , Metais Pesados/metabolismo , Medição de Risco , Estações do Ano , Esgotos/química , América do Sul , Poluentes Químicos da Água/metabolismo
14.
Artigo em Inglês | MEDLINE | ID: mdl-33095110

RESUMO

Microemulsion cleaning method has been proved to be an effective way to clean oily sludge with low interfacial tension and high solubilizing ability for non-miscible liquids. In this paper, the percentage range of the microemulsion in the formulation was obtained by studying phase behavior of the microemulsion. The response surface method was used to model and optimize the microemulsion to obtain the best formulation: n-BuOH content at 9.89%, NaCl content at 2.24% and AES/APG ratio at 3.75, and the oil removal rate reached 97.28%. Meanwhile, the cleaning conditions of oil sludge were also optimized by the response surface method and the optimal cleaning parameters were determined as liquid-solid ratio at 4.2, stirring rate at 157 r·min-1, and stirring time at 38 min. In addition, some experiments were carried out to confirm the simulation results, affording the oil removal rate of 98.79%. SEM and FTIR confirmed that the oil on the sludge can be removed by microemulsion.


Assuntos
Petróleo/análise , Esgotos/química , Tensoativos/química , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/análise , Emulsões
15.
Ecotoxicol Environ Saf ; 208: 111434, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33045436

RESUMO

A high concentration of potentially toxic elements (PTEs) can be frequently observed in the plastic processing sludge (PPS), thereby restricting its environmental applications. The main objective of this study was to investigate the effects of the co-pyrolysis of PPS and KH2PO4 (0, 5, 10 and 20 wt%) on the characteristics and environmental risks associated with the PTEs in PPS and derived chars. General characteristic analysis revealed that the char yield, ash content, pH, and particle size of the chars prepared with KH2PO4 were greater than those of the char prepared without KH2PO4 by 3.13-4.89 wt%, 2.95-4.4 wt%, 0.77-0.93, and 9.64-30.07 µm, respectively. The results of sequential extraction indicated that co-pyrolysis with KH2PO4 could considerably increase the distribution of PTEs in the F4 fraction (non-bioavailable) in PPS by 1.30-65.90% when compared with that obtained via co-pyrolysis with 5 wt% of KH2PO4. The toxic leaching tests indicated that the leaching concentrations of Cr, Ni, Cu, Zn, Cd, and Pb in the char prepared without KH2PO4 decreased to different extents when PPS was subjected to co-pyrolysis with KH2PO4, especially in case of co-pyrolysis with 5 wt% of KH2PO4. The range of decrease was 26.40-88.34%. However, in case of Cu, Zn, and Pb, the leaching concentration of the chars prepared with more than 10 wt% of KH2PO4 increased owing to the decomposition of (Cu Zn)PbVO4(OH) in an acidic environment. The results obtained using Hakanson's equations revealed that the potential ecological risk associated with the PTEs in chars obtained by co-pyrolysis with KH2PO4 decreased, with a minimum decrease of 38.17%. In addition, the risk level associated with PPS reduced from considerable to low after co-pyrolysis with KH2PO4. The observations of this study imply that the co-pyrolysis of PPS with KH2PO4 can be a promising treatment for PTE immobilization.


Assuntos
Metais Pesados/química , Fosfatos/química , Plásticos/química , Compostos de Potássio/química , Pirólise , Eliminação de Resíduos , Oligoelementos/química , Esgotos/química
16.
J Environ Sci Health B ; 56(2): 132-141, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33296229

RESUMO

Large volumes of produced water are generated as a byproduct in activities of oil and gas exploitation, which can be reused in agriculture after a treatment process. Activated sludge treatment has been successfully used to remove oil from wastewater, but systematic studies on the toxicity of this effluent using this treatment are scarce in the literature. In this study, it was investigated the performance of an activated sludge system in the treatment of a synthetic produced water under different initial conditions in terms of salinity and oil and grease concentration. Furthermore, it was evaluated this effluent phytotoxicity in the germination, and seedling and plant growths of sunflower and corn seeds using untreated and treated synthetic produced water. Results revealed the activated sludge effectiveness in oil and grease and salinity removal from produced water, viz. high removal efficiency of 99.01 ± 0.28 and 91.07 ± 0.39%., respectively. Untreated produced water showed considerable toxic effects on the germination (74.67 ± 2.31% and 82.67 ± 2.31 for sunflower and corn seeds, respectively) and growth stages of sunflower and corn seed plants. The germination percentage was approximately 100% for both types of seed. The seedling and plant growth of the two seeds irrigated with treated produced water had similar performance when used tap water. These results highlighted the potential reuse as an unconventional water resource for plant irrigation of the synthetic produced water treated by an activated sludge process, which technology has showed high removal performance of salinity and oil.


Assuntos
Irrigação Agrícola , Germinação , Helianthus/crescimento & desenvolvimento , Reciclagem , Esgotos/química , Eliminação de Resíduos Líquidos/instrumentação , Zea mays/crescimento & desenvolvimento , Germinação/efeitos dos fármacos , Helianthus/efeitos dos fármacos , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Águas Residuárias/análise , Zea mays/efeitos dos fármacos
17.
Artigo em Inglês | MEDLINE | ID: mdl-33378252

RESUMO

Petroleum hydrocarbons (PHCs) in petroleum refinery sludge (PRS) are the most adverse components because of their toxic nature, which are harmful to human health and the aquatic ecosystem. This study aimed to identify and characterize an indigenous bacterium isolated from PRS of Indian oil corporation ltd. (IOCL), Haldia, India, and evaluate its performance for biodegradation of total petroleum hydrocarbon (TPH) of PRS. The bacterium molecularly characterized as Stenotrophomonas sp. IRB19 by 16S rRNA sequencing and phylogenetic analysis. The strain IRB19 showed a significant ability to utilize four different oils (kerosene, diesel, petrol and hexadecane) in-vitro. IRB19 could able to degrade up to 65 ± 2.4% of TPH in 28 d of incubation. Solvent extraction study showed that PRS contain 180.57 ± 3.44 g kg-1 of TPH and maltene fraction composed of aliphatic, aromatics and polar components of 52 ± 4, 39 ± 2 and 9 ± 1%, respectively. The TPH degradation best fitted for the Gompertz model and followed the first-order kinetics having the rate constant (k) and half-life period (t 1/2) of 0.036 d-1 and 19 d, respectively. Results of this study verified the suitability of the novel strain IRB19 for the biodegradation of PHCs.


Assuntos
Petróleo/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Esgotos/microbiologia , Microbiologia do Solo , Poluentes do Solo/análise , Stenotrophomonas/crescimento & desenvolvimento , Biodegradação Ambiental , Ecossistema , Humanos , Índia , Modelos Teóricos , Petróleo/metabolismo , Filogenia , Hidrocarbonetos Policíclicos Aromáticos/metabolismo , RNA Ribossômico 16S/genética , Esgotos/química , Poluentes do Solo/metabolismo , Stenotrophomonas/isolamento & purificação
18.
Artigo em Inglês | MEDLINE | ID: mdl-33378253

RESUMO

Wastewater reuse has been widely discussed as an essential strategy to minimize the consumption of drinking water for less noble purposes. During biological wastewater treatment, organic matter is converted into a complex matrix containing a variety of soluble organic compounds. The objective of the present study was to evaluate the removal efficiency of the residual organic load in the final effluent from wastewater treatment plant with a conventional activated sludge process by different coagulants and parameters of coagulation-flocculation process, using dissolved organic carbon (DOC) concentration, molecular weight (MW) size distribution by size exclusion chromatography (SEC) coupled to mass spectrometry (MS), and zeta potential (ZP) analyses. The results showed a DOC removal efficiency up to 45% with iron chloride, and of 38% for aluminum sulfate and 31% for PAC coagulants. ZP was also measured during the procedures and authors conclude that the ZP also does not have a determining role in these removals. SEC and MS assessment was able to detect changes on secondary effluent molecular weight distribution profile after effluent coagulation-flocculation, this technique might be a promising tool to understand the composition of effluent organic matter and be helpful to estimate and optimize the performance of wastewater effluents treatment processes.


Assuntos
Floculação , Compostos Orgânicos/análise , Esgotos/química , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/química , Purificação da Água/métodos , Compostos de Alúmen/química , Análise da Demanda Biológica de Oxigênio , Solubilidade
19.
Chemosphere ; 262: 128387, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33182114

RESUMO

Soil degradation caused by watermelon continuous cropping obstacle is a serious problem in China. Compost, as a soil conditioner, has great potential in improving soil degradation. In order to explore how compost affects the soil quality under continuous cropping obstacle, associations among soil chemical characteristics, microbial community structures and agronomic variables were analyzed and compared. Results showed that soil pH, available potassium, alkali-hydrolyzable nitrogen and organic matter changed significantly after using maize straw compost and sludge compost, which indicated the feasibility of composts as soil remediations. This is also reflected on the significant changes of soil microbial community. Mizugakiibacter, as the main reason of watermelon continuous cropping obstacle, decreased significantly after using compost products. It also showed a negative connection with most chemical characteristics. Rhodanobacter and Galbibacter increased significantly after using compost products, which were positively related to most chemical characteristics. The increase of them was helpful to reduce Mizugakiibacter. Beneficial bacteria were positively related to beneficial fungi (Chaetomium and Chrysosporium). The increase of them and the decrease of Verticillium also helped to improve microbial community structure. The results indicated that compost as a useful and inexpensive technique could alleviate soil degradation caused by watermelon continuous cropping obstacle.


Assuntos
Agricultura , Citrullus , Microbiota , Microbiologia do Solo , Álcalis , Bactérias , China , Compostagem , Fungos , Estudos Longitudinais , Nitrogênio/análise , Esgotos/química , Solo/química , Zea mays
20.
Chemosphere ; 262: 128416, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33182118

RESUMO

In this study, papermaking sludge-based flocculant (PSBF) and commercial lignin-based flocculant (LBF) have been synthesized by the same graft copolymerization procedures. The structures of alkaline lignin (AL), commercial lignin and the two flocculants were characterized by the modern analytical methods, also, the molecular weights and charge properties were analyzed. The effects of coagulant/flocculant dosages, pH conditions and coexistent dye auxiliaries on flocculation efficiencies were studied in the treatment of reactive turquoise blue (RTB) and disperse red (DR) dye wastewater. The flocculation experiments indicated that PSBF and LBF performed better in the removals of RTB and DR than commercial PAC and PAM. PSBF and LBF were insensitive to pH variation due to their strong charge neutralizing abilities and bridging effects even with the pH changing. In the existence of dye auxiliaries, PSBF and LBF could also exhibit superior decolorization efficiencies by slightly enlarging their dosages. Furthermore, PSBF and LBF had similar flocculation behaviors under all measured experimental conditions, suggesting that PSBF also had excellent flocculation performances even if it was prepared from papermaking sludge.


Assuntos
Eliminação de Resíduos Líquidos/métodos , Floculação , Lignina/química , Peso Molecular , Esgotos/química , Águas Residuárias , Purificação da Água/métodos
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