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1.
J Hazard Mater ; 411: 125183, 2021 06 05.
Artigo em Inglês | MEDLINE | ID: mdl-33858117

RESUMO

In April 2016, a series of earthquakes (M 7.3 on the Japan Meteorological Agency scale) occurred in Kumamoto, Japan causing serious damage to underground sewerage networks. In this study, we evaluated sewer exfiltration in groundwater in the Kumamoto area after the earthquakes by using multiple tracers. We used 14 pharmaceuticals, including carbamazepine and crotamiton, and anthropogenic Gd as tracers, and we measured concentrations of these tracers from September 2016 to November 2017 seasonally. The detection frequency of caffeine, carbamazepine, crotamiton, ibuprofen, and anthropogenic Gd ranged from 29% to 45%, and the concentrations of the pharmaceuticals in the groundwater were lower than those in previous studies. The median of all pharmaceutical concentrations did not decrease, whereas the median of the sum of crotamiton and carbamazepine concentrations, which are quantitative sewage markers, decreased with time. The sewer exfiltration rates in September 2016 estimated using carbamazepine, crotamiton, and anthropogenic Gd were 0.59 ± 0.27%, 0.66 ± 0.47%, and 0.11 ± 0.18% of sewage dry weather flow, respectively, indicating that the effect of the earthquakes on sewer exfiltration was small, probably because the damaged sewers were quickly repaired. This study demonstrated that a multiple-tracer approach is useful for evaluating sewer exfiltration after major earthquakes.


Assuntos
Terremotos , Água Subterrânea , Preparações Farmacêuticas , Japão , Esgotos/análise , Eliminação de Resíduos Líquidos
2.
Sci Total Environ ; 782: 146903, 2021 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-33848851

RESUMO

Combined sewer overflows (CSOs) are a dominant contributor to urban river pollution. Therefore, reducing the environmental impacts of CSOs and improving the self-purification capacity of water bodies are essential. In this study, the side-stream supersaturation (SSS) oxygenation was applied to restore microbial function of rivers which are affected by CSOs to improve the self-purification capacity. The results showed that apart from the dissolved organic matter inputs from CSO event, the sediment had become an important contributor to pollution in the studied river. After the long-term (46 d) implementation of SSS oxygenation, dissolved oxygen and the oxidation-reduction potential of the river water increased by 98% and 238%, respectively, compared to emergency control measures implemented following individual CSO events. The NH3-N concentrations and the chemical oxygen demand also decreased by 20% and 45%, respectively. In addition, the occurrence of microbial functions related to information storage and processing, and cellular process and signaling, increased by 1.87% and 0.82% in response to SSS oxygenation, respectively, and the Shannon index of the sediment microbial community increased by more than 15%. The frequencies of genes related to nitrification and sulfur oxidation also increased by 20-450% and >50%, respectively. This research provides new insights into the ecological restoration of rivers affected by CSOs.


Assuntos
Microbiota , Rios , Monitoramento Ambiental , Água Doce , Esgotos/análise
3.
Sci Total Environ ; 769: 144642, 2021 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-33736269

RESUMO

The occurrence of man-made antibiotics in natural environment has aroused attentions from both scientists and publics. However, few studies tracked antibiotics from their production site to the end of disposal environment. Taking the coastal region of Hangzhou Bay as the study area, the fate of 77 antibiotics from 6 categories in two-step wastewater treatment plants (WTPs, i.e. pharmaceutical WTP and integrated WTP) was focused; and the antibiotics in both dissolved and adsorbed phases were investigated simultaneously in this study. The ubiquitous occurrence of antibiotics was observed in the two-step WTPs, with antibiotic concentrations following the order of PWTP (LOQ - 1.0 × 105 ng·L-1) > IWTPi (for industrial wastewater treatment, LOQ - 3.7 × 103 ng·L-1) > IWTPd (for domestic sewage treatment, LOQ - 1.3 × 103 ng·L-1). And the types of antibiotics detected in excess sludge and suspended particles were in accordance with those in wastewater. Quinolones were invariably dominant in both dissolved and adsorbed fractions. High removal efficiencies (median values >50.0%) were acquired for the dissolved quinolones (except for DFX), tetracyclines, ß-lactams, and lincosamides. Anaerobic/anoxic/oxic achieved the highest aqueous removal of antibiotics among the investigated treatment technologies in the three WTPs. PWTP and IWTP removed 9797 and 487 g·d-1 of antibiotics, respectively; and a final effluent with 126.4 g·d-1 of antibiotics was discharged into the effluent-receiving area (ERA) of Hangzhou Bay. Source apportionment analysis demonstrated that the effluents of IWTPd and IWTPd contributed respectively 39.3% and 8.9% to the total antibiotics in the ERA. The results illustrate quantitatively the antibiotic flows from engineered wastewater systems to natural water environment, on the basis of which the improvements of wastewater treatment technologies and discharge management would be put forward.


Assuntos
Águas Residuárias , Poluentes Químicos da Água , Antibacterianos/análise , Baías , China , Humanos , Esgotos/análise , Eliminação de Resíduos Líquidos , Águas Residuárias/análise , Água , Poluentes Químicos da Água/análise
4.
Huan Jing Ke Xue ; 42(4): 1956-1966, 2021 Apr 08.
Artigo em Chinês | MEDLINE | ID: mdl-33742831

RESUMO

In urban solid waste management, the scientific and reasonable disposal and utilization of sewage sludge is becoming more and more important. It can be said that the pollution status and chemical properties of sewage sludge in urban sewage treatment plants can provide a basis for the scientific disposal and utilization of sludge. In this study, the characteristics of pH, moisture content, Cd, Cr, Cu, Zn, Pb, As, Hg, Ni, mineral oil, volatile phenol, PAHs, organic matter, nitrogen, phosphorus, and potassium were evaluated in sewage sludge collected from 49 sewage treatment plants in a certain city. The pollution status of heavy metals and organic pollutants, the frequency distribution of pollutant concentrations, and changes in the nutrient content were analyzed. The Nemero index and Hakanson potential ecological hazard index were used to assess the potential ecological risks of heavy metals in the agricultural utilization process of sludge. The results showed that under the condition of neutral pH values and high moisture content, the order of heavy metal content was Zn > Cu > Cr > Pb > Ni > As > Hg > Cd. The principal component analysis (PCA) results indicated that Cd, Pb, Hg, Ni, and As constituted the main load factors of the first main component of heavy metal sources. The most concentrated contents of 8 heavy metal frequency distributions among the 49 samples were 38.9-1380.0, 62.6-182.7, 63.6-181.3, 0.0-97.8, 19.3-68.4, 0.8-29.2, 0.3-8.7, and 0.01-0.96 mg·kg-1. In addition, the most concentrated frequency distribution of mineral oil, volatile phenol, and PAH concentration were 87.0%, 87.9%, and 77.6%, respectively. Moreover, the nutrient content of sludge was higher than the average level in China, and the organic matter content was 67.4%, 75.9%, and 92.5% of that of pig manure, cow dung, and chicken manure, while the content of nitrogen, phosphorus, and potassium was not very different. The Nemero index and Hakanson ecological hazard index results showed that the sludge of urban sewage treatment plant in the city has certain ecological risks. However, four sewage treatment plants were heavily polluted or highly ecologically hazardous among the 44 plants in this study, which were in line with the Standards for pollutant control of agricultural sludge. In summary, there are certain potential ecological risks for the agricultural utilization of sludge in the city, and it is necessary to reduce the heavy metal content before resourcing. More importantly, on the premise that the sludge meets the agricultural standards, a comprehensive ecological risk assessment is required to select a reasonable sludge recycling method.


Assuntos
Metais Pesados , Esgotos , Animais , China , Cidades , Monitoramento Ambiental , Metais Pesados/análise , Medição de Risco , Esgotos/análise , Solo , Suínos
5.
J Environ Manage ; 288: 112365, 2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-33765574

RESUMO

This study evaluates the effects of electro-oxidation as a means for enhancing sludge stabilisation. Boron-doped diamond electrodes were used to treat waste activated sludge and digestate under different operating parameters (current density, conductivity, pH, and time). Electro-oxidation runs affected the solubilisation of organic matter, which seemed to improve anaerobic digestion and dewaterability characteristics. Among the tested parameters, pre-treating sludge via electro-oxidation under alkaline conditions (Treatment T5) resulted in the highest increase in soluble organic material compared to that in the control, with total organic carbon (TOC) and soluble chemical oxygen demand (COD) values of 2753 and 7819 mg L-1, respectively (control TOC and COD values were 385 and 1073 mg L-1). This pretreatment also achieved a high hydrolysis rate (higher concentration in volatile fatty acids) with a concomitant increase in methane yield (approximately 18%). On the other hand, the application of electro-oxidation as a post-treatment for improving digestate dewaterability resulted in noticeable changes in the release of water during drying due to protein and aliphatic matrix modification of the sample.


Assuntos
Esgotos , Eliminação de Resíduos Líquidos , Anaerobiose , Análise da Demanda Biológica de Oxigênio , Metano , Esgotos/análise
6.
J Hazard Mater ; 412: 125270, 2021 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-33548774

RESUMO

Triclocarban (TCC) has a high detection frequency in soil, rivers, sediments, and organisms, and its ecological risks have attracted substantial attention. In this study, we analyzed the fate of TCC in four wastewater treatment plants (WWTPs) in Zhengzhou, China, the biodegradation characteristics during the composting process, and the ecological risks of TCC when entering different environmental compartments. The concentration of TCC in the influent was 731.1-812.4 ng/L. More than 53.4% of TCC was biodegraded during the wastewater treatment process, and less than 2.5% was retained in the effluent. TCC was effectively removed through microbial degradation and sewage sludge absorption, and there were only minor differences in the different wastewater treatment processes. It is worth noting that more than 38% of TCC was enriched in sewage sludge (1430.1-1663.8 ng/g). The corresponding biodegradation rates of TCC were 65.7% and 82.8% in sewage sludge after 17 days of composting treatment with sawdust and straw as bulking agents, respectively. The estimated results showed that effluent discharge into the city rivers was safe. Composting could effectively degrade TCC and decrease the ecological risk of TCC when applied to sewage sludge.


Assuntos
Compostagem , Poluentes Químicos da Água , Purificação da Água , Carbanilidas , China , Medição de Risco , Esgotos/análise , Poluentes Químicos da Água/análise
7.
J Environ Manage ; 284: 112059, 2021 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-33556826

RESUMO

Fecal indicator bacteria (FIB) are commonly used to evaluate the pollution impact of combined sewer overflows (CSOs) in urban rivers. Although water quality assessment with FIB has a long tradition, recent studies demonstrated that FIB have a low correlation with pathogens and therefore are not accurate enough for the assessment of potential human hazards in water. Consequently, new eligible and more specific indicators have to be identified, which was done in this study via sequencing of genetic markers from total community DNA. To identify potential microbiome-based indicators, microbial communities in samples from an urban river in Tokyo under different climatic conditions (dry and rainy) were compared with the influent and effluent of three domestic wastewater treatment plants (WWTPs) by analyzing 16 S rRNA gene amplicon libraries. In the first part of this study, physicochemical parameters and FIB quantification with selective culture techniques facilitated the identification of samples contaminated with CSO, sewage, or both. This allowed the grouping of samples into CSO-contaminated and non-contaminated samples, an essential step prior to the microbiome comparison between samples. Increased turbidity, ammonia concentrations, and E. coli [up to (9.37 ± 0.95) × 102 CFU/mL after 11.5 mm of rainfall] were observed in CSO-contaminated river samples. Comparison of dry weather (including WWTP samples) and rainy weather samples showed a reduction in microbial diversity in CSO-contaminated samples. Furthermore, the results of this study suggest Bacteroides spp. as a novel indicator of sewage pollution in surface waters.


Assuntos
Escherichia coli , Rios , Monitoramento Ambiental , Fezes/química , Genes de RNAr , Humanos , RNA Ribossômico 16S/genética , Esgotos/análise , Tóquio , Microbiologia da Água
8.
Mar Pollut Bull ; 165: 112149, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33610111

RESUMO

Recent sewage contamination in Brazilian mangrove forests was evaluated using fecal sterols as biomarkers and socioeconomic indicators. The sterols were quantified by gas chromatography/mass spectrometry (GC/MS). Total fecal sterol concentrations ranged between 2.50 2.50 and 39.03 µg g-1 and coprostanol, between 0.23 and 6.97 µg g-1. Mangroves located in less urbanized regions presented low coprostanol levels and low coprostanol/cholesterol and (5ß/5ß + 5α) stanol ratios in sediment, while urban mangrove forests presented moderate fecal contamination. In the latter, an intense contribution of untreated domestic effluents associated to metropolitan areas was noted, leading to a significant correlation between coprostanol concentrations and inadequate sanitation, reflecting environmental problems associated to disorderly urbanization processes coupled to the absence of an adequate urban infrastructure. However, even in metropolitan areas, fecal sterol levels did not reach those of highly contaminated regions, probably due to the intense and accelerated degradation process typical of tropical environments. However, this study highlights the importance of fecal contamination assessment in mangrove areas since the presence of untreated sewage in these ecosystems is an issue of public and environmental health.


Assuntos
Esgotos , Esteróis , Brasil , Ecossistema , Monitoramento Ambiental , Fezes/química , Sedimentos Geológicos , Esgotos/análise , Esteróis/análise
9.
Waste Manag ; 124: 17-25, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33596535

RESUMO

Management of agro-waste is a major challenge globally due to inefficient disposal techniques, which concominantly leads pollution and loss of renewable bioenergy. Anaerobic digestion of agro-waste is one of the ways to tackle this problem but hindered by the recalcitrant nature of agro-waste. This study investigated the effect of granular activated carbon (GAC) and granular biochar (GBC) addition to enhance the thermophilic anaerobic co-digestion of wheat husk and sewage sludge. The conductive materials (particle size: 2-5 mm) were added separately at five different concentrations: 10, 20, 30, 40, 50 g/Linoculum. The findings revealed that samples amended with GAC and GBC at 20 g/L dosage had the highest biogas yield of 263 and 273 mL/gVSadded, respectively, corresponding to 22 and 27% higher yield than the control. Additionally, a shorter lag phase was observed in both cases compared to the Control. However, the GBC amended samples showed relatively stable biogas production compared to GAC and consistent results regarding pH, alkalinity, total volatile fatty acids, and soluble chemical oxygen demand. The preliminary techno-economic analysis indicates that addition of GAC or GBC may not be feasible and require other innovative engineered solutions for the addition of conductive materials. This study confirms that GAC and GBC amendments enhance the biogas productivity and process stability in anaerobic digestion of recalcitrant agro-waste under the high-temperature regime and calls for further research in this direction.


Assuntos
Reatores Biológicos , Esgotos , Anaerobiose , Biocombustíveis/análise , Análise da Demanda Biológica de Oxigênio , Digestão , Metano , Esgotos/análise
10.
Environ Res ; 195: 110843, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33548300

RESUMO

Wastewater treatment plants (WWTPs) in urban China generally face operational difficulties. To comprehensively analyze the current operation status and determine the factors that caused difficulties in urban domestic WWTPs, we conducted a questionnaire survey, and 18 operating conditions of scale-level WWTPs in seven regions in China were investigated. The research results showed that, of the 467-urban domestic WWTPs surveyed in China, approximately 63.17% of the WWTPs' hydraulic loading rates (HLRs) are greater than 80%, 67.02% of the WWTPs have mixed liquor suspended solids (MLSS) concentrations greater than 4000 mg/L, and 95.93% of the WWTPs' mixed liquor volatile suspended solids to mixed liquor suspended solids (MLVSS/MLSS) ratios are lower than 0.7. The WWTP energy consumption accounts for approximately 1% of the national electricity consumption, and approximately 100,000 tons of various chemicals are consumed every year. A high HLR, a high activated sludge concentration and low sludge activity, design value mismatches with actual values, high energy and material consumption, etc. have become the main operational difficulties of urban domestic WWTPs. In this study, the main barriers that hinder improving the operating efficiency of WWTPs were investigated, the causes of operational dilemmas were analyzed, and pathways were jointly explored to solve them. This study may provide valuable implications for industry practitioners with a comprehensive grasp of the industry's current status and related policy formulation.


Assuntos
Eliminação de Resíduos Líquidos , Purificação da Água , China , Esgotos/análise , Águas Residuárias
11.
Sci Total Environ ; 774: 145174, 2021 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-33609829

RESUMO

Concern on relatively high levels and the potential bioaccumulation of decabromodiphenylether (BDE209) has led to a European 8-year monitoring program on trends in BDE209 concentrations in birds, sewage sludge and sediments from seven countries. BDE209 was analysed in four environmental matrices: sparrowhawk eggs (UK), glaucous gull eggs (Bear Island, Norway), sewage sludge (UK, Ireland and the Netherlands) and sediment (France, Germany, the Netherlands, UK and Ireland). BDE209 was detected in most of the glaucous gull and sparrow hawk eggs but neither increasing nor decreasing trends in these BDE209 levels were observed. An indication for debromination of BDE209 in sparrowhawk eggs was found. BDE209 concentrations in sediments ranged from very low ng/g (88 ng/g on an organic carbon (OC) basis) concentrations, in the rivers Elbe, Ems, Seine and the Outer Humber, to high µg/g (120 µg/g OC), in the Western Scheldt, Liverpool Bay and River Mersey. Apart from decreasing values in the Western Scheldt sediment no further decreases in BDE209 concentrations were observed over time, neither in sediment nor in sewage sludge showing that the voluntary emissions control program of the bromine industry only had a local effect. In contrast to the sewage sludge samples from the Netherlands (mean 355 ng/g dry weight (dw) or 1026 ng/g OC), the BDE209 concentrations in the UK increased at all sites from 2006 to 2011 (8092 ng/g dw or 22,367 ng/g OC). The BDE209 levels in several UK sediments and sewage sludge were still very high at the end of the program in 2012, most likely caused by frequent use of BDE209 in the textile industry. This may be indicative of the persistence of BDE209 and the limited degradation into lower brominated congeners in sediment, although it cannot be excluded that ongoing BDE209 emissions have played a role as well.


Assuntos
Esgotos , Poluentes Químicos da Água , Animais , Aves , Monitoramento Ambiental , França , Sedimentos Geológicos , Alemanha , Irlanda , Países Baixos , Noruega , Esgotos/análise , Poluentes Químicos da Água/análise
12.
Environ Sci Pollut Res Int ; 28(16): 20717-20736, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33405159

RESUMO

Sewage contamination is a principal concern in water quality management as pathogens in sewage can cause diseases and lead to detrimental health effects in humans. This study examines the distribution of seven sterol compounds, namely coprostanol, epi-coprostanol, cholesterol, cholestanol, stigmasterol, campesterol, and ß-sitosterol in filtered and particulate phases of sewage treatment plants (STPs), groundwater, and river water. For filtered samples, solid-phase extraction (SPE) was employed while for particulate samples were sonicated. Quantification was done by using gas chromatography-mass spectrometer (GC-MS). Faecal stanols (coprostanol and epi-coprostanol) and ß-sitosterol were dominant in most STP samples. Groundwater samples were influenced by natural/biogenic sterol, while river water samples were characterized by a mixture of sources. Factor loadings from principal component analysis (PCA) defined fresh input of biogenic sterol and vascular plants (positive varimax factor (VF)1), aged/treated sewage sources (negative VF1), fresh- and less-treated sewage and domestic sources (positive VF2), biological sewage effluents (negative VF2), and fresh-treated sewage sources (VF3) in the samples. Association of VF loadings and factor score values illustrated the correlation of STP effluents and the input of biogenic and plant sterol sources in river and groundwater samples of Linggi. This study focuses on sterol distribution and its potential sources; these findings will aid in sewage assessment in the aquatic environment.


Assuntos
Fitosteróis , Esteróis , Idoso , Ecossistema , Monitoramento Ambiental , Fezes/química , Humanos , Malásia , Esgotos/análise , Esteróis/análise
13.
Environ Sci Pollut Res Int ; 28(21): 26858-26870, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33495959

RESUMO

Optimizing the locations of sewage treatment plants has enormous practical significance. In this study, a large-system mathematical model was developed for optimizing the locations of sewage treatment plants within a system and designing the associated pumping station pipe network. Head loss of pipe segments in the pipe network was the coupling constraint, the economic flow rate of pipe segments was determined by the feasible region constraints of decision variables, and the design variables were the sewage treatment plant locations, the design head of the pumping stations, the pipeline economic life, and the pipe diameter of divided pipe segments. The minimum total annual cost of the sewage treatment plant(s) and the pumping station pipe network was the objective function. A large-system quadratic orthogonal test-based selection method was used with a discrete enumeration comparison and selection method to determine pipeline economic life. A dynamic programming method was used to determine the pipe diameter of the divided pipe segments. By comparing the total annual cost of the sewage treatment plants and the associated pumping station pipe network corresponding to different pipeline economic lifetimes, the optimal solution that generates the minimum total annual cost can be identified. The sewage treatment plant and pumping station pipe network in Taizhou, China, was used as an example to compare and analyze optimization results. The new optimization method would have produced much lower annual cost than that of the existing system. This study provides valuable theoretical references for probing the layout design of urban sewage treatment plants corresponding to different pipeline economic lifetimes.


Assuntos
Modelos Teóricos , Esgotos , China , Esgotos/análise
14.
J Hazard Mater ; 411: 125047, 2021 06 05.
Artigo em Inglês | MEDLINE | ID: mdl-33453662

RESUMO

Parabens are preservatives widely used in pharmaceutical and personal care products (PPCPs). This study investigated urban water pollution by parabens from a watershed perspective. Water and sediment samples were collected from one of the most polluted urban streams in China. Six parabens and five paraben metabolites were frequently detected in the samples, whereas the overall pollution level was intermediate according to a global comparison. The spatial distributions of the chemical concentrations along the river are influenced by multiple factors, and WWTPs appear to be a major factor. In general, the target pollutants were detected at higher concentrations in the dry season than in the wet season, but extraordinary concentration peaks in water were observed downstream of wastewater treatment plants (WWTPs), indicating a dominant contribution from combined sewage overflows (CSOs) during rainfall events. In a representative WWTP-influenced reach, CSOs account for its 97.3% of ∑parabens input and 96.9% of ∑metabolites input in a typical rainfall event. Converting the existing combined sewer systems to separate stormwater drainage systems could reduce the inputs of ∑parabens and ∑metabolites by 86.9-84.5%, respectively. This study highlights the role of urban drainage systems in preventing surface water pollution by PPCPs. CAPSULE: Urban drainage systems play a critical role in controlling pollution by parabens and their metabolites in urban surface water.


Assuntos
Monitoramento Ambiental , Poluentes Químicos da Água , China , Rios , Esgotos/análise , Águas Residuárias , Água , Poluentes Químicos da Água/análise
15.
J Environ Sci (China) ; 101: 72-86, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33334539

RESUMO

Intensive agriculture activities, industrialization and growing numbers of wastewater treatment plants along river banks collectively contribute to the elevated levels of neurotoxic pollutants in natural water reservoirs across Europe. We established an in vitro bioassay based upon neural stem cells isolated from the subventricular zone of the postnatal mouse to evaluate the neurotoxic potential of raw wastewater, treated sewage effluent, groundwater and drinking water. The toxic potential of water samples was evaluated employing viability, proliferation, differentiation and migration assays. We found that raw wastewater could reduce the viability and proliferation of neural stem cells, and decreased the neuronal and astrocyte differentiation, neuronal neurite growth, astrocyte growth and cell migration. Treated sewage water also showed inhibitory effects on cell proliferation and migration. Our results indicated that relatively high concentrations of nitrogenous substances, pesticides, mercuric compounds, bisphenol-A, and phthalates, along with some other pollutants in raw wastewater and treated sewage water, might be the reason for the neuroinhibitory effects of these water samples. Our model successfully predicted the neurotoxicity of water samples collected from different sources and also revealed that the incomplete removal of contaminants from wastewater can be problematic for the developing nervous system. The presented data also provides strong evidence that more effective treatments should be used to minimize the contamination of water before release into major water bodies which may be considered as water reservoirs for human usage in the future.


Assuntos
Células-Tronco Neurais , Poluentes Químicos da Água , Animais , Bioensaio , Monitoramento Ambiental , Camundongos , Células-Tronco Neurais/química , Esgotos/análise , Águas Residuárias , Água , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
16.
Ecotoxicol Environ Saf ; 207: 111253, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32911183

RESUMO

Phytoremediation of polyester resin wastewater containing 1,4-dioxane and heavy metals using Lemna gibba (L.gibba) was enhanced by incorporation of perforated polyethylene carrier materials (PCM) onto the duckweed pond (DWP) system. The DWP module was operated at a hydraulic retention times (HRTs) of 2, 4 and 6 days and as well as 1,4-dioxane loading rate of 16, 25 and 48 g/m3.d. The maximum removal efficiency of 54 ± 2.5% was achieved for 1,4-dioxane at an HRT of 6 days and loading rate of 16 g1,4-dioxane/m3.d. Similarly, the DWP system provided removal efficiencies of 28.3 ± 2.1, 93.2 ± 7.6, 95.7 ± 8.9 and 93.6 ± 4.9% for Cd2+, Cu2+, Zn2+ and Ni2+ at influent concentration of 0.037 ± 0.01, 1.2 ± 0.9, 27.2 ± 4.7 and 4.6 ± 1.2 mg/L respectively. The structural analysis by Fourier-transform infrared spectroscopy (FTIR) clearly displayed a reduction of 1,4- dioxane in the treated effluent. A strong peak was detected for L. gibba plants at frequency of 3417.71 cm-1 due to N-H stretching, which confirm the proposed mechanism of partially conversion of 1,4-dioxane into amino acids. Glycine, serine, aspartic, threonine and alanine content were increased in L. gibba by values of 35 ± 2.2, 40 ± 3.2, 48 ± 3.7, 31 ± 2.8, and 56 ± 4.1%, respectively. The contribution of DWP unit as a greenhouse gases (GHG) emissions were relatively low (1.65 gCO2/Kg BODremoved.d., and 18.3 gCO2/Kg biomass.d) due to photosynthesis process, low excess sludge production and consumption of CO2 for nitrification process (1.4 gCO2/kgN removed.d). Based on these results, it is recommended to apply such a technology for treatment of polyester resin wastewater containing 1,4-dioxane and heavy metals at a HRT not exceeding 6 days.


Assuntos
Dioxanos/análise , Gases de Efeito Estufa/análise , Metais Pesados/análise , Eliminação de Resíduos Líquidos/métodos , Araceae , Biodegradação Ambiental , Biomassa , Nitrificação , Poliésteres , Lagoas/análise , Esgotos/análise , Águas Residuárias/análise
17.
Chemosphere ; 262: 128405, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33182156

RESUMO

This study focused on the fouling characteristics evaluation of the sludge in a membrane bioreactor integrated with microbial fuel cell (MFC-MBR) to reveal the mechanisms of membrane fouling mitigation. The filtration of soluble microbial products (SMPs) in MFC-MBR showed lower flux decline rate than those in the control system (C-MBR). Based on the extended Derjaguin-Landau-Verwey-Overbeek analysis, decreases in free energies of adhesion between the SMPs and clean membrane or SMP-fouled membrane were observed in MFC-MBR. When approaching the clean membrane or SMP-fouled membrane, the SMPs in MFC-MBR had to overcome a higher energy barrier compared to those in C-MBR, indicating the inhibition of adsorption of SMPs on the membrane surface in MFC-MBR. Additionally, sludge flocs in MFC-MBR exhibited lower hydrophobicity and were less negative surface charged in comparison to those in the C-MBR. In MFC-MBR, the sludge flocs approaching the clean membrane, SMP-fouled membrane and cake layer all experienced higher energy barriers and lower secondary energy minimums compared to those in C-MBR, exhibiting the lower potential of cake layer formation. These results confirmed that decreases of the fouling potentials of SMPs and sludge flocs were essential for the membrane fouling mitigation in the MFC-MBR.


Assuntos
Fontes de Energia Bioelétrica , Reatores Biológicos , Filtração , Interações Hidrofóbicas e Hidrofílicas , Membranas Artificiais , Esgotos/análise
18.
Chemosphere ; 268: 129391, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33360138

RESUMO

The anaerobic fermentation (AF) of waste activated sludge (WAS) with an electrochemical pretreatment (EPT) was investigated to determine its correlation with the release of phosphorus and the disintegration of WAS. The sludge was pretreated by holding under 4.5 V for 60 min, followed by AF for 9 days. Untreated sludge was used as the control group (no-EPT). Results showed that, with pretreatment, the total dissolved P (TDP), orthophosphate (PO43--P) and organic P (OP) reached the maximum values of 7.30 mg/L, 4.77 mg/L and 2.35 mg/L on day 8, respectively, which were approximately 5.3, 9.2 and 2.7 times greater than that in the control group. The analysis of soluble chemical oxygen demand (SCOD), protein and polysaccharides showed that the EPT promoted the disintegration of sludge, thereby enhancing the P release. The SCOD reached 1625 mg/L on day 6 in pretreatment experiment, which was about 9.8 times greater than that in control group. Additionally, the EPT contributed to fewer metal ions in sludge supernatant. This mechanism might have been due to the anions accumulating in the supernatant from the greater degree of sludge collapse after EPT, which caused the released metal ions to combine with anions to form insoluble compounds. In conclusion, EPT could be a promising method for the dissolution of sludge and the recovery of phosphorus from WAS under AF. Besides, the economic benefit evaluation showed the potential value of EPT for P recovery.


Assuntos
Fósforo , Esgotos , Anaerobiose , Análise da Demanda Biológica de Oxigênio , Fermentação , Esgotos/análise , Eliminação de Resíduos Líquidos
19.
Molecules ; 26(1)2020 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-33374724

RESUMO

In this study, three magnetic ionic liquids (MILs) were investigated for extraction of four estrogens, i.e., estrone (E1), estradiol (E2), estriol (E3), and ethinylestradiol (EE2), from environmental water. The cation trihexyl(tetradecyl)phosphonium ([P66614]+), selected to confer hydrophobicity to the resulting MIL, was combined with tetrachloroferrate(III), ferricyanide, and dysprosium thiocyanate to yield ([P66614][FeCl4]), ([P66614]3[Fe(CN)6]), and ([P66614]5[Dy(SCN)8]), respectively. After evaluation of various strategies to develop a liquid-liquid microextraction technique based on synthesized MILs, we placed the MILs onto a magnetic stir bar and used them as extracting solvents. After extraction, the MIL-enriched phase was dissolved in methanol and injected into an HPLC-UV for qualitative and quantitative analysis. An experimental design was used to simultaneously evaluate the effect of select variables and optimization of extraction conditions to maximize the recovery of the analytes. Under optimum conditions, limits of detection were in the range of 0.2 (for E3 and E2) and 0.5 µg L-1 (for E1), and calibration curves exhibited linearity in the range of 1-1000 µg L-1 with correlation coefficients higher than 0.998. The percent relative standard deviation (RSD) was below 5.0%. Finally, this method was used to determine concentration of estrogens in real lake and sewage water samples.


Assuntos
Estradiol/análise , Estradiol/isolamento & purificação , Líquidos Iônicos/química , Microextração em Fase Líquida/métodos , Magnetismo , Esgotos/análise , Poluentes Químicos da Água/análise , Estrogênios/análise , Estrogênios/isolamento & purificação , Esgotos/química , Poluentes Químicos da Água/química
20.
Chemosphere ; 261: 128046, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33113656

RESUMO

Compared with conventional sludge reduction techniques, electric field assisted membrane bioreactor (MBR) is a cost-effective technology with low power consumption. In this study, spontaneous electric field without extra power supply was introduced into the MBR for wastewater treatment to complete the in situ sludge reduction and membrane fouling mitigation. A novel spontaneous electric field membrane bioreactor (SEF-MBR) equipped with Cu-nanowires (Cu-NWs) conductive microfiltration membrane as cathode was established by using baffles to form anaerobic and aerobic tanks. SEF-MBR 1 with external resistance of 500 Ω maintained a highest electric field intensity of 1.25 mV/cm. Compared with Control-MBR, the reduction of mixed liquor suspended solids (MLSS) growth rate, extracellular polymeric substances (EPS) growth rate, total cell number and water content of SEF-MBR 1 reached 50.0%, 43.0%, 37.1% and 6.4%, respectively. After 43 days operation, SEF-MBR 1 obtained the minimum MLSS concentration and sludge volume, which were 29.9% and 83.8% lower than that of it in Control-MBR. The total biovolume of the contaminants (i.e., EPS and cells) on the membrane surface of SEF-MBR 1 was 68.8% lower than that of Control-MBR. SEF-MBR 1 exhibited a better performance with a lower membrane fouling rate (0.58 kPa/d) than Control-MBR (1.09 kPa/d). Economic analysis showed that a total of 148.1 kWh/m3 of electric energy was saved in the SEF-MBR 1. This technology reduced the sludge production in the sewage biological treatment process, which realized the sludge reduction had a positive impact on the membrane fouling mitigation.


Assuntos
Incrustação Biológica/prevenção & controle , Reatores Biológicos/microbiologia , Eletricidade , Membranas Artificiais , Nanofios , Esgotos/análise , Eletrodos , Matriz Extracelular de Substâncias Poliméricas/química , Esgotos/microbiologia , Águas Residuárias/química , Águas Residuárias/microbiologia
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