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1.
Sci Total Environ ; 792: 148493, 2021 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-34465043

RESUMO

Dissolved organic matter (DOM) in wet weather overflows (WWFs) of storm drainage systems mainly originates from anthropogenic sources, such as paved runoff, illegally discharged domestic sewage and the retained sediment. This study provides a promising method to quantitatively apportion the WWF DOM of storm drainage systems using degradation potential index (DPI) and end member mixing (EMM) model. DPI is derived from excitation-emission matrix parallel factor analysis (EEM-PARAFAC), which can endow the end members and itself of WWF DOM with numerical features, and thus help quantify the source contributions of WWF DOM in EMM model. Findings show that (1) DPI was a reliable tool in the quantitative source apportionment of WWF DOM, owing to its features of small variance within source and large variances between sources; (2) DPI combined with EMM model could help identify the factors that induce significant impacts on the source contributions of WWF DOM, such as the storm pumping discharge and antecedent dry days in our case study; (3) the identified factors could guide the development of effective strategies for WWF DOM control, e.g. sediment management in our case.


Assuntos
Esgotos , Tempo (Meteorologia) , Análise Fatorial , Espectrometria de Fluorescência
2.
J Environ Sci (China) ; 108: 8-21, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34465439

RESUMO

Dissolved organic matter (DOM) plays a major role in ecological systems and influences the fate and transportation of many pollutants. Despite the significance of DOM, understanding of how environmental and anthropogenic factors influence its composition and characteristics is limited, especially in urban stormwater runoff. In this article, the chemical properties (pollutant loads, molecular weight, aromaticity, sources, and molecular composition) of DOM in stormwater extracted from three typical end-members (traffic, residential, and campus regions) were characterized by UV-visible (UV-vis) spectroscopy, excitation-emission matrix spectroscopy combined with parallel factor analysis (EEM-PARAFAC), and ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). There are three findings: (1) The basic properties of DOM in stormwater runoff varied obviously from three urban fields, and the effect of initial flush was also apparent. (2) The DOM in residential areas mainly came from autochthonous sources, while allochthonous sources primarily contributed to the DOM in traffic and campus areas. However, it was mainly composed of terrestrial humic-like components with CHO and CHON element composition and HULO and aliphatic formulas. (3) The parameters characterizing DOM were primarily related to terrestrial source and aromaticity, but their correlations varied. Through the combination of optical methods and UPLC-Q-TOF spectrometry, the optical and molecular characteristics of rainwater are effectively revealed, which may provide a solid foundation for the classification management of stormwater runoff in different urban regions.


Assuntos
Ecossistema , Análise Fatorial , Espectrometria de Fluorescência
3.
Artigo em Inglês | MEDLINE | ID: mdl-33638784

RESUMO

The performance comparison studies of the autoregressive integrated moving average model (ARIMA) and the artificial neural network (ANN) were mostly carried out between the selected model structures through trial-and-error, strongly influenced by model structure uncertainty. This research aims to make up for this inadequacy. First, a surface water quality prediction case study including eight monitoring sites in China was introduced. Second, the ARIMA and ANN's performance was compared statistically between 6912 Seasonal ARIMA (SARIMA) and 110,592 feedforward ANN with different model structures, based on the mean square error (MSE) distributions depicted by boxplots. In a statistical view, the ANN models obtained a significantly lower median value and a more concentrated distribution of validation MSEs, which indicated lighter overfitting and better generalization ability. Furthermore, the optimal SARIMA models' performance is inferior to even the median of the ANN models in the case study. In contrast with the previous comparisons among selected models, the statistical comparison in this study shows lower uncertainty.

4.
Chemosphere ; 265: 129023, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33246708

RESUMO

Enhanced coagulation has been widely used in storm tanks to remove heavy metal ions (HMs) from combined sewer overflows (CSOs), but faces challenges on removing the HMs bound to dissolved organic matter (DOM) with small molecular weight (MW). DOM ubiquitously existing in CSOs generally contains a large distribution range of MW, which can significantly impact the MW distribution of HMs by complexing reaction, thereby adding uncertainties for the removal efficiency of coagulation. Therefore, realizing the potential MW distribution of the HMs bound to CSO-DOM is greatly important for cost-effectively removing HMs from CSOs in the coagulation process. This paper presents a comprehensive approach of ultrafiltration, fluorescence quenching titration, excitation-emission matrix parallel factor analysis, complexation model, and two-dimensional correlation fluorescence spectroscopy for exploring the MW-based complexing characteristics between Cu(II) ions and CSO-DOM components. Results show that: (1) Cu(II) ions that bound to the CSO-DOM were mainly distributed in the MW range of <5 kDa, which makes them very difficult to be removed from CSOs by coagulation technique. (2) Concentration effect and molecular composition exerted great impacts on the MW distribution of the Cu(II) ions bound to CSO-DOM. (3) The humic-like component of terrestrial origin with the MW range of 100 kDa∼0.45 µm possessed high binding stability, capacity, and priority with Cu(II) ions, and they could be used at a high concentration to promote the removal efficiency of coagulation for Cu(Ⅱ) ions of CSOs by competitive complexation and inter-molecular bridging.


Assuntos
Metais Pesados , Análise Fatorial , Substâncias Húmicas/análise , Íons , Espectrometria de Fluorescência
6.
J Environ Manage ; 268: 110521, 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-32383653

RESUMO

Due to the influence of buildings on the distribution of flood and their economic and social attributes, 3D spatial information such as the size of buildings and the flooded ratio of buildings relative to their height has an increasing impact on urban flood risk. However, existing flood risk assessment methods mainly use data in 2D and analysis methods are mostly 2D. In this study, flood variation processes were analyzed in the form of 3D dynamic visualization by coupling an urban drainage model and a flood simulation model with 3D visualization methods. By further combining with 3D building models, the 3D spatial information of buildings related to flood was obtained. In order to study the influence of 3D information on flood risk and combine with other multi-source heterogeneous data for integrated analysis, a 3D visualization assessment and analysis method for flood risk, coupled with the projection pursuit-particle swarm optimization algorithm (PP-PSO) was established (3DVAAM-PP-PSO). A case study from Chaohu City, China, was used to demonstrate the method. The results showed that the PP-PSO algorithm can process high-dimensional information and obtain the objective weight of each index. The 3D information from the influenced buildings had an impact on the evaluation results, which needed to be considered. Through the 3D visualization analysis, the overall distribution of flood risk and that around the buildings were obtained in multi-perspectives. The flood risk during different rainfall return periods were analyzed intuitively and comparatively. This study furnishes a novel method for flood risk assessment and analysis by making the most of 3D spatial information.


Assuntos
Inundações , Imageamento Tridimensional , Algoritmos , China , Cidades , Medição de Risco
7.
Environ Sci Pollut Res Int ; 26(29): 29857-29871, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31410825

RESUMO

Neural network models have been used to predict chlorophyll-a concentration dynamics. However, as model generalization ability decreases, (i) the performance of the models gradually decreases over time; (ii) the accuracy and performance of the models need to be improved. In this study, Transfer learning (TL) is employed to optimize neural network models (including feedforward neural networks (FNN), recurrent neural networks (RNN) and long short-term memory (LTSM)) and overcome these problems. Models using TL are able to reduce the influence of mutable data distribution and enhance generalization ability. Thus, it can improve the accuracy of prediction and maintain high performance in long-term applications. Also, TL is compared with parameter norm penalties (PNP) and dropout-two other methods used to improve model generalization ability. In general, TL has a better prediction effect than PNP and dropout. All the models, including FNN with different architectures, RNN and LSTM, as well as models optimized by PNP, dropout, and TL, are applied to an estuary reservoir in eastern China to predict chlorophyll-a dynamics at 5-min intervals. According to the results of this study, (i) models with TL produce the best prediction results; (ii) the original models and the models with PNP and dropout lose their ability to predict within 3 months, while TL models retain a high prediction accuracy.


Assuntos
Clorofila A/análise , Eutrofização , Aprendizado de Máquina , Redes Neurais de Computação , China , Cinética , Valor Preditivo dos Testes
8.
Environ Sci Pollut Res Int ; 26(26): 26563-26576, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31292865

RESUMO

In order to mitigate urban flooding and combined sewer overflows, an integrated assessment method was proposed to identify the optimum reconstruction scheme of a drainage system by considering environment, economy, and society. The integrated assessment framework consisted of the drainage system model establishment, analytic hierarchy process theory, and regret value method. Five drainage system reconstruction schemes for Chaohu city were proposed in this study, and they were evaluated according to nine assessment factors by the integrated assessment method at the initial and future stages. The integrated assessment results show that setting up interceptive equipment for a combined drainage network is the optimal reconstruction scheme at both the initial and future stages of the life cycle. This means that an interceptive combined drainage network is better than a separate drainage network or setting up storage tanks in particular situations from a comprehensive perspective.


Assuntos
Drenagem Sanitária , Inundações , Cidades , Drenagem Sanitária/métodos , Modelos Teóricos
9.
Environ Sci Pollut Res Int ; 26(7): 6436-6449, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30623332

RESUMO

Monitoring on urban water environment and analysis of engineering improvement measures are intricate and time-consuming tasks. In previous studies, the integration of hydrodynamic and water quality models and geographical information system (GIS) usually takes three approaches: loose coupling, tight coupling, and full coupling. However, this paper adopted a special loose coupling approach-case-based reasoning (CBR) to develop an integrated decision support system. This was characterized by invoking the case base stored in the GIS platform as the output of the model. The fused capability of model's water quality predication and strong spatial data processing analysis of GIS can be realized at the same time by integration. The functionality of the integrated system was illustrated through a case study of Chaohu, a medium-sized city in China, which includes case retrieval, result interpretation, and the visual display in the GIS platform. Results verified the feasibility and operability of the developed method. As a useful tool, the integrated decision support system makes it simpler and more convenient for decision makers to make decisions efficiently and quickly.


Assuntos
Monitoramento Ambiental/métodos , Sistemas de Informação Geográfica , Modelos Teóricos , China , Tomada de Decisões , Hidrodinâmica , Software , Qualidade da Água
10.
Environ Sci Pollut Res Int ; 24(26): 21038-21049, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28726227

RESUMO

In order to assist and optimize the operation of a clean water diversion project for the medium-sized inland rivers in Chaohu, China, an integrated hydrodynamic and water quality model was used in this study. Sixteen diversion scenarios and five sewage interception scenarios were defined to assess the improvement of water quality parameters including ammonia nitrogen (NH3-N), total phosphorus (TP) and chemical oxygen demand (COD) under different diverted water flows, diverting times, diverting points, diverting routines and sewage interception proportions. An index of pollutant removal rate per unit diverted water flow (PRUWF) was proposed to evaluate the effect of the clean water diversion. Results show that operating conditions played important roles in water quality improvement of medium-sized inland rivers. The optimal clean water diversion was operated under the conditions of a flow rate of 5 m3/s for 48 h with an additional constructed bridge sluice. A global sensitivity analysis using the Latin Hypercube One-Factor-at-a-Time (LH-OAT) method was conducted to distinguish the contributions of various driving forces to inland river water restoration. Results show that sewage interception was more important than diverted water flow and diverting time with respect to water quality improvement, especially for COD.


Assuntos
Modelos Teóricos , Rios , Esgotos , Poluição da Água , Qualidade da Água , Análise da Demanda Biológica de Oxigênio , China , Monitoramento Ambiental/métodos , Fósforo/análise , Esgotos/análise , Poluentes Químicos da Água/análise , Poluição da Água/análise
11.
Environ Sci Technol ; 51(3): 1157-1167, 2017 02 07.
Artigo em Inglês | MEDLINE | ID: mdl-28009500

RESUMO

The quality of dissolved organic matter (DOM) in a wet weather overflow (WWF) can be broadly influenced by anthropogenic factors, such as nonpoint sources of paved runoff and point sources of sanitary sewage within the drainage networks. This study focused on the anthropogenic influences of the paved runoff and sanitary sewage on the DOM quality of WWF using excitation-emission matrix parallel factor analysis (EEM-PARAFAC). Results show that (1) EEM-PARAFAC fitted terrestrial humic-like, anthropogenic humic-like, tryptophan-like, and tyrosine-like components can be regarded as indicators to identify the types of sewage overflows and the illicit connection status of drainage systems. (2) A short emission wavelength (em: 302-313 nm) peak of the tyrosine-like component occurred in the reserved sanitary sewage, while a type of longer emission wavelength (em: 321-325 nm) peak came from the sump deposit. These tyrosine-like components were gradually evacuated in the initial phase of the overflow process with the fading of their EEM signals. Fluorescence signal transformations of all the components confirmed the potential ability of EEM-PARAFAC to monitor the dynamic changes of the primary pollutant sources. (3) The input of the newly increased sanitary sewage had a dominant influence on the quality and yield of the WWF DOM.


Assuntos
Análise Fatorial , Esgotos , Substâncias Húmicas , Espectrometria de Fluorescência , Tempo (Meteorologia)
12.
Environ Sci Pollut Res Int ; 22(21): 16434-40, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26341334

RESUMO

In 2001, a construction campaign regarding wastewater treatment plants (WWTPs) occurred in China. Unfortunately, the treatment has not yet achieved anticipated effectiveness. A critical reason for this is that the influent chemical oxygen demand (COD) and biochemical oxygen demand (BOD) concentrations in WWTPs are unacceptably low. This paper indicates that a fundamental, but commonly overlooked contributing factor to this problem is that a large portion of easily degradable COD and BOD is degraded prematurely before entering municipal sewers, and this is directly correlated to China's standards for pollutant discharging into municipal sewers. This perspective is further unfolded through retrospection of the history of Chinese wastewater treatment and the investigation of standards among developed zones and districts. This paper suggests that in China, the standards for pollutant discharging into municipal sewers should be relaxed. Meanwhile, unnecessary pretreatment of COD and BOD should cease for the purpose of ensuring that easily degradable COD and BOD can be transferred to WWTPs to improve treatment efficiency. Moreover, additional alternatives are presented to resolve this problem.


Assuntos
Análise da Demanda Biológica de Oxigênio/normas , Cidades , Esgotos/química , Eliminação de Resíduos Líquidos/normas , China , Poluentes Químicos da Água/química
13.
Chemosphere ; 134: 127-32, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25929873

RESUMO

Even zeolite is promising in ammonia pollution disposing, its removal efficiency is frequently interfered by organics. As activated carbon has good removal efficiency on organic contaminants, combination of two adsorbents may allow their respective adsorption characteristics into full play. This paper provides a performance assessment of the combination for enhancing ammonium removal in micro-polluted raw water. Gel-filtration chromatography (GFC) was carried out to quantify the molecular weight (MW) range of organic contaminants that powdered activated carbon (PAC) and powdered zeolite (PZ) can remove. The polydispersity difference which also calculated from GFC may indicate the wider organic contaminants removal range of PAC and the relatively centralized removal range of PZ. The jar tests of combination dosing confirm a synergistic effect which promotes ammonium removing. Nevertheless, it also shows an antagonism hindering the due removal performance of the two adsorbents on CODMn, while it is not much evident on UV254. Furthermore, a comparison study with simulated coagulation-sedimentation process was conducted to evaluate the optimum dosing points (spatial and temporal) of PAC and PZ among follows: suction well, pipeline mixer, early and middle phase of flocculation. We suggest to dose both two adsorbents into the early phase of flocculation to maximize the versatile removal efficiency on turbidity, ammonium and organic contaminants.


Assuntos
Compostos de Amônio/química , Carvão Vegetal/química , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/química , Zeolitas/química , Adsorção , Amônia/análise , Compostos de Amônio/análise , Floculação , Pós , Poluentes Químicos da Água/análise , Poluição da Água/análise , Purificação da Água/métodos
15.
Mar Pollut Bull ; 64(10): 2117-28, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22850189

RESUMO

This paper focuses on the integration of technologies including Case-Based Reasoning (CBR), Genetic Algorithm (GA) and Artificial Neural Network (ANN) for establishing emergency preparedness for oil spill accidents. In CBR, the Frame method is used to define case representation, and the HEOM (Heterogeneous Euclidean-Overlap Metric) is improved to define the similarity of case properties. In GA, we introduce an Improved Genetic Algorithm (IGA) that achieves case adaptation, in which technologies include the Multi-Parameter Cascade Code method, the Small Section method for generation of an initial population, the Multi-Factor Integrated Fitness Function, and Niche technology for genetic operations including selection, crossover, and mutation. In ANN, a modified back-propagation algorithm is employed to train the algorithm to quickly improve system preparedness. Through the analysis of 32 fabricated oil spill cases, an oil spill emergency preparedness system based on the integration of CBR, GA and ANN is introduced. In particular, the development of ANN is presented and analyzed. The paper also discusses the efficacy of our integration approach.


Assuntos
Algoritmos , Defesa Civil/métodos , Redes Neurais de Computação , Poluição por Petróleo/análise , Recuperação e Remediação Ambiental , Poluição por Petróleo/prevenção & controle , Poluição por Petróleo/estatística & dados numéricos
16.
J Environ Manage ; 92(9): 2211-21, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21546149

RESUMO

The Suzhou Creek Rehabilitation Project (SCRP) is one of the largest water-related environmental rehabilitation schemes ever undertaken in the vicinity of Shanghai, China. This paper details the development and application of a River Environmental Decision Support System (REDSS) for scientific planning and decision-making on the Suzhou Creek project, and illustrates the flexibility of the REDSS framework. We developed the following components: (1) a GIS-based analysis employing Component technology; (2) a "data mart" for multi-dimensional, multi-level, integrated, dynamic, and flexible data querying; and (3) a set of hydrodynamic and water quality models which can simulate complex tidal river networks. In addition, we detail how a water quality assessment model is embedded into the REDSS by employing an Identification Index Method. With the REDSS, all GIS and non-GIS components are integrated seamlessly and data from different sources can be queried simultaneously. This allows for various scenarios to be simulated and analyzed in advance to predict and assess the effects of proposed engineering and management measures. Generated information can thus support effective decisions. All operations of the REDSS can be implemented conveniently through user-friendly interfaces. The function of the REDSS framework is demonstrated through an application to Suzhou Creek. Because the REDSS characteristics are quite general, it may be applied in different geographic regions.


Assuntos
Conservação dos Recursos Naturais/métodos , Tomada de Decisões Assistida por Computador , Técnicas de Apoio para a Decisão , Recuperação e Remediação Ambiental/métodos , Rios , Água/normas , China , Sistemas de Informação Geográfica , Modelos Teóricos , Técnicas de Planejamento
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