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Artificial neural network modeling of water quality of the Yangtze River system:a case study in reaches crossing the city of Chongqing

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Journal of Chongqing University 2009年第1期8卷 1-9页

作者：郭劲松李哲 Faculty of Urban Construction and Environmental Engineering Chongqing University

An effective approach for describing complicated water quality processes is very important for river water quality management. We built two artificial neural network(ANN) models,a feed-forward back-propagation(BP) model and a radial basis function(RBF) model,to simulate the water quality of the Yangtze and Jialing Rivers in reaches crossing the city of Chongqing,P. R. China. Our models used the historical monitoring data of biological oxygen demand,dissolved oxygen,ammonia,oil and volatile phenolic compounds. Comparison with the one-dimensional traditional water quality model suggest that both BP and RBF models are superior; their higher accuracy and better goodness-of-fit indicate that the ANN calculation of water quality agrees better with measurement. It is demonstrated that ANN modeling can be a tool for estimating the water quality of the Yangtze River. Of the two ANN models,the RBF model calculates with a smaller mean error,but a larger root mean square error. More effort to identify out the causes of these differences would help optimize the structures of neural network water-quality models.

关键词： water quality modeling Yangtze River artificial neural network back-propagation model radial basis functionmodel

Operational guidance for aeration and flow augmentation for the Chicago Area waterway System—A case study

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water Science and Engineering 2023年第4期16卷 345-358页

作者： Charles S.Melching Jennifer Wasik Ed Staudacher Thomas Minarik Melching water Solutions LLC GreenfieldWI 53221USA Metropolitan water Reclamation District of Greater Chicago ChicagoIL 60611USA Metropolitan water Reclamation District of Greater Chicago CiceroIL 60804USA

The Chicago Area waterway System(CAWS)is a 133.9 km branching network of navigable waterways controlled by hydraulic structures,in which the majority of the flow is treated wastewater effluent and there are periods of substantial combined sewer *** CAWS comprises a network of effluent dominated *** stringent dissolved oxygen(DO)standards and a reduced flow augmentation allowance have been recently applied to the ***,a carefully calibrated and verified one-dimensional flow and water quality model was applied to the CAWS to determine emission-based real-time control guidelines for the operation of flow augmentation and aeration *** goal of these guidelines was to attain DO standards at least 95%of the ***“optimal”guidelines were tested for representative normal,dry,and wet *** finally proposed guidelines were found in the simulations to attain the 95%target for nearly all locations in the CAWS for the three test *** developed operational guidelines have been applied since 2018 and have shown improved attainment of the DO standards throughout the CAWS while at the same time achieving similar energy use at the aeration stations on the Calumet River system,greatly lowered energy use on the Chicago River system,and greatly lowered discretionary diversion from Lake Michigan,meeting the recently enacted lower amount of allowed annual discretionary *** case study indicates that emission-based real-time control developed from a well calibrated model holds potential to help many receiving water bodies achieve high attainment of water quality standards.

关键词： water quality modeling water quality management Real-time control Stream aeration Flow augmentation Dissolved oxygen

Application of a water quality model for determining instream aeration station location and operational rules:A case study

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water Science and Engineering 2018年第1期11卷 8-16页

作者： Charles S.Melching Melching water Solutions LLC GreenfieldWI 53221USA

Instream aeration has been used as a supplement to secondary treatment or a substitute for tertiary treatment for meeting dissolved oxygen （DO） standards in rivers. Many studies have used water quality models to determine the number, location, and capacity of instream aeration stations （IASs） needed to meet DO standards in combination with other pollution control measures. DO concentrations have been improved in the North Shore Channel and North Branch Chicago River by the Devon Avenue IAS for more than 35 years. A study was initiated to determine whether it was better to rehabilitate or relocate this station and to determine appropriate operational guidance for the IAS at the selected location. A water quality model capable of simulating DO concentrations during unsteady flow was used to evaluate the proper location for an IAS and operational guidance for this IAS. Three test years, a dry year, a wet year, and an extreme year, were considered in the evaluation. The study found that the Devon Avenue IAS should be rehabilitated as this location performed as well as or better than any of 10 alternative locations. According to the new operational guidance for this IAS, the amount of time with blowers operating could be substantially reduced compared to traditional operations while at the same time the attainment of the DO standards could be increased. This study shows that a carefully designed modeling study is key to effective selection, location, and operation of IASs such that attainment of DO standards can be maximized while operation hours of blowers can be minimized.

关键词： Instream aeration Dissolved oxygen water quality modeling water quality management Computer simulation

The Hydrodynamic Behaviour of Euboean Gulf Coastal Areas and the Mixing of the Physico-Chemical Characteristics of Urban Sewage Discharged into Them under the Influence of Climate Change

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Computational water, Energy, and Environmental Engineering 2023年第4期12卷 27-57页

作者： Evangelos Tsirogiannis Panagiotis Angelidis Division of Hydraulics Department of Civil Engineering School of Engineering Democritus University of Thrace Kimmeria Campus Xanthi Greece

The hydrodynamic circulation within the marine environment is a complex phenomenon, characterized by the interplay of strong tidal forces, atmospheric influences, and bathymetric features. The physical and hydrodynamic attributes of this flow play a pivotal role in promoting vertical mixing of seawater masses, thereby facilitating the integration of their physical and chemical parameters, including nutrients and oxygen. Additionally, they are instrumental in governing the dispersion and diffusion of pollutants originating from urban sewage, contributing to the overall water renewal process and environmental quality. This study investigates the potential impact of anticipated increases in average air temperatures on water column stratification in coastal regions susceptible to these dynamic influences. These areas receive treated urban sewage, and the study aims to assess how these temperature changes might influence the dispersion and mixing of pollutant loads present in these coastal waters.

关键词： Hydrodynamic modeling Climate Change Euboean Gulf Greece Stratification Sewage Mixing water quality modeling

An Integrated Approach to Evaluate Benefits and Costs of Wastewater and Solid Waste Management to Improve the Living Environment: The Citarum River in West Java, Indonesia

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Journal of Environmental Protection 2016年第11期7卷 1439-1465页

作者： S. M. Kerstens G. Hutton I. Firmansyah I. Leusbrock G. Zeeman Royal HaskoningDHV Amersfoort The Netherlands UNICEF New York USA Sub-Department of Environmental Technology Wageningen University Wageningen The Netherlands AEE INTEC Gleisdorf Austria

Absence of wastewater and solid waste facilities impacts the quality of life of many people in developing countries. Implementation of these facilities will benefit public health, water quality, livelihoods and property value. Additional benefits may result from the potential recovery of valuable resources from wastewater and solid waste, such as compost, energy, phosphorus, plastics and paper. Improving water quality through implementation of wastewater and solid waste interventions requires, among others, an analysis of i) sources of pollution, ii) mitigating measures and resource recovery potentials and their effect on water quality and health, and iii) benefits and costs of interventions. We present an integrated approach to evaluate costs and benefits of domestic and industrial wastewater and solid waste interventions. To support a policy maker in formulating a cost and environmentally effective approach, we quantified the impact of these interventions on 1) water quality improvement, 2) resource recovery potential, and 3) monetized benefits versus costs. The integration of technical, hydrological, agronomical and socio-economic elements to derive these three tangible outputs in a joint approach is a novelty. The approach is demonstrated using the heavily polluted Indonesian Upper Citarum River in the Bandung region. Domestic interventions, applying simple (anaerobic filter) technologies, were economically most attractive with a benefit cost ratio (BCR) of 3.2, but could not reach target water quality standards. To approach the target water quality, both advanced domestic (nutrient removal systems) and industrial wastewater treatment interventions were required, leading to a BCR of 2. We showed that benefits from selling recovered resources represent here an additional driver for improving water quality and outweigh the additional costs for resource recovery facilities. While included benefits captured some of the major items, these may have been undervalued. B

关键词： Sanitation water quality modeling Economic Cost Benefit Analysis Resource Recovery Asia Indonesia

The Influence and Implications of Climate Change on water quality in a Large water Reservoir in the Southwest, USA

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American Journal of Climate Change 2022年第3期11卷 197-229页

作者： Deena Hannoun Todd Tietjen Keely Brooks Southern Nevada water Authority Henderson NV USA

Maintaining water quality in large reservoirs is crucial to ensure continued delivery of high-quality water to consumers for municipal and agricultural needs. Lake Mead, a large reservoir in the desert southwest, USA, is projected to be affected by both loss of volume and rising air temperatures through the end of the 21st century. In this study, reductions in lake volume, coupled with downscaled climate projections for rising air temperatures through the end of the 21st century, are incorporated into the 3D hydrodynamic and water quality model for Lake Mead. If current management practices continue in the future, simulations indicate water temperatures will increase in all scenarios and could increase by as much 2℃under the most pessimistic scenarios, but nutrient loads would not increase to concerning levels. Releases from the dam to downstream users are projected to be much warmer, and warmer water temperatures and significant dissolved oxygen in the water column are expected to cause challenges for ecosystem and recreation in the future. Surprisingly, during the Winter and Autumn, retention of heat in Lake Mead is more pronounced at higher surface elevations than the lower elevations as expected. The effects of these projections on the lake water quality and consequently, lake management decisions, are discussed.

关键词： Climate Change Lake Management water quality modeling Lake Mead AEM3D