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A comprehensive simulation approach for pollutant bio-transformation in the gravity sewer

Frontiers of Environmental Science & Engineering 2019年第4期13卷 179-190页

作者： Nan Zhao Huu Hao Ngo Yuyou Li Xiaochang Wang Lei Yang Pengkang Jin Guangxi Sun School of Environmental and Municipal Engineering Xi'an University of Architecture and TechnologyXi'an 710055China Centre for Technology in Water and Wastewater School of Civil and Environmental EngineeringUniversity of TechnologySydneyNSW 2007Australia Department of Civil and Environmental Engineering Tohoku UniversitySendaiMiyagi 980-8579Japan Research Center for Eco-Environmental Sciences Chinese Academy of SciencesBeijing 100085China

Presently, several activated sludge models (ASMs) have been developed to describe a few biochemical processes. However, the commonly used ASM neither clearly describe the migratory transformation characteristics of fermentation nor depict the relationship between the carbon source and biochemical reactions. In addition, these models also do not describe both ammonification and the integrated metabolic processes in sewage transportation. In view of these limitations, we developed a new and comprehensive model that introduces anaerobic fermentation into the ASM and simulates the process of sulfate reduction, ammonification, hydrolysis, acidogenesis and methanogenesis in a gravity sewer. The model correctly predicts the transformation of organics including proteins, lipids, polysaccharides, etc. The simulation results show that the degradation of organics easily generates acetic acid in the sewer system and the high yield of acetic acid is closely linked to methanogenic metabolism. Moreover, propionic acid is the crucial substrate for sulfate reduction and ammonification tends to be affected by the concentration of amino acids. Our model provides a promising tool for simulating and predicting outcomes in response to variations in wastewater quality in sewers.

关键词： Gravity sewer Modeling Pollutant transformation Biochemical reaction process

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Diagnosis of sewer pipe defects on image recognition of multi-features and support vector machine in a southern Chinese city

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Frontiers of Environmental Science & Engineering 2019年第2期13卷 29-41页

作者： Xiangyang Ye Jian’e Zuo Ruohan Li Yajiao Wang Lili Gan Zhonghan Yu Xiaoqing Hu State Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing 100084China Thunip Corp. Ltd.27F/Section CS&T BuildingTsinghua S&T ParkBeijing 100084China China Water Environment Group.10F Campbell Building89th Jinbao StreetBeijing 101101China

Closed circuit television(CCTV)systems are widely used to inspect sewer pipe *** the diagnosis process,the manual diagnosis of defects is time consuming,labor intensive and error *** assist inspectors in diagnosing sewer pipe defects on CCTV inspection images,this paper presents an image recognition algorithm that applies features extraction and machine learning *** algorithm of image recognition techniques,including Hu invariant moment,texture features,lateral Fourier transform and Daubechies(DBn)wavelet transform,was used to describe the features of defects,and support vector machines were used to classify sewer pipe *** to the inspection results,seven defects were defined;the diagnostic system was applied to a sewer pipe system in a southern city of China,and 28,760 m of sewer pipes were *** results revealed that the classification accuracies of the different defects ranged from 51.6% to 99.3%.The overall accuracy reached 84.1%.The diagnosing accuracy depended on the number of the training samples,and four fitting curves were applied to fit the *** to this paper,the logarithmic fitting curve presents the highest coefficient of determination of 0.882,and more than 200 images need to be used for training samples to guarantee the accuracy higher than 85%.

关键词： sewer pipe defects Defect diagnosing Image recognition Multi-features extraction Support vector machine

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Combination of sensitivity and uncertainty analyses for sediment transport modeling in sewer pipes

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International Journal of Sediment Research 2020年第2期35卷 157-170页

作者： Isa Ebtehaj Hossein Bonakdari Mir Jafar Sadegh Safari Bahram Gharabaghi Amir Hossein Zaji Hossien Riahi Madavar Zohreh Sheikh Khozani Mohammad Sadegh Es-haghi Aydin Shishegaran Ali Danandeh Mehr Department of Civil Engineering Razi University Environmental Research Center Razi University Department of Civil Engineering Yasar University 4. School of EngineeringUniversity of Guelph 5. Department of Water EngineeringVali-e-Asr University of Rafsanjan 6. Smart and Sustainable Township Research CenterFaculty of Engineering&Built EnvironmentUniversiti Kebangsaan Malaysia 7. School of Civil EngineeringK.N.Toosi University of Technology 8. Department of Waterand EnvironmentalIran University of Science and Technology 9. Department of Civil EngineeringAntalya Bilim University

Mitigation of sediment deposition in lined open channels is an essential issue in hydraulic engineering ***,the limiting velocity should be determined to keep the channel bottom clean from sediment ***,sediment transport modeling using various artificial intelligence(AI) techniques has attracted the interest of many *** current integrated study highlights unique insight for modeling of sediment transport in sewer and urban drainage systems.A novel methodology based on the combination of sensitivity and uncertainty analyses with a machine learning technique is proposed as a tool for selection of the best input combination for modeling process at non-deposition conditions of sediment *** one to seven dimensionless parameters,127 models are developed in the current *** order to evaluate the different parameter co mbinations and select the training and te sting data,four strategies are *** the densimetric Froude number(Fr) as the dependent parameter,a model with independent parameters of volumetric sediment concentration(CV) and relative particle size(d/R) gave the best results with a mean absolute relative error(MARE) of 0.1 and a root means square error(RMSE) of *** analysis is applied with a machine learning technique to investigate the credibility of the proposed *** percentage of the observed sample data bracketed by95% predicted uncertainty bound(95 PPU) is computed to assess the uncertainty of the best models.

关键词： Non-deposition Sediment transport Sensitivity analysis sewer Uncertainty analysis Urban drainage

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Multi-Level Approach of the Ecotoxicological Impact of a Combined sewer Overflow on a Peri-Urban Stream

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Journal of Water Resource and Protection 2012年第11期4卷 984-992页

作者： Céline Becouze-Lareure Christine Bazin Philippe Namour Pascal Breil Yves Perrodin INSAVALOR Division POLDEN Villeurbanne France Irstea (Cemagref) Unité de Recherche Hydrologie Hydraulique Lyon France Université de Lyon ENTPE CNRS UMR 5023 Lehna Vaulx-en-Velin France Université de Lyon UCB Lyon 1 Institut des Sciences Analytiques UMR 5280 Villeurbanne France

In periurban zones, urban wet weather discharges have been recognized as the most significant vector of pollution in aquatic environments. The discharge of this water without treatment into the aquatic environment could present an ecotoxicological risk for biocenosis. The aim of the INVASION project is to assess the potential ecotoxicological impact of a combined sewer overflow (CSO) on a peri-urban stream. A comparative study between upstream and downstream areas of the CSO allowed observing significant effects of this overflow on the river. We studied three layers of stream: surface water, benthic layer and hyporheic layer. To characterize the potential ecotoxicological risk of water and sediments, we used a battery of 4 bioassays: Daphnia magna, Vibrio fischeri, Brachionus calyciflorus and Heterocypris incongruens. In parallel, we measured the physico-chemical parameters: ammonium (NH4+), chromium (Cr), copper (Cu) and lead (Pb). An ecological risk is greatest for the hyporheic zone in downstream river, particularly for the solid phase. These results corroborated with the physico-chemical data obtained.

关键词： Combined sewer Overflow Ecotoxicity Pollutants Stormwater Stream Urban Wet-Weather Flow

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On the Importance of Sanitary sewer Overflow on the Total Discharge of Microplastics from Sewage Water

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Journal of Environmental Protection 2019年第9期10卷 1105-1118页

作者： Christian Baresel Mikael Olshammar IVL Swedish Environmental Research Institute Stockholm Sweden

The paper provides an investigation and understanding of the significance of various wastewater flows on microplastics retainment and emission to the environment. WWTPs and sewer overflows as an important pathway of microplastics to the environment are assessed by considering the removal of microplastics in WWTPs with different treatment processes and several sewer overflow types and their contribution to microplastic loads to recipients. On the example of the Baltic Sea basin, presented results indicate a considerable discharge of microplastic from WWTPs despite the relatively good overall removal efficiency. Results show that the discharge of microplastics from sewer overflows can be in the same magnitude as from treated wastewater although the total flow is much lower than that of treated wastewater. sewer overflow events frequently occur and are expected to increase due to climate change and urbanization, unless infrastructure is adapted. At the same time, sewer overflows are often neglected in conventional wastewater handling.

关键词： Microplastics Wastewater Treatment Sanitary sewer Overflow Emissions Baltic Sea Basin

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Comprehensive health condition assessment on partial sewers in a southern Chinese city based on fuzzy mathematic methods

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Frontiers of Environmental Science & Engineering 2014年第1期8卷 144-150页

作者： Lili GAN Jiane ZUO Yajiao WANG Thong Soon LOW Kaijun WANG State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Tsinghua University Beijing 100084 China

A self-developed sewer health assessment system using the fuzzy comprehensive evaluation and analytical hierarchy process was applied to give a comprehensive health condition evaluation on part of the local sewers in a southern Chinese city based on the sewer video data collected by a sewer inspection closed circuit television （CCTV） robot. Aside from the overall condition evaluation, the structure, function, and stability status of the sewer were also analyzed using the method. A comprehensive index H was proposed to give the overall health condition of pipes with different defects, and Ht, Hs, and If were used to quantify the defects affecting the tightness, stability, and function of the pipe, respectively. Results show that 48% of the inspected pipes were in good condition （0〈H〈0.25）, and about 33% of the sewer pipes analyzed were categorized to be at severe or urgent condition levels （H 〉 0.5）, although most of the pipes were installed only within five years. Frequent sedimentation affects the function of the sewer, and deformation and joint damage affect the structure of the sewer.

关键词： sewer health condition assessment analyticalhierarchy process fuzzy comprehensive evaluation fuzzymathematic method

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Multigene genetic programming for sediment transport modeling in sewers for conditions of non-deposition with a bed deposit

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International Journal of Sediment Research 2018年第3期33卷 262-270页

作者： Mir Jafar Sadegh Safari Ali Danandeh Mehr Department of Civil Engineering Urmia University Department of Civil Engineering University of Tabriz Department of Civil Engineering Antalya Bilim University

It is known that construction of large sewers based on consideration of flow with non-deposition without a bed deposit is not economical. sewer design based on consideration of flow with nondeposition with a bed deposit reduces channel bed slope and construction cost in which the presence of a small depth of sediment deposition on the bed increases the sediment transport capacity of the *** paper suggests a new Pareto-optimal model developed by the multigene genetic programming(MGGP) technique to estimate particle Froude number(Frp) in large sewers with conditions of sediment deposition on the bed. To this end, four data sets including wide ranges of sediment size and concentration, deposit thickness, and pipe size are used. On the basis of different statistical performance indices, the efficiency of the proposed Pareto-optimal MGGP model is compared to those of the best MGGP model developed in the current study as well as the conventional regression models available in the literature. The results indicate the higher efficiency of the MGGP-based models for Frp estimation in the case of no additional deposition onto a bed with a sediment deposit. Inasmuch as the Pareto-optimal MGGP model utilizes a lower number of input parameters to yield comparatively higher performance than the conventional regression models, it can be used as a parsimonious model for self-cleansing design of large sewers in practice.

关键词： Bed load Bed deposition Non-deposition Multigene genetic programming Sediment transport sewer

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Solid Transfer in Low Flow sewers, the Distance Travelled So Far Is Not Enough

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Journal of Environmental Protection 2019年第2期10卷 164-207页

作者： Rodney McDermott Alan Strong Philip Griffiths Belfast School of Architecture and the Built Environment Ulster University Belfast Northern Ireland

sewer blockages are on the increase whilst water closet (WC) flush volumes are on the decrease. Furthermore, Water UK reported figures show that the actual number of properties affected by sewer flooding is on the rise. sewer blockages can lead to sewer flooding of homes and collapse of sewers which impact negatively on social, economic and environmental factors, and therefore, they are not sustainable. Water conservation is required due to water stress but reduced water use results in less water to waste, which in turn reduces solids’ transfer in sewers. When considering reducing water usage through water conservation, these savings could be cancelled out by an increased population and the situation exacerbated by the impacts of climate change. There are issues in relation to varying design methods, a reliance on engineering judgement in sewer design, uncertainty relating to future water stress, and a lack of cross disciplinary design decision-making. Public health engineering solutions are needed to reduce the number of sewer blockages and the environmental impact of sewer flooding. This paper examines the fundamental research that have been carried out in the area of “solid transfer in sewers” resulting from “less water to waste” since the mid-20th Century. Contrary to existing literature, this paper identifies that, now more than ever, this type of research is needed to deal with the increased need for water conservation. To judge that solid transfer research is complete can be compared to supporting a statement that “water conservation is complete”.

关键词： sewer Blockages Water Conservation Low Flows in sewers

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Developing a Novel Approach for Sludge Treatment Using Microwaves Technology

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Journal of Geoscience and Environment Protection 2020年第5期8卷 195-203页

作者： David Yu Wendy Li Tsinghua International School Beijing China

The purpose of this research is to find a method that can improve the cost and efficiency of sludge treatment. Currently, large amounts of sludge are produced every day, but sludge treatment is neither efficient nor profitable. To improve the sludge treatment process, we proposed the method of using microwave technology to treat sludge. We hypothesized that using microwave technology, we can reduce the volume of the sludge up to 90%, and can save more energy and time comparing to the traditional methods that we are currently using to treat the sludge. To prove our hypothesis, we designed an experiment to compare the solid-liquid boundary height and the solid-liquid mass ratio of the sludge treated by the conventional method and the microwave technology. Prime temperature and time found for dewatering sludge are 70 Celsius degrees and five minutes. The results were rather surprising, as microwave heating demonstrated no significant advantage over conventional heating. The solid-liquid boundary height of sludge heated by conventional and by microwave methods are 22.34 mL and 22.56 mL;the solid-liquid mass ratio of sludge using conventional heating and microwave heating at 70 Celsius degrees are 14.28% and 14.55% (by separation with filter press), or 9.82% and 9.89% (by centrifugation). In conclusion, the difference is negligible.

关键词： Municipal sewer Sludge Sludge Dewatering Microwave Treatment Intracellular Water Thermal Conditioning Solid Liquid Separation

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Risk and Economic Development in the Provision of Public Infrastructure

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Journal of Environmental Protection 2018年第9期9卷 973-990页

作者： Frederick Bloetscher Florida Atlantic University Boca Raton USA

A public water and sewer utility is created to develop safe, reliable and financially self-supporting potable water and sanitary sewage systems which will meet the water and sewerage needs of the areas served by the utility;to ensure that existing and future utility facilities are constructed, operated and managed at the least possible cost to the users without outside subsidies;and to develop a system that is compatible with the area’s future growth. To gain efficiencies in operation, these new facilities must be developed in accordance with the latest technical and professional standards to protect the health, safety, and welfare of the citizens served now or in the future. Hence a utility must construct new pipelines, pump stations and other infrastructure, whether that infrastructure is for growth, to improve existing service, or to replace infrastructure that has reached the end of its useful, economic, and/or physical life. In established or stable communities, the replacement of existing infrastructure, where it is no longer economical to operate, is deteriorated to a point where replacement is more cost effective than repairs due to wear, neglect or environmental conditions, or where the infrastructure no longer serves its intended purpose or meets regulatory standards, must be pursued. As a result, many established utilities have capital plans that contain many such replacement projects. The question is how much investment should be made. The intent of this paper is to evaluate investment in infrastructure made by public water and sewer utility systems. What was found among the utilities in Florida that were evaluated was that more than half are underinvesting in their infrastructure. Some are not investing at all although more research is needed because it appears that many utilities make large investments periodically as opposed to using pay-as-you-go methods. Large scale investments like bond issues impact rates. Economies-of-scale remain for large utili

关键词： Water sewer Economy-of-Scale Utility Finance

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