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Papers in Applied Geography 2020年第4期6卷 460-470页

作者： Day, C. Andrew Seay, Garrett Department of Geography and Geosciences University of Louisville Louisville KY United States

Combined sewers often overflow during intensive storm activity as the capacity of the system is exceeded in response to excess stormwater inflow. Uncontrolled releases of untreated stormwater as sanitary sewer overflows (SSOs) are also possible but are far less documented, mainly due to a lack of available data, despite being a serious issue for many communities across the US. This study conducted a quantitative analysis of several key storm variables with the aim of identifying occurrence thresholds toward triggering overflows for a residential sewershed in the city of Louisville, Kentucky. Using 5-minute rainfall data and the SSO event database from the Louisville Metropolitan sewer District (MSD), results indicated that occurrence thresholds in total storm rainfall depth (35.6mm) and maximum storm intensity (50 mm/hr) were present which could be used to classify storms as overflow versus non-overflow events. Additionally, the majority of overflow events resulted from storms with ratios below 0.5 and could be classified as 1-year storm frequency events across all storm durations. Discriminant analysis further identified these variables as significant in grouping the storms into overflow versus non-overflow events. By analyzing the sensitivity of known SSOs within the metro sewer system to various storm characteristics and resulting stormwater inflow this research could provide stormwater planners and affected residents with better predictive and potential management capabilities for future SSO events. © 2020 Applied Geography Conferences.

关键词： rainfall sanitary sewer overflow sewer thresholds sewershed

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Enhancing the Performance of a Multiobjective Evolutionary Algorithm for sanitary sewer overflow Reduction

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JOURNAL OF WATER RESOURCES PLANNING AND MANAGEMENT 2017年第7期143卷 1-9页

作者： Ogidan, Olufunso S. Giacomoni, Marcio Univ Texas San Antonio Environm Sci & Engn Program Dept Civil & Environm Engn One UTSA Blvd San Antonio TX 78249 USA Univ Texas San Antonio Dept Civil & Environm Engn One UTSA Blvd San Antonio TX 78249 USA

The application of multiobjective evolutionary algorithms (MOEAs) to sanitary sewer overflow (SSO) optimization problems typically requires multiple runs of a simulation model and can be very computationally expensive. There is a need for simulation-optimization models that use fewer functional evaluations of the hydraulic model to identify near optimal solutions. In this study, two conflicting objectives were analyzed: maximizing SSO reduction and minimizing rehabilitation cost. This paper introduces a novel MOEA, the enhanced nondominated sorting evolution strategy (eNSES) that uses a specialized operator to guide the algorithm toward known SSOs locations. This strategy is being tested in an existing network in the eastern San Antonio Water System network. It has been compared with NSGA-II and NSES based on hypervolume and the overall nondominated vector generation ratio (ONVGR). The results show that eNSES improves the convergence rate by approximately 70% over the tested alternative algorithms, performing as well as NSGA-II and outperforming NSES in terms of the hypervolume by nearly 10%. In terms of the ONVGR, eNSES performed similarly to NSES but outperformed NSGA-II by 42%. (C) 2017 American Society of Civil Engineers.

关键词： EVOLUTIONARY algorithms sanitary sewer overflow HYDRAULIC models REHABILITATION

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Real-Time sanitary sewer blockage detection system using IoT

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MEASUREMENT 2024年 226卷

作者： Faris, Nour Zayed, Tarek Aghdam, Ehsan Fares, Ali Alshami, Ahmad Hong Kong Polytech Univ Fac Construct & Environm Dept Bldg & Real Estate Kowloon Hong Kong 999077 Peoples R China FAMU FSU Coll Engn Dept Civil & Environm Engn Tallahassee FL USA

sewer blockages and overflows have significant economic and environmental repercussions on communities. Thus, it is crucial to detect and remove sewer blockages prior to the occurrence of overflows. With the improvement in mobile networks and the development of high -quality and low -power sensors and loggers, wastewater network operators can now adopt monitoring devices enabled by the "Internet of Things" (IoT) technology for real-time monitoring. To this end, this paper studies the current state-of-the-art in sewer blockage management and introduces a novel methodology to monitor sanitary sewer blockages to prevent sanitary sewer overflows (SSO) with the least human interaction. The proposed system incorporates low -power level sensors and 4G telemetry for real-time monitoring of the manhole's sewage level to detect sewer blockages. The blockage detection methodology encompasses a set of decision rules and time series analysis to identify blockage events. The final blockage detection model offers a versatile capability to be implemented on sanitary sewer networks of different types with minimum computational costs.

关键词： Internet of Things IoT Real-time monitoring sewer blockages sanitary sewer overflow Level sensors

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Emission, Transport, and Deposition of visible Plastics in an Estuary and the Baltic Sea-a Monitoring and Modeling Approach

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ENVIRONMENTAL MANAGEMENT 2021年第6期68卷 860-881页

作者： Schernewski, Gerald Radtke, Hagen Robbe, Esther Haseler, Mirco Hauk, Rahel Meyer, Lisa Piehl, Sarah Riedel, Joana Labrenz, Matthias Leibniz Inst Baltic Sea Res Rostock Germany Klaipeda Univ Marine Res Inst Klaipeda Lithuania Wageningen Univ Hydrol & Quantitat Water Management Grp Wageningen Netherlands

Aim was to assess whether a comprehensive approach linking existing knowledge with monitoring and modeling can provide an improved insight into coastal and marine plastics pollution. We focused on large micro- and mesoplastic (1-25 mm) and selected macroplastic items. Emission calculations, samplings in the Warnow river and estuary (water body and bottom sediments) and a flood accumulation zone monitoring served as basis for model simulations on transport and behavior in the entire Baltic Sea. Considered were the most important pathways, sewage overflow and stormwater. The coastline monitoring together with calculations allowed estimating plastics emissions for Rostock city and the Warnow catchment. Average concentrations at the Warnow river mouth were 0.016 particles/m(3) and in the estuary 0.14 particles/m(3) (300 mu m net). The estuary and nearby Baltic Sea beaches were hot-spots for plastic accumulation with 6-31 particles/m(2). With increasing distance from the estuary, the concentrations dropped to 0.3 particles/m(2). This spatial pattern, the plastic pollution gradients and the observed annual accumulation values were consistent with the model results. Indicator items for sewer overflow and stormwater emissions exist, but were only found at low numbers in the environment. The considered visible plastics alone can hardly serve as indicator for microplastic pollution (<1 mm). The use of up-scaled emission data as input for Baltic Sea model simulations provided information on large scale emission, transport and deposition patterns of visible plastics. The results underline the importance of plastic retention in rivers and estuaries.

关键词： Stormwater sanitary sewer overflow Pollution Monitoring Microplastic Cigarette butts

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Evaluating the sensory and health impacts of exposure to sewer overflows on urban population

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JOURNAL OF CLEANER PRODUCTION 2023年第1期413卷

作者： Aghdam, Ehsan Mohandes, Saeed Reza Zayed, Tarek Hong Kong Polytech Univ Fac Construct & Environm FCE Dept Bldg & Real Estate BRE Hung HomKowloon Hong Kong Peoples R China Univ Manchester Sch Engn Dept Engn Management Manchester M13 9PL England

sewer overflow contains several hazardous contaminants causing adverse health effects and annoyance to the public. Despite this importance, few studies has hitherto been undertaken on examining the odor nuisance and risk of diseases due to contact with untreated overflow. However, quantitative investigation of odor emission from the sanitary sewage overflows has not been addressed. As such, this study aims to scrupulously investigate the deleterious impact of such phenomenon on public health in terms of the aforesaid matters. To this end, a multi-stage methodological approach was employed. Firstly, field data was collected from the vicinity of a wastewater treatment plant for three years, and then the concentrations of H2S in the aqueous phase and gaseous phase were estimated based on the environmental parameters. Afterward, the Gaussian aerial dispersion model and Quantitative Microbial Risk Assessment (QMRA) were employed. In parallel, the impact of the exposure to the malodorous H2S emitted from overflow cases was assessed. Furthermore, the results obtained from impact assessment were validated using the developed questionnaire survey. From the results obtained, the following major conclusions are drawn: (1) levels of H2S(g) near the overflow were high enough to be perceived by in-dividuals, (2) concentrations of NH3(g) in the ambient air were estimated lower than the perception threshold, (3) the sulfide concentration in the overflow was the most influential parameter with positive linear correlation with the concentration of H2S(g), (4) the concentration of odor causes high annoyance, according to the questioning from the residents near the overflow events (5) exponential dose-response indicated 89-95% infection risk and (6) the good correlation between the estimated values of annoyance and the real annoyance level perceived by the residents proved accuracy of the methodology for estimation of H2S concentration and annoyance level. The unique findings obtained

关键词： sanitary sewer overflow Odor emission E coli Impact assessment Gaussian dispersion model QMRA

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Spatiotemporal analysis of fluorescent dissolved organic matter to identify the impacts of failing sewer infrastructure in urban streams

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WATER RESEARCH 2023年 229卷

作者： Batista-Andrade, Jahir A. Diaz, Erick Vega, Diego Iglesias Hain, Ethan Rose, Michael R. Blaney, Lee Univ Maryland Baltimore Cty Dept Chem Biochem & Environm Engn 1000 Hilltop Circle Engn 314 Baltimore MD 21250 USA

Failing sewer infrastructure introduces raw wastewater into streams. We used fluorescence excitation-emission matrix (EEM) spectroscopy and parallel factor analysis (PARAFAC) to track hotspots of raw wastewater in low- and medium-order urban streams that do not receive wastewater effluent but are impacted by sanitary sewer overflows, septic systems, and sewer exfiltration. After analyzing 296 surface water samples from 27 sites in two watersheds over a one-year period, we proposed that the (i) area-normalized ratio of soluble microbial product-like to humic acid-like fluorescence (R4/R5 > 0.85) and (ii) ratio of EEM-PARAFAC components with tryptophan-like and fulvic acid-like fluorescence (C4/C3 > 1.45) could distinguish when and where untreated wastewater is introduced to urban streams. The proposed ratios were validated by co-detection of contaminants of emerging concern, such as sucralose, antibiotics, and UV filters, at concentrations as high as 1354, 108, and 212 ng L-1, respectively. Based on the aggregate data, we identified three sites in rural/suburban areas that were impacted by septic systems and ten sites in urban sections affected by sanitary sewer overflows and/or sewer exfiltration. Moreover, the ratiometric C4/C3 and R4/R5 parameters were immune to dilution effects caused by rain events. Impacts on upstream sites were mostly identified in spring and early summer, but urban hotspots occurred in almost every month. These findings confirmed the potential for EEM-PARAFAC-based wastewater indicators as a quick, easy, cost-effective, and scalable technique to screen for failing sewer infrastructure in loworder streams.

关键词： Dissolved organic matter Fluorescence sewer exfiltration sanitary sewer overflow Septic system Excitation-emission matrix

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Persistence of Fecal Indicators and Microbial Source Tracking Markers in Water Flushed from Riverbank Soils

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WATER AIR AND SOIL POLLUTION 2022年第3期233卷 83-83页

作者： Calderon, Jose S. Verbyla, Matthew E. Gil, Mia Pinongcos, Federick Kinoshita, Alicia M. Mladenov, Natalie San Diego State Univ Dept Civil Construct & Environm Engn San Diego CA 92182 USA

sewer overflows and exfiltration can potentially contaminate water bodies with pathogens from wastewater. Microbial source tracking (MST) methods such as the detection of the HF183 gene target of Bacteroides have been proposed to monitor human fecal pollution inputs to surface waters;however, the persistence of HF183 and other MST markers in water flushed from soils after contamination events is not well understood. In this study, the persistence and decay of two culture-based fecal indicators, Escherichia coli and enterococci, and two molecular MST markers, HF183 and pepper mild mottle virus (PMMoV), were evaluated in riverbank soils spiked with untreated sewage, which were left idle for 1, 14, 28, 60, and 121 days under dark conditions and then flushed with synthetic rainwater. All four microbial indicators were still detected in flush water 4 months after the soil was contaminated. PMMoV persisted much longer and had a slower decay rate than the other microbial indicators, and E. coli degraded most rapidly. In consecutive flushing experiments with fresh (1 day) sewage-spiked soils, HF183, E. coli, and enterococci were all detected after 20 consecutive flushes with rainwater, but PMMoV was not detected after the fifth flush. Our findings indicate that water (e.g., stormwater interflow) flushing through riverbank soils that have previously been contaminated by sewer overflows or sewer exfiltration can potentially be a source of microbial pollution to surface waters, even for several months after the contamination occurs. Results from this study also demonstrate the benefits of using multiple human-associated fecal indicators to distinguish pollution from different microbial groups in water bodies.

关键词： Microbial source tracking HF183 PMMoV Non-point source sanitary sewer overflow sewer exfiltration

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Prioritizing Rehabilitation of sanitary sewers in Pinellas County, FL

Prioritizing Rehabilitation of Sanitary Sewers in Pinellas C...

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作者： Hillman, Jesse T. University of South Florida

学位级别：M.S.C.E.

Following large rain events, extraneous freshwater contributions known as inflow and infiltration (I/I) bypass the storm sewer and enter the sanitary sewer system. In areas with a high water table, like Pinellas County and the surrounding Tampa Bay area, a majority of the wastewater infrastructure is submerged year round exacerbating the rate of groundwater infiltration. This excess flow overloads the existing wastewater infrastructure leading to sanitary sewer overflows (SSOs). These SSOs result in serious problems for municipalities and utilities across the country. This study was performed in order to assist Pinellas County Utilities in rehabilitating their southern sewer system. To do this, 59 sub-basins across 8 sewer zones were monitored through Pinellas County’s Phase 1 Flow Monitoring Program accounting for over 150 miles of gravity pipe. For each sub-basin, a flow meter was utilized to measure the flow from May to October, 2017. This data was analyzed to separately quantify the amount of infiltration and inflow in each sub-basin, respectively. Once quantified, a Severity Index (SI) was developed in order to give each sub-basin a score from 1-100 as it relates to the condition of the gravity mains in the sub-basin. The SI was a function of locational features available with the use of a Geographic Information System (GIS), such as the distance to water bodies and the soil hydrologic group (SHG), as well as intrinsic pipe properties including the type of pipe material and the age of pipe. Once validated with additional flow monitoring data, the developed SI framework can serve as an additional tool utilized by Pinellas County Utilities to identify areas in need of sanitary sewer rehabilitation. Being that the model only requires easily attainable information, this approach is less time consuming and is inexpensive as compared to traditional flow monitoring efforts. The study also examined the required monetary investment by Pinellas County Utilities in order

关键词： Infiltration Inflow Infrastructure Rehabilitation sanitary sewer overflow sewer Management

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Quantifying rainfall-derived inflow and infiltration in sanitary sewer systems based on conductivity monitoring

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JOURNAL OF HYDROLOGY 2018年 558卷 174-183页

作者： Zhang, Mingkai Liu, Yanchen Cheng, Xun Zhu, David Z. Shi, Nanchang Yuan, Zhiguo Tsinghua Univ Sch Environm State Key Joint Lab Environm Simulat & Pollut Con Beijing 100084 Peoples R China Univ Alberta Dept Civil & Environm Engn Edmonton AB T6G 2W2 Canada Univ Queensland AWMC St Lucia Qld 4072 Australia

Quantifying rainfall-derived inflow and infiltration (RDII) in a sanitary sewer is difficult when RDII and overflow occur simultaneously. This study proposes a novel conductivity-based method for estimating RDII. The method separately decomposes rainfall-derived inflow (RDI) and rainfall-induced infiltration (RII) on the basis of conductivity data. Fast Fourier transform was adopted to analyze variations in the flow and water quality during dry weather. Nonlinear curve fitting based on the least squares algorithm was used to optimize parameters in the proposed RDII model. The method was successfully applied to real-life case studies, in which inflow and infiltration were successfully estimated for three typical rainfall events with total rainfall volumes of 6.25 mm (light), 28.15 mm (medium), and 178 mm (heavy). Uncertainties of model parameters were estimated using the generalized likelihood uncertainty estimation (GLUE) method and were found to be acceptable. Compared with traditional flow-based methods, the proposed approach exhibits distinct advantages in estimating RDII and overflow, particularly when the two processes happen simultaneously. (C) 2018 Elsevier B.V. All rights reserved.

关键词： Conductivity Inflow Infiltration sanitary sewer overflow sewer system

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Application of a Multiobjective Genetic Algorithm to Reduce Wet Weather sanitary sewer overflows and Surcharge

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JOURNAL OF SUSTAINABLE WATER IN THE BUILT ENVIRONMENT 2017年第3期3卷

作者： Itaquy, Bruno Ogidan, Olufunso Giacomoni, Marcio H. Merrick & Co 401 East Sonterra BlvdSuit 250 San Antonio TX 78258 USA Univ Texas San Antonio Dept Civil & Environm Engn One UTSA Circle San Antonio TX 78249 USA

sanitary sewer overflow (SSO) is the discharge of wastewater from the collection network into the environment. SSOs are significant environmental and public health hazards. The EPA estimates that up to 75,000 SSO events occur in the United States each year. One of the main causes of SSOs is excessive rainfall derived inflow and infiltration into the sanitary sewer network. This study applies a multiobjective genetic algorithm (MOGA) to identify near-optimal solutions to maximize the reduction of the number of SSOs, volume of SSOs, and surcharge, while minimizing costs for sewer rehabilitation. Three approaches are investigated: (1) enhancing the flow capacity of the collection and conveyance system by pipe diameter increase, (2) peak flow reduction using decentralized inline storage tanks, and (3) combining pipe capacity enhancement with inline storages. The approach is tested in a 15.3-square-kilometer sewer network located west of downtown San Antonio, Texas. The results show that the Combination strategy outperforms both the pipe capacity enhancement and the inline storage strategies. Reduction of surcharge lowers the pressure in the entire network and also provides substantial reduction of SSOs volumes. (C) 2017 American Society of Civil Engineers.

关键词： sanitary sewer overflow Multiobjective genetic algorithm sanitary sewer systems Surcharge

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