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A Potential sanitary sewer overflow Treatment Technology: Fixed-Media Bioreactors

WATER ENVIRONMENT RESEARCH 2011年第8期83卷 714-721页

作者： Tao, Jing Mancl, Karen M. Tuovinen, Olli H. Ohio State Univ Environm Sci Grad Program Columbus OH 43210 USA Ohio State Univ Dept Food Agr & Biol Engn Columbus OH 43210 USA Ohio State Univ Dept Microbiol Columbus OH 43210 USA

Under certain conditions, sanitary sewer overflows (SSOs) containing raw wastewater may be discharged to public land and can contribute to environmental and public health issues. Although this problem has attracted the attention of local, state, and federal government and regulators, relatively little SSO abatement research has been published. This study used fixed-media bioreactors, a proven onsite technology in rural areas, to treat wet weather SSO wastewater and reduce its effects on the receiving water environment. The results of this 32-month laboratory study showed that fixed-media bioreactors, especially sand bioreactors, efficiently removed organic matter, solids, and nutrients during six-hour simulated SSO peak flows. Five-day biochemical oxygen demand (BOD5) of the simulated SSO varied between 40 and 125 mg/L. The average effluent concentration of BOD5 was 13 mg/L in sand bioreactors at a hydraulic loading rate of 20.4 cm/h. In addition to having high hydraulic loadings, SSO events occur infrequently. This irregularity requires that treatment systems quickly start up and effectively treat wastewater after a period of no flow. This research found that an interval up to six months between two SSO peak flows did not affect the bioreactor performance. Based on this work, fixed-media bioreactors have the potential to reduce the effects of SSOs on the water environment by following proper design parameters and operation strategies. The pollution loading of approximately 18 g BOD5/m(2).h is recommended for the efficient performance of sand bioreactors in the SSO treatment. Water Environ. Res., 83, 714 (2011).

关键词： sanitary sewer overflow fixed media bioreactor high hydraulic loading wastewater treatment

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Attenuation of pollutants in sanitary sewer overflow: Comparative evaluation of treatment with fixed media bioreactors

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BIORESOURCE TECHNOLOGY 2010年第6期101卷 1781-1786页

Five types of fixed media bioreactors (biofilters) - sand, felt (textile), peat, felt/sand, and peat/sand - were used to treat sanitary sewer overflow (SSO). A simulated 6-h peak flow of a 25-yr SSO event contained 40-125 mg/l biochemical oxygen demand (BOD5) and was loaded on the bioreactors at a high hydraulic loading rate of 0.2 m/h. The sand bioreactors were the most effective in the treatment, reducing BOD5 by 84 +/- 9%. The combination media peat/sand and felt/sand showed similar efficiency with peat, higher than felt. After the initial start-up, all the bioreactors;reached >90% reduction of total suspended solids. The bioreactors also effectively removed ammonia and total phosphorus concentrations in a 2-h SSO loading, which would occur more often than a 6-h peak flow in a 25-yr SSO event. The effluent concentration of nutrients increased with continued loadings after the first 2 h. (C) 2009 Elsevier Ltd. All rights reserved.

关键词： Fixed media bioreactor sanitary sewer overflow Biochemical oxygen demand Total suspended solids Nutrient removal

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TREATMENT OF sanitary sewer overflow WITH FIXED MEDIA BIOREACTORS

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APPLIED ENGINEERING IN AGRICULTURE 2009年第1期25卷 39-43页

作者： Tao, J. Mancl, K. M. Tuovinen, O. H. Ohio State Univ Dept Food Agr & Biol Engn Columbus OH 43210 USA Ohio State Univ Environm Sci Grad Program Columbus OH 43210 USA Ohio State Univ Dept Microbiol Columbus OH 43210 USA

Fixed media bioreactors (biofilters) are a promising and proven technology used for wastewater treatment in unsewered rural areas. As an on-site treatment system, it cart potentially provide high treatment efficiency with a relatively low cost and maintenance. This research expanded the application of fixed media bioreactors and tested their feasibility in the treatment of sanitary sewer overflows (SSO) at high hydraulic loading of 0.2 m/h. Sand, peat, and textile (felt) were used as media to treat simulated 6-h peak flows for a 25-year SSO event in the city of Columbus, Ohio. The influent SSO was a mixture of primary sludge from a wastewater treatment plant diluted with tap water. The efficiency of treatment was measured as changes in the concentrations of biochemical oxygen demand (BOD5), chemical oxygen demand (COD), and total suspended solids (TSS). Sand as a filter medium had the best removal of organic matter with average 84% reduction of BOD5 and 90% of COD. The TSS removal was more than 90% in all media. Peat and felt were,somewhat more efficient than the sand in the TSS removal. The media type and influent BOD5 concentration were two major factors that impacted the treatment of BOD5 (p<0.007). For the treatment of COD, significant factors were media type, influent concentration, and time course of loading in each SSO event (ps <= 0.001).

关键词： Fixed media bioreactor Sand Peat Textile sanitary sewer overflow BOD5 COD TSS

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Treatment of sanitary sewer overflow using fixed media bioreactors

Treatment of sanitary sewer overflow using fixed media biore...

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作者： Tao, Jing The Ohio State University

学位级别：Ph.D.

Fixed media bioreactor (biofilter) is a proven technology used for wastewater treatment in unsewered rural areas. As an on-site treatment system, it provides high treatment efficiency with relatively low cost and maintenance. sanitary sewer overflow (SSO) has characteristics of high flow rate, low and varying pollutant concentrations, and low frequency of events. Abatement of pollution from SSO is one of the most challenging areas in the environmental engineering field. No previous research has been published on SSO treatment with fixed media bioreactors. This study expands the application of fixed media bioreactor technology by testing its feasibility in the treatment of SSO wastewater at high hydraulic loading rates. Five types of fixed media bioreactors—sand, textile peat, textile/sand, and peat/sand—were set up in the laboratory and used to treat SSO once a month. Wastewater from a simulated 25-year peak flow was loaded to the surface of bioreactors at a high hydraulic loading rate of 0.2 m/hr for 6 hr. One influent sample and three effluent samples were collected for each bioreactor at each 6-hr loading. Biochemical oxygen demand (BOD 5 ), total suspended solids (TSS), ammonia nitrogen (NH 4 -N) and total phosphorus (TP) were measured as waster quality characteristics. The actual influent concentrations were 40–125 mg BOD 5 /L and 91–200 mg TSS/L. Sand bioreactors showed the best system performance for treating SSO with effluent concentration of 14 mg BOD 5 /L, which met 7-day effluent limit for stream discharge from conventional treatment technologies in Ohio's antidegradation rule (3745-1-05). All bioreactors removed >85% TSS in the SSO wastewater and three achieved >90% reduction. The effluent concentrations of TSS in all bioreactors were lower than 18 mg/L, the discharge standard of the Ohio antidegradation rule. These data suggested excellent performance of fixed media bioreactors in filtering solids at high hydraulic loading rates. The bioreactors h

关键词： Environmental Engineering Environmental Science Technology sanitary sewer overflow fixed media bioreactor biochemical oxygen demand total suspended solids ammonia nitrogen total phosphorus statistical model

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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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Impacts of Storm Characteristics on Generating sanitary sewer overflow (SSO) Events for an Urban sewershed

Papers in Applied Geography

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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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Multiobjective Genetic Optimization Approach to Identify Pipe Segment Replacements and Inline Storages to Reduce sanitary sewer overflows

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WATER RESOURCES MANAGEMENT 2016年第11期30卷 3707-3722页

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

sanitary sewer overflows (SSOs) is the unintentional discharge of untreated sewage from the sanitary sewer system and pose serious risk to public health and to the environment. Rehabilitation plans to reduce SSOs involve increasing conveyance capacity and shaving peak flow using detention storages. Identifying the best location for rehabilitating the sanitary sewer network is a difficult task because of the great length of sanitary sewer systems. This study utilized single and multiobjective genetic algorithms (GAs) to design rehabilitation strategies for SSOs reduction in an existing sewer network. The Nondominated Sorting Genetic Algorithm II was linked to the EPA-SWMM to generate non-dominated sets of solutions that characterizes the tradeoffs between reduction in number of SSOs and cost (Case I), and the tradeoff between of volume of SSOs and cost (Case II). The results show that, when maximizing the reduction of number SSOs, the algorithm target first regions of the network with higher density of SSOs. When maximizing the reduction of volume of SSOs, the solutions prioritize the nodes with the largest overflow volumes. The tested approach provides a range of options to decision makers that seek to reduce or eliminate SSOs in an existing sanitary sewer system.

关键词： sanitary sewer rehabilitation Multiobjective optimization sanitary sewer overflow Genetic algorithm

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Arrival Analysis of Dry Weather sanitary sewer overflows

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Open Journal of Civil Engineering 2016年第3期6卷 462-468页

作者： Kenneth Tuffour Chris Samba Facility Solution Technology Inc. BaKau Gambia

This study investigates arrivals of sanitary sewer overflows collected from a municipality. The data set consists of recorded overflows from 2011 to 2014 during dry weather. Reliability analysis is conducted upon each data set. The Weibull distribution is adopted to evaluate the data sets. The results show that the arrival of dry weather SSOs cannot be simply modeled with a Poisson process that is featured with a constant arrival rate. For annual data set, 2-parameter Weibull generally has an acceptable fitting (except 2014 data). The shape parameters are close to 1 or a little greater than 1, indicating relatively constant arrival rate or slightly increased rate. For the entire data set, the 3-parameter Weibull distribution is able to fit the data well. The shape parameter is also greater than 1. Therefore, an increased SSO arrival rate is noticed for this data set. There are needs to make more efforts in maintaining the sewer system.

关键词： Poisson Process Weibull Distribution sanitary sewer overflow Shapeparameter

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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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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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