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Quantifying and Modeling Surface Inflow and Groundwater Infiltration into Sanitary Sewers in Southern Pinellas County, FLLong, Megan E. 20 June 2017 (has links)
Following large rain events, excess flow in sanitary sewers from inflow and infiltration (I/I) cause sanitary sewer overflows (SSO), resulting in significant problems for Pinellas County and the Tampa Bay area. Stormwater enters the sanitary sewers as inflow from improper or illegal surface connections, and groundwater enters the system as infiltration through cracks in subsurface infrastructure. This pilot study was designed to develop methods to separate and quantify the components of I/I and to build a predictive model using flowmeter and rainfall data.
To identify surface inflow, daily wastewater production and groundwater infiltration patterns were filtered from the flow data, leaving a residual signal of random variation and possible inflow. The groundwater infiltration (as base infiltration, BI) was calculated using the Stevens-Schutzbach method, and daily wastewater flow curves were generated from dry weather flow (DWF) data. Filtered DWF values were used to construct a range of expected residuals, encompassing 95% of the variability inherent in the system. Filtered wet weather flows were compared to this range, and values above the range were considered significant, indicating the presence of surface inflow.
At all 3 flow meters in the pilot study site, no surface inflow was detected, and the I/I was attributed to groundwater infiltration (as BI). Flow data from 2 smaller sub-sewersheds within the greater sewershed allowed analysis of the spatial variability in BI and provided a method to focus in on the most problematic areas. In the sub-sewershed with the shallowest water table and most submerged sanitary sewer infrastructure, an average of 56% of the average daily flow consisted of groundwater, compared to 44% for the entire study site.
Cross-correlation analysis suggests that rain impacts the water table for up to 9 days, with the highest impact 1 to 3 days after rain events, and the water table, in turn, impacts infiltration for up to 6 days. The highest correlation between rainfall and infiltration occurs 3 to 5 days after a rain event, which corroborates observations from Pinellas County that severe flows to the reclamation facility continue for 3 to 5 days after severe storms. These results were used to build a linear regression model to predict base infiltration (per mile of pipeline) during the wet season using the previous 7 days of daily rainfall depths. The model tended to under-predict infiltration response to large storm events with a R2 value of 0.52 and standard error of regression of 5.3.
The results of the study show that inflow can be detected using simple time series analysis instead of traditional smoke and dye testing. In this study site, however, groundwater infiltration is the only significant source of I/I. Additionally, water table and sewer invert elevations serve as useful indicators of potential sites of groundwater infiltration. Infiltration can be modeled as a function of the previous 7 days of rainfall, however simple linear regression cannot fully capture the complexity of the system response.
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Prioritizing Rehabilitation of Sanitary Sewers in Pinellas County, FLHillman, Jesse T. 20 June 2019 (has links)
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 to abate the 17 sub-basins observed in the study with an infiltration rate greater than the marginal threshold put forth by the Environmental Protection Agency (EPA). The study indicated that gravity pipe rehabilitation does not make a significant impact on groundwater infiltration until at least 30% of the gravity pipes in the sub-basin are lined. This is due to the groundwater table submerging a majority of the wastewater infrastructure. Once this threshold is met, lining was observed to abate groundwater infiltration linearly. The results found that $4.4 million will be required to rehabilitate the affected sub-basins to a marginal rate of infiltration and reduce the flow to South Cross Bayou Water Reclamation Facility (SCBWRF) by an average of 0.72 mgd (million gallons per day). On an annual basis, this reduction in flow will result in approximately $650,000 in treatment costs savings.
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Treatment of sanitary sewer overflow using fixed media bioreactorsTao, Jing January 2008 (has links)
No description available.
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Estimativa da infiltração e do afluxo devidos à precipitação na rede de esgoto sanitário em município de pequeno porte.Festi, Aparecido Vanderlei 28 February 2006 (has links)
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Previous issue date: 2006-02-28 / The main purpose of this work was to identify and to estimate the rainfall derived infiltration
and inflow (IADP) into the sewer in a small city and to do an analysis of their influence on
this collection system. This work was composed by field measurements on the sewage
flowrate output and volume arriving to the Sewage Pumping Plant Station, simultaneously to
the collection and measurement of rainfall on the corresponding same urban watershed area of
the Borborema, in São Paulo State.
The existing methodologies were divided in the follow steps: choosing and characterization of
the working field; data collection of the sewage volume and flowrate; collection of the rainfall
data; choosing and characterization of the data collected; employment of existing models and
methodologies useful to the present available data, in order to derive the underground water
infiltration rate and the overflow occurring in the sewage colletion network.
The volumetric and percentile IADP were quantified. The constant unitary rate (TUC) was
also estimated, by several ways. The results allowed obtaining mathematical formulations to
derive the IADP and TUC of the Borborema s sewage network. Such mathematical
formulations are suitable to be applied in urban areas of cities of a similar to that of
Borborema.
It was estimated that the IADP can generate flowrates 2,5 times greater than the sewage flows
in dry weather and infiltration rates in the sewage network similar to those adopted for system
design.
The work allowed to estimate how complex are the infiltration and inflow of stormwater in
the sewer network. The methodologies applied were quite simple and may be easily applied in
other cities. / O objetivo precípuo desta pesquisa foi identificar e estimar a infiltração e o afluxo devidos da
precipitação (IADP) na rede de esgoto sanitário em município de pequeno porte e efetuar uma
análise da sua influência no sistema de esgotamento sanitário. Este trabalho foi realizado
através da medição em campo de vazão e volume de esgoto sanitário a montante da EEE
Estação Elevatória de Esgoto, simultaneamente com a coleta e medição da chuva precipitada
na correspondente área urbanizada da bacia hidrográfica da cidade de Borborema/SP. As
metodologias empregadas foram divididas nas seguintes fases: escolha e caracterização do
local da pesquisa; coleta de dados de vazão e volume dos efluentes de esgotos sanitários e
coleta de dados de precipitação de chuva no local do estudo; seleção e caracterização dos
dados coletados; aplicação das metodologias e modelagens existentes possíveis de aplicar em
função dos dados disponíveis, para a obtenção da taxa de infiltração das águas subterrâneas e
da sobrecarga na rede de esgoto sanitário. Quantificou-se o IADP volumétrica e
percentualmente. Calculou-se também a taxa unitária constante (TUC), sob diferentes
formatos. Os resultados desta pesquisa permitiram a obtenção de equações matemáticas para
avaliação da IADP e da TUC do sistema de esgoto da cidade de Borborema que
possivelmente poderão ser aplicadas em áreas urbanizadas de outras cidades do mesmo porte.
Estimou-se que a IADP pode gerar volumes 2,5 vezes maiores que o volume de esgotos em
tempo seco, bem como taxas de infiltração na rede coletora próximas àquelas adotadas para
cálculo da rede.
O trabalho possibilitou avaliar quão complexos são a infiltração e o afluxo de águas de chuva
na rede de esgoto sanitário. Os métodos empregados, tanto de coleta quanto de modelagem,
foram muito simples e podem ser aplicados em outras cidades com certa facilidade.
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琵琶湖・淀川水系における河川水中の蛍光性溶存態有機物の動態に及ぼす雨天時下水の簡易指標化に関する研究山口, 武志 23 March 2021 (has links)
京都大学 / 新制・課程博士 / 博士(工学) / 甲第23179号 / 工博第4823号 / 新制||工||1754(附属図書館) / 京都大学大学院工学研究科都市環境工学専攻 / (主査)教授 田中 宏明, 教授 清水 芳久, 講師 中田 典秀 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM
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