No description available.

Master of Landscape Architecture / Department of Landscape Architecture/Regional and Community Planning / Timothy Keane / Kansas City’s outdated sewer system is presently incapable of capturing and treating the increased runoff volumes in Turkey Creek Basin during rainstorm events. As a result, 2.66 billion gallons of untreated sewer system overflow is released annually into the Kansas River and nearby properties. In 2002, the Environmental Protection Agency issued a civil action requiring the City of Kansas City, Missouri, to take appropriate and necessary actions needed to prevent or minimize the discharge of untreated sewage. In response, the City of Kansas City adopted a comprehensive Overflow Control Plan intended to reduce sewer system overflow volumes in Turkey Creek Basin by 85% at a cost of approximately $244 million. Initially, the City of Kansas City seriously considered implementing stormwater best management practices (BMPs) in place of sewer system improvements. Stormwater BMPs infiltrate, filter, store, and evaporate stormwater runoff close to its source, preventing stormwater runoff from reaching the sewer system. Subsequently, many BMPs were eliminated from the Overflow Control Plan and replaced with conventional sewer system technologies because of performance concerns. However, the Overflow Control Plan acknowledged that BMPs located on private property would indirectly benefit Kansas City’s stormwater management strategy. Using geographic information system (GIS) analysis, suitability maps were generated for twelve different BMPs to determine suitable locations in Turkey Creek Basin for reducing stormwater runoff. Analysis concluded that the most effective strategy for sustainable stormwater management would be to locate BMPs at higher elevations within the watershed to prevent upland runoff from flooding sewer system pipes at lower elevations. Areas having the highest suitability are located primarily on residential land, implying that Kansas City could benefit most from encouraging its residents to equip their properties with site-appropriate BMPs. This can be achieved through educational initiatives, policy adoption, and homeowner incentives. Therefore, policies and incentives targeting Kansas City’s residents should be implemented to reduce sewer overflow volumes and prevent future costly improvements to Kansas City’s sewer system.

Antibiotic resistance is a major threat to human health. Clinical situations are the main focus for antibiotic resistance research, but understanding the spread of resistance in the environment is also vital. A major contributor to this spread is wastewater from combined sewer overflow (CSO) events. The effect of CSO events on antibiotic resistance in the James River near Richmond, Virginia was studied using genomic and microbiological approaches. The abundance of genes associated with resistance to quinolones (qnrA) and tetracycline (tetW) was strongly correlated with the presence of fecal indicator bacteria (E. coli abundance) as well as total nitrogen and phosphorus loads, which suggests an anthropogenic source of these genes. Abundance of the blaTEM gene, which confers resistance to β-lactam antibiotics, was elevated during CSO events and increased with precipitation and river discharge. Bacteria isolated during a CSO event were resistant to more antibiotics and had higher multi-drug resistance when compared to isolates from a non-event. This study demonstrated that CSO events are contributing to the spread of antibiotic resistance.

This study showed that hydrodynamic particle breakage had potential as a method to help improve the disinfection of wastewater effluents. The physicochemical properties of flocs from four distinct effluents sources (combined sewer overflow, settled combined sewer overflow, primary effluent, and final effluent) were compared before and after hydrodynamic treatment. The use of hydrodynamic force to cause floc breakage was shown to be effective, though variable, across all source types. This variation in floc breakage did not have a significant impact on the UV disinfection achieved, as the UV dose kinetics were similar across samples from the same source type. The results of this study demonstrate how the physicochemical properties of floc are affected when exposed to shear force. These observations further the understanding of floc composition and behaviour when shear forces are applied while also providing evidence to indicate this process improves the performance of UV disinfection technology.

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.

No description available.

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.

No description available.

No description available.

Ett allt vanligare uppdrag inom hydraulisk modellering är att undersöka hur nya bostads- och handelsområden påverkar statusen för äldre befintliga ledningsnät. I nya områden anläggs nästan uteslutande separatsystem och eftersom nya områden oftast uppförs utanför den befintliga bebyggelsen måste spillvattnet från dessa områden transporteras genom det befintliga avloppsnätet, vilket kan vara helt eller delvis kombinerat. I stadsdelen Hjorthagen i Stockholm planeras 5000 nya lägenheter att byggas och spillvattenflödet från dessa skall anslutas uppströms det befintliga kombinerade ledningsnätet i området. Examensarbetet har gått ut på att undersöka hur det kombinerade ledningssystemet påverkas av den tillkommande spillvattenbelastningen. Syftet var att undersöka hur den dimensionerande spillvattenavrinningen påverkar de åtgärder och kostnader som behövs för att få det utökade ledningsnätet att fungera, samt att utreda behovet av ytterligare anpassningar av ledningsnätet inför framtida klimatförändringar. Vid beräkning av bräddvolymer simuleras vanligen spillvattenavrinningen från medeldygnsförbrukning av vatten. I studien har det även ingått att undersöka om detta sätt ger lägre bräddvolymer jämfört med att variera vattenförbrukningen med ett veckomönster. Med modelleringsprogrammet MIKE Urban undersöktes tre fall av dimensionerande spillvattenflöde från det tillkommande området i Hjorthagen. Olika stor säkerhetsmarginal användes vid dimensioneringen. I alla tre fallen fick det tillkommande spillvattenflödet kapaciteten i det kombinerade ledningssystemet att överskridas redan vid torrväder, med bräddning som följd. Undersökningen visade att ju högre säkerhetsmarginal dimensioneringen innebar desto mer omfattande blev de åtgärder som krävdes för att få bräddningen att upphöra. Fallet med störst säkerhetsmarginal krävde ett utjämningsmagasin på 142 m3 och att dimensionen på 670 m ledning ökades från 400 mm till 600 mm med en uppskattad åtgärdskostnad på omkring nio miljoner kronor. De åtgärder som krävdes för att undvika bräddning vid torrväder var i alla tre fallen tillräckliga för att både minska bräddningen vid regnväder och för att klimatanpassa ledningsnätet. I de fall som undersöktes kunde ingen trend ses som visade att simulering av dag- och spillvattenavrinning, utan veckovariationer i vattenförbrukningen, skulle ge för låga bräddvolymer. / An increasingly common assignment in hydraulic modeling is to investigate how sewage from new residential and commercial areas affect the status of existing sewer systems. In new areas the sewer systems are constructed to operate separately from storm drains and since new areas often are founded in the outskirt of existing areas the sanitary sewage from these areas must be transported through the older existing sewer system, which can be completely or partly combined. In the district of Hjorthagen in Stockholm 5,000 new apartments are planned to be built and sewage from these must be connected upstream of existing combined sewer system in the area. The purpose of this master thesis was to investigate how combined sewer system is affected by additional sewage load. The aim was to investigate how the choice of design sewage flow affects the measures and costs necessary to get the extended sewer system to function, and to consider the need for further adjustments to future climate change. When calculating volumes of combined sewer overflow the sewage flow usually is simulated as discharge from average water use. One objective with this thesis was to investigate whether this method gave lower volumes of combined sewer overflow as compared to using a weekly pattern. By using the modeling program MIKE Urban three choices of design sewage flow, from the new area in Hjorthagen, were investigated. The margin of safety when designing the sewage flow was increased in each case. The results showed that the capacity of the combined sewer system was exceeded during dry weather, with overflow as a result. The investigation showed that the higher margin of safety used the more extensive measures was needed. The greatest margin of safety required a storage basin of 142 m3 and that the dimension of 670 m of pipes was increased. To stop the overflow at dry weather the measures required in each case were sufficient to both reduce overflow during wet weather and to adjust the sewer system to future climate. Simulating the rainfall runoff and sewage flow, without weekly variations in water consumption did not underestimate the volumes of combined sewer overflow compared to varying the water use.