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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
281

Předčištění dešťové vody před vtokem do zasakovací nádrže / Pre-treatment of rainwater before entering the infiltration tank

Spurný, Martin January 2021 (has links)
The diploma thesis is focused on the topic of pre-treatment of rainwater before entering the infiltration tank. The theoretical part deals with the issue of rainwater, their division and pollution, as well as technical solutions for rainwater management. In the practical part, testing of selected street drains of various construction systems in the laboratory of VHO (municipal water management) was performed and subsequently these drains were evaluated according to various criteria - the amount of captured material, drain cleaning system and filter construction.
282

Experimental Studies on Infiltration/Soil-Water Movement Processes and Green-AMPT Modeling

Sande, Leif Andrew January 2011 (has links)
Experimental studies on infiltration/soil-water movement processes are vital to better understanding movement of soil-water in the vadose zone. The objective of this experimental research was to investigate infiltration/soil-water movement processes utilizing laboratory experiments and computer modeling. Small scale laboratory soil box infiltration experiments were conducted and utilized for the improved parameterization of the Green-Ampt (GA) saturated moisture content parameter to produce an effective moisture content parameter (Be) for utilization in a modified GA model. By incorporating ⊖e values into GA modeling, modeling results showed greatly improved wetting front prediction across different soil conditions. A new soil packing method was proposed for replicating complex microtopographical surfaces with uniform bulk densities in laboratory soil box experiments which proved efficient and effective at accomplishing both objectives. A rainfall simulator and an instantaneous-profile laser scanner were used to simulate rainfall and quantify surface microtopography for experiments. The results clearly show the effect of microtopography on infiltration and soil-water movement characteristics. This offers valuable insight into infiltration/soil-water movement processes as affected by different soil and surface microtopographic conditions. / National Science Foundation (Grant No. EAR-0907588)
283

Effective machine learning techniques for detecting inflow and infiltration water in wastewater channels

Johansson, Jonas, Westlund, Viktor January 2021 (has links)
In this degree thesis, the research team analyses different ways of monitoring water flow in wastewater channels finds an effective way of processing data using machine learning on collected data from a specific area and sets up a system for finding correlations between rain levels, water usages and wastewater flow to detect infiltrations and inflow water in wastewater channels. The study concludes that a sensor network is most suited for monitoring wastewater channels and that machine learning could be used to detect infiltration and inflow water using different types of data.
284

Srovnání výsledků vsakovaní vody z polních experimentů a numerického modelování / Comparement of results from infiltration tests

Blahut, Dominik January 2017 (has links)
The aim of this thesis is to compare the results of water infiltration from field tests, from laboratories and from numerical modeling at two selected locations. The first objective is the search procedure and the description of both sites and its adjacent areas. Further work continues with infiltration field tests using ring infiltrometer, at first theoretically for each method, and then practically with own personal measurements in the field. Further from the collected soil samples the measurements are performed in the laboratory, first in the permeameter, and followed by the grain size distribution test, from which the hydraulic conductivity is derived by using empirical formulas. At last the numerical modeling is used and all the results are compared. In the final phase of thesis the recommendations are given for infiltration at various locations and comparsion of the infiltration methods.
285

Prioritizing Rehabilitation of Sanitary Sewers in Pinellas County, FL

Hillman, 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.
286

Phosphorus Removal from Domestic Wastewater Using Dual Reactive Materials Polonite® and Absol®.

Fatehi Pouladi, Soheil January 2011 (has links)
Private wastewater treatment facilities release tons of phosphorus to the aquatic environment due to the insufficient removal efficiency in conventional soil infiltration systems. Reactive filter materials have demonstrated promising P removal rates. Laboratory-scale column experiments were carried out using Absol® and Polonite® in dual infiltration media and results were compared with Polonite® functioning as the only layer of reactive filter material. Two sets of experiments were arranged with layer lengths of 5 cm and 15 cm which were operated for 50 and 119 days respectively. Columns with an additional layer of Absol® demonstrated very good average removal rates of 85.99 % and 99.13 % in both experiments while the effluent in the former exceeded the maximum allowed P concentration shortly after half of the total time of the experiment. On the other hand, O-P concentration in collected samples from dual filter media with 15 cm layers of Absol® and Polonite® (column B1) was as low as 0.04 mg/l after 119 days of operation exhibiting high potentials for Absol® in local wastewater treatment. Levels of pH in treated samples showed a decreasing trend in all columns which was similarly simultaneous with high removal rates observed in B1.
287

Modeling the Longevity of Infiltration System for Phosphorus Removal.

Yu, Lin January 2011 (has links)
A new modeling method for estimation of the longevity of infiltration system was suggested in this study. The model was one-dimensional, based on results from long-term infiltration sites in Sweden, taking some physical and chemical parameters as controlling factors. It defines the longevity of infiltration systems as the time during which the P solution in effulent is under national criteria (1 mg/L in this study), and it aims at providing the longevity for any given point of the infiltration system. The soil in the model was assumed to be totally homogenous and isotropic and water flow was assumed to be unsaturated flow and constant continuous inflow. The flow rate was calculated from the Swedish criteria for infiltration systems. The dominant process in the model would be the solute transport process; however, retardation controlled by sorption would play a more important role than advection and dispersion in determining the longevity in the model. By using the definition of longevity in this study, the longevity of the three soil columns at 1 m depth (Knivingaryd, Ringamåla and Luvehult) were 1703 days, 1674 days and 2575 days. The exhaustion time of the three soil columns under inflow of 5 mg/L were 2531 days, 2709 days and 3673 days. The calculated sorbed phosphorus quantity for soil from sites Kn, Lu and Ri when they reach estimated longevity were 0.177, 0.288 and 0.168 mg/g, while the maximum sorption of Kn, Lu and Ri were 0.182, 0.293 and 0.176 mg/g separately. From the result of sensitivity study of the model, the sorption capacity and flow velocity were most important to the longevity of the infiltration system. Lower flow velocity and higher P sorption capacity extend the longevity of an infiltration bed. Due to the sorption isotherm selected in this study and the assumption of instant equilibrium, the sorption rate of the soil column was quite linear, although the estimated longevity was much shorter than the real exhaustion time of the soil column. In fact the soil has almost reached its sorption maximum when the system reaches its longevity.
288

Inducerad infiltration och Vyredox - Studie av Tranås nya vattentäkt. / Induced infiltration and Vyredox. A study of Trånas new water supply.

Regazzoni, Marco January 2011 (has links)
Målet med projektet var att beskriva de biogeokemiska processer som påverkar grundvattenkvaliteten i Tranås nya vattentäkt. Grundvattenbildningen på platsen sker framför allt genom inducerad infiltration av vatten från sjön Sommen. I syfte att avskilja järn och mangan pumpas grundvattnet upp, syresätts och injekteras sedan i brunnar för att skapa en oxiderande grundvattenmiljö. Metoden kallas Vyredox. Med en 15 månader lång provtagningsserie och automatiskt registrerade processvärden och driftdata från anläggningen som underlag görs i rapporten bedömningar om trender, säsongsmässiga variationer och samband mellan driftsituation och kvalitet på utgående vatten. Dessutom görs en provtagning på flera platser runt anläggningen för att undersöka rumsliga variationer av grundvattnets sammansättning. Den statistiska metoden principalkomponentanalys har använts i syfte att utreda vattnets ursprung. Arbetet resulterade i en beskrivning av vattenkvalitetens utveckling under vattentäktens första år i drift, och en diskussion om framtida scenarion. En slutsats är att en form av mark/vatten-kemisk jämvikt uppstår i akviferen ungefär 6 månader efter det att den nya anläggningen började köras. En annan slutsats är att manganhalten kommer minska i framtiden. Provtagningen visar att utgående råvatten i högre grad än vad som förutspåtts innehåller vatten med annat ursprung än sjön. Samband mellan driftsituation och vattenkvalitet förtydligas och resultaten pekar mot att det utgående vattnets sammansättning påverkas av de förändrade flödesvägar och avsänkningar kring uttagsbrunnarna som uppstår vid olika driftfall.
289

En mikrobiologisk studie av Tranås nya vattentäkt / A microbiological study of the watersupply in the municipality of Tranås

Eriksson, Louise January 2011 (has links)
No description available.
290

Dagvattenhantering vid högtrafikerade motorvägar-Avrinning från en ytförlagd vägsträcka i Förbifart Stockholm.

Pantzar, Elisa January 2012 (has links)
Avrinning av vägdagvatten omfattar en rad händelseförlopp såsom infiltration i vägens närhet, vattnets möjliga flödesvägar i vägområdet och olika föroreningars transportmekanismer. I denna studie har dessa processer behandlats i syfte att undersöka avrinningsförloppet vid en ytförlagd sektion i det planerade motorvägs-projektet Förbifart Stockholm. Eftersom höga föroreningshalter förväntas att genereras då vägen är i drift måste vägdagvattnet tas om hand och renas innan utsläpp till recipient sker. Huvudprincipen för omhändertagandet av vägdagvattnet är att det ska ledas via öppna gräsklädda diken längs med vägen till dagvattendammar där rening ska ske. Majoriteten av avrinningen från nederbördstillfällena under ett år kommer dock inte att nå dikesbotten och därmed inte dagvattendammarna utan kommer att infiltrera direkt i vägens stödremsa, åtminstone då denna är nylagd. Via stödremsan kommer vattnet att ledas till närmaste recipient genom vägens terrassdränering där sådan finns eller eventuellt röra sig mot undergrunden och grundvattnet. I och med att majoriteten av avrinningen från nederbördstillfällena infiltrerar i stödremsan kommer dammarna inte att utföra sin tänkta reningsfunktion i någon större utsträckning. Endast vid nederbördstillfällen större än c:a 5 mm kan vatten potentiellt nå dikes-botten för vidare transport mot dammarna, vilket inträffar c:a 20 gånger per år. Dock är det troligt att det vatten som når dammarna inte är förorenat i någon större utsträckning. Detta då det mesta av föroreningarna rinner av med den första avrinningen vid nederbörden och i och med faktumet att infiltrationen i vägområdet är som störst i början av infiltrationsförloppet. Därmed finns underlag för att denna typ av dagvattenhanteringssystem med gräsklädda diken och dagvattendammar i dagsläget kan ifrågasättas som den bästa tillgängliga tekniken då det gäller hantering av vägdagvatten från högtrafikerade motorvägar.

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