• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 15
  • 9
  • 2
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 36
  • 36
  • 9
  • 8
  • 7
  • 6
  • 6
  • 6
  • 5
  • 5
  • 5
  • 5
  • 5
  • 4
  • 4
  • 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.
11

Reducing pollutants in industrial stormwater runoff: Improved water quality protection using prioritized facility regulation

Griffen, Lindsay M 01 June 2005 (has links)
Stormwater pollutants originating from industrial facilities can lead to degraded water quality, even in residentially dominated regions of the country. The National Pollutant Discharge Elimination System permit program regulates stormwater pollutants generated at industrial sites using Multi-Sector General Permits (Generic permits) for industrial facilities and a permit requirement for Municipal Separate Storm Sewer System (MS4) operators. All industrial facilities within 11 broad categories of industry are responsible for self-identifying the need to comply with the Generic permit, and subsequently, implementing self-selected pollution prevention strategies. MS4 operators are required to identify and inspect high risk industrial and commercial facilities that may be contributing substantial pollutant loads to the MS4, in addition to other requirements. This is partially in recognition that compliance with the Generic permit has been poor. This dual level of regulations is designed to enhance water quality protection, however, the reliance on local inspectors to develop a definition of high risk has led to irregular implementation. This research developed a methodology to identify industrial facilities and then screen out facilities that may not require inspection by the MS4 operator. Phone questionnaires were administered to 250 industrial facilities. Results were validated using fenceline visits and on-site inspections with local inspectors. Overall compliance by participating facilities with the Generic permit was approximately 10%. Neither the Generic permit nor the MS4 permit has been effective because numerous facilities have gone unregulated. Currently, the Generic permit has attempted to regulate too many facilities, many of which may not be affecting water quality. MS4 high risk inspections have not improved compliance with Generic permit either because of the prioritization of facilities. The reliance on local interpretation, which requires MS4 operators to select a definition of high risk based on their desired level of water quality protection and available resources, can potentially exclude many facilities from inspection. Adopting a definition of intensity for regulating industry may both improve compliance with the General permit, ensure water quality protection, and improve resource usage.
12

Reducing Pollutants in Industrial Stormwater Runoff: Improved Water Quality Protection Using Prioritized Facility Regulation

Griffen, Lindsay M. 31 October 2005 (has links)
Stormwater pollutants originating from industrial facilities can lead to degraded water quality, even in residentially dominated regions of the country. The National Pollutant Discharge Elimination System permit program regulates stormwater pollutants generated at industrial sites using Multi-Sector General Permits (Generic permits) for industrial facilities and a permit requirement for Municipal Separate Storm Sewer System (MS4) operators. All industrial facilities within 11 broad categories of industry are responsible for self-identifying the need to comply with the Generic permit, and subsequently, implementing self-selected pollution prevention strategies. MS4 operators are required to identify and inspect “high risk” industrial and commercial facilities that may be contributing substantial pollutant loads to the MS4, in addition to other requirements. This is partially in recognition that compliance with the Generic permit has been poor. This dual level of regulations is designed to enhance water quality protection, however, the reliance on local inspectors to develop a definition of “high risk” has led to irregular implementation. This research developed a methodology to identify industrial facilities and then screen out facilities that may not require inspection by the MS4 operator. Phone questionnaires were administered to 250 industrial facilities. Results were validated using fenceline visits and on-site inspections with local inspectors. Overall compliance by participating facilities with the Generic permit was approximately 10%. Neither the Generic permit nor the MS4 permit has been effective because numerous facilities have gone unregulated. Currently, the Generic permit has attempted to regulate too many facilities, many of which may not be affecting water quality. MS4 “high risk” inspections have not improved compliance with Generic permit either because of the prioritization of facilities. The reliance on local interpretation, which requires MS4 operators to select a definition of “high risk” based on their desired level of water quality protection and available resources, can potentially exclude many facilities from inspection. Adopting a definition of intensity for regulating industry may both improve compliance with the General permit, ensure water quality protection, and improve resource usage.
13

Eliminace zápachu na stokové síti / Eliminating odors in the sewer network

Novotný, Jiří January 2018 (has links)
The diploma thesis focusses on the elimination of odor in the sewer system. Firstly, the paper contains the research in problematics of the origin, control and risks of the hydrogen sulfide for humans as well as for the sewer system. Secondly, the paper describes methods for hydrogen sulfide removal from water, air and in addition to that the selected sorbents are described in detail. Practical part deals with sorbent testing for hydrogen sulfide removal in laboratory environment. The practical part also follows up the odor in the particular area through sorption on sewer filters. From the measured data and from the results of the laboratory analyzes the consequences of the odor are evaluated and recommendations for the operator are presented.
14

Renovace stokové sítě CIPP metodami / Renovation of sewer network with CIPP methods

Holeš, Petr January 2014 (has links)
Diploma thesis makes a summary of today’s state of CIPP methods designed for sewer relining. Thesis presents classification of CIPP methods between other NO-DIG technologies. Then CIPP methods are divided into groups according to the material used for the liner, applied resin, installation method and curing method. Designing of the CIPP liner used for sewer renovation is also part of this diploma thesis. The result of the theoretical part of this work is a table, which states suitability of particular methods for use in a sewer of specific technical properties. Practical part of bachelor’s thesis is dealing with the analysis of defects of an existing sewer in the city Přerov. Analysis was done due to the camera examination provided by the company Wombat s.r.o. Later the table developed in theoretical part was applied, and then the suitability of use of all parameters of CIPP liners was commented. At the end the plan of works is designed, with the plan for pumping of water included.
15

Hydraulické posouzení stokové sítě obce Lipůvka / Hydraulic calculation of sewage system in Lipůvka

Balas, Jan January 2017 (has links)
Diploma thesis is focused on hydraulic assessment of Lipůvka´s sewer system, done by dynamic rainfall-runoff simulation model. Because of this fact, chapter about mathematical models is included. Commonly used programs to this actions are listed as well. Next part of the thesis describes monitoring campaign, which was done in Lipůvka and results are used to calibrate the simulation model. Hydraulic assessment of sewer system by this calibrated model was done.
16

Characterization of domestic wastewater discharge and its impact on material flows in urban Hue, Vietnam / ベトナム国フエ都市部における生活排水の排出特性及び物質フローへの影響

Tran, Nguyen Quynh Anh 23 September 2016 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(地球環境学) / 甲第20039号 / 地環博第155号 / 新制||地環||31(附属図書館) / 33135 / 京都大学大学院地球環境学舎環境マネジメント専攻 / (主査)教授 藤井 滋穂, 准教授 田中 周平, 准教授 大下 和徹 / 学位規則第4条第1項該当 / Doctor of Global Environmental Studies / Kyoto University / DFAM
17

Natural Air Circulation Model Development for The DigIndy Tunnel

Luis Carlos Maldonado jaime (11191881) 28 July 2021 (has links)
The DigIndy tunnel is an extension of the Indianapolis combined sewer system that stores the combined sewer overflow during heavy rain conditions. The tunnel system has several openings in and around the city of Indianapolis. Gasses emitted from the tunnel may create health concerns and affect the quality of life for nearby residents. Understanding the air circulation patterns provides valuable insight into where gases are likely to emerge from the tunnel and what steps may be taken to mitigate gas emissions in undesirable locations. The objective of the present work is to develop a computational fluid dynamics (CFD) model capable of predicting the air circulation patterns in the DigIndy tunnel under dry weather conditions. In order to inform and validate the CFD model, an experimental campaign was designed and executed to measure weather data and air flow rates within the DigIndy tunnel. Obtaining accurate results requires careful consideration of key physical phenomena to include in the model, geometric simplification strategies, mesh generation strategies, and numerical modeling strategies. Results showed that the seasonal effect, manifest by thermally-driven flow, plays a significant role in the air circulation patterns within the tunnel. Furthermore, results show that tunnel alignment affects the natural air circulation within the tunnel. Large diameter shafts, as the working and retrieval shafts, lead to significant circulation rates in the new tunnel alignments.
18

The application of A/O-MBR system for domestic wastewater treatment in Hanoi: Research Article

Tran, Thi Viet Nga, Tran, Hoai Son 06 August 2012 (has links)
The study aims to investigate an appropriate wastewater treatment process to treat domestic wastewater in Hanoi City which contain low-strength for COD (120-200 mg/L) but high in nitrogen content (10-40 mg/L). A lab scale anoxic-oxic system with a hollow fiber-Membrane Separation Bioreactor was operated at a flow rate of 5-10 L/h over a period of 150 days. The reactor was operated at different sludge recirculation rates. The MBR maintained relatively constant transmembrane pressure. During 150 days of reactor operation, treated water quality have COD of around 20 mg/L, NH4-N of less than 1 mg/L, NO3-N of less than 5 mg/L. The system shows good and stable efficiency for organic matter and nitrogen removal without adding an external carbon source and coagulants. The results based on the study indicated that the proposed process configuration has potential to treat the low-strength wastewater in Hanoi. / Mục tiêu của nghiên cứu là đề xuất được một công nghệ hiệu quả và phù hợp để xử lý nước thải sinh họat ở các đô thị của Việt nam, là loại nước thải được thu gom từ hệ thống thoát nước chung có nồng độ chất hữu cơ thấp (COD 120-200 mg/l) nhưng hàm lượng chất dinh dưỡng như Nitơ, Phốt pho khá cao (T-N: 10-40 mg/L). Chúng tôi đã nghiên cứu và vận hành chạy thử mô hình xử lý sinh học yếm khí - kỵ khí (AO) kết hợp với màng vi lọc ở quy mô mô hình phòng thí nghiệm (công suất 5-10 L/h) ở các chế độ công suất bùn tuần hoàn khác nhau. Kết quả xử lý trong thời gian 5 tháng vận hành mô hình cho thấy chất lượng nước thải sau xử lý có hàm lượng COD nhỏ hơn 20 mg/L, NH4-N nhỏ hơn 1 mg/L, NO3-N nhỏ hơn 5 mg/L. Hiệu suất xử lý chất hữu cơ và chất dinh dưỡng rất ổn định và hệ thống không phải sử dụng các nguồn bổ sung chất hữu cơ hay các hóa chất trợ lắng như các công nghệ đang áp dụng. Kết quả cho thấy công nghệ AO kết hợp màng vi lọc có khả năng áp dụng thực tế, phù hợp với những nơi có quỹ đất nhỏ, chất lượng nước sau xử lý rất cao có thể phục vụ cho mục đích tái sử dụng.
19

Trycksatt avloppssystem och självfallssystem i Fredrikstad kommun. En jämförande fallstudie. / Pressure sewer system and gravity system in Fredrikstad municipality. A comparative case study.

Dahllöf, Karin January 2014 (has links)
Krav om förbättrad spillvattenrening och städer som förgrenar sig över större områden är några av anledningarna till att dagens avloppsledningsnät får allt längre ledningssträckor. Att med gravitationens hjälp föra avloppsvatten framåt kräver ett kontinuerligt fall som vid långa avstånd kan innebära mycket schaktning, den ekonomiskt mest belastande delen vid nyinstallation av avloppsledningsnät. Ett fördelaktigt alternativ kan vara trycksatt avloppssystem, som sedan 70-talet har kompletterat de traditionella självfallssystem i kuperade och bergiga områden. På senare tid har trycksatt avloppsystem fått större användningsområde utanför sina etablerade bruksområden med anledning av skärpta krav på rening och kostnadseffektivitet. Självfallssystem är dock det mest använda avloppssystemet i urbana områden. För ett bostadsområde i utkanten av centrum, utanför de båda systemens vedertagna användningsområden, vore det därför intressant att undersöka vilket av avloppssystemen som är bäst lämpat. För VA-branschen generellt vore det också intressant att utreda hur de båda systemen står sig vid en jämförelse. Med anledning av detta var syftet med examensarbetet att jämföra trycksatt avloppssystem med självfallssystem på grundval av ekonomi, miljö och kapacitet. I tillägg undersöktes om några generella slutsatser kunde fastställas utifrån fallstudien. Undersökningen baserades på ett bostadsområde i utkanten av Fredrikstad centrum, som nyligen projekterats med självfall. Ett teoretiskt trycksatt avloppssystem projekterades. Ekonomi värderades utifrån drift- och underhållskostnader samt grund- och reinvesteringskostnader. Kapaciteten jämfördes numeriskt och via dimensioneringsmodeller. Vad gäller den miljömässiga jämförelsen utvärderades systemet med hjälp av rapporter utgivna av Svenskt Vatten och Norsk Vann. Det planerades en utbyggnad för området till dubbla antalet fastigheter vilket visade sig bli avgörande för det ekonomiska resultatet. Den vitala faktorn var de höga investerings- och driftskostnaderna för pumpenheterna vilket gjorde självfallssystemet mer ekonomiskt lämpligt. Även ur ett miljömässigt perspektiv var självfallssystemet marginellt bättre, givet att riskeffekterna inte rankades inbördes. Kapacitetsmässigt dimensioneras självfallssystem för nästan det dubbla flödet jämfört med trycksatt system, vilket ger det trycksatta systemet en kapacitet mer anpassad till behovet. Generellt sett antydde resultatet att trycksatt system var mer gynnsamt vid glesare bebyggelse. / As a result of stricter treatment requirements and city expantion the length of the sewer network is steadily increasing. To drain wastewater by gravity requires a continuous slope which often results in great excavation - a very costly part in the process. An advantageous alternative could be a pressurized sewer system, which has been a useful complement to traditional gravity systems in hilly or rocky areas since the 70’s. Even though pressurized sewer systems lately have tended to be more frequently used outside their common application area due to stricter requirements on treatment and cost-efficiency, gravity systems are still the most common sewer system in urban areas. Concerning this, it would be intresting to investigate which of the two systems that suites a residental area on the outskirts of a city center best, since the area is outside the traditional usage of the two established systems. In addition it would be interesting for the wastewater industry in general to investigate how the two systems compare.  For this reason the aim of this master thesis was to compare pressure sewer systems with gravity systems on the basis of economy, environment and capacity. In addition, it was examined whether any general conclusions could be determined from the case study. The survey was based on a residental area in the outskirts of Fredrikstad city center, recently designed with a gravity system. A theoretical pressure sewer system was designed. Economy was evaluated based on the operating and maintenance costs and basic and reinvestment costs. The capacity was compared numerically and through design templates. As for the environmental comparison, an evaluation was done on the basis of reports from the Swedish Water & Wastewater Association and Norwegian Water BA. An expansion to double the number of real properties was planned for the area of study, which proved to be crucial to the financial results. The gravity system was most appropriate from an economic standpoint and the vital factor was the high investment and operating costs for the pumping units. Even from an environmental point of view, the gravity system was maginally better. Given that the risk effects are not ranked relative to each other. In terms of capacity the gravity system was dimensioned for almost twice the flow compared to the pressure sewer systems, which gave the pressure sewer system a more adusted capacity. The result indicated that the pressure sewer system is favorable in densely built flexible areas.
20

Studie variant odkanalizování obce Kamenný Malíkov / The study alternatives village sewer system Kamenný Malíkov

Rőssová, Markéta January 2019 (has links)
The diploma thesis is focused on the possibilities of drainage of waste water and its subsequent liquidation in the village of Kamenný Malíkov. The aim of this diploma thesis is the elaboration of variant solutions for drainage of Kamenný Malíkov. Furthermore, the proposal for wastewater treatment, the economic comparison of variants and the recommendation of the unsuitable variant. The diploma thesis deals with the proposal of predominantly gravitational way of drainage of waste water in combination with the pressure, due to incline terrain in the village. Each eventuality has wastewater treatment method designed.

Page generated in 0.0565 seconds