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Sample records for rising main sewers

  1. Impact of reduced water consumption on sulfide and methane production in rising main sewers.

    PubMed

    Sun, Jing; Hu, Shihu; Sharma, Keshab Raj; Bustamante, Heriberto; Yuan, Zhiguo

    2015-05-01

    Reduced water consumption (RWC), for water conservation purposes, is expected to change the wastewater composition and flow conditions in sewer networks and affect the in-sewer transformation processes. In this study, the impact of reduced water consumption on sulfide and methane production in rising main sewers was investigated. Two lab-scale rising main sewer systems fed with wastewater of different strength and flow rates were operated to mimic sewers under normal and RWC conditions (water consumption reduced by 40%). Sulfide concentration under the RWC condition increased by 0.7-8.0 mg-S/L, depending on the time of a day. Batch test results showed that the RWC did not change the sulfate-reducing activity of sewer biofilms, the increased sulfide production being mainly due to longer hydraulic retention time (HRT). pH in the RWC system was about 0.2 units lower than that in the normal system, indicating that more sulfide would be in molecular form under the RWC condition, which would result in increased sulfide emission to the atmosphere as confirmed by the model simulation. Model based analysis showed that the cost for chemical dosage for sulfide mitigation would increase significantly per unit volume of sewage, although the total cost would decrease due to a lower sewage flow. The dissolved methane concentration under the RWC condition was over two times higher than that under the normal flow condition and the total methane discharge was about 1.5 times higher, which would potentially result in higher greenhouse gas emissions. Batch tests showed that the methanogenic activity of sewer biofilms increased under the RWC condition, which along with the longer HRT, led to increased methane production.

  2. Impact of nitrate addition on biofilm properties and activities in rising main sewers.

    PubMed

    Mohanakrishnan, J; Gutierrez, O; Sharma, K R; Guisasola, A; Werner, U; Meyer, R L; Keller, J; Yuan, Z

    2009-09-01

    Anaerobic sewer biofilm is a composite of many different microbial populations, including sulfate reducing bacteria (SRB), methanogens and heterotrophic bacteria. Nitrate addition to sewers in an attempt to control hydrogen sulfide concentrations affects the behaviour of these populations, which in turn impacts on wastewater characteristics. Experiments were carried out on a laboratory reactor system simulating a rising main to determine the impact of nitrate addition on the microbial activities of anaerobic sewer biofilm. Nitrate was added to the start of the rising main during sewage pump cycles at a concentration of 30 mg-N L(-1) for over 5 months. While it reduced sulfide levels at the outlet of the system by 66%, nitrate was not toxic or inhibitory to SRB activity and did not affect the dominant SRB populations in the biofilm. Long-term nitrate addition in fact stimulated additional SRB activity in downstream biofilm. Nitrate addition also stimulated the activity of nitrate reducing, sulfide oxidizing bacteria that appeared to be primarily responsible for the prevention of sulfide build up in the wastewater in the presence of nitrate. A short adaptation period of three to four nitrate exposure events (approximately 10 h) was required to stimulate biological sulfide oxidation, beyond which no sulfide accumulation was observed under anoxic conditions. Nitrate addition effectively controlled methane concentrations in the wastewater. The nitrate uptake rate of the biofilm increased with repeated exposure to nitrate, which in turn increased the consumption of biodegradable COD in the wastewater. These results provide a comprehensive understanding of the impact of nitrate addition on wastewater composition and sewer biofilm microbial activities, which will facilitate optimization of nitrate dosing for effective sulfide control in rising main sewers.

  3. Dissolved methane in rising main sewer systems: field measurements and simple model development for estimating greenhouse gas emissions.

    PubMed

    Foley, Jeff; Yuan, Zhiguo; Lant, Paul

    2009-01-01

    At present, the potential generation of methane in wastewater collection systems is ignored under international greenhouse gas (GHG) accounting protocols, despite recent reports of substantial dissolved methane formation in sewers. This suggests that the current national GHG inventories for wastewater handling systems are likely to be underestimated for some situations. This study presents a new catalogue of field data on methane formation in rising main sewerage systems and proposes an empirically-fitted, theoretical model to predict dissolved methane concentrations, based upon the independent variables of pipeline geometry (i.e. surface area to volume ratio, A/V) and hydraulic retention time (HRT). Systems with longer HRT and/or larger A/V ratios are shown to have higher dissolved methane concentrations. This simple predictive model provides a means for water authorities to estimate the methane emissions from other pressurised sewerage systems of similar characteristics.

  4. Constructing and dismantling frameworks of disease etiology: the rise and fall of sewer gas in America, 1870-1910.

    PubMed Central

    An, Perry G.

    2004-01-01

    For roughly forty years, from 1870 to 1910, Americans recognized and feared gases emanating from sewers, believing that they were responsible for causing an array of diseases. Fears of sewer gas arose from deeper anxieties toward contact with decomposing organic matter and the vapors emitted from such refuse. These anxieties were exacerbated by the construction of sewers across the country during the mid-to-late-nineteenth century, which concentrated waste emanations and connected homes to one another. The result was the birth of sewer gas and the attribution of sickness and death to it, as well as the development of a host of plumbing devices and, especially, bathroom fixtures, to combat sewer gas. The rise of the germ theory, laboratory science, and belief in disease specificity, however, transformed the threat of sewer gas, eventually replacing it (and the larger fear of miasmas) with the threat of germs. The germ theory framework, by 1910, proved more suitable than the sewer gas framework in explaining disease causation; it is this suitability that often shapes the relationship between science and society. PMID:15829149

  5. Constructing and dismantling frameworks of disease etiology: the rise and fall of sewer gas in America, 1870-1910.

    PubMed

    An, Perry G

    2004-05-01

    For roughly forty years, from 1870 to 1910, Americans recognized and feared gases emanating from sewers, believing that they were responsible for causing an array of diseases. Fears of sewer gas arose from deeper anxieties toward contact with decomposing organic matter and the vapors emitted from such refuse. These anxieties were exacerbated by the construction of sewers across the country during the mid-to-late-nineteenth century, which concentrated waste emanations and connected homes to one another. The result was the birth of sewer gas and the attribution of sickness and death to it, as well as the development of a host of plumbing devices and, especially, bathroom fixtures, to combat sewer gas. The rise of the germ theory, laboratory science, and belief in disease specificity, however, transformed the threat of sewer gas, eventually replacing it (and the larger fear of miasmas) with the threat of germs. The germ theory framework, by 1910, proved more suitable than the sewer gas framework in explaining disease causation; it is this suitability that often shapes the relationship between science and society.

  6. State of Technology for Renewal of Sewer Force Mains

    EPA Science Inventory

    This paper presents the results of a review of the state of technology for renewal of force mains (EPA, 2010). The review identified several needs, including the need for rational and common design approaches for rehabilitation systems, quality assurance/quality control procedur...

  7. State of Technology for Renewal of Sewer Force Mains

    EPA Science Inventory

    This paper presents the results of a review of the state of technology for renewal of force mains (EPA, 2010). The review identified several needs, including the need for rational and common design approaches for rehabilitation systems, quality assurance/quality control procedur...

  8. Report: American Recovery and Reinvestment Act Site Visit of the Clifton Street Sewer Separation and Water Main Replacement Projects, Portland, Maine

    EPA Pesticide Factsheets

    Report #11-R-0248, June 7, 2011. We conducted an unannounced site visit of the Clifton Street Sewer Separation and Water Main Replacement Projects in the City of Portland, Maine, from June 15 through June 17, 2009.

  9. Sulfide and methane production in sewer sediments.

    PubMed

    Liu, Yiwen; Ni, Bing-Jie; Ganigué, Ramon; Werner, Ursula; Sharma, Keshab R; Yuan, Zhiguo

    2015-03-01

    Recent studies have demonstrated significant sulfide and methane production by sewer biofilms, particularly in rising mains. Sewer sediments in gravity sewers are also biologically active; however, their contribution to biological transformations in sewers is poorly understood at present. In this study, sediments collected from a gravity sewer were cultivated in a laboratory reactor fed with real wastewater for more than one year to obtain intact sediments. Batch test results show significant sulfide production with an average rate of 9.20 ± 0.39 g S/m(2)·d from the sediments, which is significantly higher than the areal rate of sewer biofilms. In contrast, the average methane production rate is 1.56 ± 0.14 g CH4/m(2)·d at 20 °C, which is comparable to the areal rate of sewer biofilms. These results clearly show that the contributions of sewer sediments to sulfide and methane production cannot be ignored when evaluating sewer emissions. Microsensor and pore water measurements of sulfide, sulfate and methane in the sediments, microbial profiling along the depth of the sediments and mathematical modelling reveal that sulfide production takes place near the sediment surface due to the limited penetration of sulfate. In comparison, methane production occurs in a much deeper zone below the surface likely due to the better penetration of soluble organic carbon. Modelling results illustrate the dependency of sulfide and methane productions on the bulk sulfate and soluble organic carbon concentrations can be well described with half-order kinetics.

  10. Gas pockets in a wastewater rising main: a case study.

    PubMed

    Pozos-Estrada, Oscar; Fuentes-Mariles, Oscar A; Pozos-Estrada, Adrian

    2012-01-01

    This paper presents a case study of an existing wastewater rising main (WWRM) in which an extreme transient event produced by simultaneous power failure of the pumps caused the rupture of a 1.2 m (48 in) prestressed concrete cylinder pipe (PCCP), causing an important leakage of sewage. The event and the methodology followed in order to validate the diagnostics of the failure are described. The detail study included in situ observation of the system, experimental investigation in a setup, hydraulic analysis, as well as details of the structural strength of the WWRM. After the extensive investigation and several simulations of fluid transients for different scenarios and flow conditions, it was found that stationary small gas pockets accumulated at high points of the WWRM were identified as the principal contributory factor of the failure. This case study serves as clear warning of the consequences of operating a WWRM with gas pockets at its high points.

  11. Evaluation of in-sewer transformation of selected illicit drugs and pharmaceutical biomarkers.

    PubMed

    Gao, Jianfa; Banks, Andrew; Li, Jiaying; Jiang, Guangming; Lai, Foon Yin; Mueller, Jochen F; Thai, Phong K

    2017-08-04

    Wastewater-based epidemiology (WBE) is considered to be a useful tool for monitoring chemical consumption in the population. However, the lack of information on potential transformation of biomarkers in the sewer system can compromise the accuracy of the consumption estimation. The present study contributes to addressing this issue by investigating the in-sewer stability of biomarkers from a number of commonly used drugs using laboratory sewer reactors that can mimic different sewer conditions. A stable and an unstable chemical (carbamazepine and caffeine) were also used as benchmarking chemicals to reflect the chemical degradation potential in different sewer conditions. The results suggested that ketamine and norketamine were unstable in gravity and rising main sewers, ketamine was unstable in bulk liquid while norketamine was stable under the same condition. Similarly, mephedrone and methylone were unstable in sewer conditions with considerable deviation. Significant loss of buprenorphine, methadone, oxycodone and codeine was observed in the rising main sewer. Morphine and codeine glucuronide were found to be deconjugated from their glucuronides quickly in the presence of biofilms. This study indicates that it is important to evaluate the stability of biomarkers in the sewer system before using them in WBE for estimating consumption/exposure to reduce uncertainties. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Assessment of pH shock as a method for controlling sulfide and methane formation in pressure main sewer systems.

    PubMed

    Gutierrez, Oriol; Sudarjanto, Gatut; Ren, Guo; Ganigué, Ramon; Jiang, Guangming; Yuan, Zhiguo

    2014-01-01

    Caustic dosing to raise pH above 10.0 for short periods (hours) is often used by water utilities for controlling sulfide formation in sewers. However the effectiveness of this strategy is rarely reported and the impact of pH level and exposure time on the effectiveness is largely unknown. The effectiveness of this strategy under various pH levels (10.5-12.5) and exposure time (0.5-6.0 h) in controlling sulfide and methane production was evaluated in laboratory scale anaerobic sewer reactors and then in a real sewer system. Laboratory studies showed that the sulfide production rate of the laboratory sewer biofilm was reduced by 70-90% upon the completion of the pH shock, while the methane production rate decreased by 95-100%. It took approximately one week for the sulfate-reducing activity to recover to normal levels. In comparison, the methanogenic activities recovered to only about 10% in 4 weeks. The slow recovery is explained by the substantially loss of cell viability upon pH shocks, which recovered slowly after the shocks. Laboratory studies further revealed that a pH level of 10.5 for 1-2 h represent cost-effective conditions for the pH shock treatment. However, field trials showed a higher pH (11.5) and larger dosing times are needed due to the pH decreases along the sewer line and at the two ends of the caustic-receiving wastewater slugs due to dilution. To have effective sulfide and methane control, it is important to ensure effective conditions (pH > 10.5 and duration >1-2 h) for the entire sewer line.

  13. Remaining Sites Verification Package for the 100-C-9:1 Main Process Sewer Collection Line, Waste Site Reclassification Form 2004-012

    SciTech Connect

    L. M. Dittmer

    2007-06-11

    The 100-C-9:1 main process sewer pipeline, also known as the twin box culvert, was a dual reinforced process sewer that collected process effluent from the 183-C and 190-C water treatment facilities, discharging at the 132-C-2 Outfall. For remedial action purposes, the 100-C-9:1 waste site was subdivided into northern and southern sections. The 100-C-9:1 subsite has been remediated to achieve the remedial action objectives specified in the Remaining Sites ROD. The results of verification sampling show that residual contaminant concentrations do not preclude any future uses and allow for unrestricted use of shallow zone soils. The results also demonstrate that residual contaminant concentrations are protective of groundwater and the Columbia River.

  14. Global sensitivity analysis of an in-sewer process model for the study of sulfide-induced corrosion of concrete.

    PubMed

    Donckels, B M R; Kroll, S; Van Dorpe, M; Weemaes, M

    2014-01-01

    The presence of high concentrations of hydrogen sulfide in the sewer system can result in corrosion of the concrete sewer pipes. The formation and fate of hydrogen sulfide in the sewer system is governed by a complex system of biological, chemical and physical processes. Therefore, mechanistic models have been developed to describe the underlying processes. In this work, global sensitivity analysis was applied to an in-sewer process model (aqua3S) to determine the most important model input factors with regard to sulfide formation in rising mains and the concrete corrosion rate downstream of a rising main. The results of the sensitivity analysis revealed the most influential model parameters, but also the importance of the characteristics of the organic matter, the alkalinity of the concrete and the movement of the sewer gas phase.

  15. Evidence of a sewer vapor transport pathway at the USEPA ...

    EPA Pesticide Factsheets

    The role of sewer lines as preferential pathways for vapor intrusion is poorly understood. Although the importance of sewer lines for volatile organic compound (VOC) transport has been documented at a small number of sites with vapor intrusion, sewer lines are not routinely sampled during most vapor intrusion investigations. We have used a tracer study and VOC concentration measurements to evaluate the role of the combined sanitary/storm sewer line in VOC transport at the USEPA vapor intrusion research duplex in Indianapolis, Indiana. The results from the tracer study demonstrated gas migration from the sewer main line into the duplex. The migration pathway appears to be complex and may include leakage from the sewer lateral at a location below the building foundation. Vapor samples collected from the sewer line demonstrated the presence of tetrachloroethene (PCE) and chloroform in the sewer main in front of the duplex and at multiple sample locations within the sewer line upstream of the duplex. These test results combined with results from the prior multi-year study of the duplex indicate that the sewer line plays an important role in transport of VOCs from the subsurface source to the immediate vicinity of the duplex building envelope. Highlights • The sewer line is an important pathway for VOC transport at the USEPA duplex. • The importance of this pathway was not identified during prior study of the duplex. • Sewer lines should be routinely evaluated

  16. Online dissolved methane and total dissolved sulfide measurement in sewers.

    PubMed

    Liu, Yiwen; Sharma, Keshab R; Fluggen, Markus; O'Halloran, Kelly; Murthy, Sudhir; Yuan, Zhiguo

    2015-01-01

    Recent studies using short-term manual sampling of sewage followed by off-line laboratory gas chromatography (GC) measurement have shown that a substantial amount of dissolved methane is produced in sewer systems. However, only limited data has been acquired to date due to the low frequency and short span of this method, which cannot capture the dynamic variations of in-sewer dissolved methane concentrations. In this study, a newly developed online measuring device was used to monitor dissolved methane concentrations at the end of a rising main sewer network, over two periods of three weeks each, in summer and early winter, respectively. This device uses an online gas-phase methane sensor to measure methane under equilibrium conditions after being stripped from the sewage. The data are then converted to liquid-phase methane concentrations according to Henry's Law. The detection limit and range are suitable for sewer application and can be adjusted by varying the ratio of liquid-to-gas phase volume settings. The measurement presented good linearity (R² > 0.95) during field application, when compared to off-line measurements. The overall data set showed a wide variation in dissolved methane concentration of 5-15 mg/L in summer and 3.5-12 mg/L in winter, resulting in a significant average daily production of 24.6 and 19.0 kg-CH₄/d, respectively, from the network with a daily average sewage flow of 2840 m³/day. The dissolved methane concentration demonstrated a clear diurnal pattern coinciding with flow and sulfide fluctuation, implying a relationship with the wastewater hydraulic retention time (HRT). The total dissolved sulfide (TDS) concentration in sewers can be determined simultaneously with the same principle.

  17. Laboratory assessment of bioproducts for sulphide and methane control in sewer systems.

    PubMed

    Sudarjanto, Gatut; Gutierrez, Oriol; Ren, Guo; Yuan, Zhiguo

    2013-01-15

    The effectiveness of three bioproducts (also known as biomaterials) for liquid-phase biological treatment (LPBT) of sewer biofilms to control detrimental build-up of sulphide (H(2)S) and methane (CH(4)) in sewers was tested in a laboratory system mimicking a rising/force main sewer pipe. Bioproduct A claims to disrupt cell-to-cell communication of sewer anaerobic biofilms while Bioproducts B and C claim to enhance sulphidotrophic (sulphide-oxidising) capacity of the sewer biofilm, to avoid sulphide accumulation. The results demonstrated that all three bioproducts tested had no or negligible impact on sulphide or methane control, as opposed to traditional sulphide-controlling chemicals widely used by the wastewater industry such as oxygen, nitrate, iron salts and magnesium hydroxide. Those had previously been demonstrated to be effective using the same laboratory system with the same testing protocol. The implications of the findings are discussed. It is concluded that field application/trials of these three bioproducts are not warranted. It is recommended that other bioproducts should be subject to similar rigorous tests prior to being taken up by the water industry for field trials/application.

  18. Combined impacts of tidal energy extraction and sea level rise in the Gulf of Maine

    NASA Astrophysics Data System (ADS)

    Hashemi, M. R.; Kresning, B.

    2016-12-01

    The objective of this study was to assess the combined effects of SLR and tidal energy extraction on the dynamics of tides in the Gulf of Maine in both US and Canadian waters. The dynamics of tides in the Gulf of Maine is dominated by tidal resonance, which generates one of the largest tidal ranges in the world. Further, sea level rise (SLR) is affecting tidal circulations globally, and in the Gulf of Maine. A large tidal energy resource is available in the Gulf of Maine, particularly in the Bay of Fundy, and is expected to be harvested in the future. Currently, more than 6 projects are operational or under development in this region (in both US and Canadian waters). Understanding the far-field impacts of tidal-stream arrays is important for future development of tidal energy extraction. The impacts include possible changes in water elevation, which can potentially increase flooding in coastal areas. Further, SLR can affect tidal energy resources and the impacts of tidal energy extraction during the project lifetime - which is usually more than 25 years. A tidal model of the Gulf of Maine was developed using Regional Ocean Model System (ROMS) at one arcminute scale. An array of turbines were simulated in the model. After validation of the model at NOAA tidal gauge stations and NERACOOS buoys, several scenarios; including SLR scenario, and tidal extraction scenario, were examined. In particular, the results of a recent research was used to assess the impacts of SLR on the boundary of the model domain, which was neglected in previous studies. The results of the impacts of the tidal energy extraction with and without the SLR were presented, and compared with those from literature. This includes the decrease of tidal range and M2 amplitude in Minas Basin due to the 2.5 GW extraction scenario, and possible changes in Massachusetts coastal area. The impacts were compared with the level of uncertainty in the model. It was shown that the impact of SLR on the dynamics of

  19. Remaining Sites Verification Package for the 100-F-26:12, 1.8-m (72-in.) Main Process Sewer Pipeline, Waste Site Reclassification Form 2007-034

    SciTech Connect

    J. M. Capron

    2008-04-29

    The 100-F-26:12 waste site was an approximately 308-m-long, 1.8-m-diameter east-west-trending reinforced concrete pipe that joined the North Process Sewer Pipelines (100-F-26:1) and the South Process Pipelines (100-F-26:4) with the 1.8-m reactor cooling water effluent pipeline (100-F-19). In accordance with this evaluation, the verification sampling results support a reclassification of this site to Interim Closed Out. The results of verification sampling show that residual contaminant concentrations do not preclude any future uses and allow for unrestricted use of shallow zone soils. The results also demonstrate that residual contaminant concentrations are protective of groundwater and the Columbia River.

  20. Long term impacts of combined sewer overflow remediation on water quality and population dynamics of Culex quinquefasciatus, the main urban West Nile virus vector in Atlanta, GA.

    PubMed

    Lund, Andrea; McMillan, Joseph; Kelly, Rosmarie; Jabbarzadeh, Shirin; Mead, Daniel G; Burkot, Thomas R; Kitron, Uriel; Vazquez-Prokopec, Gonzalo M

    2014-02-01

    Combined sewers are a significant source of urban water pollution due to periodic discharges into natural streams. Such events (called combined sewer overflows, or CSOs) contribute to the impairment of natural waterways and are associated with increased mosquito productivity and elevated risk of West Nile virus transmission. We investigated the impact of CSOs on water quality and immature mosquito productivity in the city of Atlanta, Georgia, one year before and four years after CSO facility remediation. Water quality (ammonia, phosphate, nitrate and dissolved oxygen concentrations), immature mosquitoes (larvae and pupae), water temperature and rainfall were quantified biweekly between June-October at two urban creeks during 2008-2012. A before-after control-intervention design tested the impact of remediation on mosquito productivity and water quality, whereas generalized linear mixed-effect models quantified the factors explaining the long term impacts of remediation on mosquito productivity. Ammonia and phosphate concentrations and late immature (fourth-instar and pupae) mosquito populations were significantly higher in CSO than in non-CSO creeks, while dissolved oxygen concentrations were lower. Remediation significantly improved water quality estimates (particularly ammonia and dissolved oxygen) and reduced the number of overflows, mosquito productivity and the overall contribution of CSO-affected streams as sources of vectors of West Nile virus. The quality of water in CSOs provided a suitable habitat for immature mosquitoes. Remediation of the CSO facility through the construction of a deep storage tunnel improved water quality indices and reduced the productivity of mosquito species that can serve as vectors of West Nile virus. Copyright © 2013 Elsevier Inc. All rights reserved.

  1. Sewer Maintenance Manual.

    ERIC Educational Resources Information Center

    Ontario Ministry of the Environment, Toronto.

    Outlined are practices and procedures that should be followed in order to protect and fully realize the benefits of sewer systems and also to maximize service and minimize inconveniences to the public. Written in practical terms, the manual is designed to be of immediate use to municipal employees and others involved in sewer maintenance…

  2. Methane emission from sewers.

    PubMed

    Liu, Yiwen; Ni, Bing-Jie; Sharma, Keshab R; Yuan, Zhiguo

    2015-08-15

    Recent studies have shown that sewer systems produce and emit a significant amount of methane. Methanogens produce methane under anaerobic conditions in sewer biofilms and sediments, and the stratification of methanogens and sulfate-reducing bacteria may explain the simultaneous production of methane and sulfide in sewers. No significant methane sinks or methanotrophic activities have been identified in sewers to date. Therefore, most of the methane would be emitted at the interface between sewage and atmosphere in gravity sewers, pumping stations, and inlets of wastewater treatment plants, although oxidation of methane in the aeration basin of a wastewater treatment plant has been reported recently. Online measurements have also revealed highly dynamic temporal and spatial variations in methane production caused by factors such as hydraulic retention time, area-to-volume ratio, temperature, and concentration of organic matter in sewage. Both mechanistic and empirical models have been proposed to predict methane production in sewers. Due to the sensitivity of methanogens to environmental conditions, most of the chemicals effective in controlling sulfide in sewers also suppress or diminish methane production. In this paper, we review the recent studies on methane emission from sewers, including the production mechanisms, quantification, modeling, and mitigation.

  3. Sewer Maintenance Manual.

    ERIC Educational Resources Information Center

    Ontario Ministry of the Environment, Toronto.

    Outlined are practices and procedures that should be followed in order to protect and fully realize the benefits of sewer systems and also to maximize service and minimize inconveniences to the public. Written in practical terms, the manual is designed to be of immediate use to municipal employees and others involved in sewer maintenance…

  4. City sewer collectors biocorrosion

    NASA Astrophysics Data System (ADS)

    Ksiażek, Mariusz

    2014-12-01

    This paper presents the biocorrosion of city sewer collectors impregnated with special polymer sulphur binders, polymerized sulphur, which is applied as the industrial waste material. The city sewer collectors are settled with a colony of soil bacteria which have corrosive effects on its structure. Chemoautotrophic nitrifying bacteria utilize the residues of halites (carbamide) which migrate in the city sewer collectors, due to the damaged dampproofing of the roadway and produce nitrogen salts. Chemoorganotrophic bacteria utilize the traces of organic substrates and produce a number of organic acids (formic, acetic, propionic, citric, oxalic and other). The activity of microorganisms so enables the origination of primary and secondary salts which affect physical properties of concretes in city sewer collectors unfavourably.

  5. DEVELOPMENT OF SANITARY SEWER OVERFLOW ANALYSIS AND PLANNING (SSOAP) TOOLBOX

    EPA Science Inventory

    Rainfall Derived Infiltration and Inflow (RDII) into sanitary sewer systems has long been recognized as a source of operating problems in sewerage systems. RDII is the main cause of sanitary sewer overflows (SSOs) to basements, streets, or nearby streams. RDII can also cause se...

  6. Review of Sewer Design Criteria and RDII Prediction Methods

    EPA Science Inventory

    Rainfall-derived Infiltration and Inflow (RDII) into sanitary sewer systems has long been recognized as a source of operating problems in sewerage systems. RDII is the main cause of sanitary sewer overflows (SSOs) to basements, streets, or nearby streams and can also cause serio...

  7. DEVELOPMENT OF SANITARY SEWER OVERFLOW ANALYSIS AND PLANNING (SSOAP) TOOLBOX

    EPA Science Inventory

    Rainfall Derived Infiltration and Inflow (RDII) into sanitary sewer systems has long been recognized as a source of operating problems in sewerage systems. RDII is the main cause of sanitary sewer overflows (SSOs) to basements, streets, or nearby streams. RDII can also cause se...

  8. COMPUTER TOOLS FOR SANITARY SEWER SYSTEM CAPACITY ANALYSIS AND PLANNING

    EPA Science Inventory

    Rainfall-derived infiltration and inflow (RDII) into sanitary sewer systems has long been recognized as a major source of operating problems, causing poor performance of many sewer systems. RDII is the main cause of SSOs to customer basements, streets, or nearby streams and can a...

  9. SSOAP - A TOOLBOX FOR SANITARY SEWER OVERFLOW ANALYSIS AND PLANNING

    EPA Science Inventory

    Rainfall Derived Infiltration and Inflow (RDII) into sanitary sewer systems has long been recognized as a source of operating problems in sewerage systems. RDII is the main cause of sanitary sewer overflows (SSOs) to basements, streets, or nearby streams and can also cause serio...

  10. Sanitary Sewer Overflow Analysis and Planning (SSOAP) Toolbox

    EPA Science Inventory

    Rainfall-derived infiltration and inflow (RDII) into sanitary sewer systems has long been recognized as a source of operating problems in sewerage systems. RDII is the main cause of sanitary sewer overflows (SSOs) to basements, streets, or nearby receiving waters and can also ...

  11. SSOAP - A TOOLBOX FOR SANITARY SEWER OVERFLOW ANALYSIS AND PLANNING

    EPA Science Inventory

    Rainfall Derived Infiltration and Inflow (RDII) into sanitary sewer systems has long been recognized as a source of operating problems in sewerage systems. RDII is the main cause of sanitary sewer overflows (SSOs) to basements, streets, or nearby streams and can also cause seriou...

  12. Review of Sewer Design Criteria and RDII Prediction Methods

    EPA Science Inventory

    Rainfall-derived Infiltration and Inflow (RDII) into sanitary sewer systems has long been recognized as a source of operating problems in sewerage systems. RDII is the main cause of sanitary sewer overflows (SSOs) to basements, streets, or nearby streams and can also cause serio...

  13. COMPUTER TOOLS FOR SANITARY SEWER SYSTEM CAPACITY ANALYSIS AND PLANNING

    EPA Science Inventory

    Rainfall-derived infiltration and inflow (RDII) into sanitary sewer systems has long been recognized as a major source of operating problems, causing poor performance of many sewer systems. RDII is the main cause of SSOs to customer basements, streets, or nearby streams and can a...

  14. Sanitary Sewer Overflow Analysis and Planning (SSOAP) Toolbox

    EPA Science Inventory

    Rainfall-derived infiltration and inflow (RDII) into sanitary sewer systems has long been recognized as a source of operating problems in sewerage systems. RDII is the main cause of sanitary sewer overflows (SSOs) to basements, streets, or nearby receiving waters and can also ...

  15. SSOAP - A TOOLBOX FOR SANITARY SEWER OVERFLOW ANALYSIS AND PLANNING

    EPA Science Inventory

    Rainfall Derived Infiltration and Inflow (RDII) into sanitary sewer systems has long been recognized as a source of operating problems in sewerage systems. RDII is the main cause of sanitary sewer overflows (SSOs) to basements, streets, or nearby streams and can also cause seriou...

  16. SSOAP - A TOOLBOX FOR SANITARY SEWER OVERFLOW ANALYSIS AND PLANNING

    EPA Science Inventory

    Rainfall Derived Infiltration and Inflow (RDII) into sanitary sewer systems has long been recognized as a source of operating problems in sewerage systems. RDII is the main cause of sanitary sewer overflows (SSOs) to basements, streets, or nearby streams and can also cause serio...

  17. Future sea-level rise from Greenland's main outlet glaciers in a warming climate.

    PubMed

    Nick, Faezeh M; Vieli, Andreas; Andersen, Morten Langer; Joughin, Ian; Payne, Antony; Edwards, Tamsin L; Pattyn, Frank; van de Wal, Roderik S W

    2013-05-09

    Over the past decade, ice loss from the Greenland Ice Sheet increased as a result of both increased surface melting and ice discharge to the ocean. The latter is controlled by the acceleration of ice flow and subsequent thinning of fast-flowing marine-terminating outlet glaciers. Quantifying the future dynamic contribution of such glaciers to sea-level rise (SLR) remains a major challenge because outlet glacier dynamics are poorly understood. Here we present a glacier flow model that includes a fully dynamic treatment of marine termini. We use this model to simulate behaviour of four major marine-terminating outlet glaciers, which collectively drain about 22 per cent of the Greenland Ice Sheet. Using atmospheric and oceanic forcing from a mid-range future warming scenario that predicts warming by 2.8 degrees Celsius by 2100, we project a contribution of 19 to 30 millimetres to SLR from these glaciers by 2200. This contribution is largely (80 per cent) dynamic in origin and is caused by several episodic retreats past overdeepenings in outlet glacier troughs. After initial increases, however, dynamic losses from these four outlets remain relatively constant and contribute to SLR individually at rates of about 0.01 to 0.06 millimetres per year. These rates correspond to ice fluxes that are less than twice those of the late 1990s, well below previous upper bounds. For a more extreme future warming scenario (warming by 4.5 degrees Celsius by 2100), the projected losses increase by more than 50 per cent, producing a cumulative SLR of 29 to 49 millimetres by 2200.

  18. Dosing free nitrous acid for sulfide control in sewers: results of field trials in Australia.

    PubMed

    Jiang, Guangming; Keating, Anthony; Corrie, Shaun; O'halloran, Kelly; Nguyen, Lam; Yuan, Zhiguo

    2013-09-01

    Intermittent dosing of free nitrous acid (FNA), with or without the simultaneous dosing of hydrogen peroxide, is a new strategy developed recently for the control of sulfide production in sewers. Six-month field trials have been carried out in a rising main sewer in Australia (150 mm in diameter and 1080 m in length) to evaluate the performance of the strategy that was previously demonstrated in laboratory studies. In each trial, FNA was dosed at a pumping station for a period of 8 or 24 h, some with simultaneous hydrogen peroxide dosing. The sulfide control effectiveness was monitored by measuring, on-line, the dissolved sulfide concentration at a downstream location of the pipeline (828 m from the pumping station) and the gaseous H2S concentration at the discharge manhole. Effective sulfide control was achieved in all nine consecutive trials, with sulfide production reduced by more than 80% in 10 days following each dose. Later trials achieved better control efficiency than the first few trials possibly due to the disrupting effects of FNA on sewer biofilms. This suggests that an initial strong dose (more chemical consumption) followed by maintenance dosing (less chemical consumption) could be a very cost-effective way to achieve consistent control efficiency. It was also found that heavy rainfall slowed the recovery of sulfide production after dosing, likely due to the dilution effects and reduced retention time. Overall, intermittent dose of FNA or FNA in combination with H2O2 was successfully demonstrated to be a cost-effective method for sulfide control in rising main sewers. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. SEWER PIPELINE PERFORMANCE INDICATORS

    EPA Science Inventory

    Wastewater collection systems are an extensive part of the nation's infrastructure. In the United States, approximately 150 million people are served by about 19,000 municipal wastewater collection systems representing about 500,000 miles of sewer pipe (not including privately o...

  20. EXFILTRATION IN SEWER SYSTEMS

    EPA Science Inventory

    This study focused on the quantification of leakage of sanitary and industrial sewage from sanitary sewer pipes on a national basis. The method for estimating exfiltration amounts utilized groundwater talbe information to identify areas of the country where the hydraulic gradient...

  1. EXFILTRATION IN SEWER SYSTEMS

    EPA Science Inventory

    This study focused on the quantification of leakage of sanitary and industrial sewage from sanitary sewer pipes on a national basis. The method for estimating exfiltration amounts utilized groundwater talbe information to identify areas of the country where the hydraulic gradient...

  2. SEWER PIPELINE PERFORMANCE INDICATORS

    EPA Science Inventory

    Wastewater collection systems are an extensive part of the nation's infrastructure. In the United States, approximately 150 million people are served by about 19,000 municipal wastewater collection systems representing about 500,000 miles of sewer pipe (not including privately o...

  3. SANITARY SEWER CALCULATION

    SciTech Connect

    Roy D. Clark

    1995-01-13

    This analysis defines and evaluates the surface sanitary sewer system on the North Portal, and addresses the requirements for the collection of sanitary sewage from each of the proposed surface buildings. A sewage treatment system will be defined that meets the needs of the North Portal, conforms to the existing site conditions, and meets the needs of the state and local permitting agencies.

  4. The hazard of Sea Level Rise (SLR) in Greece: from scientific knowledge towards risk awareness of main actors

    NASA Astrophysics Data System (ADS)

    Dandoulaki, Miranda; Karymbalis, Efthimios; Yorgos, Melissourgos; Skordili, Sophia; Valkanou, Kanella

    2014-05-01

    A natural hazard that is expected to affect coastal areas in the near future is Sea-Level Rise (SLR) due to climate change. According to recent reports the eustatic sea-level rise caused by global warming will reach approximately 18-59 cm by the year 2100. Potential impacts of future sea-level rise include coastal erosion, frequent and intensified cyclonic activity and associated storm surge flooding that may affect the coastal zones, saltwater intrusion into groundwater aquifers, the inundation of ecologically significant wetlands, and threats to cultural and historical resources, as well as to infrastructure. The identification of sensitive sections of coasts and the assessment of potential impacts of SLR on these is therefore a fundamental, yet initial, step towards their protection. Greece has the most extensive coastline among all Mediterranean countries with most of the socio-economic activities concentrated along the coastal zone. Almost all big urban centres are coastal ones and the same stands for a great part of infrastructure (ports, airports, roads, electricity and telecommunications network etc). As a result, the impacts of a potential rise of the sea level are expected to seriously affect the entire country. The paper examines the vulnerability to SLR of coastal zones in Greece; however its main focus is how knowledge can lead to policy making and the protection of coastal areas. The main actors in respect to protection from SLR in Greece are identified and there is an attempt to pin point how the knowledge is communicated and shared between them. Barriers, bridges and gaps are detected as regards how information and knowledge lead to risk awareness and finally to the implementation of protection policies. A main finding of the paper is that SLR risk is far from becoming a policy priority in Greece, although steps are taken for addressing impacts attributed to SLR such as coastal erosion. In order to address this risk, there are many potential

  5. Damage estimation of sewer pipe using subtitles of CCTV inspection video

    NASA Astrophysics Data System (ADS)

    Park, Kitae; Kim, Byeongcheol; Kim, Taeheon; Seo, Dongwoo

    2017-04-01

    Recent frequent occurrence of urban sinkhole serves as a momentum of the periodic inspection of sewer pipelines. Sewer inspection using a CCTV device needs a lot of time and efforts. Many of previous studies which reduce the laborious tasks are mainly interested in the developments of image processing S/W and exploring H/W. And there has been no attempt to find meaningful information from the existing CCTV images stored by the sewer maintenance manager. This study adopts a cross-correlation based image processing method and extracts sewer inspection device's location data from CCTV images. As a result of the analysis of location-time relation, it show strong correlation between device stand time and the sewer damages. In case of using this method to investigate sewer inspection CCTV images, it will save the investigator's efforts and improve sewer maintenance efficiency and reliability.

  6. Turning Main Street into a Green Street

    EPA Pesticide Factsheets

    With EPA assistance, a small community near Pittsburgh is turning its main street into a green street to control stormwater runoff that has caused flooding, sewer backups and combined sewer overflows.

  7. SCORe-CT: a new method for testing effectiveness of sulfide-control chemicals used in sewer systems.

    PubMed

    Gutierrez, Oriol; Sudarjanto, Gatut; Sharma, Keshab R; Keller, Jurg; Yuan, Zhiguo

    2011-01-01

    A new method for testing the effectiveness of chemical products for sulfide control in sewers is reported. The method, called SCORe-CT (Sewer Corrosion and Odour Research - Chemical Testing), consists of two specially designed laboratory-scale systems that mimic sulfide production in real rising main sewers, and a multi-phase and multi-facet testing protocol. The monitoring tools/methods include both routine chemical analysis of various sulfurous and carbonaceous compounds in liquid and their on-line monitoring using advanced sensors. Molecular methods and microelectrodes can also be employed to examine the microbial structure and activity of sewer biofilms. The SCORe-CT method is not proposed to replace field trials but to screen chemicals prior to their often costly trials/applications in field conditions. For effective chemicals the method helps to reveal the mechanisms involved, and assists with the design of optimal dosage strategies, which would significantly reduce application costs. In this paper, the method is explained in detail and demonstrated with several case studies.

  8. Evidence of a sewer vapor transport pathway at the USEPA vapor intrusion research duplex

    DOE PAGES

    McHugh, Thomas; Beckley, Lila; Sullivan, Terry; ...

    2017-04-26

    We report the role of sewer lines as preferential pathways for vapor intrusion is poorly understood. Although the importance of sewer lines for volatile organic compound (VOC) transport has been documented at a small number of sites with vapor intrusion, sewer lines are not routinely sampled during most vapor intrusion investigations. We have used a tracer study and VOC concentration measurements to evaluate the role of the combined sanitary/storm sewer line in VOC transport at the USEPA vapor intrusion research duplex in Indianapolis, Indiana. The results from the tracer study demonstrated gas migration from the sewer main line into themore » duplex. The migration pathway appears to be complex and may include leakage from the sewer lateral at a location below the building foundation. Vapor samples collected from the sewer line demonstrated the presence of tetrachloroethene (PCE) and chloroform in the sewer main in front of the duplex and at multiple sample locations within the sewer line upstream of the duplex. Finally, these test results combined with results from the prior multi-year study of the duplex indicate that the sewer line plays an important role in transport of VOCs from the subsurface source to the immediate vicinity of the duplex building envelope.« less

  9. Aerobic and anaerobic transformations of sulfide in a sewer system--field study and model simulations.

    PubMed

    Nielsen, Asbjørn Haaning; Vollertsen, Jes; Jensen, Henriette Stokbro; Madsen, Heidi Ina; Hvitved-Jacobsen, Thorkild

    2008-01-01

    The formation and fate of sulfide in a force main and a downstream-located gravity sewer were investigated in an extensive field study. Sulfide formation in the force main was significant. However, during 14 minutes of transport in the gravity sewer, the sulfide concentration decreased 30%, on average. An application of a conceptual sewer process model for simulating the formation and fate of sulfide was demonstrated. Overall, the model predicted that approximately 90% of the decrease of the sulfide concentration in the gravity sewer was the result of sulfide oxidation and that only a small fraction entered the sewer atmosphere, causing odor and corrosion. Even so, the model predicted concrete corrosion rates of up to 1.2 mm/y in the gravity sewer section.

  10. Water engineering. Reducing sewer corrosion through integrated urban water management.

    PubMed

    Pikaar, Ilje; Sharma, Keshab R; Hu, Shihu; Gernjak, Wolfgang; Keller, Jürg; Yuan, Zhiguo

    2014-08-15

    Sewer systems are among the most critical infrastructure assets for modern urban societies and provide essential human health protection. Sulfide-induced concrete sewer corrosion costs billions of dollars annually and has been identified as a main cause of global sewer deterioration. We performed a 2-year sampling campaign in South East Queensland (Australia), an extensive industry survey across Australia, and a comprehensive model-based scenario analysis of the various sources of sulfide. Aluminum sulfate addition during drinking water production contributes substantially to the sulfate load in sewage and indirectly serves as the primary source of sulfide. This unintended consequence of urban water management structures could be avoided by switching to sulfate-free coagulants, with no or only marginal additional expenses compared with the large potential savings in sewer corrosion costs.

  11. Development of Sediment Deposition Height Capacity Equation in Sewer Networks

    NASA Astrophysics Data System (ADS)

    Song, Yangho; Jo, Deokjun; Lee, Jungho

    2017-04-01

    Sediment characteristics and transport processes in sewers are markedly different from river. There is a wide range of particle densities and smaller particle size variation in sewers. Sediment supply and the available erodible material are more limited in sewers, and the diverse hydraulic characteristics in sewer systems are more unsteady. Prevention of sewer sediment accumulation, which can cause major sewer operational problems, is imperative and has been an immense concern for engineers. The effects of sediment formation in sewer systems, an appropriate sediment transport modelling with the ability to determine the location and depth of sediment deposit is needed. It is necessary to design efficiently considering the transfer and settling phenomena of the sediment coming into the sewer systems. During transport in the sewer, the minimum shear flow velocity and possible shear stress at which the sediment is transported smoothly. However, the interaction of sediment and fluid within the sewer systems has been very complex and the rigorous theoretical handling of this problem has not been developed. It is derived from the empirical values obtained from the river bed. The basic theory that particles float is based on the balance between sedimentation of particles by gravity and turbulent diffusion of fluids. There are many variables related. Representative parameters include complex phenomena due to collisions between particles, particles and fluids, and interactions between particles and tube walls. In general, the main parameters that form the boundary between the main transport and sediment are particle size, density, volume fraction, pipe diameter and gravity. As the particle size and volume concentration increase, the minimum feed rate increases and the same tendency is observed for the change of the capillary diameter. Based on this tendency, this study has developed a sediment deposition height capacity formula to take into consideration the sewer discharge

  12. Vacuum Flushing of Sewer Solids

    EPA Science Inventory

    The vacuum sewer and tank cleaning (flushing) technology removes sewer solids from urban drainage systems, such as storage tanks and pipes. This technology is both effective and inexpensive. In addition, it can be considered a true green technology. It operates under atmospheri...

  13. Vacuum Flushing of Sewer Solids

    EPA Science Inventory

    The vacuum sewer and tank cleaning (flushing) technology removes sewer solids from urban drainage systems, such as storage tanks and pipes. This technology is both effective and inexpensive. In addition, it can be considered a true green technology. It operates under atmospheri...

  14. Feasibility of sulfide control in sewers by reuse of iron rich drinking water treatment sludge.

    PubMed

    Sun, Jing; Pikaar, Ilje; Sharma, Keshab Raj; Keller, Jürg; Yuan, Zhiguo

    2015-03-15

    Dosage of iron salt is the most commonly used method for sulfide control in sewer networks but incurs high chemical costs. In this study, we experimentally investigate the feasibility of using iron rich drinking water treatment sludge for sulfide control in sewers. A lab-scale rising main sewer biofilm reactor was used. The sulfide concentration in the effluent decreased from 15.5 to 19.8 mgS/L (without dosing) to below 0.7-2.3 mgS/L at a sludge dosing rate achieving an iron to total dissolved inorganic sulfur molar ratio (Fe:S) of 1:1, with further removal of sulfide possible by prolonging the reaction time. In fact, batch tests revealed an Fe consumption to sulfide removal ratio of 0.5 ± 0.02 (mole:mole), suggesting the possible occurrence of other reactions involving the removal of sulfide. Modelling revealed that the reaction between iron in sludge and sulfide has reaction orders of 0.65 ± 0.01 and 0.77 ± 0.02 with respect to the Fe and sulfide concentrations, respectively. The addition of sludge slightly increased the total chemical oxidation demand (tCOD) concentration (by approximately 12%) as expected, but decreased the soluble chemical oxidation demand (sCOD) concentration and methane formation by 7% and 20%, respectively. Some phosphate removal (13%) was also observed at the sludge dosing rate of 1:1 (Fe:S), which is beneficial to nutrient removal from the wastewater. Overall, this study suggests that dosing iron-rich drinking water sludge to sewers could be an effective strategy for sulfide removal in sewer systems, which would also reduce the sludge disposal costs for drinking water treatment works. However, its potential side-effects on sewer sedimentation and on the wastewater treatment plant effluent remain to be investigated. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Poison-based commensal rodent control strategies in urban ecosystems: some evidence against sewer-baiting.

    PubMed

    Mughini Gras, Lapo; Patergnani, Matteo; Farina, Marco

    2012-03-01

    Sewers are historically considered the main reservoir for commensal rodents, posing threats to urban ecosystem health. Aboveground rodent signs are often assumed to give clues to high sewer infestation, which can chronically restock surface areas. Thus, current sewer-baiting programmes are mostly reactive, responding to increased surface infestation. Conversely, proactive sewer-baiting (regardless of infestation levels) is often disregarded because cost-effectiveness is not always addressed. We explored the extent to which the surface infestation is related to rodent feeding activity on sewer and surface baits by analysing a set of proactive bait records in Bologna city, Italy. Sewer bait intakes were significantly lower than surface ones, suggesting that proactive sewer-baiting is generally less effective. As surface infestation increased, probability of recording surface bait intake increased significantly but this was not reflected by increased sewer bait intake, suggesting that surface infestation is not always a reliable indicator of sewer infestation. This should discourage the use of reactive sewer-baiting as a routine strategy. Poison-based control programmes by themselves are scarcely predictable and strategically limited, and ideally they should be handled within an ecologically based integrated pest management approach for achieving satisfactory results.

  16. COMBINED-SEWER OVERFLOW CONTROL AND TREATMENT

    EPA Science Inventory

    Combined-sewer overflow (CSO), along with sanitary-sewer overflow and stormwater are significant contributors of contamination to surface waters. During a rain event, the flow in a combined sewer system may exceed the capacity of the intercepting sewer leading to the wastewater t...

  17. COMBINED-SEWER OVERFLOW CONTROL AND TREATMENT

    EPA Science Inventory

    Combined-sewer overflow (CSO), along with sanitary-sewer overflow and stormwater are significant contributors of contamination to surface waters. During a rain event, the flow in a combined sewer system may exceed the capacity of the intercepting sewer leading to the wastewater t...

  18. Municipal gravity sewers: an unrecognised source of nitrous oxide.

    PubMed

    Short, Michael D; Daikeler, Alexander; Peters, Gregory M; Mann, Kirsten; Ashbolt, Nicholas J; Stuetz, Richard M; Peirson, William L

    2014-01-15

    Nitrous oxide (N2O) is a primary ozone-depleting substance and powerful greenhouse gas. N2O emissions from secondary-level wastewater treatment processes are relatively well understood as a result of intensive international research effort in recent times, yet little information exists to date on the role of sewers in wastewater management chain N2O dynamics. Here we provide the first detailed assessment of N2O levels in the untreated influent (i.e. sewer network effluent) of three large Australian metropolitan wastewater treatment plants. Contrary to current international (IPCC) guidance, results show gravity sewers to be a likely source of N2O. Results from the monitoring program revealed hydraulic flow rate as a strong driver for N2O generation in gravity sewers, with microbial processes (nitrification and possibly denitrification) implicated as the main processes responsible for its production. Results were also used to develop a presumptive emission factor for N2O in the context of municipal gravity sewers. Considering the discrepancy with current IPCC Guidelines, further work is warranted to assess the scale and dynamics of N2O production in sewers elsewhere. © 2013.

  19. Sewer rehabilitation strategy in Berlin.

    PubMed

    Jacobi, D; Sympher, K J

    2002-01-01

    Berlin Wasserbetriebe is in need of a significant and longterm investment in the rehabilitation of is sewer system. With ratification of the European Standard EN 752 Part 5, comprehensive rules have been set out for the rehabilitation of drain and sewer systems: hydraulic performance, environmental impact and structural integrity of complete catchment areas are given equal consideration. Taking this into account, Berliner Wasserbetriebe has developed a sewer rehabilitation strategy. Economic aspects are integrated with a cost-benefit-analysis; the significance of the remaining useful life of a pipe section is examined.

  20. A TOOLBOX FOR SANITARY SEWER OVERFLOW ANALYSIS AND PLANNING (SSOAP) AND APPLICATIONS

    EPA Science Inventory

    Rainfall Derived Infiltration and Inflow (RDII) into sanitary sewer systems has long been recognized as a source of operating problems in sewerage systems. RDII is the main cause of sanitary sewer overflows (SSOs) to basements, streets, or nearby streams and can also cause seriou...

  1. A TOOLBOX FOR SANITARY SEWER OVERFLOW ANALYSIS AND PLANNING (SSOAP) AND APPLICATIONS

    EPA Science Inventory

    Rainfall-derived infiltration and inflow (RDII) into sanitary sewer systems has long been recognized as a source of operating problems in these systems. RDII is the main cause of sanitary sewer overflows (SSOs) to basements, streets, or nearby streams and the resulting high flows...

  2. A TOOLBOX FOR SANITARY SEWER OVERFLOW ANALYSIS AND PLANNING (SSOAP) AND APPLICATIONS

    EPA Science Inventory

    Rainfall-derived infiltration and inflow (RDII) into sanitary sewer systems has long been recognized as a source of operating problems in these systems. RDII is the main cause of sanitary sewer overflows (SSOs) to basements, streets, or nearby streams and the resulting high flows...

  3. A TOOLBOX FOR SANITARY SEWER OVERFLOW ANALYSIS AND PLANNING (SSOAP) AND APPLICATIONS

    EPA Science Inventory

    Rainfall Derived Infiltration and Inflow (RDII) into sanitary sewer systems has long been recognized as a source of operating problems in sewerage systems. RDII is the main cause of sanitary sewer overflows (SSOs) to basements, streets, or nearby streams and can also cause seriou...

  4. Inventory and protection of salt marshes from risks of sea-level rise at Acadia National Park, Maine

    USGS Publications Warehouse

    Dudley, Robert W.; Nielsen, Martha G.

    2011-01-01

    Recent U.S. Geological Survey (USGS) climate studies in the northeastern United States have shown substantial evidence of climate-related changes during the last 100 years, including earlier snowmelt runoff, decreasing occurrence of river ice, and decreasing winter snowpack. These studies related to climate change are being expanded to include investigation of coastal wetlands that might be at risk from sealevel rise. Coastal wetlands, particularly salt marshes, are important ecosystems that provide wildlife nursery and breeding habitat, migratory bird habitat, water quality enhancement, and shoreline erosion control. The USGS is investigating salt marshes in Acadia National Park with the goal of determining which salt marshes may be threatened by sea-level rise and which salt marshes may be able to adapt to sea-level rise by migrating into adjacent low-lying lands.

  5. A model for methane production in sewers.

    PubMed

    Chaosakul, Thitirat; Koottatep, Thammarat; Polprasert, Chongrak

    2014-09-19

    Most sewers in developing countries are combined sewers which receive stormwater and effluent from septic tanks or cesspools of households and buildings. Although the wastewater strength in these sewers is usually lower than those in developed countries, due to improper construction and maintenance, the hydraulic retention time (HRT) could be relatively long and resulting considerable greenhouse gas (GHG) production. This study proposed an empirical model to predict the quantity of methane production in gravity-flow sewers based on relevant parameters such as surface area to volume ratio (A/V) of sewer, hydraulic retention time (HRT) and wastewater temperature. The model was developed from field survey data of gravity-flow sewers located in a peri-urban area, central Thailand and validated with field data of a sewer system of the Gold Coast area, Queensland, Australia. Application of this model to improve construction and maintenance of gravity-flow sewers to minimize GHG production and reduce global warming is presented.

  6. HANDBOOK: SEWER SYSTEM INFRASTRUCTURE ANALYSIS AND REHABILITATION

    EPA Science Inventory

    Many of our Nation's sewer systems date back to the 19th Century when brick sewers were common. hese and more recent sewer systems can be expected to fail in time, but because they are placed underground, signs of accelerated deterioration and capacity limitations are not readily...

  7. HANDBOOK: SEWER SYSTEM INFRASTRUCTURE ANALYSIS AND REHABILITATION

    EPA Science Inventory

    Many of our Nation's sewer systems date back to the 19th Century when brick sewers were common. hese and more recent sewer systems can be expected to fail in time, but because they are placed underground, signs of accelerated deterioration and capacity limitations are not readily...

  8. Quantitative assessment of the groundwater-sewer network interaction in Bucharest city (Romania)

    NASA Astrophysics Data System (ADS)

    Boukhemacha, M. A.; Diaconescu, A.; Bica, I.; Gogu, C. R.; Gaitanaru, D.

    2012-04-01

    Groundwater management in urban area must take account of every possible and relevant phenomena arising from the complex interaction between subsurface water, surface water, and urban infrastructure. In Bucharest, the need of the sewer system rehabilitation initiated a study of the interaction between groundwater and the sewer network. Recent conclusions show that the sewer network acts mainly like a drainage system for the groundwater. However, it could be easily proven that several sewer segments located mainly in the unsaturated zone contaminate the groundwater by leakage. The groundwater infiltration in the sewer conduits can cause the decrease of the groundwater level leading to structures instability problems as well as to the increase flow-rates of the sewer system. The last one affects seriously the wastewater treatment plants efficiency. The sewer network leakage cause groundwater pollution and locally could increase the groundwater level triggering buildings instability or other urban operational problems. The current study focuses on the consequences of sealing a part of the sewer system and so disturbing the existing groundwater behavior which may lead to serious consequences. In this framework, the analysis results of a groundwater flow model used to quantify the interaction between the groundwater and the sewer network are presented. The two-layers groundwater flow model simulating the Colentina and Mostistea overlaid sedimentary aquifers covers about 75 km2. Its conceptual model relies on a 3D geological model made by using 23 accurate geological cross-sections of the studied domain. The model set-up and its calibration are done using pumping tests data, groundwater hydraulic heads, and water levels of the sewer system. Infiltration rates into sewers are modeled by applying a modified form of Darcy's law that uses the notion of infiltration factor. This last encompasses the hydraulic conductivity of the clogging layer, the infiltration area and the

  9. Demonstration of Innovative Sewer System Inspection Technology SewerBatt

    EPA Science Inventory

    The overall objective of this EPA-funded study was to demonstrate innovative a sewer line assessment technology that is designed for rapid deployment using portable equipment. This study focused on demonstration of a technology that is suitable for smaller diameter pipes (less th...

  10. Demonstration of Innovative Sewer System Inspection Technology SewerBatt

    EPA Science Inventory

    The overall objective of this EPA-funded study was to demonstrate innovative a sewer line assessment technology that is designed for rapid deployment using portable equipment. This study focused on demonstration of a technology that is suitable for smaller diameter pipes (less th...

  11. Space-Derived Sewer Monitor

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The QuadraScan Longterm Flow Monitoring System is a second generation sewer monitor developed by American Digital Systems, Inc.'s founder Peter Petroff. Petroff, a former spacecraft instrumentation designer at Marshall Space Flight Center, used expertise based on principles acquired in Apollo and other NASA programs. QuadraScan borrows even more heavily from space technology, for example in its data acquisition and memory system derived from NASA satellites. "One-time" measurements are often plagued with substantial errors due to the flow of groundwater absorbed into the system. These system sizing errors stem from a basic informational deficiency: accurate, reliable data on how much water flows through a sewer system over a long period of time is very difficult to obtain. City officials are turning to "permanent," or long-term sewer monitoring systems. QuadraScan offers many advantages to city officials such as the early warning capability to effectively plan for city growth in order to avoid the crippling economic impact of bans on new sewer connections in effect in many cities today.

  12. Is temperature the main cause of dengue rise in non-endemic countries? The case of Argentina.

    PubMed

    Carbajo, Aníbal E; Cardo, María V; Vezzani, Darío

    2012-07-06

    Dengue cases have increased during the last decades, particularly in non-endemic areas, and Argentina was no exception in the southern transmission fringe. Although temperature rise has been blamed for this, human population growth, increased travel and inefficient vector control may also be implicated. The relative contribution of geographic, demographic and climatic of variables on the occurrence of dengue cases was evaluated. According to dengue history in the country, the study was divided in two decades, a first decade corresponding to the reemergence of the disease and the second including several epidemics. Annual dengue risk was modeled by a temperature-based mechanistic model as annual days of possible transmission. The spatial distribution of dengue occurrence was modeled as a function of the output of the mechanistic model, climatic, geographic and demographic variables for both decades. According to the temperature-based model dengue risk increased between the two decades, and epidemics of the last decade coincided with high annual risk. Dengue spatial occurrence was best modeled by a combination of climatic, demographic and geographic variables and province as a grouping factor. It was positively associated with days of possible transmission, human population number, population fall and distance to water bodies. When considered separately, the classification performance of demographic variables was higher than that of climatic and geographic variables. Temperature, though useful to estimate annual transmission risk, does not fully describe the distribution of dengue occurrence at the country scale. Indeed, when taken separately, climatic variables performed worse than geographic or demographic variables. A combination of the three types was best for this task.

  13. Is temperature the main cause of dengue rise in non-endemic countries? The case of Argentina

    PubMed Central

    2012-01-01

    Background Dengue cases have increased during the last decades, particularly in non-endemic areas, and Argentina was no exception in the southern transmission fringe. Although temperature rise has been blamed for this, human population growth, increased travel and inefficient vector control may also be implicated. The relative contribution of geographic, demographic and climatic of variables on the occurrence of dengue cases was evaluated. Methods According to dengue history in the country, the study was divided in two decades, a first decade corresponding to the reemergence of the disease and the second including several epidemics. Annual dengue risk was modeled by a temperature-based mechanistic model as annual days of possible transmission. The spatial distribution of dengue occurrence was modeled as a function of the output of the mechanistic model, climatic, geographic and demographic variables for both decades. Results According to the temperature-based model dengue risk increased between the two decades, and epidemics of the last decade coincided with high annual risk. Dengue spatial occurrence was best modeled by a combination of climatic, demographic and geographic variables and province as a grouping factor. It was positively associated with days of possible transmission, human population number, population fall and distance to water bodies. When considered separately, the classification performance of demographic variables was higher than that of climatic and geographic variables. Conclusions Temperature, though useful to estimate annual transmission risk, does not fully describe the distribution of dengue occurrence at the country scale. Indeed, when taken separately, climatic variables performed worse than geographic or demographic variables. A combination of the three types was best for this task. PMID:22768874

  14. Changes in Microbial Biofilm Communities during Colonization of Sewer Systems

    PubMed Central

    Auguet, O.; Pijuan, M.; Batista, J.; Gutierrez, O.

    2015-01-01

    The coexistence of sulfate-reducing bacteria (SRB) and methanogenic archaea (MA) in anaerobic biofilms developed in sewer inner pipe surfaces favors the accumulation of sulfide (H2S) and methane (CH4) as metabolic end products, causing severe impacts on sewerage systems. In this study, we investigated the time course of H2S and CH4 production and emission rates during different stages of biofilm development in relation to changes in the composition of microbial biofilm communities. The study was carried out in a laboratory sewer pilot plant that mimics a full-scale anaerobic rising sewer using a combination of process data and molecular techniques (e.g., quantitative PCR [qPCR], denaturing gradient gel electrophoresis [DGGE], and 16S rRNA gene pyrotag sequencing). After 2 weeks of biofilm growth, H2S emission was notably high (290.7 ± 72.3 mg S-H2S liter−1 day−1), whereas emissions of CH4 remained low (17.9 ± 15.9 mg COD-CH4 liter−1 day−1). This contrasting trend coincided with a stable SRB community and an archaeal community composed solely of methanogens derived from the human gut (i.e., Methanobrevibacter and Methanosphaera). In turn, CH4 emissions increased after 1 year of biofilm growth (327.6 ± 16.6 mg COD-CH4 liter−1 day−1), coinciding with the replacement of methanogenic colonizers by species more adapted to sewer conditions (i.e., Methanosaeta spp.). Our study provides data that confirm the capacity of our laboratory experimental system to mimic the functioning of full-scale sewers both microbiologically and operationally in terms of sulfide and methane production, gaining insight into the complex dynamics of key microbial groups during biofilm development. PMID:26253681

  15. Corrosion and odor management in sewer systems.

    PubMed

    Jiang, Guangming; Sun, Jing; Sharma, Keshab R; Yuan, Zhiguo

    2015-06-01

    Sewers emit hydrogen sulfide and various volatile organic sulfur and carbon compounds, which require control and mitigation. In the last 5-10 years, extensive research was conducted to optimize existing sulfide abatement technologies based on newly developed in-depth understanding of the in-sewer processes. Recent advances have also led to low-cost novel solutions targeting sewer biofilms. Online control has been demonstrated to greatly reduce the chemical usage. Dynamic models for both the water, air and solid (concrete) phases have been developed and used for the planning and maintenance of sewer systems. Existing technologies primarily focused on 'hotspots' in sewers. Future research should aim to achieve network-wide corrosion and emission control and management of sewers as an integrated component of an urban water system.

  16. Network condition simulator for benchmarking sewer deterioration models.

    PubMed

    Scheidegger, A; Hug, T; Rieckermann, J; Maurer, M

    2011-10-15

    An accurate description of aging and deterioration of urban drainage systems is necessary for optimal investment and rehabilitation planning. Due to a general lack of suitable datasets, network condition models are rarely validated, and if so with varying levels of success. We therefore propose a novel network condition simulator (NetCoS) that produces a synthetic population of sewer sections with a given condition-class distribution. NetCoS can be used to benchmark deterioration models and guide utilities in the selection of appropriate models and data management strategies. The underlying probabilistic model considers three main processes: a) deterioration, b) replacement policy, and c) expansions of the sewer network. The deterioration model features a semi-Markov chain that uses transition probabilities based on user-defined survival functions. The replacement policy is approximated with a condition-class dependent probability of replacing a sewer pipe. The model then simulates the course of the sewer sections from the installation of the first line to the present, adding new pipes based on the defined replacement and expansion program. We demonstrate the usefulness of NetCoS in two examples where we quantify the influence of incomplete data and inspection frequency on the parameter estimation of a cohort survival model and a Markov deterioration model. Our results show that typical available sewer inventory data with discarded historical data overestimate the average life expectancy by up to 200 years. Although NetCoS cannot prove the validity of a particular deterioration model, it is useful to reveal its possible limitations and shortcomings and quantifies the effects of missing or uncertain data. Future developments should include additional processes, for example to investigate the long-term effect of pipe rehabilitation measures, such as inliners.

  17. MANAGEMENT AND CONTROL OF COMBINED SEWER OVERFLOWS

    EPA Science Inventory

    The paper gives a basic overview of the U.S. government's involvements in developing countermeasures for the abatement of combined sewer overflow pollution. batement or prevention of pollution stormwater runoff and combined sewer overflows is one of the most challenging areas in ...

  18. SANITARY-SEWER OVERFLOW CONTROL STRATEGY

    EPA Science Inventory

    This paper presents a strategy for the abatement of pollution from storm-generated sanitary-sewer overflows (SSO). Because of the great lengths of sanitary-sewer systems and their associated vast number of house-service laterals or building connections, it is often less expensive...

  19. Vacuum Flushing of Sewer Solids (Slides)

    EPA Science Inventory

    The vacuum sewer and tank cleaning (flushing) technology removes sewer solids from urban drainage systems, such as storage tanks and pipes. This technology is both effective and inexpensive. In addition, it can be considered a true green technology. It operates under atmospheri...

  20. Boston Water & Sewer Commission (BWSC) | Stormwater ...

    EPA Pesticide Factsheets

    2017-04-10

    The Boston Water and Sewer Commission (BWSC) was issued National Pollutant Discharge Elimination System (NPDES) Permit MAS010001, which became effective on October 29, 1999, authorizing stormwater and allowable non-stormwater discharges from its municipal separate storm sewer system (MS4).

  1. SANITARY-SEWER OVERFLOW CONTROL STRATEGY

    EPA Science Inventory

    This paper presents a strategy for the abatement of pollution from storm-generated sanitary-sewer overflows (SSO). Because of the great lengths of sanitary-sewer systems and their associated vast number of house-service laterals or building connections, it is often less expensive...

  2. Vacuum Flushing of Sewer Solids (Slides)

    EPA Science Inventory

    The vacuum sewer and tank cleaning (flushing) technology removes sewer solids from urban drainage systems, such as storage tanks and pipes. This technology is both effective and inexpensive. In addition, it can be considered a true green technology. It operates under atmospheri...

  3. In-place rehabilitation of process sewers

    SciTech Connect

    Arles, K.R.; Faller, C.C.

    1996-07-01

    The majority of petrochemical manufacturing facilities have thousands of feet of existing underground gravity sewers that convey the site`s industrial wastes to treatment facilities. The integrity of these sewer systems is a serious concern to owners. A potential consequence of leaks is soil and groundwater contamination. Prior to 1992, only two options were available to remedy this situation. The sewer systems could be replaced with either a new dual-walled, monitored underground pipe system via direct bury, or with an above ground pumped system. In 1992, Engineering, in conjunction with several trenchless technology vendors, developed and demonstrated modified relining systems that can rehabilitate existing sewers and result in monitored dual-walled gravity sewer systems. These proven systems have since been enhanced, upgraded, and installed at two operating facilities. With thorough sewer investigation and assessments, industry now has viable, cost effective options to rehabilitate underground chemical process sewers. These upgraded sewer systems provide the environmental security of monitored dual-walled pipe, enhanced flow characteristics, and retain accessibility for maintenance and inspections.

  4. Wastewater temperature decrease in pressure sewers.

    PubMed

    Sallanko, Jarmo; Pekkala, Mari

    2008-12-01

    The centralization of wastewater treatment in large central treatment plants and the connection of sparsely populated areas to sewerage systems have increased the time wastewater is retained in sewers. These retention times lead to a decrease in wastewater temperature and affect wastewater treatment, especially the removal of nitrogen. In this study, temperature changes in long transfer sewers were examined. The temperature change was greatest at the end of winter and in the front part of the sewer. Temperature changes in the front parts of the sewers ranged from 0.16 to 0.27 degree C/km, and in the end parts from 0.02 to 0.10 degree C/km. When expressed in terms of the retention time for wastewater in the sewer, the temperature changes ranged from 0.12 to 0.17 degree C per retention hour.

  5. Potential impacts of sea level rise on native plant communities and associated cultural sites in coastal areas of the main Hawaiian Islands

    USGS Publications Warehouse

    Jacobi, James D.; Warshauer, Frederick R.

    2017-01-01

    Hawaiian coastal vegetation is comprised of plant species that are adapted to growing in extremely harsh conditions (salt spray, wave wash, wind, and substrates with limited nutrients) found in this habitat zone. Prior to human colonization of Hawai‘i coastal vegetation extended as a continuous ring around each of the islands, broken only by stretches of recent lava flows or unstable cliff faces. However, since humans arrived in Hawai‘i many areas that originally supported native coastal plant communities have been highly altered or the native vegetation totally removed for agriculture, housing, or resort development, destroyed by fire, displaced by invasive plants, eaten by introduced mammals, or damaged by recreational use. This study was focused on identifying sites that still retain relatively intact and highly diverse native coastal plant communities throughout the main Hawaiian Islands that may be further impacted by projected sea level rise. Approximately 40 percent of Hawai‘i’s coastlines were found to still contain high quality native coastal plant communities. Most of these sites were located in areas where the coastal vegetation can still migrate inshore in response to rising sea level and associated inundation by waves. However, six sites with high-quality native coastal vegetation were found on low-lying offshore islets that will be totally inundated with a one meter increase in sea level and thirty sites were found to have some type of fixed barrier, such as a paved road or structure, which would restrict the plants from colonizing the adjacent inland areas. Many of these sites also have other cultural resources that are fixed in place and will definitely be impacted by rising sea level. The results of this study can help refine our understanding of Hawai‘i’s remaining native coastal vegetation and aid with the development of management and restoration strategies to ensure the long-term survival of these unique plant communities.

  6. Effects of long-term pH elevation on the sulfate-reducing and methanogenic activities of anaerobic sewer biofilms.

    PubMed

    Gutierrez, Oriol; Park, Donghee; Sharma, Keshab Raj; Yuan, Zhiguo

    2009-05-01

    The dosage of alkali is often applied by the wastewater industry to reduce the transfer of hydrogen sulfide from wastewater to the sewer atmosphere. In this paper the activities of Sulfate Reducing Bacteria (SRB) and Methanogenic Archaea (MA) under elevated pH conditions (8.6 and 9.0) were evaluated in a laboratory scale anaerobic sewer reactor. Compared to those in a control reactor without pH control (pH 7.6+/-0.1), the SRB activity was reduced by 30% and 50%, respectively, at pH 8.6 and pH 9.0. When normal pH was resumed, it took approximately 1 month for the SRB activity to fully recover. Methanogenic activities developed in the control reactor in 3 months after the reactor start-up, while no significant methanogenic activities were detected in the experimental reactor until normal pH was resumed. The results suggest that elevated pH at 8.6-9.0 suppressed the growth of methanogens. These experimental results clearly showed that, in addition to its well-known effect of reducing H(2)S transfer from the liquid to the gas phase, pH elevation considerably reduces sulfide and methane production by anaerobic sewer biofilms. These findings are significant for the optimal use of alkali addition to sewers for the control of H(2)S and CH(4) emissions. A model-based study showed that, by adding the alkali at the beginning rather than towards the end of a rising main, substantial savings in chemicals can be achieved while achieving the same level of sulfide emission control, and complete methane emission control.

  7. 40 CFR 35.927-2 - Sewer system evaluation survey.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 1 2011-07-01 2011-07-01 false Sewer system evaluation survey. 35.927... § 35.927-2 Sewer system evaluation survey. (a) The sewer system evaluation survey shall identify the... results of the sewer system evaluation survey. In addition, the report shall include: (1) A...

  8. 40 CFR 35.927-2 - Sewer system evaluation survey.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 1 2012-07-01 2012-07-01 false Sewer system evaluation survey. 35.927... § 35.927-2 Sewer system evaluation survey. (a) The sewer system evaluation survey shall identify the... results of the sewer system evaluation survey. In addition, the report shall include: (1) A...

  9. 40 CFR 35.927-2 - Sewer system evaluation survey.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 1 2014-07-01 2014-07-01 false Sewer system evaluation survey. 35.927... § 35.927-2 Sewer system evaluation survey. (a) The sewer system evaluation survey shall identify the... results of the sewer system evaluation survey. In addition, the report shall include: (1) A...

  10. 40 CFR 35.927-2 - Sewer system evaluation survey.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Sewer system evaluation survey. 35.927... § 35.927-2 Sewer system evaluation survey. (a) The sewer system evaluation survey shall identify the... results of the sewer system evaluation survey. In addition, the report shall include: (1) A...

  11. 40 CFR 35.927-2 - Sewer system evaluation survey.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 1 2013-07-01 2013-07-01 false Sewer system evaluation survey. 35.927... § 35.927-2 Sewer system evaluation survey. (a) The sewer system evaluation survey shall identify the... results of the sewer system evaluation survey. In addition, the report shall include: (1) A...

  12. Odours in sewer networks: nuisance assessment.

    PubMed

    Pérez, A; Manjón, C; Martínez, J V; Juárez-Galan, J M; Barillon, B; Bouchy, L

    2013-01-01

    As odour nuisance can affect the quality of life, the population is more and more demanding and in many cities sewers are a critical source of odours. Both factors can lead to increasing numbers of complaints due to the odour nuisance perceived by the residents, affecting also the public image of the sewer management companies. Odours associated with sewer networks are very heterogeneous, in as much as the different 'types of odours' encountered are sewer site specific. The state of the art indicates that there are three parameters that play an important role with the nuisance generated by an odour: hedonic odour tone, odour concentration and odour intensity. This paper presents the results of the study on odour nuisance carried out in different points of the sewer network, with the aim to assess the nuisance generated and identify which points of the sewer should be targeted to implement corrective actions. Considering the different parameters assessed, pumping stations have been identified as critical points of odour nuisance in the sewers, being recommended to implement an odour treatment system in order to guarantee the odour comfort of residents.

  13. Model Predictive Control of Sewer Networks

    NASA Astrophysics Data System (ADS)

    Pedersen, Einar B.; Herbertsson, Hannes R.; Niemann, Henrik; Poulsen, Niels K.; Falk, Anne K. V.

    2017-01-01

    The developments in solutions for management of urban drainage are of vital importance, as the amount of sewer water from urban areas continues to increase due to the increase of the world’s population and the change in the climate conditions. How a sewer network is structured, monitored and controlled have thus become essential factors for effcient performance of waste water treatment plants. This paper examines methods for simplified modelling and controlling a sewer network. A practical approach to the problem is used by analysing simplified design model, which is based on the Barcelona benchmark model. Due to the inherent constraints the applied approach is based on Model Predictive Control.

  14. Estimates of future inundation of salt marshes in response to sea-level rise in and around Acadia National Park, Maine

    USGS Publications Warehouse

    Nielsen, Martha G.; Dudley, Robert W.

    2013-01-01

    Salt marshes are ecosystems that provide many important ecological functions in the Gulf of Maine. The U.S. Geological Survey investigated salt marshes in and around Acadia National Park from Penobscot Bay to the Schoodic Peninsula to map the potential for landward migration of marshes using a static inundation model of a sea-level rise scenario of 60 centimeters (cm; 2 feet). The resulting inundation contours can be used by resource managers to proactively adapt to sea-level rise by identifying and targeting low-lying coastal areas adjacent to salt marshes for conservation or further investigation, and to identify risks to infrastructure in the coastal zone. For this study, the mapping of static inundation was based on digital elevation models derived from light detection and ranging (LiDAR) topographic data collected in October 2010. Land-surveyed control points were used to evaluate the accuracy of the LiDAR data in the study area, yielding a root mean square error of 11.3 cm. An independent accuracy assessment of the LiDAR data specific to salt-marsh land surfaces indicated a root mean square error of 13.3 cm and 95-percent confidence interval of ± 26.0 cm. LiDAR-derived digital elevation models and digital color aerial photography, taken during low tide conditions in 2008, with a pixel resolution of 0.5 meters, were used to identify the highest elevation of the land surface at each salt marsh in the study area. Inundation contours for 60-cm of sea-level rise were delineated above the highest marsh elevation for each marsh. Confidence interval contours (95-percent,± 26.0 cm) were delineated above and below the 60-cm inundation contours, and artificial structures, such as roads and bridges, that may present barriers to salt-marsh migration were mapped. This study delineated 114 salt marshes totaling 340 hectares (ha), ranging in size from 0.11 ha (marshes less than 0.2 ha were mapped only if they were on Acadia National Park property) to 52 ha, with a median

  15. SEWER AND TANK SEDIMENT FLUSHING: CASE STUDIES

    EPA Science Inventory

    The objective of the report summarized here is to demonstrate that sewer system and storage tank flushing that reduces sediment deposition and accumulation is of prime importance to optimizing performance, maintaining structural integrity, and minimizing pollution of receiving wa...

  16. SEWER AND TANK SEDIMENT FLUSHING: CASE STUDIES

    EPA Science Inventory

    The objective of the report summarized here is to demonstrate that sewer system and storage tank flushing that reduces sediment deposition and accumulation is of prime importance to optimizing performance, maintaining structural integrity, and minimizing pollution of receiving wa...

  17. Risk assessment of sewer condition using artificial intelligence tools: application to the SANEST sewer system.

    PubMed

    Sousa, V; Matos, J P; Almeida, N; Saldanha Matos, J

    2014-01-01

    Operation, maintenance and rehabilitation comprise the main concerns of wastewater infrastructure asset management. Given the nature of the service provided by a wastewater system and the characteristics of the supporting infrastructure, technical issues are relevant to support asset management decisions. In particular, in densely urbanized areas served by large, complex and aging sewer networks, the sustainability of the infrastructures largely depends on the implementation of an efficient asset management system. The efficiency of such a system may be enhanced with technical decision support tools. This paper describes the role of artificial intelligence tools such as artificial neural networks and support vector machines for assisting the planning of operation and maintenance activities of wastewater infrastructures. A case study of the application of this type of tool to the wastewater infrastructures of Sistema de Saneamento da Costa do Estoril is presented.

  18. Recent findings on sinks for sulfide in gravity sewer networks.

    PubMed

    Nielsen, A H; Hvitved-Jacobsen, T; Vollertsen, J

    2006-01-01

    Sulfide buildup in sewer networks is associated with several problems, including health impacts, corrosion of sewer structures and odor nuisance. In recent years, significant advances in the knowledge of the major processes governing sulfide buildup in sewer networks have been made. This paper summarizes this newly obtained knowledge and emphasizes important implications of the findings. Model simulations of the in-sewer processes important for the sulfur cycle showed that sulfide oxidation in the wetted biofilm is typically the most important sink for dissolved sulfide in gravity sewers. However, sulfide emission and thereby potential hydrogen sulfide buildup in the sewer atmosphere is of particular importance in sewers constructed with large diameter pipes, in sewers constructed with steep slopes and in sewers conveying low pH wastewater. Precipitation of metal sulfides is only important when the sulfide concentration in the wastewater is low; i.e. less than 1 g Sm(-3).

  19. The hydraulic capacity of deteriorating sewer systems.

    PubMed

    Pollert, J; Ugarelli, R; Saegrov, S; Schilling, W; Di Federico, V

    2005-01-01

    Sewer and wastewater systems suffer from insufficient capacity, construction flaws and pipe deterioration. Consequences are structural failures, local floods, surface erosion and pollution of receiving waters bodies. European cities spend in the order of five billion Euro per year for wastewater network rehabilitation. This amount is estimated to increase due to network ageing. The project CARE-S (Computer Aided RE-habilitation of Sewer Networks) deals with sewer and storm water networks. The final project goal is to develop integrated software, which provides the most cost-efficient system of maintenance, repair and rehabilitation of sewer networks. Decisions on investments in rehabilitation often have to be made with uncertain information about the structural condition and the hydraulic performance of a sewer system. Because of this, decision-making involves considerable risks. This paper presents the results of research focused on the study of hydraulic effects caused by failures due to temporal decline of sewer systems. Hydraulic simulations are usually carried out by running commercial models that apply, as input, default values of parameters that strongly influence results. Using CCTV inspections information as dataset to catalogue principal types of failures affecting pipes, a 3D model was used to evaluate their hydraulic consequences. The translation of failures effects in parameters values producing the same hydraulic conditions caused by failures was carried out through the comparison of laboratory experiences and 3D simulations results. Those parameters could be the input of 1D commercial models instead of the default values commonly inserted.

  20. State of Technology Report for Force Main Rehabilitation

    EPA Science Inventory

    Force mains that carry sewage flows under pressure represent a special set of challenges for sewer rehabilitation. Force mains represent about 7.5% of the wastewater system and they typically use materials that are not commonly used in gravity sewer systems. Ductile iron (DI), ...

  1. State of Technology Report for Force Main Rehabilitation

    EPA Science Inventory

    Force mains that carry sewage flows under pressure represent a special set of challenges for sewer rehabilitation. Force mains represent about 7.5% of the wastewater system and they typically use materials that are not commonly used in gravity sewer systems. Ductile iron (DI), ...

  2. Impacts and managerial implications for sewer systems due to recent changes to inputs in domestic wastewater - A review.

    PubMed

    Mattsson, Jonathan; Hedström, Annelie; Ashley, Richard M; Viklander, Maria

    2015-09-15

    Ever since the advent of major sewer construction in the 1850s, the issue of increased solids deposition in sewers due to changes in domestic wastewater inputs has been frequently debated. Three recent changes considered here are the introduction of kitchen sink food waste disposers (FWDs); rising levels of inputs of fat, oil and grease (FOG); and the installation of low-flush toilets (LFTs). In this review these changes have been examined with regard to potential solids depositional impacts on sewer systems and the managerial implications. The review indicates that each of the changes has the potential to cause an increase in solids deposition in sewers and this is likely to be more pronounced for the upstream reaches of networks that serve fewer households than the downstream parts and for specific sewer features such as sags. The review has highlighted the importance of educational campaigns directed to the public to mitigate deposition as many of the observed problems have been linked to domestic behaviour in regard to FOGs, FWDs and toilet flushing. A standardized monitoring procedure of repeat sewer blockage locations can also be a means to identify depositional hot-spots. Interactions between the various changes in inputs in the studies reviewed here indicated an increased potential for blockage formation, but this would need to be further substantiated. As the precise nature of these changes in inputs have been found to be variable, depending on lifestyles and type of installation, the additional problems that may arise pose particular challenges to sewer operators and managers because of the difficulty in generalizing the nature of the changes, particularly where retrofitting projects in households are being considered. The three types of changes to inputs reviewed here highlight the need to consider whether or not more or less solid waste from households should be diverted into sewers. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Simulating groundwater-induced sewer flooding

    NASA Astrophysics Data System (ADS)

    Mijic, A.; Mansour, M.; Stanic, M.; Jackson, C. R.

    2016-12-01

    During the last decade, Chalk catchments of southern England experienced severe groundwater flooding. High groundwater levels resulted in the groundwater ingress into the sewer network that led to restricted toilet use and the overflow of diluted, but untreated sewage to road surfaces, rivers and water courses. In response to these events the water and sewerage company Thames Water Utilities Ltd (TWUL) had to allocate significant funds to mitigate the impacts. It was estimated that approximately £19m was spent responding to the extreme wet weather of 2013-14, along with the use of a fleet of over 100 tankers. However, the magnitude of the event was so large that these efforts could not stop the discharge of sewage to the environment. This work presents the analysis of the risk of groundwater-induced sewer flooding within the Chalk catchment of the River Lambourn, Berkshire. A spatially distributed groundwater model was used to assess historic groundwater flood risk and the potential impacts of changes in future climate. We then linked this model to an urban groundwater model to enable us to simulate groundwater-sewer interaction in detail. The modelling setup was used to identify relationships between infiltration into sewers and groundwater levels at specific points on TWUL's sewer network, and to estimate historic and future groundwater flood risk, and how this varies across the catchment. The study showed the significance of understanding the impact of groundwater on the urban water systems, and producing information that can inform a water company's response to groundwater flood risk, their decision making process and their asset management planning. However, the knowledge gained through integrated modelling of groundwater-sewer interactions has highlighted limitations of existing approaches for the simulation of these coupled systems. We conclude this work with number of recommendations about how to improve such hydrological/sewer analysis.

  4. Long-term impacts on sewers following food waste disposer installation in housing areas.

    PubMed

    Mattsson, Jonathan; Hedström, Annelie; Viklander, Maria

    2014-01-01

    To increase biogas generation and decrease vehicle transportation of solid waste, the integration of food waste disposers (FWDs) into the wastewater system has been proposed. However, concerns have been raised about the long-term impact of the additional load of the FWDs on sewer systems. To examine the said impact, this study has used closed-circuit television inspection techniques to evaluate the status of 181 concrete pipes serving single family housing areas with a diameter of 225 mm, ranging from a 100% connection rate of households with an FWD to none. A minor study was also performed on a multi-family housing area, where mainly plastic pipes (200 mm) were used. The extent and distribution of deposits related to the ratio of FWDs, inclination and pipe sagging (backfalls) were ascertained by using linear regression and analysis of variance. The results showed that FWDs have had an impact on the level of deposits in the sewer, but this has, in turn, been of minor significance. With a high connection rate of FWDs upstream of a pipe, the extent of the total level of deposits, as well as finer sediments, was statistically determined to be greater. However, the majority of the deposits were observed to be small, which would suggest the impact of FWDs on sewer performance to be minor. As food waste not compatible with the FWD was seen in the sewers, educational campaigns could be beneficial to further lower the risks of sewer blocking.

  5. Influence of pipe material and surfaces on sulfide related odor and corrosion in sewers.

    PubMed

    Nielsen, Asbjørn Haaning; Vollertsen, Jes; Jensen, Henriette Stokbro; Wium-Andersen, Tove; Hvitved-Jacobsen, Thorkild

    2008-09-01

    Hydrogen sulfide oxidation on sewer pipe surfaces was investigated in a pilot scale experimental setup. The experiments were aimed at replicating conditions in a gravity sewer located immediately downstream of a force main where sulfide related concrete corrosion and odor is often observed. During the experiments, hydrogen sulfide gas was injected intermittently into the headspace of partially filled concrete and plastic (PVC and HDPE) sewer pipes in concentrations of approximately 1,000 ppm(v). Between each injection, the hydrogen sulfide concentration was monitored while it decreased because of adsorption and subsequent oxidation on the pipe surfaces. The experiments showed that the rate of hydrogen sulfide oxidation was approximately two orders of magnitude faster on the concrete pipe surfaces than on the plastic pipe surfaces. Removal of the layer of reaction (corrosion) products from the concrete pipes was found to reduce the rate of hydrogen sulfide oxidation significantly. However, the rate of sulfide oxidation was restored to its background level within 10-20 days. A similar treatment had no observable effect on hydrogen sulfide removal in the plastic pipe reactors. The experimental results were used to model hydrogen sulfide oxidation under field conditions. This showed that the gas-phase hydrogen sulfide concentration in concrete sewers would typically amount to a few percent of the equilibrium concentration calculated from Henry's law. In the plastic pipe sewers, significantly higher concentrations were predicted because of the slower adsorption and oxidation kinetics on such surfaces.

  6. Cause and effect oriented sewer degradation evaluation to support scheduled inspection planning.

    PubMed

    Fuchs-Hanusch, D; Günther, M; Möderl, M; Muschalla, D

    2015-01-01

    Managing the subsurface urban infrastructure, while facing limited budgets, is one of the main challenges wastewater utilities currently face. In this context targeted planning of inspection and maintenance measures plays a crucial role. This paper introduces a cause and effect oriented sewer degradation evaluation approach to support decisions on inspection frequencies and priorities. Therefore, the application of logistic regression models, to predict the probability of failure categories as an alternative to the prediction of sewer condition classes, was introduced. We assume that analysing the negative effects resulting from different failure categories in extension to a condition class-based planning approach offers new possibilities for targeted inspection planning. In addition, a cross validation process was described to allow for a more accurate prediction of sewer degradation. The described approach was applied to an Austrian sewer system. The results show that the failure category-based regression models perform better than the conventional condition class-oriented models. The results of the failure category predictions are presented with respect to negative effects the failure may have on the hydraulic performance of the system. Finally, suggestions are given for how this performance-oriented sewer section evaluation can support scheduled inspection planning.

  7. FLUSHING FOR SEWER SEDIMENT, CORROSION, AND POLLUTION CONTROL

    EPA Science Inventory

    This presentation overviews causes of sewer deterioration and heavy pollutant discharges caused by rain events together with a discussion of their control methods. In particular, it covers in-sewer- and combined sewer overflow- (CSO-) storage-tank-flushing systems for removal of ...

  8. Predicting concrete corrosion of sewers using artificial neural network.

    PubMed

    Jiang, Guangming; Keller, Jurg; Bond, Philip L; Yuan, Zhiguo

    2016-04-01

    Corrosion is often a major failure mechanism for concrete sewers and under such circumstances the sewer service life is largely determined by the progression of microbially induced concrete corrosion. The modelling of sewer processes has become possible due to the improved understanding of in-sewer transformation. Recent systematic studies about the correlation between the corrosion processes and sewer environment factors should be utilized to improve the prediction capability of service life by sewer models. This paper presents an artificial neural network (ANN)-based approach for modelling the concrete corrosion processes in sewers. The approach included predicting the time for the corrosion to initiate and then predicting the corrosion rate after the initiation period. The ANN model was trained and validated with long-term (4.5 years) corrosion data obtained in laboratory corrosion chambers, and further verified with field measurements in real sewers across Australia. The trained model estimated the corrosion initiation time and corrosion rates very close to those measured in Australian sewers. The ANN model performed better than a multiple regression model also developed on the same dataset. Additionally, the ANN model can serve as a prediction framework for sewer service life, which can be progressively improved and expanded by including corrosion rates measured in different sewer conditions. Furthermore, the proposed methodology holds promise to facilitate the construction of analytical models associated with corrosion processes of concrete sewers.

  9. SANITARY SEWER OVERFLOW ANALYSIS AND PLANNING (SSOAP) TOOLBOX

    EPA Science Inventory

    Description: The Nation's sanitary-sewer infrastructure is aging, with some sewers dating back over 100 years. Nationwide, there are more than 19,500 municipal sanitary-sewer collection systems serving an estimated 150 million people and about 40,000 SSO events per year. Becau...

  10. SEWER SEDIMENT AND CONTROL: A MANAGEMENT PRACTICES REFERENCES GUIDE

    EPA Science Inventory

    Sewer-solids sediment is one of major sources of pollutants in urban wet-weather flow (WWF) discharges that include combined-sewer overflow (CSO), separate sanitary-sewer overflow (SSO), and stormwater runoff. During low-flow, dry-weather periods, sanitary wastewater solids depo...

  11. FLUSHING FOR SEWER SEDIMENT, CORROSION, AND POLLUTION CONTROL

    EPA Science Inventory

    This paper overviews causes of combined-sewer deterioration and their heavy pollutant discharges caused by rain events together with a discussion of their control methods. In particular, it covers in-sewer and combined-sewer overflow (CSO) storage-tank-flushing systems for removi...

  12. FLUSHING FOR SEWER SEDIMENT, CORROSION, AND POLLUTION CONTROL

    EPA Science Inventory

    This presentation overviews causes of sewer deterioration and heavy pollutant discharges caused by rain events together with a discussion of their control methods. In particular, it covers in-sewer- and combined sewer overflow- (CSO-) storage-tank-flushing systems for removal of ...

  13. SEWER SEDIMENT AND CONTROL: A MANAGEMENT PRACTICES REFERENCES GUIDE

    EPA Science Inventory

    Sewer-solids sediment is one of major sources of pollutants in urban wet-weather flow (WWF) discharges that include combined-sewer overflow (CSO), separate sanitary-sewer overflow (SSO), and stormwater runoff. During low-flow, dry-weather periods, sanitary wastewater solids depo...

  14. SANITARY SEWER OVERFLOW ANALYSIS AND PLANNING (SSOAP) TOOLBOX

    EPA Science Inventory

    Description: The Nation's sanitary-sewer infrastructure is aging, with some sewers dating back over 100 years. Nationwide, there are more than 19,500 municipal sanitary-sewer collection systems serving an estimated 150 million people and about 40,000 SSO events per year. Becau...

  15. FLUSHING FOR SEWER SEDIMENT, CORROSION, AND POLLUTION CONTROL

    EPA Science Inventory

    This paper overviews causes of combined-sewer deterioration and their heavy pollutant discharges caused by rain events together with a discussion of their control methods. In particular, it covers in-sewer and combined-sewer overflow (CSO) storage-tank-flushing systems for removi...

  16. Dynamic online sewer modelling in Helsingborg.

    PubMed

    Hernebring, C; Jönsson, L E; Thorén, U B; Møller, A

    2002-01-01

    Within the last decade, the sewer system in Helsingborg, Sweden has been rehabilitated in many ways along with the reconstruction of the WWTP Oresundsverket in order to obtain a high degree of nitrogen and phosphorus removal. In that context a holistic view has been applied in order to optimise the corrective measures as seen from the effects in the receiving waters. A sewer catchment model has been used to evaluate several operation strategies and the effect of introducing RTC. Recently, a MOUSE ONLINE system was installed. In this phase the objective is to establish a stable communication with the SCADA system and to generate short-term flow forecasts.

  17. Water Sensitive Urban Design retrofits in Copenhagen - 40% to the sewer, 60% to the city.

    PubMed

    Fryd, O; Backhaus, A; Birch, H; Fratini, C F; Ingvertsen, S T; Jeppesen, J; Panduro, T E; Roldin, M; Jensen, M B

    2013-01-01

    Water Sensitive Urban Design (WSUD) is emerging in Denmark. This interdisciplinary desk study investigated the options for WSUD retrofitting in a 15 km(2) combined sewer catchment area in Copenhagen. The study was developed in collaboration with the City of Copenhagen and its water utility, and involved researchers representing hydrogeology, sewer hydraulics, environmental chemistry/economics/engineering, landscape architecture and urban planning. The resulting catchment strategy suggests the implementation of five sub-strategies. First, disconnection is focused within sites that are relatively easy to disconnect, due to stormwater quality, soil conditions, stakeholder issues, and the provision of unbuilt sites. Second, stormwater runoff is infiltrated in areas with relatively deep groundwater levels at a ratio that doesn't create a critical rise in the groundwater table to the surface. Third, neighbourhoods located near low-lying streams and public parks are disconnected from the sewer system and the sloping terrain is utilised to convey runoff. Fourth, the promotion of coherent blue and green wedges in the city is linked with WSUD retrofits and urban climate-proofing. Fifth, WSUD is implemented with delayed and regulated overflows to the sewer system. The results are partially adopted by the City of Copenhagen and currently under pilot testing.

  18. Locations of Combined Sewer Overflow Outfalls - US EPA Region 3

    EPA Pesticide Factsheets

    This data layer identifies the locations of Combined sewer overflow outfalls. Combined sewer systems are sewers that are designed to collect rainwater runoff, domestic sewage, and industrial wastewater in the same pipe. Most of the time, combined sewer systems transport all of their wastewater to a sewage treatment plant, where it is treated and then discharged to a water body. During periods of heavy rainfall or snowmelt, however, the wastewater volume in a combined sewer system can exceed the capacity of the sewer system or treatment plant. For this reason, combined sewer systems are designed to overflow occasionally and discharge excess untreated wastewater directly to nearby streams, rivers, or other water bodies. For further information visit: http://cfpub1.epa.gov/npdes/home.cfm?program_id=5

  19. Modelling total suspended solids, E. coli and carbamazepine, a tracer of wastewater contamination from combined sewer overflows

    NASA Astrophysics Data System (ADS)

    Pongmala, Khemngeun; Autixier, Laurène; Madoux-Humery, Anne-Sophie; Fuamba, Musandji; Galarneau, Martine; Sauvé, Sébastien; Prévost, Michèle; Dorner, Sarah

    2015-12-01

    Urban source water protection requires knowledge of sources of fecal contamination upstream of drinking water intakes. Combined and sanitary sewer overflows (CSOs and SSOs) are primary sources of microbiological contamination and wastewater micropollutants (WWMPs) in urban water supplies. To quantify the impact of sewer overflows, predictive simulation models are required and have not been widely applied for microbial contaminants such as fecal indicator bacteria and pathogens in urban drainage networks. The objective of this study was to apply a simulation model to estimate the dynamics of three contaminants in sewer overflows - total suspended solids, Escherichia coli (E. coli) and carbamazepine, a WWMP. A mixed combined and pseudo-sanitary drainage network in Québec, Canada was studied and modelled for a total of 7 events for which water quality data were available. Model results were significantly correlated with field water quality data. The model confirmed that the contributions of E. coli from runoff and sewer deposits were minor and their dominant source was from sewage. In contrast, the main sources of total suspended solids were stormwater runoff and sewer resuspension. Given that it is not present in stormwater, carbamazepine was found to be a useful stable tracer of sewage contributions to total contaminant loads and also provided an indication of the fraction of total suspended solids originating from sewer deposits because of its similar response to increasing flowrates.

  20. Urban Runoff and Combined Sewer Overflow.

    ERIC Educational Resources Information Center

    Field, Richard; Gardner, Bradford B.

    1978-01-01

    Presents a literature review of wastewater treatment, covering publications of 1976-77. This review includes areas such as: (1) urban runoff quality and quantity; (2) urban hydrology; (3) management practices; and (4) combined sewer overflows. A list of 140 references is also presented. (HM)

  1. An Environmental Innovation: The Sewer Mouse

    NASA Technical Reports Server (NTRS)

    1979-01-01

    In the effort to clean up America's waters, there is a little-known complicating factor: because they leak, sewer systems in many American cities are causing rather than preventing pollution of rivers and lakes. Fixing the leaks is difficult because their locations are unknown. Maintenance crews can't tear up a whole city looking for cracks in the pipes; they must first determine which areas are most likely suspects. An aerospace spinoff is providing help in that regard. The problem starts with heavy rains. Rainwater naturally flows into the sewers from streets, but sewage systems are designed to accommodate it. However, they are not designed to handle the additional flow of "groundwater", rain absorbed by the earth which seeps into the sewers through leaks in pipes and sewer walls. After a storm, groundwater seepage can increase the waterflow to deluge proportions, with the result that sewage treatment plants are incapable of processing the swollen flow. When that happens the sluices must be opened, dumping raw sewage into rivers and lakes.

  2. OPIMIZATION OF COMBINED SEWER OVERFLOW CONTROL SYSTEMS

    EPA Science Inventory

    The highly variable and intermittent pollutant concentrations and flowrates associated with wet-weather events in combined sewersheds necessitates the use of storage-treatment systems to control pollution. A strategy should be adopted to develop an optimized combined sewer overfl...

  3. Enforcement to Address Sewer Overflows | Eliminating ...

    EPA Pesticide Factsheets

    2017-04-10

    EPA's compliance goal is to eliminate sanitary sewer overflows (SSOs) from municipal collection systems and to ensure that wastewater is being conveyed to treatment plants in accordance with the requirements of the Clean Water Act. To eliminate SSOs, EPA uses a mix of compliance and enforcement tools.

  4. Urban Runoff and Combined Sewer Overflow.

    ERIC Educational Resources Information Center

    Field, Richard; Gardner, Bradford B.

    1978-01-01

    Presents a literature review of wastewater treatment, covering publications of 1976-77. This review includes areas such as: (1) urban runoff quality and quantity; (2) urban hydrology; (3) management practices; and (4) combined sewer overflows. A list of 140 references is also presented. (HM)

  5. OPTIMIZATION OF COMBINED SEWER OVERFLOW CONTROL SYSTEMS

    EPA Science Inventory

    The highly variable and intermittent pollutant concentrations and flowrates associated with wet-weather events in combined sewersheds necessitates the use of storage-treatment systems to control pollution.An optimized combined-sewer-overflow (CSO) control system requires a manage...

  6. Multistakeholder Evaluation of Condominial Sewer Services

    ERIC Educational Resources Information Center

    Nance, Earthea

    2005-01-01

    A multistakeholder evaluation procedure is presented to address the many challenges in evaluating the performance of condominial sewer projects in Brazil. Condominial sewerage is a promising appropriate technology that is coproduced by users and public agencies, but little is known about project performance. This article shows that…

  7. MANUAL: REAL TIME CONTROL OF COMBINED SEWERS

    EPA Science Inventory

    Managers, engineers, and operators of combined urban sewer systems are faced with difficult problems related to the operation and maintenance of their facilities. In addition to the issues related to the operation and upkeep of the system, many sewerage agencies are facing increa...

  8. MANUAL: REAL TIME CONTROL OF COMBINED SEWERS

    EPA Science Inventory

    Managers, engineers, and operators of combined urban sewer systems are faced with difficult problems related to the operation and maintenance of their facilities. In addition to the issues related to the operation and upkeep of the system, many sewerage agencies are facing increa...

  9. OPTIMIZATION OF COMBINED SEWER OVERFLOW CONTROL SYSTEMS

    EPA Science Inventory

    The highly variable and intermittent pollutant concentrations and flowrates associated with wet-weather events in combined sewersheds necessitates the use of storage-treatment systems to control pollution.An optimized combined-sewer-overflow (CSO) control system requires a manage...

  10. OPIMIZATION OF COMBINED SEWER OVERFLOW CONTROL SYSTEMS

    EPA Science Inventory

    The highly variable and intermittent pollutant concentrations and flowrates associated with wet-weather events in combined sewersheds necessitates the use of storage-treatment systems to control pollution. A strategy should be adopted to develop an optimized combined sewer overfl...

  11. Sources, nature, and fate of heavy metal-bearing particles in the sewer system.

    PubMed

    Houhou, J; Lartiges, B S; Montarges-Pelletier, E; Sieliechi, J; Ghanbaja, J; Kohler, A

    2009-11-15

    A preliminary insight into metal cycling within the urban sewer was obtained by determining both the heavy metal concentrations (Cu, Zn, Pb, Cd, Ni, Cr) in sewage and sediments, and the nature of metal-bearing particles using TEM-EDX, SEM-EDX and XRD. Particles collected from tap water, sump-pit deposits, and washbasin siphons, were also examined to trace back the origin of some mineral species. The results show that the total levels in Cu, Pb, Zn, Ni, and Cr in sewage are similar to that reported in the literature, thus suggesting that a time-averaged heavy metal fingerprint of domestic sewage can be defined for most developed cities at the urban catchment scale. Household activities represent the main source of Zn and Pb, the water supply system is a significant source of Cu, and in our case, groundwater infiltration in the sewer system provides a supplementary source of Ni and Cd. Concentrations in heavy metals were much higher in sewer sediments than in sewage suspended solids, the enrichment being due to the preferential settling of metal-bearing particles of high density and/or the precipitation of neoformed mineral phases. TEM and SEM-EDX analyses indicated that suspended solids, biofilms, and sewer sediments contained similar heavy metal-bearing particles including alloys and metal fragments, oxidized metals and sulfides. Copper fragments, metal carbonates (Cu, Zn, Pb), and oxidized soldering materials are released from the erosion of domestic plumbing, whereas the precipitation of sulfides and the sulfurization of metal phases occur primarily within the household connections to the sewer trunk. Close examination of sulfide phases also revealed in most cases a complex growth history recorded in the texture of particles, which likely reflects changes in physicochemical conditions associated with successive resuspension and settling of particles within the sewer system.

  12. Effects Of Leaky Sewers On Groundwater Quality

    NASA Astrophysics Data System (ADS)

    Leschik, S.; Musolff, A.; Reinstorf, F.; Strauch, G.; Oswald, S. E.; Schirmer, M.

    2007-12-01

    The impact of urban areas on groundwater quality has become an emerging research field in hydrogeology. Urban subsurface infrastructures like sewer networks are often leaky, so untreated wastewater may enter the urban aquifer. The transport of wastewater into the groundwater is still not well understood under field conditions. In the research platform WASSER Leipzig (Water And Sewershed Study of Environmental Risk in Leipzig- Germany) the effects of leaky sewers on the groundwater quality are investigated. The research is focused on the occurrence and transport of so-called "xenobiotics" such as pharmaceuticals and personal care product additives. Xenobiotics may pose a threat on human health, but can also be considered a marker for an urban impact on water resources. A new test site was established in Leipzig to quantify mass fluxes of xenobiotics into the groundwater from a leaky sewer. Corresponding to the leaks which were detected by closed circuit television inspections, monitoring wells were installed up- and downstream of the sewer. Concentrations of eight xenobiotics (technical-nonylphenol, bisphenol-a, caffeine, galaxolide, tonalide, carbamazepine, phenazone, ethinylestradiol) obtained from first sampling programmes were found to be highly heterogeneous, but a relation between the position of the sampling points and the sewer could not be clearly identified. However, concentrations of sodium, chloride, potassium and nitrate increased significantly downstream of the sewer which may be due to wastewater exfiltration, since no other source is known on the water flowpath from the upstream to the downstream wells. Because of the highly heterogeneous spatial distribution of xenobiotics at the test site, a monitoring concept was developed comprising both high-resolution sampling and an integral approach to obtain representative average concentrations. Direct-push techniques were used to gain insight into the fine-scale spatial distribution of the target compounds

  13. Urban flood risk assessment using sewer flooding databases.

    PubMed

    Caradot, Nicolas; Granger, Damien; Chapgier, Jean; Cherqui, Frédéric; Chocat, Bernard

    2011-01-01

    Sustainable water management is a global challenge for the 21st century. One key aspect remains protection against urban flooding. The main objective is to ensure or maintain an adequate level of service for all inhabitants. However, level of service is still difficult to assess and the high-risk locations difficult to identify. In this article, we propose a methodology, which (i) allows water managers to measure the service provided by the urban drainage system with regard to protection against urban flooding; and (ii) helps stakeholders to determine effective strategies for improving the service provided. One key aspect of this work is to use a database of sewer flood event records to assess flood risk. Our methodology helps urban water managers to assess the risk of sewer flooding; this approach does not seek to predict flooding but rather to inform decision makers on the current level of risk and on actions which need to be taken to reduce the risk. This work is based on a comprehensive definition of risk, including territorial vulnerability and perceptions of urban water stakeholders. This paper presents the results and the methodological contributions from implementing the methodology on two case studies: the cities of Lyon and Mulhouse.

  14. Kinetics and stoichiometry of sulfide oxidation by sewer biofilms.

    PubMed

    Nielsen, Asbjørn Haaning; Hvitved-Jacobsen, Thorkild; Vollertsen, Jes

    2005-10-01

    Oxidation of sulfide under aerobic conditions by biofilms grown on municipal wastewater in 6 identical pipe reactors was investigated. The biofilms were grown at pH 7.6 and temperatures of 20 and 25 degrees C under aerobic-anaerobic transient conditions with pulse dosing of sulfide in the bulk water. The pulse dosing of sulfide served to simulate conditions in a gravity sewer located downstream of a pressure main. During growth of the biofilms, sulfide was pulse dosed in concentrations of 0, 0.5, 2.0 and 5.0 g Sm(-3) with a frequency of 1h(-1). Based on a series of batch experiments, kinetics and stoichiometry of sulfide oxidation by the sewer biofilms was investigated and a rate equation and a stoichiometric constant proposed. Sulfide oxidation kinetics was significantly faster for biofilms grown at sulfide loadings of 0.5, 2.0 and 5.0 g Sm(-3)h(-1) than for biofilms grown in the absence of sulfide. However, the kinetics of sulfide oxidation was relatively constant for biofilms grown at sulfide loadings above 0.5 g Sm(-3)h(-1). Mass balance calculations of dissolved oxygen and sulfur compounds suggested the oxidation product to be elemental sulfur. Further oxidation of elemental sulfur could not be documented.

  15. Integrated planning of rehabilitation strategies for sewers.

    PubMed

    Kleidorfer, Manfred; Möderl, Michael; Tscheikner-Gratl, Franz; Hammerer, Max; Kinzel, Heiko; Rauch, Wolfgang

    2013-01-01

    Building measures in sewer systems are increasingly driven by rehabilitation/retrofitting and adaptation needs. Aging infrastructure together with changing boundary conditions (due to climate change, land-use change, demographic change) and also changing design standards and legislation require a prospective design to preserve the functionality of urban drainage systems not only today, but also in a long-term perspective. To improve a prospective design of urban water infrastructure, the Austrian Research Promotion Agency funded the research project 'REHAB - Integrated planning of rehabilitation strategies of urban infrastructure systems'. Therein a novel strategic planning tool which considers these external drivers of rehabilitation strategies is developed. In this study the scope of the project is described and, as well as first results regarding sewer pipe conditions, future development and vulnerability assessment are also discussed.

  16. In situ measurements of shear stresses of a flushing wave in a circular sewer using ultrasound.

    PubMed

    Staufer, P; Pinnekamp, J

    2008-01-01

    Deposits build up in sewer networks during both spells of dry weather and in connection with storm water events. In order to reduce the negative effects of deposit on the environment, different cleaning technologies and strategies are applied to remove the deposits. Jet cleaning represents the most widely used method to clean sewers. Another alternative cleaning procedure is flushing. On account of new developments in measurement and control panels, the flushing method is becoming more important. Therefore, in the last few years a number of new flushing devices have been constructed for application in basins, main sewers and initial reaches. Today, automatic flushing gates are able to accomplish cleaning procedures under economical and ecological conditions. The properties of flushing waves for cleaning sewers have been determined by several mathematical-numerical studies. These various investigations use altering numerical schemes, are based on different sets of physical equations and take one- or more dimensional aspects into account. Considering that bottom shear stress is the key value to evaluate the beginning of motion of any deposit, one may use this value that has to be determined by measurements. This paper deals with shear stresses caused by flushing waves which have been measured by an ultrasonic device that can determine the velocity in different depths of flow. Thus, it is possible, within certain limits, to calculate bottom shear stresses based on the log-wall law. Further discussion will deal with the requirements of measurements, its uncertainty and aspects in respect to the application of simulation of flushing waves.

  17. Bayesian analysis for erosion modelling of sediments in combined sewer systems.

    PubMed

    Kanso, A; Chebbo, G; Tassin, B

    2005-01-01

    Previous research has confirmed that the sediments at the bed of combined sewer systems are the main source of particulate and organic pollution during rain events contributing to combined sewer overflows. However, existing urban stormwater models utilize inappropriate sediment transport formulas initially developed from alluvial hydrodynamics. Recently, a model has been formulated and profoundly assessed based on laboratory experiments to simulate the erosion of sediments in sewer pipes taking into account the increase in strength with depth in the weak layer of deposits. In order to objectively evaluate this model, this paper presents a Bayesian analysis of the model using field data collected in sewer pipes in Paris under known hydraulic conditions. The test has been performed using a MCMC sampling method for calibration and uncertainty assessment. Results demonstrate the capacity of the model to reproduce erosion as a direct response to the increase in bed shear stress. This is due to the model description of the erosional strength in the deposits and to the shape of the measured bed shear stress. However, large uncertainties in some of the model parameters suggest that the model could be over-parameterised and necessitates a large amount of informative data for its calibration.

  18. A review of sulfide emissions in sewer networks: overall approach and systemic modelling.

    PubMed

    Carrera, Lucie; Springer, Fanny; Lipeme-Kouyi, Gislain; Buffiere, Pierre

    2016-01-01

    The problems related to hydrogen sulfide in terms of deterioration of sewer networks, toxicity and odor nuisance have become very clear to the network stakeholders and the public. The hydraulic and (bio)chemical phenomena and parameters controlling sulfide formation, emission and their incidences in sewer networks are very complex. Recent research studies have been developed in gravity and pressure sewers and some transfer models have been published. Nevertheless, the models do not take into account all the physical phenomena influencing the emission process. After summing up the main scientific knowledge concerning the production, oxidation, transfer and emission processes, the present review includes: (i) a synthetic analysis of sulfide and hydrogen sulfide emission models in sewer networks, (ii) an estimation of their limit, (iii) perspectives to improve the modelling approach. It shows that sulfide formation and uptake models still need refinements especially for some phenomena such as liquid to gas mass transfer. Transfer models that have been published so far are purposely simplified and valid for simple systems. More efforts have to be undertaken in order to better understand the mechanisms and the dynamics of hydrogen sulfide production and emission in real conditions.

  19. Analyzing hydrocarbons in sewer to help in PAH source apportionment in sewage sludges.

    PubMed

    Mansuy-Huault, Laurence; Regier, Annette; Faure, Pierre

    2009-05-01

    A multi-molecular approach for polycyclic aromatic hydrocarbons (PAH) source apportionment in sewage sludge was tested. Three simple catchment areas with corresponding wastewater treatment plants (WWTP) were chosen. Sewage sludges of these WWTPs chronically exceeded the French guide values for PAHs. Aliphatic and aromatic hydrocarbons were quantified in sediments or wastewater suspended particulate matter sampled in different locations of the sewer as well as in sewage sludge. Various molecular indices including PAH ratios were calculated. The results showed that the ratios calculated from sewage sludge analyses provided a rather unspecific hydrocarbon fingerprint where combustion input appear as the main PAH sources. The complexity of the inputs as well as degradation occurring during wastewater treatment prevent any detailed diagnosis. Coupled to the analyses of samples collected in the sewer, the multi-molecular approach becomes more efficient especially for the identification of specific petroleum inputs such as fuel or used lubricating oils which can be important PAH sources. Indeed, the sampling in the sewer allows a spatial screening of the hydrocarbon inputs and facilitates the PAH source apportionment by avoiding the dilution of specific inputs with the whole wastewater inputs and by limiting the degradation of the molecular fingerprint that could occur during transfer and treatment in the WWTP. Then, the combination of PAH ratios and aliphatic distribution analyses is a very valuable approach that can help in sewer and WWTP management.

  20. Measuring Flow Reductions in a Combined Sewer System using Green Infrastructure - abstract

    EPA Science Inventory

    In 2009, the Louisville and Jefferson County Metropolitan Sewer District (MSD) submitted an Integrated Overflow Abatement Plan (IOAP) addressing combined sewer overflows (CSOs) and sanitary sewer overflows. Many of the solutions involve gray infrastructure, such as large, end-of...

  1. Measuring Flow Reductions in a Combined Sewer System using Green Infrastructure - abstract

    EPA Science Inventory

    In 2009, the Louisville and Jefferson County Metropolitan Sewer District (MSD) submitted an Integrated Overflow Abatement Plan (IOAP) addressing combined sewer overflows (CSOs) and sanitary sewer overflows. Many of the solutions involve gray infrastructure, such as large, end-of...

  2. Dynamics of rain-induced pollutographs of solubles in sewers.

    PubMed

    Rutsch, M; Müller, I; Krebs, P

    2005-01-01

    When looking at acute receiving water impacts due to combined sewer overflows the characteristics of the background diurnal sewage flux variation may influence the peak loads from combined sewer overflows (CSO) and wastewater treatment plant (WWTP) effluent significantly. In this paper, effects on the dynamic compounds transported in the sewer, on CSO discharges and WWTP loading are evaluated by means of hydrodynamic simulations. The simulations are based on different scenarios for diurnal dry-weather flow variations induced by different infiltration rates.

  3. Simulation of the wastewater temperature in sewers with TEMPEST.

    PubMed

    Dürrenmatt, David J; Wanner, Oskar

    2008-01-01

    TEMPEST is a new interactive simulation program for the estimation of the wastewater temperature in sewers. Intuitive graphical user interfaces assist the user in managing data, performing calculations and plotting results. The program calculates the dynamics and longitudinal spatial profiles of the wastewater temperature in sewer lines. Interactions between wastewater, sewer air and surrounding soil are modeled in TEMPEST by mass balance equations, rate expressions found in the literature and a new empirical model of the airflow in the sewer. TEMPEST was developed as a tool which can be applied in practice, i.e., it requires as few input data as possible. These data include the upstream wastewater discharge and temperature, geometric and hydraulic parameters of the sewer, material properties of the sewer pipe and surrounding soil, ambient conditions, and estimates of the capacity of openings for air exchange between sewer and environment. Based on a case study it is shown how TEMPEST can be applied to estimate the decrease of the downstream wastewater temperature caused by heat recovery from the sewer. Because the efficiency of nitrification strongly depends on the wastewater temperature, this application is of practical relevance for situations in which the sewer ends at a nitrifying wastewater treatment plant.

  4. Transformation of AgCl nanoparticles in a sewer system--A field study.

    PubMed

    Kaegi, Ralf; Voegelin, Andreas; Sinnet, Brian; Zuleeg, Steffen; Siegrist, Hansruedi; Burkhardt, Michael

    2015-12-01

    Silver nanoparticles (Ag-NP) are increasingly used in consumer products and their release during the use phase may negatively affect aquatic ecosystems. Research efforts, so far, have mainly addressed the application and use of metallic Ag(0)-NP. However, as shown by recent studies on the release of Ag from textiles, other forms of Ag, especially silver chloride (AgCl), are released in much larger quantities than metallic Ag(0). In this field study, we report the release of AgCl-NP from a point source (industrial laundry that applied AgCl-NP during a piloting phase over a period of several months to protect textiles from bacterial regrowth) to the public sewer system and investigate the transformation of Ag during its transport in the sewer system and in the municipal wastewater treatment plant (WWTP). During the study period, the laundry discharged ~85 g of Ag per day, which dominated the Ag loads in the sewer system from the respective catchment (72-95%) and the Ag in the digested WWTP sludge (67%). Combined results from electron microscopy and X-ray absorption spectroscopy revealed that the Ag discharged from the laundry to the sewer consisted of about one third AgCl and two thirds Ag2S, both forms primarily occurring as nanoparticles with diameters<100 nm. During the 800 m transport in the sewer channel to the nearby WWTP, corresponding to a travel time of ~30 min, the remaining AgCl was transformed into nanoparticulate Ag2S. Ag2S-NP also dominated the Ag speciation in the digested sludge. In line with results from earlier studies, the very low Ag concentrations measured in the effluent of the WWTP (<0.5 μg L(-1)) confirmed the very high removal efficiency of Ag from the wastewater stream (>95%). Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Modelling the effects of on-site greywater reuse and low flush toilets on municipal sewer systems.

    PubMed

    Penn, R; Schütze, M; Friedler, E

    2013-01-15

    On-site greywater reuse (GWR) and installation of water-efficient toilets (WET) reduce urban freshwater demand. Research on GWR and WET has generally overlooked the effects that GWR may have on municipal sewer systems. This paper discusses and quantifies these effects. The effects of GWR and WET, positive and negative, were studied by modelling a representative urban sewer system. GWR scenarios were modelled and analysed using the SIMBA simulation system. The results show that, as expected, the flow, velocity and proportional depth decrease as GWR increases. Nevertheless, the reduction is not evenly distributed throughout the day but mainly occurs during the morning and evening peaks. Examination of the effects of reduced toilet flush volumes revealed that in some of the GWR scenarios flows, velocities and proportional depths in the sewer were reduced, while in other GWR scenarios discharge volumes, velocities and proportional depths did not change. Further, it is indicated that as a result of GWR and installation of WET, sewer blockage rates are not expected to increase significantly. The results support the option to construct new sewer systems with smaller pipe diameters. The analysis shows that as the penetration of GWR systems increase, and with the installation of WET, concentrations of pollutants also increase. In GWR scenarios (when toilet flush volume is not reduced) the increase in pollutant concentrations is lower than the proportional reduction of sewage flow. Moreover, the results show that the spatial distribution of houses reusing GW does not significantly affect the parameters examined.

  6. HIGH-RATE DISINFECTION OF COMBINED SEWER OVERFLOW

    EPA Science Inventory

    Wet-weather flow (WWF), including combined-sewer overflow (CSO, sanitary-sewer overflow, and stormwater (SW), is a significant contributor of microbial contamination to surface water and ground water. By using effective wastewater or SW disinfection, introduction of pathogen con...

  7. Control Strategy for Storm-Generated Sanitary Sewer Overflows

    EPA Science Inventory

    This presentation covers a strategy for the abatement of pollution from sanitary-sewer overflows (SSO). Because of the great lengths of sanitary sewer systems, it is often less expensive to use alternatives to sewerline rehabilitation for infiltration/inflow (I/I) and associated ...

  8. CONTROL STRATEGY FOR STORM-GENERATED SANITARY-SEWER OVERFLOWS

    EPA Science Inventory

    This paper presents a strategy for the abatement of pollution from storm-generated sanitary-sewer overflows (SSO). Because of the great lengths of sanitary-sewer systems and their associated vast number of house-service laterals or building connections, it is often less expensiv...

  9. CONTROL STRATEGY FOR STORM-GENERATED SANITARY-SEWER OVERFLOWS

    EPA Science Inventory

    This paper presents a strategy for the abatement of pollution from storm-generated sanitary-sewer overflows (SSO). Because of the great lengths of sanitary sewer systems, it is often less expensive to use alterantives to sewerline rehabilitation for infiltration/inflow (I/I) and ...

  10. GATE AND VACUUM FLUSHING OF SEWER SEDIMENT: LABORATORY TESTING

    EPA Science Inventory

    The objective of this study was to test the performance of a traditional gate-flushing device and a newly-designed vacuum-flushing device in removing sediment from combined sewers and CSO storage tanks. A laboratory hydraulic flume was used to simulate a reach of sewer or storag...

  11. 40 CFR 35.925-21 - Storm sewers.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Storm sewers. 35.925-21 Section 35.925... STATE AND LOCAL ASSISTANCE Grants for Construction of Treatment Works-Clean Water Act § 35.925-21 Storm... treatment works for control of pollutant discharges from a separate storm sewer system (as defined in § 35...

  12. INNOVATIVE METHODS FOR THE OPTIMIZATION OF GRAVITY STORM SEWER DESIGN

    EPA Science Inventory

    The purpose of this paper is to describe a new method for optimizing the design of urban storm sewer systems. Previous efforts to optimize gravity sewers have met with limited success because classical optimization methods require that the problem be well behaved, e.g. describ...

  13. 7. VIEW TO NORTH SHOWING SEWER CONSTRUCTION IN FOREGROUND AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. VIEW TO NORTH SHOWING SEWER CONSTRUCTION IN FOREGROUND AND BUILDING F IN THE LEFT BACKGROUND. 8X10 black and white gelatin print. United States Coast Guard, Air Station Contract 1247, Sewer System. 1956. - U.S. Coast Guard Air Station San Francisco, 1020 North Access Road, San Francisco, San Francisco County, CA

  14. SEWER AND TANK FLUSHING FOR SEDIMENT, CORROSION AND POLLUTION CONTROL

    EPA Science Inventory

    This paper presents an overview of causes of sewer deterioration together with a discussion of control methods that can prevent or arrest this deterioration. In particular, the paper covers inline- and combined sewer overflow- (CSO) storage-tank-flushing systems for removal of se...

  15. SEWER AND TANK FLUSHING FOR CORROSION AND POLLUTION CONTROL

    EPA Science Inventory

    This paper presents an overview of the causes of sewer deterioration and control methods that can prevent or arrest this deterioration. articular, the paper addresses the use of inline- and combined sewer overflow (CSO) storage tank-flushing systems for removing sediments and mi...

  16. 40 CFR 35.925-21 - Storm sewers.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 1 2014-07-01 2014-07-01 false Storm sewers. 35.925-21 Section 35.925... STATE AND LOCAL ASSISTANCE Grants for Construction of Treatment Works-Clean Water Act § 35.925-21 Storm... treatment works for control of pollutant discharges from a separate storm sewer system (as defined in §...

  17. 40 CFR 35.925-21 - Storm sewers.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 1 2011-07-01 2011-07-01 false Storm sewers. 35.925-21 Section 35.925... STATE AND LOCAL ASSISTANCE Grants for Construction of Treatment Works-Clean Water Act § 35.925-21 Storm... treatment works for control of pollutant discharges from a separate storm sewer system (as defined in §...

  18. 40 CFR 35.925-21 - Storm sewers.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 1 2012-07-01 2012-07-01 false Storm sewers. 35.925-21 Section 35.925... STATE AND LOCAL ASSISTANCE Grants for Construction of Treatment Works-Clean Water Act § 35.925-21 Storm... treatment works for control of pollutant discharges from a separate storm sewer system (as defined in §...

  19. 40 CFR 35.925-21 - Storm sewers.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 1 2013-07-01 2013-07-01 false Storm sewers. 35.925-21 Section 35.925... STATE AND LOCAL ASSISTANCE Grants for Construction of Treatment Works-Clean Water Act § 35.925-21 Storm... treatment works for control of pollutant discharges from a separate storm sewer system (as defined in §...

  20. GATE AND VACUUM FLUSHING OF SEWER SEDIMENT: LABORATORY TESTING

    EPA Science Inventory

    The objective of this study was to test the performance of a traditional gate-flushing device and a newly-designed vacuum-flushing device in removing sediment from combined sewers and CSO storage tanks. A laboratory hydraulic flume was used to simulate a reach of sewer or storag...

  1. CONTROL STRATEGY FOR STORM-GENERATED SANITARY-SEWER OVERFLOWS

    EPA Science Inventory

    This paper presents a strategy for the abatement of pollution from storm-generated sanitary-sewer overflows (SSO). Because of the great lengths of sanitary-sewer systems and their associated vast number of house-service laterals or building connections, it is often less expensiv...

  2. SEWER AND TANK FLUSHING FOR CORROSION AND POLLUTION CONTROL

    EPA Science Inventory

    This paper presents an overview of the causes of sewer deterioration and control methods that can prevent or arrest this deterioration. articular, the paper addresses the use of inline- and combined sewer overflow (CSO) storage tank-flushing systems for removing sediments and mi...

  3. Control Strategy for Storm-Generated Sanitary Sewer Overflows

    EPA Science Inventory

    This presentation covers a strategy for the abatement of pollution from sanitary-sewer overflows (SSO). Because of the great lengths of sanitary sewer systems, it is often less expensive to use alternatives to sewerline rehabilitation for infiltration/inflow (I/I) and associated ...

  4. CONTROL STRATEGY FOR STORM-GENERATED SANITARY-SEWER OVERFLOWS

    EPA Science Inventory

    This paper presents a strategy for the abatement of pollution from storm-generated sanitary-sewer overflows (SSO). Because of the great lengths of sanitary sewer systems, it is often less expensive to use alterantives to sewerline rehabilitation for infiltration/inflow (I/I) and ...

  5. HIGH-RATE DISINFECTION OF COMBINED SEWER OVERFLOW

    EPA Science Inventory

    Wet-weather flow (WWF), including combined-sewer overflow (CSO, sanitary-sewer overflow, and stormwater (SW), is a significant contributor of microbial contamination to surface water and ground water. By using effective wastewater or SW disinfection, introduction of pathogen con...

  6. INNOVATIVE METHODS FOR THE OPTIMIZATION OF GRAVITY STORM SEWER DESIGN

    EPA Science Inventory

    The purpose of this paper is to describe a new method for optimizing the design of urban storm sewer systems. Previous efforts to optimize gravity sewers have met with limited success because classical optimization methods require that the problem be well behaved, e.g. describ...

  7. SEWER AND TANK FLUSHING FOR SEDIMENT, CORROSION AND POLLUTION CONTROL

    EPA Science Inventory

    This paper presents an overview of causes of sewer deterioration together with a discussion of control methods that can prevent or arrest this deterioration. In particular, the paper covers inline- and combined sewer overflow- (CSO) storage-tank-flushing systems for removal of se...

  8. Integrated design of sewers and wastewater treatment plants.

    PubMed

    Vollertsen, J; Hvitved-Jacobsen, T; Ujang, Z; Talib, S A

    2002-01-01

    Sewer system design must be integrated with wastewater treatment plant design when moving towards a more sustainable urban wastewater management. This integration allows an optimization of the design of both systems to achieve a better and more cost-effective wastewater management. Hitherto integrated process design has not been an option because the tools to predict in-sewer wastewater transformations have been inadequate. In this study the WATS model--being a new and validated tool for in-sewer microbial process simulations--is presented and its application for integrated sewer and treatment plant design is exemplified. A case study on a Malaysian catchment illustrates this integration. The effects of centralization of wastewater treatment and the subsequently longer transport distances are addressed. The layout of the intercepting sewer is optimized to meet the requirements of different treatment scenarios.

  9. Modelling the viability of heat recovery from combined sewers.

    PubMed

    Abdel-Aal, M; Smits, R; Mohamed, M; De Gussem, K; Schellart, A; Tait, S

    2014-01-01

    Modelling of wastewater temperatures along a sewer pipe using energy balance equations and assuming steady-state conditions was achieved. Modelling error was calculated, by comparing the predicted temperature drop to measured ones in three combined sewers, and was found to have an overall root mean squared error of 0.37 K. Downstream measured wastewater temperature was plotted against modelled values; their line gradients were found to be within the range of 0.9995-1.0012. The ultimate aim of the modelling is to assess the viability of recovering heat from sewer pipes. This is done by evaluating an appropriate location for a heat exchanger within a sewer network that can recover heat without impacting negatively on the downstream wastewater treatment plant (WWTP). Long sewers may prove to be more viable for heat recovery, as heat lost can be reclaimed before wastewater reaching the WWTP.

  10. A biofilm model for prediction of pollutant transformation in sewers.

    PubMed

    Jiang, Feng; Leung, Derek Hoi-Wai; Li, Shiyu; Chen, Guang-Hao; Okabe, Satoshi; van Loosdrecht, Mark C M

    2009-07-01

    This study developed a new sewer biofilm model to simulate the pollutant transformation and biofilm variation in sewers under aerobic, anoxic and anaerobic conditions. The biofilm model can describe the activities of heterotrophic, autotrophic, and sulfate-reducing bacteria (SRB) in the biofilm as well as the variations in biofilm thickness, the spatial profiles of SRB population and biofilm density. The model can describe dynamic biofilm growth, multiple biomass evolution and competitions among organic oxidation, denitrification, nitrification, sulfate reduction and sulfide oxidation in a heterogeneous biofilm growing in a sewer. The model has been extensively verified by three different approaches, including direct verification by measurement of the spatial concentration profiles of dissolved oxygen, nitrate, ammonia, and hydrogen sulfide in sewer biofilm. The spatial distribution profile of SRB in sewer biofilm was determined from the fluorescent in situ hybridization (FISH) images taken by a confocal laser scanning microscope (CLSM) and were predicted well by the model.

  11. Sulfide elimination by intermittent nitrate dosing in sewer sediments.

    PubMed

    Liu, Yanchen; Wu, Chen; Zhou, Xiaohong; Zhu, David Z; Shi, Hanchang

    2015-01-01

    The formation of hydrogen sulfide in biofilms and sediments in sewer systems can cause severe pipe corrosions and health hazards, and requires expensive programs for its prevention. The aim of this study is to propose a new control strategy and the optimal condition for sulfide elimination by intermittent nitrate dosing in sewer sediments. The study was carried out based on lab-scale experiments and batch tests using real sewer sediments. The intermittent nitrate dosing mode and the optimal control condition were investigated. The results indicated that the sulfide-intermittent-elimination strategy by nitrate dosing is advantageous for controlling sulfide accumulation in sewer sediment. The oxidation-reduction potential is a sensitive indicator parameter that can reflect the control effect and the minimum N/S (nitrate/sulfide) ratio with slight excess nitrate is necessary for optimal conditions of efficient sulfide control with lower carbon source loss. The optimal control condition is feasible for the sulfide elimination in sewer systems.

  12. Prediction of sulphide build-up in filled sewer pipes.

    PubMed

    Alani, Amir M; Faramarzi, Asaad; Mahmoodian, Mojtaba; Tee, Kong Fah

    2014-08-01

    Millions of dollars are being spent worldwide on the repair and maintenance of sewer networks and wastewater treatment plants. The production and emission of hydrogen sulphide has been identified as a major cause of corrosion and odour problems in sewer networks. Accurate prediction of sulphide build-up in a sewer system helps engineers and asset managers to appropriately formulate strategies for optimal sewer management and reliability analysis. This paper presents a novel methodology to model and predict the sulphide build-up for steady state condition in filled sewer pipes. The proposed model is developed using a novel data-driven technique called evolutionary polynomial regression (EPR) and it involves the most effective parameters in the sulphide build-up problem. EPR is a hybrid technique, combining genetic algorithm and least square. It is shown that the proposed model can provide a better prediction for the sulphide build-up as compared with conventional models.

  13. Water Quality of Combined Sewer Overflows, Stormwater, and Streams, Omaha, Nebraska, 2006-07

    USGS Publications Warehouse

    Vogel, Jason R.; Frankforter, Jill D.; Rus, David L.; Hobza, Christopher M.; Moser, Matthew T.

    2009-01-01

    criterion in all but four stream samples (266 of 270). Similarly, only 2 of 84 Missouri River samples had total phosphorus concentrations less than the proposed criterion. The proposed total nitrogen criterion for the Corn Belt and Northern Great Plains ecoregion was surpassed in 80 percent of the water samples collected from the stream sites. Samples with total nitrogen concentrations greater than the proposed criterion were most common at Papillion Creek and Big Papillion Creek sites, where the proposed criterion was surpassed in 90 and 96 percent of the samples collected, respectively. Elevated concentrations of total nitrogen were less common at the Missouri River sites, with 33 percent of the samples analyzed having concentrations that surpassed the proposed nutrient criterion for total nitrogen. The three constituents with measured concentrations greater than their respective health-based screening levels were nickel, zinc, and dichlorvos. Differences in water quality during the beginning, middle, and end of the combined sewer overflow discharge and the stream hydrograph rise, peak, and recession were investigated. Concentrations from the ending part of the combined sewer overflow hydrograph were significantly different than those from the beginning and middle parts for 3 and 11 constituents, respectively. No constituents were significantly different between the beginning and middle parts of the combined sewer overflow discharge hydrograph. For the stream site upstream from combined sewer overflow outfalls on Cole Creek, the constituents with geometric mean values for the hydrograph rise that were at least twice those for the values of the peak and recession were specific conductance, magnesium, nitrite, N,N-diethyl-meta-toluamide (DEET), methyl salicylate, p-cresol, and Escherichia coli. Similarly, the constituents where the hydrograph peak was at least twice that for the rise and recession at the upstream Cole Creek site were total suspended solids, silver, an

  14. U.S. EPA Issues Technical Guides and Computer Tools for Sewer Condition and Capacity Assessment

    EPA Science Inventory

    The nation's sanitary sewer infrastructure is aging, with some sewers more than100 years old. Nationwide, there are more than 19,500 municipal sanitary-sewer collection systems serving an estimated 150 million people and about 40,000 sanitary sewer overflow (SSO) events per year...

  15. Advances in Sewer Condition and Capacity Assessment – Development and Applications of EPA SSOAP Toolbox

    EPA Science Inventory

    In the United States, sanitary sewer infrastructure is aging, with some sewers dating back over 100 years. Nationwide, there are more than 19,500 municipal sanitary-sewer collection systems serving an estimated 150 million people and about 40,000 sanitary sewer overflow (SSO) ev...

  16. Advances in Sewer Condition and Capacity Assessment – Development and Applications of EPA SSOAP Toolbox

    EPA Science Inventory

    In the United States, sanitary sewer infrastructure is aging, with some sewers dating back over 100 years. Nationwide, there are more than 19,500 municipal sanitary-sewer collection systems serving an estimated 150 million people and about 40,000 sanitary sewer overflow (SSO) ev...

  17. Factors That Influence Properties of FOG Deposits and Their Formation in Sewer Collection Systems.

    USDA-ARS?s Scientific Manuscript database

    Understanding the formation of Fat, Oil, and Grease (FOG) deposits in sewer systems is critical to the sustainability of sewer collection systems since they have been implicated in causing sewerage blockages, which eventually lead to sanitary sewer overflows (SSOs). Recently, FOG deposits in sewer ...

  18. U.S. EPA Issues Technical Guides and Computer Tools for Sewer Condition and Capacity Assessment

    EPA Science Inventory

    The nation's sanitary sewer infrastructure is aging, with some sewers more than100 years old. Nationwide, there are more than 19,500 municipal sanitary-sewer collection systems serving an estimated 150 million people and about 40,000 sanitary sewer overflow (SSO) events per year...

  19. Reducing pathogens in combined sewer overflows using ozonation or UV irradiation.

    PubMed

    Tondera, Katharina; Klaer, Kassandra; Gebhardt, Jens; Wingender, Jost; Koch, Christoph; Horstkott, Marina; Strathmann, Martin; Jurzik, Lars; Hamza, Ibrahim Ahmed; Pinnekamp, Johannes

    2015-11-01

    Fecal contamination of water resources is a major public health concern in densely populated areas since these water bodies are used for drinking water production or recreational purposes. A main source of this contamination originates from combined sewer overflows (CSOs) in regions with combined sewer systems. Thus, the treatment of CSO discharges is urgent. In this study, we explored whether ozonation or UV irradiation can efficiently reduce pathogenic bacteria, viruses, and protozoan parasites in CSOs. Experiments were carried out in parallel settings at the outflow of a stormwater settling tank in the Ruhr area, Germany. The results showed that both techniques reduce most hygienically relevant bacteria, parasites and viruses. Under the conditions tested, ozonation yielded lower outflow values for the majority of the tested parameters.

  20. Surface water sewer misconnections in England and Wales: Pollution sources and impacts.

    PubMed

    Ellis, J B; Butler, D

    2015-09-01

    In urban areas served by separate sewerage consisting of separate pipe systems it is not uncommon for misconnections to be made either accidentally or deliberately, whereby the wrong effluent is connected to the wrong sewer. The main focus of this problem has been on in-household appliances that are wrongly connected to separate surface water sewers, potentially leading to pollution of receiving waters and non-compliance with statutory water quality standards. This paper examines the available evidence to evaluate the potential scale, severity and cost of the problem in England and Wales in comparison to that reported from investigations in the United States. The particular difficulties associated with distinguishing specific sewage sources in the wastewater "cocktail" discharged at polluted surface water outfalls are reviewed. The deficiencies of existing legislation and enforcing compliance with respect to misconnections are also discussed and the pollution potential resulting from domestic misconnections is explored based on sampled data.

  1. Performance of partially separate sewer systems and impacts on receiving waters.

    PubMed

    Ferreira, F M; Matos, J S; Rodrigues, A C; do Monte, H M

    2002-01-01

    The aim of this document is to present and discuss the results of the experimental work undertaken in Laje stream, in a section near the village of Oeiras in Portugal. The work was developed with the main objective of characterising stormwater quality in Portuguese drainage systems, and to predict the effects of the performance of partially separate sewer systems on receiving waters. For this purpose, volume and characteristics of stormwater carried by a partially separated sewer system were estimated, both in terms of flow and Chemical Oxygen Demand (COD) loads. The study also analyses the eventual implementation of non-conventional solutions, as a way of reducing problems of bacteriological contamination of seawaters. This aspect is particularly important in Portugal, where the population is mainly concentrated in urban areas located down-stream of important drainage basins, close to the coastline. Therefore, sanitary sewer overflows discharging directly into receiving waters are frequent, with possible consequences in terms of bacteriological contamination of bathing areas. Based on experimental research and available data it was possible to collect informations regarding stormwater average COD and overflow coliform loads, and the occurrence of first flush effects.

  2. 300 Area process sewer piping upgrade and 300 Area treated effluent disposal facility discharge to the City of Richland Sewage System, Hanford Site, Richland, Washington

    SciTech Connect

    1995-05-01

    The U.S. Department of Energy (DOE) is proposing to upgrade the existing 300 Area Process Sewer System by constructing and operating a new process sewer collection system that would discharge to the 300 Area Treated Effluent Disposal Facility. The DOE is also considering the construction of a tie-line from the TEDF to the 300 Area Sanitary Sewer for discharging the process wastewater to the City of Richland Sewage System. The proposed action is needed because the integrity of the old piping in the existing 300 Area Process Sewer System is questionable and effluents might be entering the soil column from leaking pipes. In addition, the DOE has identified a need to reduce anticipated operating costs at the new TEDF. The 300 Area Process Sewer Piping Upgrade (Project L-070) is estimated to cost approximately $9.9 million. The proposed work would involve the construction and operation of a new process sewer collection system. The new system would discharge the effluents to a collection sump and lift station for the TEDF. The TEDF is designed to treat and discharge the process effluent to the Columbia River. The process waste liquid effluent is currently well below the DOE requirements for radiological secondary containment and is not considered a RCRA hazardous waste or a State of Washington Hazardous Waste Management Act dangerous waste. A National Pollutant Discharge Elimination, System (NPDES) permit has been obtained from the U.S. Environmental Protection Agency for discharge to the Columbia River. The proposed action would upgrade the existing 300 Area Process Sewer System by the construction and operation of a new combined gravity, vacuum, and pressurized process sewer collection system consisting of vacuum collection sumps, pressure pump stations, and buried polyvinyl chloride or similar pipe. Two buildings would also be built to house a main collection station and a satellite collection station.

  3. Hydrocarbons and heavy metals in the different sewer deposits in the 'Le Marais' catchment (Paris, France): stocks, distributions and origins.

    PubMed

    Rocher, Vincent; Azimi, Sam; Moilleron, Régis; Chebbo, Ghassan

    2004-05-05

    The knowledge of the pollution stored in combined sewers is of prime importance in terms of management of wet weather flow pollution since sewer deposits play a significant role as source of pollution in combined sewer overflows. This work, which focused on the hydrocarbon (aliphatic and aromatic hydrocarbons) and metallic (Fe, Zn, Pb, Cu and Cd) pollution fixed to the different kinds of sewer deposits (gross bed sediment [GBS], organic layer [OL] and biofilm), was performed in order to provide a complete overview of the contaminant storage in the 'Le Marais' combined sewer (Central Paris, France). Firstly, our results have shown that, for all kinds of pollutants, a major part was stored in the GBS (87 to 98%), a lesser part in the OL (2 to 13%) and an insignificant part in the biofilm (<1%). These results demonstrated that the potential contribution of biofilm to wet weather pollution was negligible compared to the OL one. Secondly, the investigation of hydrocarbon fingerprints in each deposit has provided relevant information about contamination origins: (1) aliphatic hydrocarbon distributions were indicative of petroleum input in the GBS and reflected a mixture of biogenic and petroleum inputs in the OL and biofilm, (2) aromatic hydrocarbon distributions suggested an important pyrolytic contamination in all the deposits. Finally, the study of pollutant fingerprints in the different deposits and in the suspended solids going through the collector has shown that: (1) the suspended solids were the major component of OL and biofilm while urban runoff seemed to be the main transport mechanism introducing pollutants in the GBS and (2) the residence times in sewer of OL and biofilm were quite short compared to those for GBS.

  4. A sewer ventilation model applying conservation of momentum.

    PubMed

    Ward, M; Hamer, G; McDonald, A; Witherspoon, J; Loh, E; Parker, W

    2011-01-01

    The work presented herein was completed in an effort to characterize the forces influencing ventilation in gravity sewers and to develop a mathematical model, based on conservation of momentum, capable of accounting for friction at the headspace/pipe interface, drag at the air/water interface, and buoyancy caused by air density differences between a sewer headspace and ambient. Experiments were completed on two full scale sewer reaches in Australia. A carbon monoxide-based tracer technique was used to measure the ventilation rate within the sewer headspaces. Additionally, measurements of pressure, relative humidity, and temperature were measured in the ambient air and sewer headspace. The first location was a five kilometre long sewer outfall beginning at a wastewater treatment plant and terminating at the ocean. The second location was a large gravity sewer reach fitted with ventilation fans. At the first location the headspace was entirely sealed except for openings that were controlled during the experiments. In this situation forces acting on the headspace air manifested mostly as a pressure distribution within the reach, effectively eliminating friction at the pipe wall. At the second location, air was forced to move near the same velocity as the wastewater, effectively eliminating drag at the air/water interface. These experiments allowed individual terms of the momentum equation to be evaluated. Experimental results were compared to the proposed mathematical model. Conclusions regarding model accuracy are provided along with model application guidance and assumptions.

  5. The erosion of organic solids in combined sewers.

    PubMed

    Ahyerre, M; Oms, C; Chebbo, G

    2001-01-01

    Many studies undertaken on urban catchments show, thanks to indirect approaches, that the contribution of eroded sewer sediments to pollution of combined sewer overflows is significant and highly organic. An in situ study of the erosion of sewer sediments has been implemented to validate those results with a direct approach and to observe the processes of erosion. Two experiments have been carried out on a 150 m length of combined sewer in "Le Marais" catchment in Paris, in order to determine the rate of erosion and the nature of the particles eroded by an injection of drinking water in the sewer system. Hydraulic and quality parameters have been measured in situ. Those injections have shown that the rate of erosion is important (maximum rate of 146 g/s) at each stage of the injection, which has been conducted in three stages with a maximum flow of 370 m3/h. The erosion does not only occur locally but happens along the entire length of the section even at low shear stresses (0.5 N/m2). The eroded particles are highly organic (VS = 54-86%) and their loads in volatile solids, COD, BOD5 decrease as the flow increases. So, this work confirms, by direct measurements, that eroded sewer sediments are a significant source of organic matter that contribute to combined sewer overflow.

  6. Stable isotopes of water as a natural tracer for infiltration into urban sewer systems

    NASA Astrophysics Data System (ADS)

    Kracht, O.; Gresch, M.; de Bénédittis, J.; Prigiobbe, V.; Gujer, W.

    2003-04-01

    endmembers is basically sufficient to estimate the ratio of infiltrating water in the sewer. Uncertainties yet derive from varying amounts of local groundwater in the water supply mains. These will be substituted by additionally purchased lake water in the next experimental stage. 2) The experimental site Toraccia (suburb of Rome, Italy) obtains drinking water from the Peschiera springs group that is situated in the central Apennines chain about 90 km north east of Rome. This spring water is transported to Rome by an aqueduct. A first campaign revealed an average mains water δ18O value of -8,4 per mill and δ^2H value of -53 per mill. Potential sources of infiltration are occurrences of perched groundwater. These appear to be enriched compared to the drinking water about 2 to 3 per mill in the δ18O and 10 to 20 per mill in the δ^2H value, but show disadvantageous strong variations. 3) Investigations in the urban area of Lyon (France) benefit from the isotopic differences between underground waters originating from the two rivers Rhone and Saone and their associated alluvial aquifers. The oxygen isotope composition of the Rhone water is roughly 3 per mill lighter than that of the river Saone, due to the large differences in the mean altitude and topographic situation of their catchment basins. Considerable amounts of mains water are extracted by production wells in the Rhone aquifer. In consequence a usable difference in the oxygen isotope composition between wastewater and local groundwater of about 1.5 per mill is available for application studies in certain parts of the city.

  7. Moon Rise

    NASA Image and Video Library

    Aboard the International Space Station in May 2012, Expedition 31 astronaut Don Pettit opened the shutters covering the cupola observation windows in time to watch the moon rise. The time-lapse sce...

  8. AOX in sewer slime -- Identification of industrial wastewater discharges into public sewers

    SciTech Connect

    Antusch, E.; Ripp, C.; Hahn, H.H.

    1995-12-31

    In this study, the authors present the measurements of halogenated organic compounds in sewer slimes. Many of the halogenated organic substances are anthropogenic origin, and, although only some are hazardous, their emission into the natural environment should be avoided. Therefore, the summary parameter AOX has become one of the most important criteria for regulating industrial wastewater discharge in German water quality legislation. The discharge limits have a preventative character, as there is no quantitative relation between the concentration of AOX and its toxicity. If an exceeding value is found in the sewer system, one should look for single components to indicate or to exclude toxic substances. The authors used this method to determine total organic halides as chloride by active carbon adsorption and microcoulometric-titration detection. All samples had been run in duplicate and the reliable limit of sensitivity under these conditions was 5 {micro}g/L. The ``sewer-slime-method`` is explained as a useful tool for localization and identification of indirect discharges.

  9. Lymphatic Lipid Transport: Sewer or Subway?

    PubMed Central

    Dixon, J. Brandon

    2010-01-01

    The lymphatics began receiving attention in the scientific community as early as 1622, when Gasparo Aselli noted the appearance of milky white vessels in the mesentery of a well-fed dog. Since this time, the lymphatic system has been historically regarded as the sewer of the vasculature, passively draining fluid and proteins from the interstitial spaces (along with lipid from the gut) into the blood. Recent reports, however, suggest that the lymphatic role in lipid transport is an active and intricate process and when lymphatic function is compromised, there are systemic consequences to lipid metabolism and transport. This review highlights these recent findings and suggests future directions for understanding the interplay between lymphatic and lipid biology in health and disease. PMID:20541951

  10. Treatment shaft for combined sewer overflow detention.

    PubMed

    Wright, Steven J; Ghalib, Saad; Eloubaidy, Aziz

    2010-05-01

    A deep, large-diameter underground shaft to provide detention storage for combined sewer overflow control may be advantageous in urban environments, where space limitations require solutions with a small footprint. An underflow baffle wall is provided at the center of the treatment shaft to prevent short-circuiting of the flow. An additional objective is to maintain low headlosses through the structure. A physical model study was conducted to determine the effect of the bottom elevation of the baffle wall on the headloss and breakthrough curve for dye injected to the inflow. It was found that there is a considerable range of elevations for which the structure behaves acceptably in providing adequate contact time for disinfectant while maintaining small headlosses.

  11. Transport of large solids in sewer pipes.

    PubMed

    Walski, Thomas; Edwards, Bryce; Helfer, Emil; Whitman, Brian E

    2009-07-01

    This paper presents a method for determining the conditions under which large solids (i.e., solids with a vertical dimension greater than the depth of water) are able to move in a pipe. Depending on the value of a dimensionless number [s(d/y) - 1], where s = specific gravity of the solids, d = water depth, and y = height of solids, motion will occur if a sufficient velocity (also reported as a Froude number or modified "solids" Froude number) is exceeded. Flume experiments were used to determine the coefficients to be used in the design. The velocity required to reach fluid movement was approximately 0.6 to 1.0 m/s (2 to 3 ft/s), which is consistent, although slightly higher than values generally used in conventional sewer design practice. However, it was demonstrated that increasing the pipe slope to achieve a higher velocity does not ensure that the solid will move.

  12. A novel freeze protection strategy for shallow buried sewer pipes: temperature modelling and field investigation.

    PubMed

    Pericault, Youen; Risberg, Mikael; Vesterlund, Mattias; Viklander, Maria; Hedström, Annelie

    2017-07-01

    The burial of sewer and water pipes below the maximum ground frost depth can be very costly and laborious in regions with cold winters. If a freeze protection measure is applied, the utility lines can be installed in a shallower trench to reduce the excavation needs. One freeze protection measure, so called heat tracing, consists of supplying heat along the pipes. In this work, the use of 4th generation district heating as a heat tracing solution was investigated at a pilot site in Kiruna, Sweden. The influence of the system on sewer and water pipe temperatures was studied at a snow-free and snow-covered cross section. To this end, five heat tracing temperatures were tested and the corresponding sewer and water pipe temperatures were measured. The field experiment was also simulated with a two dimensional finite volume model. The study showed that, under the climatic conditions of the experiment, a heat tracing temperature of 25 °C allowed prevention of freezing of the pipes while keeping drinking water pipes in a safe temperature range at both cross sections. The other main result was that the developed finite volume model of the sections showed a good fitting to the experimental data.

  13. Sewer-mining: A water reuse option supporting circular economy, public service provision and entrepreneurship.

    PubMed

    Makropoulos, C; Rozos, E; Tsoukalas, I; Plevri, A; Karakatsanis, G; Karagiannidis, L; Makri, E; Lioumis, C; Noutsopoulos, C; Mamais, D; Rippis, C; Lytras, E

    2017-07-17

    Water scarcity, either due to increased urbanisation or climatic variability, has motivated societies to reduce pressure on water resources mainly by reducing water demand. However, this practice alone is not sufficient to guarantee the quality of life that high quality water services underpin, especially within a context of increased urbanisation. As such, the idea of water reuse has been gaining momentum for some time and has recently found a more general context within the idea of the Circular Economy. This paper is set within the context of an ongoing discussion between centralized and decentralized water reuse techniques and the investigation of trade-offs between efficiency and economic viability of reuse at different scales. Specifically, we argue for an intermediate scale of a water reuse option termed 'sewer-mining', which could be considered a reuse scheme at the neighbourhood scale. We suggest that sewer mining (a) provides a feasible alternative reuse option when the geography of the wastewater treatment plant is problematic, (b) relies on mature treatment technologies and (c) presents an opportunity for Small Medium Enterprises (SME) to be involved in the water market, securing environmental, social and economic benefits. To support this argument, we report on a pilot sewer-mining application in Athens, Greece. The pilot, integrates two subsystems: a packaged treatment unit and an information and communications technology (ICT) infrastructure. The paper reports on the pilot's overall performance and critically evaluates the potential of the sewer-mining idea to become a significant piece of the circular economy puzzle for water. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Sandia National Laboratories, California sewer system management plan.

    SciTech Connect

    Holland, Robert C.

    2010-02-01

    A Sewer System Management Plan (SSMP) is required by the State Water Resources Control Board (SWRCB) Order No. 2006-0003-DWQ Statewide General Waste Discharge Requirements (WDR) for Sanitary Sewer Systems (General Permit). DOE, National Nuclear Security Administration (NNSA), Sandia Site Office has filed a Notice of Intent to be covered under this General Permit. The General Permit requires a proactive approach to reduce the number and frequency of sanitary sewer overflows (SSOs) within the State. SSMPs must include provisions to provide proper and efficient management, operation, and maintenance of sanitary sewer systems and must contain a spill response plan. Elements of this Plan are under development in accordance with the SWRCB's schedule.

  15. Colorado River Sewer System Joint Venture to Upgrade Wastewater System

    EPA Pesticide Factsheets

    SAN FRANCISCO -Today, the Colorado River Sewer System Joint Venture, located in Parker, Ariz. entered into an agreement with the EPA to upgrade their wastewater treatment system to meet stringent water quality standards. The cost of the upgrade is ap

  16. MANAGEMENT OF COMBINED SEWER OVERFLOW RESEARCH PROGRAM CAPSTONE

    EPA Science Inventory


    Combined-sewer overflow (CSO) is a mixture of urban storm drainage, municipal-industrial wastewater, and subterranean infiltration. Untreated discharges of CSOs have caused substantial pollution impacts on the quality of receiving-water bodies. Problem constituents include ...

  17. MANAGEMENT OF COMBINED SEWER OVERFLOW: RESEARCH PROGRAM CAPSTONE

    EPA Science Inventory

    Combined-sewer overflow (CSO) is a mixture of urban storm drainage, municipal-industrial wastewater, and subterranean infiltration. Untreated discharges of CSOs have caused substantial pollution impacts on the quality of receiving-water bodies. Problem constituents include visi...

  18. MANAGEMENT OF COMBINED SEWER OVERFLOW: RESEARCH PROGRAM CAPSTONE

    EPA Science Inventory

    Combined-sewer overflow (CSO) is a mixture of urban storm drainage, municipal-industrial wastewater, and subterranean infiltration. Untreated discharges of CSOs have caused substantial pollution impacts on the quality of receiving-water bodies. Problem constituents include visi...

  19. MANAGEMENT OF COMBINED SEWER OVERFLOW RESEARCH PROGRAM CAPSTONE

    EPA Science Inventory


    Combined-sewer overflow (CSO) is a mixture of urban storm drainage, municipal-industrial wastewater, and subterranean infiltration. Untreated discharges of CSOs have caused substantial pollution impacts on the quality of receiving-water bodies. Problem constituents include ...

  20. Sewer deterioration modeling with condition data lacking historical records.

    PubMed

    Egger, C; Scheidegger, A; Reichert, P; Maurer, M

    2013-11-01

    Accurate predictions of future conditions of sewer systems are needed for efficient rehabilitation planning. For this purpose, a range of sewer deterioration models has been proposed which can be improved by calibration with observed sewer condition data. However, if datasets lack historical records, calibration requires a combination of deterioration and sewer rehabilitation models, as the current state of the sewer network reflects the combined effect of both processes. Otherwise, physical sewer lifespans are overestimated as pipes in poor condition that were rehabilitated are no longer represented in the dataset. We therefore propose the combination of a sewer deterioration model with a simple rehabilitation model which can be calibrated with datasets lacking historical information. We use Bayesian inference for parameter estimation due to the limited information content of the data and limited identifiability of the model parameters. A sensitivity analysis gives an insight into the model's robustness against the uncertainty of the prior. The analysis reveals that the model results are principally sensitive to the means of the priors of specific model parameters, which should therefore be elicited with care. The importance sampling technique applied for the sensitivity analysis permitted efficient implementation for regional sensitivity analysis with reasonable computational outlay. Application of the combined model with both simulated and real data shows that it effectively compensates for the bias induced by a lack of historical data. Thus, the novel approach makes it possible to calibrate sewer pipe deterioration models even when historical condition records are lacking. Since at least some prior knowledge of the model parameters is available, the strength of Bayesian inference is particularly evident in the case of small datasets.

  1. Exposure to airborne endotoxins among sewer workers: an exploratory study.

    PubMed

    Duquenne, Philippe; Ambroise, Denis; Görner, Pierre; Clerc, Frédéric; Greff-Mirguet, Guylaine

    2014-04-01

    Exploratory bioaerosol sampling was performed in order to assess exposure to airborne endotoxins during sewer work. Personal samples were collected in underground sewer pipes using 37-mm closed-face cassettes containing fibreglass filters (CFC-FG method) or polycarbonate filters (CFC-PC method). Endotoxins were quantified using the limulus amoebocyte lysate assay. Concentrations of airborne endotoxins at sewer workplaces (16-420 EU m(-3)) were higher than those measured outside the sewer network (0.6-122 EU m(-3)). Sewer worker exposure to airborne endotoxins depended on the workplace and on the tasks. Exposure levels were the highest for tasks involving agitation of water and matter, especially for 'chamber cleanup' and 'pipes cleanup' with a high-pressure water jet. Airborne endotoxin levels at the workplace tended to be higher when CFC-FG was used as the sampling method rather than CFC-PC. The adjusted mean of the measured concentrations for CFC-PC represents 57% of the mean observed with CFC-FG. The number of samples collected in the descriptive study was too low for drawing definitive conclusions and further exposure investigations are needed. Therefore, our exploratory study provides new exposure data for the insufficiently documented sewer working environment and it would be useful for designing larger exposures studies.

  2. Predicting wastewater temperatures in sewer pipes using abductive network models.

    PubMed

    Abdel-Aal, M; Mohamed, M; Smits, R; Abdel-Aal, R E; De Gussem, K; Schellart, A; Tait, S

    2015-01-01

    A predictive modelling technique was employed to estimate wastewater temperatures in sewer pipes. The simplicity of abductive predictive models attracts large numbers of users due to their minimal computation time and limited number of measurable input parameters. Data measured from five sewer pipes over a period of 12 months provide 33,900 training entries and 39,000 evaluation entries to support the models' development. Two simple predictive models for urban upstream combined sewers and large downstream collector sewers were developed. They delivered good correlation between measured and predicted wastewater temperatures proven by their R(2) values of up to 0.98 and root mean square error (RMSE) of the temperature change along the sewer pipe ranging from 0.15 °C to 0.33 °C. Analysis of a number of potential input parameters indicated that upstream wastewater temperature and downstream in-sewer air temperature were the only input parameters that are needed in the developed models to deliver this level of accuracy.

  3. Stratified microbial structure and activity in sulfide- and methane-producing anaerobic sewer biofilms.

    PubMed

    Sun, Jing; Hu, Shihu; Sharma, Keshab Raj; Ni, Bing-Jie; Yuan, Zhiguo

    2014-11-01

    Simultaneous production of sulfide and methane by anaerobic sewer biofilms has recently been observed, suggesting that sulfate-reducing bacteria (SRB) and methanogenic archaea (MA), microorganisms known to compete for the same substrates, can coexist in this environment. This study investigated the community structures and activities of SRB and MA in anaerobic sewer biofilms (average thickness of 800 μm) using a combination of microelectrode measurements, molecular techniques, and mathematical modeling. It was seen that sulfide was mainly produced in the outer layer of the biofilm, between the depths of 0 and 300 μm, which is in good agreement with the distribution of SRB population as revealed by cryosection-fluorescence in situ hybridization (FISH). SRB had a higher relative abundance of 20% on the surface layer, which decreased gradually to below 3% at a depth of 400 μm. In contrast, MA mainly inhabited the inner layer of the biofilm. Their relative abundances increased from 10% to 75% at depths of 200 μm and 700 μm, respectively, from the biofilm surface layer. High-throughput pyrosequencing of 16S rRNA amplicons showed that SRB in the biofilm were mainly affiliated with five genera, Desulfobulbus, Desulfomicrobium, Desulfovibrio, Desulfatiferula, and Desulforegula, while about 90% of the MA population belonged to the genus Methanosaeta. The spatial organizations of SRB and MA revealed by pyrosequencing were consistent with the FISH results. A biofilm model was constructed to simulate the SRB and MA distributions in the anaerobic sewer biofilm. The good fit between model predictions and the experimental data indicate that the coexistence and spatial structure of SRB and MA in the biofilm resulted from the microbial types and their metabolic transformations and interactions with substrates. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  4. Stratified Microbial Structure and Activity in Sulfide- and Methane-Producing Anaerobic Sewer Biofilms

    PubMed Central

    Sun, Jing; Hu, Shihu; Sharma, Keshab Raj; Ni, Bing-Jie

    2014-01-01

    Simultaneous production of sulfide and methane by anaerobic sewer biofilms has recently been observed, suggesting that sulfate-reducing bacteria (SRB) and methanogenic archaea (MA), microorganisms known to compete for the same substrates, can coexist in this environment. This study investigated the community structures and activities of SRB and MA in anaerobic sewer biofilms (average thickness of 800 μm) using a combination of microelectrode measurements, molecular techniques, and mathematical modeling. It was seen that sulfide was mainly produced in the outer layer of the biofilm, between the depths of 0 and 300 μm, which is in good agreement with the distribution of SRB population as revealed by cryosection-fluorescence in situ hybridization (FISH). SRB had a higher relative abundance of 20% on the surface layer, which decreased gradually to below 3% at a depth of 400 μm. In contrast, MA mainly inhabited the inner layer of the biofilm. Their relative abundances increased from 10% to 75% at depths of 200 μm and 700 μm, respectively, from the biofilm surface layer. High-throughput pyrosequencing of 16S rRNA amplicons showed that SRB in the biofilm were mainly affiliated with five genera, Desulfobulbus, Desulfomicrobium, Desulfovibrio, Desulfatiferula, and Desulforegula, while about 90% of the MA population belonged to the genus Methanosaeta. The spatial organizations of SRB and MA revealed by pyrosequencing were consistent with the FISH results. A biofilm model was constructed to simulate the SRB and MA distributions in the anaerobic sewer biofilm. The good fit between model predictions and the experimental data indicate that the coexistence and spatial structure of SRB and MA in the biofilm resulted from the microbial types and their metabolic transformations and interactions with substrates. PMID:25192994

  5. SSOAP - A USEPA Toolbox for Sanitary Sewer Overflow Analysis and Control Planning - Presentation

    EPA Science Inventory

    The United States Environmental Protection Agency (USEPA) has identified a need to use proven methodologies to develop computer tools that help communities properly characterize rainfall-derived infiltration and inflow (RDII) into sanitary sewer systems and develop sanitary sewer...

  6. SSOAP - A USEPA Toolbox for Sanitary Sewer Overflow Analysis and Control Planning - Presentation

    EPA Science Inventory

    The United States Environmental Protection Agency (USEPA) has identified a need to use proven methodologies to develop computer tools that help communities properly characterize rainfall-derived infiltration and inflow (RDII) into sanitary sewer systems and develop sanitary sewer...

  7. Identifying biases in deterioration models using synthetic sewer data.

    PubMed

    Scheidegger, A; Maurer, M

    2012-01-01

    The assessment and validation of sewer deterioration models is difficult because reliable data are missing. This makes it hard to find the most suitable model for a particular application. A network condition simulator (NetCoS) is used to generate synthetic sewer data for defined test scenarios. Thereby, the deterioration and replacement of pipes, the expansion of the sewer network, and classification errors are considered. Based on such synthetic data, deterioration models are calibrated and their results compared with the predefined scenario. While this approach is not capable of proving that a model performs correctly on a real application, it highlights the strengths and weaknesses of a model. The influence of condition classification errors and the age of the sewer system is investigated for two deterioration models. The results show, that classification errors can introduce substantial biases in the parameter estimation of the Markov model while in comparison the applied cohort model is fairly robust. Young sewer systems with fewer pipes in bad condition states on the other hand, have a very strong influence on the parameter uncertainties of the cohort model while the Markov model proved to be less sensitive.

  8. Wastewater-Enhanced Microbial Corrosion of Concrete Sewers.

    PubMed

    Jiang, Guangming; Zhou, Mi; Chiu, Tsz Ho; Sun, Xiaoyan; Keller, Jurg; Bond, Philip L

    2016-08-02

    Microbial corrosion of concrete in sewers is known to be caused by hydrogen sulfide, although the role of wastewater in regulating the corrosion processes is poorly understood. Flooding and splashing of wastewater in sewers periodically inoculates the concrete surface in sewer pipes. No study has systematically investigated the impacts of wastewater inoculation on the corrosion of concrete in sewers. This study investigated the development of the microbial community, sulfide uptake activity, and the change of the concrete properties for coupons subjected to periodic wastewater inoculation. The concrete coupons were exposed to different levels of hydrogen sulfide under well-controlled conditions in laboratory-scale corrosion chambers simulating real sewers. It was evident that the periodic inoculation induced higher corrosion losses of the concrete in comparison to noninoculated coupons. Instantaneous measurements such as surface pH did not reflect the cumulative corrosion losses caused by long-term microbial activity. Analysis of the long-term profiles of the sulfide uptake rate using a Gompertz model supported the enhanced corrosion activity and greater corrosion loss. The enhanced corrosion rate was due to the higher sulfide uptake rates induced by wastewater inoculation, although the increasing trend of sulfide uptake rates was slower with wastewater. Increased diversity in the corrosion-layer microbial communities was detected when the corrosion rates were higher. This coincided with the environmental conditions of increased levels of gaseous H2S and the concrete type.

  9. On-line monitoring of methane in sewer air

    PubMed Central

    Liu, Yiwen; Sharma, Keshab R.; Murthy, Sudhir; Johnson, Ian; Evans, Ted; Yuan, Zhiguo

    2014-01-01

    Methane is a highly potent greenhouse gas and contributes significantly to climate change. Recent studies have shown significant methane production in sewers. The studies conducted so far have relied on manual sampling followed by off-line laboratory-based chromatography analysis. These methods are labor-intensive when measuring methane emissions from a large number of sewers, and do not capture the dynamic variations in methane production. In this study, we investigated the suitability of infrared spectroscopy-based on-line methane sensors for measuring methane in humid and condensing sewer air. Two such sensors were comprehensively tested in the laboratory. Both sensors displayed high linearity (R2 > 0.999), with a detection limit of 0.023% and 0.110% by volume, respectively. Both sensors were robust against ambient temperature variations in the range of 5 to 35°C. While one sensor was robust against humidity variations, the other was found to be significantly affected by humidity. However, the problem was solved by equipping the sensor with a heating unit to increase the sensor surface temperature to 35°C. Field studies at three sites confirmed the performance and accuracy of the sensors when applied to actual sewer conditions, and revealed substantial and highly dynamic methane concentrations in sewer air. PMID:25319343

  10. On-line monitoring of methane in sewer air.

    PubMed

    Liu, Yiwen; Sharma, Keshab R; Murthy, Sudhir; Johnson, Ian; Evans, Ted; Yuan, Zhiguo

    2014-10-16

    Methane is a highly potent greenhouse gas and contributes significantly to climate change. Recent studies have shown significant methane production in sewers. The studies conducted so far have relied on manual sampling followed by off-line laboratory-based chromatography analysis. These methods are labor-intensive when measuring methane emissions from a large number of sewers, and do not capture the dynamic variations in methane production. In this study, we investigated the suitability of infrared spectroscopy-based on-line methane sensors for measuring methane in humid and condensing sewer air. Two such sensors were comprehensively tested in the laboratory. Both sensors displayed high linearity (R(2) > 0.999), with a detection limit of 0.023% and 0.110% by volume, respectively. Both sensors were robust against ambient temperature variations in the range of 5 to 35°C. While one sensor was robust against humidity variations, the other was found to be significantly affected by humidity. However, the problem was solved by equipping the sensor with a heating unit to increase the sensor surface temperature to 35°C. Field studies at three sites confirmed the performance and accuracy of the sensors when applied to actual sewer conditions, and revealed substantial and highly dynamic methane concentrations in sewer air.

  11. Sewer rehabilitation. (Latest citations from the Selected Water Resources Abstracts database). Published Search

    SciTech Connect

    Not Available

    1993-02-01

    The bibliography contains citations concerning the maintenance and rehabilitation of sewers. The citations discuss joint weatherization treatments, sewer grouts, and plastic sleeves for cover cracked pipes. Maintenance and rehabilitation programs in specific cities are also discussed. The citations also reference the economics of sewer repair. (Contains a minimum of 164 citations and includes a subject term index and title list.)

  12. COMPUTER MODEL ANALYSIS FOR CONTROL PLANNING OF SANITARY-SEWER OVERFLOWS

    EPA Science Inventory

    The Nation's sanitary-sewer infrastructure is aging with some sewers dating back over 100 years. There are more than 19,500 municipal sanitary-sewer collection systems nationwide serving an estimated 150 million people and comprising about 800,000 km (500,000 mi) of municipally ...

  13. Tree root intrusion in sewer systems: A review of extent and costs

    Treesearch

    T.B. Randrup; E.G. McPherson; L.R. Costello

    2001-01-01

    Interference between trees and sewer systems is likely to occur in old systems and in cracked pipes. Factors that contribute to damage include old pipes with joints, shallow pipes, small-dimension pipes, and fast-growing tree species. Because roots are reported to cause >50% of all sewer blockages, costs associated with root removal from sewers is substantial. In...

  14. 40 CFR 35.935-16 - Sewer use ordinance and evaluation/rehabilitation program.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    .../rehabilitation program. 35.935-16 Section 35.935-16 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY...-Clean Water Act § 35.935-16 Sewer use ordinance and evaluation/rehabilitation program. (a) The grantee... sewer use ordinance, and the grantee is complying with the sewer system evaluation and rehabilitation...

  15. 40 CFR 35.935-16 - Sewer use ordinance and evaluation/rehabilitation program.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    .../rehabilitation program. 35.935-16 Section 35.935-16 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY...-Clean Water Act § 35.935-16 Sewer use ordinance and evaluation/rehabilitation program. (a) The grantee... sewer use ordinance, and the grantee is complying with the sewer system evaluation and rehabilitation...

  16. 40 CFR 35.2208 - Adoption of sewer use ordinance and user charge system.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 1 2014-07-01 2014-07-01 false Adoption of sewer use ordinance and user charge system. 35.2208 Section 35.2208 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... § 35.2208 Adoption of sewer use ordinance and user charge system. The grantee shall adopt its sewer use...

  17. COMPUTER MODEL ANALYSIS FOR CONTROL PLANNING OF SANITARY-SEWER OVERFLOWS

    EPA Science Inventory

    The Nation's sanitary-sewer infrastructure is aging with some sewers dating back over 100 years. There are more than 19,500 municipal sanitary-sewer collection systems nationwide serving an estimated 150 million people and comprising about 800,000 km (500,000 mi) of municipally ...

  18. Contaminant transport pathways between urban sewer networks and water supply wells

    USDA-ARS?s Scientific Manuscript database

    Water supply wells and sanitary sewers are critical components of urban infrastructure, but sewer leakage threatens the quality of groundwater in sewered areas. Previous work by our group has documented the presence of human enteric viruses in deep public supply wells. Our current research uses such...

  19. Evidence of a sewer vapor transport pathway at the USEPA vapor intrusion research duplex

    EPA Science Inventory

    The role of sewer lines as preferential pathways for vapor intrusion is poorly understood. Although the importance of sewer lines for volatile organic compound (VOC) transport has been documented at a small number of sites with vapor intrusion, sewer lines are not routinely sampl...

  20. 40 CFR 35.2208 - Adoption of sewer use ordinance and user charge system.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 1 2011-07-01 2011-07-01 false Adoption of sewer use ordinance and user charge system. 35.2208 Section 35.2208 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... § 35.2208 Adoption of sewer use ordinance and user charge system. The grantee shall adopt its sewer use...

  1. 40 CFR 35.2208 - Adoption of sewer use ordinance and user charge system.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Adoption of sewer use ordinance and user charge system. 35.2208 Section 35.2208 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... § 35.2208 Adoption of sewer use ordinance and user charge system. The grantee shall adopt its sewer use...

  2. 76 FR 35215 - Notice of EPA Workshop on Sanitary Sewer Overflows and Peak Wet Weather Discharges

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-16

    ... of issues. These include views on how the National Pollutant Discharge Elimination System (NPDES) regulations should apply to municipal sanitary sewer collection systems, sanitary sewer overflows (SSOs), and..., operated, and maintained sanitary sewer systems are meant to collect and transport all of the sewage that...

  3. Rapid sonic characterisation of sewer change and obstructions.

    PubMed

    Podd, F J; Ali, M T B; Horoshenkov, K V; Wood, A S; Tait, S J; Boot, J C; Long, R; Saul, A J

    2007-01-01

    This paper reports on the development of a low-cost, rapidly deployable sensor for surveying live sewers for blockages and structural failures. The anticipated cost is an order of magnitude lower than current techniques. The technology is based on acoustic normal model decomposition, The instrument emits short coded acoustic signals which are reflected from any sewer wall defect. The acoustic signals can be short Gaussian pulses or longer sinusoidal sweeps and pseudo-random noise. The processing algorithms used on the reflected signal can predict the extent and geometry of the pipe deformation, and the locations and approximate size of common blockages. The effect of the water level on the frequency of the fundamental mode has also been investigated. It is shown that the technique can be adapted to work reliably in relatively large 600 mm diameter sewer pipes.

  4. Long-term pollution simulation in combined sewer networks.

    PubMed

    Masse, B; Zug, M; Tabuchi, J P; Tisserand, B

    2001-01-01

    This paper presents results of long term pollution simulations on the example of the sewerage system of Grand-Couronne. This modelling work is part of a study where objective is to develop a method to define the reference flow of a WWTP. The model HYDROWORKS DM has been successfully validated in hydraulics and pollution for the sewer network, for long time simulations. A conceptual model has been built to model the pollution in the tank at the outlet of the combined system. One synthetic year of rain has been used to simulate the working of the "up stream system" of the WWTP (combined sewer + tank + separate sewer + pre-treatments) and has been successfully validated by measurements of the 1998-1999 year. If this paper is focused on the "up stream system", the SIMBA/SIMBAD WWTP model has been successfully calibrated and validated too, and the combination represents a fully validated "Integrated Model" for the sewerage system.

  5. Molecular survey of concrete sewer biofilm microbial communities.

    PubMed

    Santo Domingo, Jorge W; Revetta, Randy P; Iker, Brandon; Gomez-Alvarez, Vicente; Garcia, Jarissa; Sullivan, John; Weast, James

    2011-10-01

    The microbial composition of concrete biofilms within wastewater collection systems was studied using molecular assays. SSU rDNA clone libraries were generated from 16 concrete surfaces of manholes, a combined sewer overflow, and sections of a corroded sewer pipe. Of the 2457 sequences analyzed, α-, β-, γ-, and δ-Proteobacteria represented 15%, 22%, 11%, and 4% of the clones, respectively. β-Proteobacteria (47%) sequences were more abundant in the pipe crown than any of the other concrete surfaces. While 178 to 493 Operational Taxonomic Units (OTUs) were associated with the different concrete samples, only four sequences were shared among the different clone libraries. Bacteria implicated in concrete corrosion were found in the clone libraries while archaea, fungi, and several bacterial groups were also detected using group-specific assays. The results showed that concrete sewer biofilms are more diverse than previously reported. A more comprehensive molecular database will be needed to better study the dynamics of concrete biofilms.

  6. Idaho National Engineering Laboratory Sewer System Upgrade Project. Environmental Assessment

    SciTech Connect

    Not Available

    1994-04-01

    The Department of Energy (DOE) has prepared an environmental assessment for a proposed Sewer System Upgrade Project at the Idaho National Engineering Laboratory (INEL) near Idaho Falls, Idaho. The proposed action would include activities conducted at the Central Facilities Area, Test Reactor Area, and the Containment Test Facility at the Test Area North at INEL. The proposed action would consist of replacing or remodeling the existing sewage treatment plants at the Central Facilities Area, Test Reactor Area, and Containment Test Facility. Also, a new sewage testing laboratory would be constructed at the Central Facilities Area. Finally, the proposed action would include replacing, repairing, and/or adding sewer lines in areas where needed.

  7. Assessment of the contribution of sewer deposits to suspended solids loads in combined sewer systems during rain events.

    PubMed

    Hannouche, A; Chebbo, G; Joannis, C

    2014-04-01

    Within the French observatories network SOERE "URBIS," databases of continuous turbidity measurements accumulating hundreds of events and many dry weather days are available for two sites with different features (Clichy in Paris and Ecully in Lyon). These measurements, converted into total suspended solids (TSS) concentration using TSS-turbidity relationships and combined with a model of runoff event mean concentration, enable the assessment of the contribution of sewer deposits to wet weather TSS loads observed at the outlet of the two watersheds. Results show that the contribution of sewer deposits to wet weather suspended solid's discharges is important but variable (between 20 and 80 % of the mass at the outlet depending on the event), including a site allegedly free of (coarse) sewer deposits. The uncertainties associated to these results are assessed too.

  8. Europa Rising

    NASA Technical Reports Server (NTRS)

    2007-01-01

    New Horizons took this image of the icy moon Europa rising above Jupiter's cloud tops with its Long Range Reconnaissance Imager (LORRI) at 11:48 Universal Time on February 28, 2007, six hours after the spacecraft's closest approach to Jupiter.

    The picture was one of a handful of the Jupiter system that New Horizons took primarily for artistic, rather than scientific, value. This particular scene was suggested by space enthusiast Richard Hendricks of Austin, Texas, in response to an Internet request by New Horizons scientists for evocative, artistic imaging opportunities at Jupiter.

    The spacecraft was 2.3 million kilometers (1.4 million miles) from Jupiter and 3 million kilometers (1.8 million miles) from Europa when the picture was taken. Europa's diameter is 3,120 kilometers (1,939 miles). The image is centered on Europa coordinates 5 degrees south, 6 degrees west. In keeping with its artistic intent - and to provide a more dramatic perspective - the image has been rotated so south is at the top.

  9. Copernicus Rising

    NASA Astrophysics Data System (ADS)

    Rose, Michael A.

    2007-08-01

    Copernicus Rising began as a historical biography when it was first conceived, but as the writing progressed it quickly became a rather absurd play that took historical research and twisted it through the lens of my own wit, philosophy and personal affection for the characters. When working with historical figures--characters who existed in a very tangible way in our own history--the playwriting process opens a dialogue between different points in time and space. The difficulty lies in finding a unique and clear voice amongst the discordant personalities involved in this time and space overlap, both in the writing and production processes, in order to get to the heart of what the play is really all about. This thesis follows the journey of the play from its historical roots through the creation of an absurd journey both insides and outside time, space and the human mind. The first part of the thesis explains the beginnings of the concept and outlines much of the research and development that went into the play. The next part outlines the process of production and integrating the world on paper with that of moving bodies on stage. In the final part, post-production discussions and audience feedback sessions shape the play into the draft included in this thesis.

  10. 78 FR 9908 - Notice of Availability of the Draft Issuance of the Small Municipal Separate Storm Sewer System...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-12

    ... AGENCY Notice of Availability of the Draft Issuance of the Small Municipal Separate Storm Sewer System... Storm Sewer Systems (MS4s) to certain waters of the State of New Hampshire. The draft NPDES general...)(16) define a small municipal separate storm sewer system as ``all separate storm sewers that are:...

  11. Toxicity and pollutant impact analysis in an urban river due to combined sewer overflows loads.

    PubMed

    Casadio, A; Maglionico, M; Bolognesi, A; Artina, S

    2010-01-01

    The Navile Channel (Bologna, Italy) is an ancient artificial water course derived from the Reno river. It is the main receiving water body for the urban catchment of Bologna sewer systems and also for the Waste Water Treatment Plant (WWTP) main outlet. The aim of this work is to evaluate the Combined Sewer Overflows (CSOs) impact on Navile Channel's water quality. In order to collect Navile flow and water quality data in both dry and wet weather conditions, two measuring and sampling stations were installed, right upstream and downstream the WWTP outflow. The study shows that even in case of low intensity rain events, CSOs have a significant effect on both water quantity and quality, spilling a considerable amount of pollutants into the Navile Channel and presenting also acute toxicity effects. The collected data shown a good correlations between the concentrations of TSS and of chemical compounds analyzed, suggesting that the most part of such substances is attached to suspended solids. Resulting toxicity values are fairly high in both measuring points and seem to confirm synergistic interactions between heavy metals.

  12. ULTRAVIOLET LIGHT DISINFECTION OF COMBINED SEWER OVERFLOW (NEW ORLEANS)

    EPA Science Inventory

    The objective of this state-of-the-art review is to examine the performance and effectiveness of ultraviolet (UV) light disinfection for combined sewer overflow (CSO) applications. Topics presented include the use of UV light as a disinfecting agent, its practical applications, d...

  13. 40 CFR 35.927-4 - Sewer use ordinance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... project before the completion of construction. The ordinance shall prohibit any new connections from... ASSISTANCE STATE AND LOCAL ASSISTANCE Grants for Construction of Treatment Works-Clean Water Act § 35.927-4 Sewer use ordinance. Each applicant for grant assistance for a step 2 or step 3 project shall...

  14. 40 CFR 35.927-4 - Sewer use ordinance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... project before the completion of construction. The ordinance shall prohibit any new connections from... ASSISTANCE STATE AND LOCAL ASSISTANCE Grants for Construction of Treatment Works-Clean Water Act § 35.927-4 Sewer use ordinance. Each applicant for grant assistance for a step 2 or step 3 project shall...

  15. A novel cellular automata based approach to storm sewer design

    NASA Astrophysics Data System (ADS)

    Guo, Y.; Walters, G. A.; Khu, S. T.; Keedwell, E.

    2007-04-01

    Optimal storm sewer design aims at minimizing capital investment on infrastructure whilst ensuring good system performance under specified design criteria. An innovative sewer design approach based on cellular automata (CA) principles is introduced in this paper. Cellular automata have been applied as computational simulation devices in various scientific fields. However, some recent research has indicated that CA can also be a viable and efficient optimization engine. This engine is heuristic and largely relies on the key properties of CA: locality, homogeneity, and parallelism. In the proposed approach, the CA-based optimizer is combined with a sewer hydraulic simulator, the EPA Storm Water Management Model (SWMM). At each optimization step, according to a set of transition rules, the optimizer updates all decision variables simultaneously based on the hydraulic situation within each neighbourhood. Two sewer networks (one small artificial network and one large real network) have been tested in this study. The CA optimizer demonstrated its ability to obtain near-optimal solutions in a remarkably small number of computational steps in a comparison of its performance with that of a genetic algorithm.

  16. Demonstration of Innovative Sewer System Inspection Technology: SL-RAT

    EPA Science Inventory

    The overall objective of this EPA-funded study was to demonstrate innovative sewer line assessment technologies that are designed for rapid deployment using portable equipment. This study focused on demonstration of technologies that are suitable for smaller diameter pipes (less ...

  17. HIGH-RATE DISINFECTION TECHNIQUES FOR COMBIND SEWER OVERFLOW

    EPA Science Inventory

    This paper presents high-rate disinfection technologies for combined sewer overflow (CSO). The high-rate disinfection technologies of interest are: chlorination/dechlorination, ultraviolet light irradiation (UV), chlorine dioxide (ClO2 ), ozone (O3), peracetic acid (CH3COOOH )...

  18. Demonstration of Innovative Sewer System Inspection Technology: SL-RAT

    EPA Science Inventory

    The overall objective of this EPA-funded study was to demonstrate innovative sewer line assessment technologies that are designed for rapid deployment using portable equipment. This study focused on demonstration of technologies that are suitable for smaller diameter pipes (less ...

  19. EXFILTRATION IN SANITARY SEWER SYSTEMS IN THE U.S.

    EPA Science Inventory

    Many municipalities throughout the US have sewerage systems (separate and combined) that may experience exfiltration of untreated wastewater. This study was conducted to focus on the magnitude of the exfiltration problem from sewer pipes on a national basis. The method for estima...

  20. Decision making in flood risk based storm sewer network design.

    PubMed

    Sun, S A; Djordjević, S; Khu, S T

    2011-01-01

    It is widely recognised that flood risk needs to be taken into account when designing a storm sewer network. Flood risk is generally a combination of flood consequences and flood probabilities. This paper aims to explore the decision making in flood risk based storm sewer network design. A multiobjective optimization is proposed to find the Pareto front of optimal designs in terms of low construction cost and low flood risk. The decision making process then follows this multi-objective optimization to select a best design from the Pareto front. The traditional way of designing a storm sewer system based on a predefined design storm is used as one of the decision making criteria. Additionally, three commonly used risk based criteria, i.e., the expected flood risk based criterion, the Hurwicz criterion and the stochastic dominance based criterion, are investigated and applied in this paper. Different decisions are made according to different criteria as a result of different concerns represented by the criteria. The proposed procedure is applied to a simple storm sewer network design to demonstrate its effectiveness and the different criteria are compared.

  1. EXFILTRATION IN SEWER SYSTEMS: IS IT A NATIONAL PROBLEM?

    EPA Science Inventory

    Many municipalities throughout the US have sewerage systems (separate and combined) that may experience exfiltration of untreated wastewater. This study was conducted to focus on the magnitude of the exfiltration problem from sewer pipes on a national basis. The method for estima...

  2. ULTRAVIOLET LIGHT DISINFECTION OF COMBINED SEWER OVERFLOW (NEW ORLEANS)

    EPA Science Inventory

    The objective of this state-of-the-art review is to examine the performance and effectiveness of ultraviolet (UV) light disinfection for combined sewer overflow (CSO) applications. Topics presented include the use of UV light as a disinfecting agent, its practical applications, d...

  3. REAL TIME CONTROL OF SEWERS: US EPA MANUAL

    EPA Science Inventory

    The problem of sewage spills and local flooding has traditionally been addressed by large scale capital improvement programs that focus on construction alternatives such as sewer separation or construction of storage facilities. The cost of such projects is often high, especiall...

  4. STREET SURFACE STORAGE FOR CONTROL OF COMBINED SEWER SURCHARGE

    EPA Science Inventory

    One type of Best Management Practices (BMPs) available is the use of street storage systems to prevent combined sewer surcharging and to mitigate basement flooding. A case study approach, based primarily on two largely implemented street storage systems, will be used to explain ...

  5. COMBINED SEWER OVERFLOW CONTROL USING STORAGE IN SEAWATER

    EPA Science Inventory

    This paper describes the flow balance method facility (FBM) used to control a combined sewer overflow (CSO) and a statistically based efficiency evaluation for the system. he FBM uses containment within a receiving water body (in this case seawater) to store CSO followed by pumpb...

  6. Notification: Review of Atlanta Combined Sewer Overflow Consent Decree

    EPA Pesticide Factsheets

    Project #OPE-FY17-0014, March 30, 2017. The EPA OIG plans to begin a review of EPA Region 4’s oversight of the Atlanta combined sewer overflow consent decree. For more information, please click on the link above.

  7. 31. RECORD PLAN, METROPOLITAN SEWER, GENERAL PLAN OF PUMPING STATION ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    31. RECORD PLAN, METROPOLITAN SEWER, GENERAL PLAN OF PUMPING STATION GROUNDS, DEER ISLAND. METROPOLITAN SEWERAGE COMMISSION, JUNE 1896. Photocopy of image of aperture card 4977-1. Aperture cards and original drawings at Massachusetts Water Resources Authority Archives, Building 39, Charlestown Navy Yard, Boston, MA - Deer Island Pumping Station, Boston, Suffolk County, MA

  8. EXFILTRATION IN SANITARY SEWER SYSTEMS IN THE U.S.

    EPA Science Inventory

    Many municipalities throughout the US have sewerage systems (separate and combined) that may experience exfiltration of untreated wastewater. This study was conducted to focus on the magnitude of the exfiltration problem from sewer pipes on a national basis. The method for estima...

  9. PERFORMANCE OF OZONE AS A DISINFECTANT FOR COMBINED SEWER OVERFLOW

    EPA Science Inventory

    Disinfection of combined sewer overflow (CSO) minimizes the amount of disease-causing microorganisms (pathogens) released into receiving waters. Currently, the primary disinfecting agent used in the US for wastewater treatment is chlorine (Cl2); however, Cl2 produces problems in ...

  10. 40 CFR 35.927-4 - Sewer use ordinance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 1 2014-07-01 2014-07-01 false Sewer use ordinance. 35.927-4 Section 35.927-4 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GRANTS AND OTHER FEDERAL ASSISTANCE STATE AND LOCAL ASSISTANCE Grants for Construction of Treatment Works-Clean Water Act § 35.927-4...

  11. 40 CFR 35.927-4 - Sewer use ordinance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 1 2012-07-01 2012-07-01 false Sewer use ordinance. 35.927-4 Section 35.927-4 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GRANTS AND OTHER FEDERAL ASSISTANCE STATE AND LOCAL ASSISTANCE Grants for Construction of Treatment Works-Clean Water Act § 35.927-4...

  12. 40 CFR 35.927-4 - Sewer use ordinance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 1 2013-07-01 2013-07-01 false Sewer use ordinance. 35.927-4 Section 35.927-4 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GRANTS AND OTHER FEDERAL ASSISTANCE STATE AND LOCAL ASSISTANCE Grants for Construction of Treatment Works-Clean Water Act § 35.927-4...

  13. EXFILTRATION IN SEWER SYSTEMS: IS IT A NATIONAL PROBLEM?

    EPA Science Inventory

    Many municipalities throughout the US have sewerage systems (separate and combined) that may experience exfiltration of untreated wastewater. This study was conducted to focus on the magnitude of the exfiltration problem from sewer pipes on a national basis. The method for estima...

  14. PERFORMANCE OF OZONE AS A DISINFECTANT FOR COMBINED SEWER OVERFLOW

    EPA Science Inventory

    Disinfection of combined sewer overflow (CSO) minimizes the amount of disease-causing microorganisms (pathogens) released into receiving waters. Currently, the primary disinfecting agent used in the US for wastewater treatment is chlorine (Cl2); however, Cl2 produces problems in ...

  15. HIGH-RATE DISINFECTION TECHNIQUES FOR COMBIND SEWER OVERFLOW

    EPA Science Inventory

    This paper presents high-rate disinfection technologies for combined sewer overflow (CSO). The high-rate disinfection technologies of interest are: chlorination/dechlorination, ultraviolet light irradiation (UV), chlorine dioxide (ClO2 ), ozone (O3), peracetic acid (CH3COOOH )...

  16. REAL TIME CONTROL OF SEWERS: US EPA MANUAL

    EPA Science Inventory

    The problem of sewage spills and local flooding has traditionally been addressed by large scale capital improvement programs that focus on construction alternatives such as sewer separation or construction of storage facilities. The cost of such projects is often high, especiall...

  17. CHALLENGES OF COMBINED SEWER OVERFLOW DISINFECTION BY ULTRAVIOLET LIGHT IRRADIATION

    EPA Science Inventory

    This article examines the performance and effectiveness of ultraviolet (UV) light irradiation for disinfection of combined sewer overflow (CSO). Due to the negative impact of conventional water disinfectants on aquatic life, new agents (e.g., UV light) are being investigated for ...

  18. Incorporating Storm Sewer Exfiltration into SWMM: Proof of Concept

    EPA Science Inventory

    This study evaluates the peak flow and volume reduction achieved by exfiltration from a perforated storm sewer in an urban catchment. There are three related objectives: [1] quantify peak flow and volume reduction; [2] demonstrate adaptability to climate change; and [3] evaluate ...

  19. Impervious surfaces and sewer pipe effects on stormwater runoff temperature

    NASA Astrophysics Data System (ADS)

    Sabouri, F.; Gharabaghi, B.; Mahboubi, A. A.; McBean, E. A.

    2013-10-01

    The warming effect of the impervious surfaces in urban catchment areas and the cooling effect of underground storm sewer pipes on stormwater runoff temperature are assessed. Four urban residential catchment areas in the Cities of Guelph and Kitchener, Ontario, Canada were evaluated using a combination of runoff monitoring and modelling. The stormwater level and water temperature were monitored at 10 min interval at the inlet of the stormwater management ponds for three summers 2009, 2010 and 2011. The warming effect of the ponds is also studied, however discussed in detail in a separate paper. An artificial neural network (ANN) model for stormwater temperature was trained and validated using monitoring data. Stormwater runoff temperature was most sensitive to event mean temperature of the rainfall (EMTR) with a normalized sensitivity coefficient (Sn) of 1.257. Subsequent levels of sensitivity corresponded to the longest sewer pipe length (LPL), maximum rainfall intensity (MI), percent impervious cover (IMP), rainfall depth (R), initial asphalt temperature (AspT), pipe network density (PND), and rainfall duration (D), respectively. Percent impervious cover of the catchment area (IMP) was the key parameter that represented the warming effect of the paved surfaces; sensitivity analysis showed IMP increase from 20% to 50% resulted in runoff temperature increase by 3 °C. The longest storm sewer pipe length (LPL) and the storm sewer pipe network density (PND) are the two key parameters that control the cooling effect of the underground sewer system; sensitivity analysis showed LPL increase from 345 to 966 m, resulted in runoff temperature drop by 2.5 °C.

  20. Particle velocity and sediment transport at the limit of deposition in sewers.

    PubMed

    Ota, J J; Perrusquía, G S

    2013-01-01

    This paper focuses on the sediment particle while it is transported at the limit of deposition in storm sewers, i.e. as bed load at the limit of concentration that leads to sediment deposition. Although many empirical sediment transport equations are known in the literature, there is only limited knowledge concerning particle velocity. Sediment particle and sphere velocity measurements were carried out in two pipe channels and these results led to the development of a semi-theoretical equation for sediment transport at the limit of deposition in sewers. Even in the transport process without deposition, sediment movement is slower than water velocity and depends on the angle of repose of sediment with a diameter d on the roughness k of the pipe channel. Instead of classical dimensionless bed shear stress ψ, a modified dimensionless bed shear stress ψ (d/k)(2/3) was suggested, based on the angle of repose and this parameter was proved to be significant for quantifying the transport capacity. The main purpose of this article is to emphasize the importance of careful observation of experiments. Not only number of tests, but physical understanding are essential for better empirical equations.

  1. Diabetes Continues Its Relentless Rise

    MedlinePlus

    ... medlineplus.gov/news/fullstory_164596.html Diabetes Continues Its Relentless Rise But doctors making headway with heart ... main risk factor for type 2 diabetes, though it's not the only factor involved in the disease. ...

  2. Sulfide and methane production in sewer sediments: Field survey and model evaluation.

    PubMed

    Liu, Yiwen; Tugtas, A Evren; Sharma, Keshab R; Ni, Bing-Jie; Yuan, Zhiguo

    2016-02-01

    Sewer sediment processes have been reported to significantly contribute to overall sulfide and methane production in sewers, at a scale comparable to that of sewer biofilms. The physiochemical and biological characteristics of sewer sediments are heterogeneous; however, the variability of in-sediments sulfide and methane production rates among sewers has not been assessed to date. In this study, five sewer sediment samples were collected from two cities in Australia with different climatic conditions. Batch assays were conducted to determine the rates of sulfate reduction and methane production under different flow velocity (shear stress) conditions as well as under completely mixed conditions. The tests showed substantial and variable sulfate reduction and methane production activities among different sediments. Sulfate reduction and methane production from sewer sediments were confirmed to be areal processes, and were dependent on flow velocity/shear stress. Despite of the varying characteristics and reactions kinetics, the sulfate reduction and methane production processes in all sediments could be well described by a one-dimensional sewer sediment model recently developed based on results obtained from a laboratory sewer sediment reactor. Model simulations indicated that the in-situ contribution of sewer sediment emissions could be estimated without the requirement of measuring the specific sediment characteristics or the sediment depths.

  3. Degradation of methanethiol in anaerobic sewers and its correlation with methanogenic activities.

    PubMed

    Sun, Jing; Hu, Shihu; Sharma, Keshab Raj; Ni, Bing-Jie; Yuan, Zhiguo

    2015-02-01

    Methanethiol (MT) is considered one of the predominant odorants in sewer systems. Therefore, understanding MT transformation in sewers is essential to sewer odor assessment and abatement. In this study, we investigated the degradation of MT in laboratory anaerobic sewers. Experiments were carried out in seven anaerobic sewer reactors with biofilms at different stages of development. MT degradation was found to be strongly dependent on the methanogenic activity of sewer biofilms. The MT degradation rate accelerated with the increase of methanogenic activity of sewer biofilms, resulting in MT accumulation (i.e. net production) in sewer reactors with relatively low methanogenic activities, and MT removal in reactors with higher methanogenic activities. A Monod-type kinetic expression was developed to describe MT degradation kinetics in anaerobic sewers, in which the maximum degradation rate was modeled as a function of the maximum methane production rate through a power function. It was also found that MT concentration had a linear relationship with acetate concentration, which may be used for preliminary assessment of MT presence in anaerobic sewers.

  4. Study for Reliability Assessment considering the Sedimentation in Urban Sewer Networks

    NASA Astrophysics Data System (ADS)

    Song, Yangho; Park, Moojong; Lee, Jungho

    2016-04-01

    In this study, analysis of reliability of sewer network was progressed with the number of overflow nodes and overflow volume simultaneously for urban areas considering sedimentation. Reliability analysis shows that it is possible to quantify the difference in the phenomenon of the destruction of sedimentation in urban sewer system under the same design frequency. This study focuses on the release to bed of sedimentations having being accumulated inside a urban sewer network. It is proposed as one of the indicators evaluated as full reliability for sewer system. To analyze detailed changes in conduit designs in urban sewer networks, tried to reduction of sedimentation in sewer networks using modified pipe slope in Bujeon-dong catchment, Busan. The various sewer designs were applied and then, the most effective improvement of reliability over 10%. Suggested reliability process can produce the quantitative evaluations about sewer systems using the results of the system simulations and use of possible the objective function for the sewer network designed with a relative evaluation. Sewer network is designed to pass the inflow rate depending on the design frequency smoothly. However, taking a look at the example of flooding generated in urban area shows that an increase in the generation and damage of flooding can be often caused by the deposition of sediment in the sewer. This is a problem in the maintenance of sewers, but this implies that the effect of sediment deposition should be considered to some degree for the design of a conduit itself in another aspect. Thus, it is necessary to realize design in a direction to reduce flood damage pursuant to it by considering the deposition aspect of sediment in a conduit when designing a storm sewer.

  5. An analytical probabilistic model of the quality efficiency of a sewer tank

    NASA Astrophysics Data System (ADS)

    Balistrocchi, Matteo; Grossi, Giovanna; Bacchi, Baldassare

    2009-12-01

    The assessment of the efficiency of a storm water storage facility devoted to the sewer overflow control in urban areas strictly depends on the ability to model the main features of the rainfall-runoff routing process and the related wet weather pollution delivery. In this paper the possibility of applying the analytical probabilistic approach for developing a tank design method, whose potentials are similar to the continuous simulations, is proved. In the model derivation the quality issues of such devices were implemented. The formulation is based on a Weibull probabilistic model of the main characteristics of the rainfall process and on a power law describing the relationship between the dimensionless storm water cumulative runoff volume and the dimensionless cumulative pollutograph. Following this approach, efficiency indexes were established. The proposed model was verified by comparing its results to those obtained by continuous simulations; satisfactory agreement is shown for the proposed efficiency indexes.

  6. Quality of local control for simple sewer networks

    NASA Astrophysics Data System (ADS)

    Kolechkina, Alla; van Nooijen, Ronald

    2016-04-01

    Combined sewer networks, where both foul water and storm water are transported through the same system, tend to develop into complex networks due to expansion of towns and villages. The transport capacity of these systems is always limited, so occasional controlled spills into surface water, combined sewer overflows (CSO), are part of the normal operating procedure. Occasionally the ideas and rules present in the original design are not respected when the system is extended to cover a larger area. One way to deal with this problem is to implement central control. Another is to add pipes and hardware to bring the extended system into line with the original rules and ideas. We show that for a design rule often followed in the Netherlands, local control does quite well as long as the rule is respected and there are no large variations in precipitation intensity over the area covered by the system.

  7. Airflow in Gravity Sewers - Determination of Wastewater Drag Coefficient.

    PubMed

    Bentzen, Thomas Ruby; Østertoft, Kristian Kilsgaard; Vollertsen, Jes; Fuglsang, Emil Dietz; Nielsen, Asbjørn Haaning

    2016-03-01

    Several experiments have been conducted in order to improve the understanding of the wastewater drag and the wall frictional force acting on the headspace air in gravity sewers. The aim of the study is to improve the data basis for a numerical model of natural sewer ventilation. The results of the study shows that by integrating the top/side wall shear stresses the log-law models for the air velocity distribution along the unwetted perimeter resulted in a good agreement with the friction forces calculated by use of the Colebrook-White formula for hydraulic smooth pipes. Secondly, the water surface drags were found by log-law models of the velocity distribution in turbulent flows to fit velocity profiles measured from the water surface and by integrating the water surface drags along the wetted perimeter, mean water surface drags were found and a measure of the water surface drag coefficient was found.

  8. A software-based sensor for combined sewer overflows.

    PubMed

    Leonhardt, G; Fach, S; Engelhard, C; Kinzel, H; Rauch, W

    2012-01-01

    A new methodology for online estimation of excess flow from combined sewer overflow (CSO) structures based on simulation models is presented. If sufficient flow and water level data from the sewer system is available, no rainfall data are needed to run the model. An inverse rainfall-runoff model was developed to simulate net rainfall based on flow and water level data. Excess flow at all CSO structures in a catchment can then be simulated with a rainfall-runoff model. The method is applied to a case study and results show that the inverse rainfall-runoff model can be used instead of missing rain gauges. Online operation is ensured by software providing an interface to the SCADA-system of the operator and controlling the model. A water quality model could be included to simulate also pollutant concentrations in the excess flow.

  9. Detailed observation and measurement of sewer sediment erosion under aerobic and anaerobic conditions.

    PubMed

    Schellart, A; Veldkamp, R; Klootwijk, M; Clemens, F; Tait, S; Ashley, R; Howes, C

    2005-01-01

    A greater understanding of the erosion behaviour of sewer sediments is necessary in order to reliably estimate the amount and nature of the sewer sediments released from deposits in sewers and transported either to waste water treatment plants or discharged into the environment. Research has indicated that microbial activity in sediment can influence the physical release of sediment from in-pipe deposits. This paper reports on a series of erosion tests in which sewer sediments from different sewer networks are kept under different environmental conditions and their resistance to erosion is examined. The erosion tests are carried out under aerobic and anaerobic conditions and two temperatures, one representing ambient sewer temperatures and a lower temperature that significantly suppresses bacterial activity.

  10. Life cycle assessment of urban wastewater systems: Quantifying the relative contribution of sewer systems.

    PubMed

    Risch, Eva; Gutierrez, Oriol; Roux, Philippe; Boutin, Catherine; Corominas, Lluís

    2015-06-15

    This study aims to propose a holistic, life cycle assessment (LCA) of urban wastewater systems (UWS) based on a comprehensive inventory including detailed construction and operation of sewer systems and wastewater treatment plants (WWTPs). For the first time, the inventory of sewers infrastructure construction includes piping materials and aggregates, manholes, connections, civil works and road rehabilitation. The operation stage comprises energy consumption in pumping stations together with air emissions of methane and hydrogen sulphide, and water emissions from sewer leaks. Using a real case study, this LCA aims to quantify the contributions of sewer systems to the total environmental impacts of the UWS. The results show that the construction of sewer infrastructures has an environmental impact (on half of the 18 studied impact categories) larger than both the construction and operation of the WWTP. This study highlights the importance of including the construction and operation of sewer systems in the environmental assessment of centralised versus decentralised options for UWS.

  11. Worcester Municipal Separate Storm Sewer System (MS4) ...

    EPA Pesticide Factsheets

    2017-04-10

    Worcester was issued NPDES Permit MAS010002 for discharging storm water from its municipal separate storm sewer system (MS4) which became effective on October 30, 1998. The permit expired five years later on October 30, 2003; however, EPA administratively continued the permit as allowed by regulation. Proceeding to reissue this NPDES permit, EPA and MassDEP have now issued a draft permit and fact sheet (which provides EPA's technical basis for establishing permit conditions).

  12. Investigation of sewer exfiltration using integral pumping tests and wastewater indicators

    NASA Astrophysics Data System (ADS)

    Leschik, Sebastian; Musolff, Andreas; Martienssen, Marion; Krieg, Ronald; Bayer-Raich, Marti; Reinstorf, Frido; Strauch, Gerhard; Schirmer, Mario

    2009-11-01

    Leaky sewers affect urban groundwater by the exfiltration of untreated wastewater. However, the impact of sewer exfiltration on the groundwater is poorly understood. Most studies on sewer exfiltration focus on water exfiltration, but not on the impact on groundwater quality. In this paper we present a new monitoring approach to estimate mass flow rates Mex of different wastewater indicators (WWIs) from leaky sewers by applying integral pumping tests (IPTs). The problem of detecting and assessing heterogeneous concentrations in the vicinity of leaky sewers can be overcome with the IPT approach by the investigation of large groundwater volumes up- and downstream of leaky sewers. The increase in concentrations downstream of a leaky sewer section can be used to calculate Mex with a numerical groundwater model. The new monitoring approach was first applied using four IPT wells in Leipzig (Germany). Over a pumping period of five days we sampled five inorganic WWIs: B , Cl -, K +, NO 3-, NH 4+ and three xenobiotics: bisphenol-a, caffeine and tonalide. The resulting concentration-time series indicated an influence of wastewater at one IPT well downstream of the leaky sewer. We defined ranges of Mex by implementing the uncertainty of chemical analyses. The results showed a Mex of 0-10.9 g m - 1 d - 1 . The combination of Mex with wastewater concentrations from the target sewer yielded an exfiltration rate Qex of 28.0-63.9 L m - 1 d - 1 for the conservative ion Cl -. Most non-conservative WWIs showed reduced mass flow rates in the groundwater downstream of the leaky sewer that indicate a mass depletion during their passage from the sewer to the pumping well. Application of the IPT methodology at other field sites is possible. The IPT monitoring approach provides reliable Mex values that can help to assess the impact of leaky sewers on groundwater.

  13. A performance investigation of small-bore sewers.

    PubMed

    Memon, F A; Fidar, A; Littlewood, K; Butler, D; Makropoulos, C; Liu, S

    2007-01-01

    This paper describes a full-scale physical model and its application to investigate the effectiveness/performance of small-bore sewers for a range of operational and design parameters. The implementation methodology involves observing the movement of synthetic gross solids in three small bore sewers (150, 100 and 75 mm diameter) for different volumes of simulated flush waves and gradients. The simulated flush waves were generated, using an automated wave sequencer, for three different flush volumes (3, 4.5 and 6 litres). To investigate the impact of solid shape factor, a number of tests were carried out using synthetic solids in combination with toilet tissue paper. In total, more than 1,000 tests were performed for different operational and design parameter combinations. Results obtained to date have confirmed earlier studies, particularly with respect to the role of flush volume in solids transport, and identified the impact of gradient variation and its significance particularly in small-bore sewers receiving low flush volume. Results from the physical model application exercise will be used to propose new design guidelines for wastewater collection systems with specific consideration to new developments and inform the decision support system, currently being developed as part of a research project on water cycle management for new developments (WaND).

  14. Numerical modelling of air-water flows in sewer drops.

    PubMed

    Beceiro, Paula; Almeida, Maria do Céu; Matos, Jorge

    2017-07-01

    The presence of dissolved oxygen (DO) in water flows is an important factor to ensure the aerobic conditions recognised as beneficial to preventing the occurrence of detrimental effects. The incorporation of DO in wastewater flowing in sewer systems is a process widely investigated in order to quantify the effect of continuous reaeration through the air-liquid interface or air entrained due to the presence of singularities such as drops or junctions. The location of sewer drops to enhance air entrainment and subsequently reaeration is an effective practice to promote aerobic conditions in sewers. In the present paper, vertical drops, backdrops and stepped drops were modelled using the computational fluid dynamics (CFD) code FLOW-3D(®) to evaluate the air-water flows due to the turbulence induced by the presence of these types of structures. An assessment of the hydraulic variables and an analysis of the air entrainment based on the available experimental studies were carried out. The results of the CFD models for these structures were validated using measurements of discharge, pressure head and water depth obtained in the corresponding physical models. A very good fit was obtained for the hydraulic behaviour. After validation of numerical models, analysis of the air entrainment was carried out.

  15. Mechanism and kinetics of biofilm growth process influenced by shear stress in sewers.

    PubMed

    Ai, Hainan; Xu, Jingwei; Huang, Wei; He, Qiang; Ni, Bingjie; Wang, Yinliang

    2016-01-01

    Sewer biofilms play an important role in the biotransformation of substances for methane and sulfide emission in sewer networks. The dynamic flows and the particular shear stress in sewers are the key factors determining the growth of the sewer biofilm. In this work, the development of sewer biofilm with varying shear stress is specifically investigated to gain a comprehensive understanding of the sewer biofilm dynamics. Sewer biofilms were cultivated in laboratory-scale gravity sewers under different hydraulic conditions with the corresponding shell stresses are 1.12 Pa, 1.29 Pa and 1.45 Pa, respectively. The evolution of the biofilm thickness were monitored using microelectrodes, and the variation in total solids (TS) and extracellular polymer substance (EPS) levels in the biofilm were also measured. The results showed that the steady-state biofilm thickness were highly related to the corresponding shear stresses with the biofilm thickness of 2.4 ± 0.1 mm, 2.7 ± 0.1 mm and 2.2 ± 0.1 mm at shear stresses of 1.12 Pa, 1.29 Pa and 1.45 Pa, respectively, which the chemical oxygen demand concentration is 400 mg/L approximately. Based on these observations, a kinetic model for describing the development of sewer biofilms was developed and demonstrated to be capable of reproducing all the experimental data.

  16. Impact of water source management practices in residential areas on sewer networks - a review.

    PubMed

    Marleni, N; Gray, S; Sharma, A; Burn, S; Muttil, N

    2012-01-01

    Prolonged drought which has occurred everywhere around the world has caused water shortages, leading many countries to consider more sustainable practices, which are called source management practices (SMPs) to ensure water availability for the future. SMPs include the practices of water use reduction, potable water substitution and wastewater volume reduction such as water demand management, rainwater harvesting, greywater recycling and sewer mining. Besides the well known advantages from SMPs, they also contribute to the alteration of wastewater characteristics which finally affect the process in downstream infrastructure such as sewerage networks. Several studies have shown that the implementation of SMPs decreases the wastewater flow, whilst increasing its strength. High-strength wastewater can cause sewer problems such as sewer blockage, odour and corrosion. Yet, not all SMPs and their impact on existing sewer networks have been investigated. Therefore, this study reviews some examples of four common SMPs, the wastewater characteristics and the physical and biochemical transformation processes in sewers and the problems that might caused by them, and finally the potential impacts of those SMPs on wastewater characteristics and sewer networks are discussed. This paper provides sewer system managers with an overview of potential impacts on the sewer network due to the implementation of some SMPs. Potential research opportunities for the impact of SMPs on existing sewers are also identified.

  17. Searching for storm water inflows in foul sewers using fibre-optic distributed temperature sensing.

    PubMed

    Schilperoort, Rémy; Hoppe, Holger; de Haan, Cornelis; Langeveld, Jeroen

    2013-01-01

    A major drawback of separate sewer systems is the occurrence of illicit connections: unintended sewer cross-connections that connect foul water outlets from residential or industrial premises to the storm water system and/or storm water outlets to the foul sewer system. The amount of unwanted storm water in foul sewer systems can be significant, resulting in a number of detrimental effects on the performance of the wastewater system. Efficient removal of storm water inflows into foul sewers requires knowledge of the exact locations of the inflows. This paper presents the use of distributed temperature sensing (DTS) monitoring data to localize illicit storm water inflows into foul sewer systems. Data results from two monitoring campaigns in foul sewer systems in the Netherlands and Germany are presented. For both areas a number of storm water inflow locations can be derived from the data. Storm water inflow can only be detected as long as the temperature of this inflow differs from the in-sewer temperatures prior to the event. Also, the in-sewer propagation of storm and wastewater can be monitored, enabling a detailed view on advection.

  18. Acetate removal in sewer biofilms under aerobic conditions.

    PubMed

    Raunkjaer, K; Nielsen, P H; Hvitved-Jacobsen, T

    1997-11-01

    Removal of acetate has been investigated in sewer biofilms by continuous-flow biofilm reactor studies simulating the conditions in a gravity sewer. Non-steady-state conditions are prevailing in sewers, due to periodic variations in substrate concentrations. In order to simulate two extreme situations in a gravity sewer, biofilms defined as high-loaded and low-loaded, respectively, were grown by continuously feeding wastewater to the reactors with and without supplementary addition of acetate. During short-term experiments with high acetate concentrations (1-2 h), surface removal rates of acetate and dissolved oxygen (DO) and observed yield coefficients were determined, as well as the influence of DO concentration on acetate removal rates. The low-loaded biofilms showed very high acetate removal rates in short-term experiments at high acetate concentrations. The DO uptake rates were low, resulting in an average observed yield coefficient of 0.79 g biomass produced per gram acetate (as chemical oxygen demand, COD) consumed. This indicated a luxury uptake by the cells probably for storage inside the cells or for production of extracellular polymeric substances. The high-loaded biofilms showed lower acetate removal rates during the short-term experiments, with an average yield coefficient of 0.49 g biomass produced per gram acetate (as COD) consumed. The level of the acetate removal rates seemed to be related to the structure of the biofilm. The highest acetate removal rates were found for the low-loaded biofilm, where the biofilm was very hairy with 'streamers" with a length of 8-9 mm. At low acetate removal rates (high-loaded biofilm), the "streamer" lengths were only 3-5 mm. The surface removal rates for acetate and DO seemed to follow 1/2 order approximations to biofilm kinetics. For a DO of 0.8 and 6.0 g/m3, the limiting acetate concentrations were about 34 and 20 g-COD/m3, respectively. Under real gravity sewer conditions, the typical concentration ranges for

  19. Design and performance evaluation of a simplified dynamic model for combined sewer overflows in pumped sewer systems

    NASA Astrophysics Data System (ADS)

    van Daal-Rombouts, Petra; Sun, Siao; Langeveld, Jeroen; Bertrand-Krajewski, Jean-Luc; Clemens, François

    2016-07-01

    Optimisation or real time control (RTC) studies in wastewater systems increasingly require rapid simulations of sewer systems in extensive catchments. To reduce the simulation time calibrated simplified models are applied, with the performance generally based on the goodness of fit of the calibration. In this research the performance of three simplified and a full hydrodynamic (FH) model for two catchments are compared based on the correct determination of CSO event occurrences and of the total discharged volumes to the surface water. Simplified model M1 consists of a rainfall runoff outflow (RRO) model only. M2 combines the RRO model with a static reservoir model for the sewer behaviour. M3 comprises the RRO model and a dynamic reservoir model. The dynamic reservoir characteristics were derived from FH model simulations. It was found that M2 and M3 are able to describe the sewer behaviour of the catchments, contrary to M1. The preferred model structure depends on the quality of the information (geometrical database and monitoring data) available for the design and calibration of the model. Finally, calibrated simplified models are shown to be preferable to uncalibrated FH models when performing optimisation or RTC studies.

  20. Contemporary sea level rise.

    PubMed

    Cazenave, Anny; Llovel, William

    2010-01-01

    Measuring sea level change and understanding its causes has considerably improved in the recent years, essentially because new in situ and remote sensing observations have become available. Here we report on most recent results on contemporary sea level rise. We first present sea level observations from tide gauges over the twentieth century and from satellite altimetry since the early 1990s. We next discuss the most recent progress made in quantifying the processes causing sea level change on timescales ranging from years to decades, i.e., thermal expansion of the oceans, land ice mass loss, and land water-storage change. We show that for the 1993-2007 time span, the sum of climate-related contributions (2.85 +/- 0.35 mm year(-1)) is only slightly less than altimetry-based sea level rise (3.3 +/- 0.4 mm year(-1)): approximately 30% of the observed rate of rise is due to ocean thermal expansion and approximately 55% results from land ice melt. Recent acceleration in glacier melting and ice mass loss from the ice sheets increases the latter contribution up to 80% for the past five years. We also review the main causes of regional variability in sea level trends: The dominant contribution results from nonuniform changes in ocean thermal expansion.

  1. Localization of groundwater infiltration in the combined sewers of Brussels by stable isotopes measurements (δ18O, δD) by Cavity Ring Down Spectroscopy.

    NASA Astrophysics Data System (ADS)

    De Bondt, Kevin; Claeys, Philippe

    2014-05-01

    In the last 20 years research has been conducted to quantify the infiltration of groundwater into the sewers. This groundwater, called parasitic water, increases the volume of waste-water to be treated and consequently the cost of this treatment. Moreover, in the case of combined sewer systems, the parasitic water also limits the sewer capacity and indirectly increases the risks of combined sewer overflows and floods. The infiltration of groundwater occurs trough cracks, sewer collapses and from direct connections with old springs. Different methods quantify the intrusion of parasitic water. Among these, the use of the stable isotopes of water (δ18O & δD) shows good result in catchments or cities close to Mountainous regions (example from Lyon, Zurich), where isotopic signals vary significantly because of continental and altitude effects. However many cities, such as Brussels, are located in more oceanic settings and theoretically offer less potential for the application of the stable isotopes method. In the case of Brussels, river-water from the Meuse is used to produce domestic-water. The catchment of this river extends into the Ardennes, which are affected by slightly different climatic conditions. δ18O & δD analyzes of groundwater from the main aquifer (Ledo-Paniselian-Brusselian) and domestic-water from the Callois reservoir fed by the Meuse River show sufficient isotopic differences in the south of Brussels, but only during the summer. The discrimination potential is better with δD than with δ18O. The improvement of δD measurements (precision, costs,...) brought by Cavity Ring Down Spectroscopy largely contributes to the potential of using stable isotopes method to trace water in Brussels. The first campaigns in the sewers also show a little enrichment (in heavy isotopes) of the waste-water in comparison with the reservoir waters and tap waters. This increases the potential of the method but constrains the sampling to pure waste-water in sewer segments

  2. PPCPs wet weather mobilization in a combined sewer in NW Spain.

    PubMed

    Del Río, Héctor; Suárez, Joaquín; Puertas, Jerónimo; Ures, Pablo

    2013-04-01

    An intense campaign was carried out over a 14 month period to characterize concentrations and loads of 7 well-known Pharmaceuticals and Personal Care Products (PPCPs), during dry and wet weather conditions, in an urban combined catchment in the northwest of Spain, a geographical zone with an average annual rainfall over 1500 mm. The main objective was to gather more in-depth knowledge of the mobilization of these "micropollutants" in an urban combined sewer and the possible pressures on water receiving bodies due to combined sewer overflows (CSOs). Hydrographs and pollutographs of these substances in dry weather flows (DWF), on weekdays and weekends, and wet weather flows (WWF) during 10 rain events have been characterized to obtain data that are sufficiently representative for statistical analysis. The research findings show that there is a considerable mobilization of these substances during rain events, mainly in the first part of the hydrographs, especially HHCB galaxolide, ibuprofen and paracetamol with maximum concentrations of 9.76, 8.51 and 5.71 μg/L respectively, whereas these concentrations in dry weather only reached 2.57, 2.11 and 0.72 μg/L respectively. There is a good correlation between the degree of mobilization in wet weather flows and the percentage of dry weather particulate phase of each studied substance, indicating that such mobilization may be associated with adsorption on the sediments deposited on the collectors during the antecedent dry period. These results are in good agreement with removal in conventional WWTP, especially for compounds that tend to adsorb onto sewage sludge.

  3. Melting Ice, Rising Seas

    NASA Image and Video Library

    Sea level rise is an indicator that our planet is warming. Much of the world's population lives on or near the coast, and rising seas are something worth watching. Sea level can rise for two reason...

  4. Association between Gastrointestinal Illness and Precipitation in Areas Impacted by Combined Sewer Systems: Utilizing a Distributed Lag Model

    EPA Science Inventory

    Combined sewer systems collect rainwater runoff, sewage, and industrial wastewater for transit to treatment facilities. With heavy precipitation, volumes can exceed capacity of treatment facilities, and wastewater discharges directly to receiving waters. These combined sewer over...

  5. Association between Gastrointestinal Illness and Precipitation in Areas Impacted by Combined Sewer Systems: Utilizing a Distributed Lag Model

    EPA Science Inventory

    Combined sewer systems collect rainwater runoff, sewage, and industrial wastewater for transit to treatment facilities. With heavy precipitation, volumes can exceed capacity of treatment facilities, and wastewater discharges directly to receiving waters. These combined sewer over...

  6. Sanitary Sewer Systems and Association with Gastrointestinal Illness: A case crossover analysis of Massachusetts Data, 2006-2008

    EPA Science Inventory

    Sanitary sewer overflows (SSOs) occur when untreated sewage is discharged into water sources before reaching the treatment facility potentially contaminating them with gastrointestinal pathogens. Causes of SSOs include heavy rainfall and rupture/blockage of sewer lines. Few studi...

  7. Sanitary Sewer Systems and Association with Gastrointestinal Illness: A case crossover analysis of Massachusetts Data, 2006-2008

    EPA Science Inventory

    Sanitary sewer overflows (SSOs) occur when untreated sewage is discharged into water sources before reaching the treatment facility potentially contaminating them with gastrointestinal pathogens. Causes of SSOs include heavy rainfall and rupture/blockage of sewer lines. Few studi...

  8. Quality Assurance and Quality Control Practices For Rehabilitation of Sewer and Water Mains

    EPA Science Inventory

    As part of the US Environmental Protection Agency (EPA)’s Aging Water Infrastructure Research Program, several areas of research are being pursued including a review of quality assurance and quality control (QA/QC) practices and acceptance testing during the installation of rehab...

  9. Quality Assurance and Quality Control Practices For Rehabilitation of Sewer and Water Mains

    EPA Science Inventory

    As part of the US Environmental Protection Agency (EPA)’s Aging Water Infrastructure Research Program, several areas of research are being pursued including a review of quality assurance and quality control (QA/QC) practices and acceptance testing during the installation of rehab...

  10. Quality Assurance and Quality Control Practices for Rehabilitation of Sewer and Water Mains

    EPA Science Inventory

    As part of the US Environmental Protection Agency (EPA)’s Aging Water Infrastructure Research Program, several areas of research are being pursued, including a review of quality assurance and quality control (QA/QC) practices and acceptance testing during the installation of reha...

  11. Quality Assurance and Quality Control Practices for Rehabilitation of Sewer and Water Mains

    EPA Science Inventory

    As part of the US Environmental Protection Agency (EPA)’s Aging Water Infrastructure Research Program, several areas of research are being pursued, including a review of quality assurance and quality control (QA/QC) practices and acceptance testing during the installation of reha...

  12. Flood Grouting for Infiltration Reduction on Private Side Sewers (WERF Report INFR5R11)

    EPA Science Inventory

    The sewers in Seattle’s Broadview neighborhood, built in the 1950s, experience significant inflow and infiltration. Intense wet weather events have resulted in sewer overflows into private residences and the environment and previous work indicates that the majority of this excess...

  13. SEWER SEDIMENT CONTROL: AN OVERVIEW OF THE EPA WET WEATHER FLOW (WWF) RESEARCH PROGRAM

    EPA Science Inventory

    This paper presents an overview of EPA WWF Research Program projects related to causes of sewer solids deposition and control methods that can prevent accumulation of sewer sediments. In particular, discussion will focus on the relationship of wastewater characteristics to flow ...

  14. Focused Field Investigations for Sewer Condition Assessment with EPA SSOAP Toolbox - abstract

    EPA Science Inventory

    The Nation’s sanitary sewer infrastructure is aging, and it is currently one of the top national water program priorities, and is one of the top priorities of the U.S. Conference of Mayors. The U.S. Environmental Protection Agency developed the Sanitary Sewer Overflow Analysis a...

  15. Focused Field Investigations for Sewer Condition Assessment with EPA SSOAP Toolbox - slides

    EPA Science Inventory

    The Nation’s sanitary sewer infrastructure is aging, and is currently one of the top national water program priorities. The U.S. Environmental Protection Agency (EPA) developed the Sanitary Sewer Overflow Analysis and Planning (SSOAP) Toolbox to assist communities in developing S...

  16. Focused Field Investigations for Sewer Condition Assessment with EPA SSOAP Toolbox

    EPA Science Inventory

    The Nation’s sanitary sewer infrastructure is aging, and is currently one of the top national water program priorities. The U.S. Environmental Protection Agency (EPA) developed the Sanitary Sewer Overflow Analysis and Planning (SSOAP) Toolbox to assist communities in developing ...

  17. Focused Field Investigations for Sewer Condition Assessment with EPA SSOAP Toolbox

    EPA Science Inventory

    The Nation’s sanitary sewer infrastructure is aging, and it is currently one of the top national water program priorities, and is one of the top priorities of the U.S. Conference of Mayors. The U.S. Environmental Protection Agency (EPA) developed the Sanitary Sewer Overflow Anal...

  18. 40 CFR 35.935-16 - Sewer use ordinance and evaluation/rehabilitation program.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-Clean Water Act § 35.935-16 Sewer use ordinance and evaluation/rehabilitation program. (a) The grantee... 40 Protection of Environment 1 2012-07-01 2012-07-01 false Sewer use ordinance and evaluation/rehabilitation program. 35.935-16 Section 35.935-16 Protection of Environment ENVIRONMENTAL PROTECTION...

  19. 40 CFR 35.935-16 - Sewer use ordinance and evaluation/rehabilitation program.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-Clean Water Act § 35.935-16 Sewer use ordinance and evaluation/rehabilitation program. (a) The grantee... 40 Protection of Environment 1 2013-07-01 2013-07-01 false Sewer use ordinance and evaluation/rehabilitation program. 35.935-16 Section 35.935-16 Protection of Environment ENVIRONMENTAL PROTECTION...

  20. 40 CFR 35.935-16 - Sewer use ordinance and evaluation/rehabilitation program.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-Clean Water Act § 35.935-16 Sewer use ordinance and evaluation/rehabilitation program. (a) The grantee... 40 Protection of Environment 1 2014-07-01 2014-07-01 false Sewer use ordinance and evaluation/rehabilitation program. 35.935-16 Section 35.935-16 Protection of Environment ENVIRONMENTAL PROTECTION...

  1. Update on the Status of Sanitary Sewer Overflow Analysis and Planning (SSOAP) Toolbox

    EPA Science Inventory

    A properly designed, operated and maintained sanitary sewer system is meant to collect and convey all of the sewage that flows into it to a wastewater treatment plant. However, occasional unintentional discharges of raw sewage from municipal sanitary sewers – called sanitary sewe...

  2. Evidence for fat, oil and grease (FOG) deposit formation mechanisms in sewer lines

    USDA-ARS?s Scientific Manuscript database

    The presence of hardened and insoluble fats, oil, and grease (FOG) deposits in sewer lines is a major cause of line blockages leading to sanitary sewer overflows (SSOs). Despite the central role that FOG deposits play in SSOs, little is known about the mechanisms of FOG deposit formation in sanitary...

  3. Flood Grouting for Infiltration Reduction on Private Side Sewers (WERF Report INFR5R11)

    EPA Science Inventory

    The sewers in Seattle’s Broadview neighborhood, built in the 1950s, experience significant inflow and infiltration. Intense wet weather events have resulted in sewer overflows into private residences and the environment and previous work indicates that the majority of this excess...

  4. SEWER-SEDIMENT CONTROL: OVERVIEW OF AN EPA WET-WEATHER FLOW RESEARCH PROGRAM

    EPA Science Inventory

    This paper presents a historical overview of the sewer sediment control projects conducted by the Wet-Weather Flow Research Program of the USEPA. Research presented includes studies of the causes of sewer solids deposition and development/evaluation of control methods that can pr...

  5. Focused Field Investigations for Sewer Condition Assessment with EPA SSOAP Toolbox

    EPA Science Inventory

    The Nation’s sanitary sewer infrastructure is aging, and is currently one of the top national water program priorities. The U.S. Environmental Protection Agency (EPA) developed the Sanitary Sewer Overflow Analysis and Planning (SSOAP) Toolbox to assist communities in developing ...

  6. Focused Field Investigations for Sewer Condition Assessment with EPA SSOAP Toolbox - slides

    EPA Science Inventory

    The Nation’s sanitary sewer infrastructure is aging, and is currently one of the top national water program priorities. The U.S. Environmental Protection Agency (EPA) developed the Sanitary Sewer Overflow Analysis and Planning (SSOAP) Toolbox to assist communities in developing S...

  7. Focused Field Investigations for Sewer Condition Assessment with EPA SSOAP Toolbox - abstract

    EPA Science Inventory

    The Nation’s sanitary sewer infrastructure is aging, and it is currently one of the top national water program priorities, and is one of the top priorities of the U.S. Conference of Mayors. The U.S. Environmental Protection Agency developed the Sanitary Sewer Overflow Analysis a...

  8. Cost Comparison of Conventional Gray Combined Sewer Overflow Control Infrastructure versus a Green/Gray Combination

    EPA Science Inventory

    This paper outlines a life-cycle cost analysis comparing a green (rain gardens) and gray (tunnels) infrastructure combination to a gray-only option to control combined sewer overflow in the Turkey Creek Combined Sewer Overflow Basin, in Kansas City, MO. The plan area of this Bas...

  9. SEWER-SEDIMENT CONTROL: OVERVIEW OF AN EPA WET-WEATHER FLOW RESEARCH PROGRAM

    EPA Science Inventory

    This paper presents a historical overview of the sewer sediment control projects conducted by the Wet-Weather Flow Research Program of the USEPA. Research presented includes studies of the causes of sewer solids deposition and development/evaluation of control methods that can pr...

  10. Cost Comparison of Conventional Gray Combined Sewer Overflow Control Infrastructure versus a Green/Gray Combination

    EPA Science Inventory

    This paper outlines a life-cycle cost analysis comparing a green (rain gardens) and gray (tunnels) infrastructure combination to a gray-only option to control combined sewer overflow in the Turkey Creek Combined Sewer Overflow Basin, in Kansas City, MO. The plan area of this Bas...

  11. Update on the Status of Sanitary Sewer Overflow Analysis and Planning (SSOAP) Toolbox

    EPA Science Inventory

    A properly designed, operated and maintained sanitary sewer system is meant to collect and convey all of the sewage that flows into it to a wastewater treatment plant. However, occasional unintentional discharges of raw sewage from municipal sanitary sewers – called sanitary sewe...

  12. SEWER SEDIMENT CONTROL: AN OVERVIEW OF THE EPA WET WEATHER FLOW (WWF) RESEARCH PROGRAM

    EPA Science Inventory

    This paper presents an overview of EPA WWF Research Program projects related to causes of sewer solids deposition and control methods that can prevent accumulation of sewer sediments. In particular, discussion will focus on the relationship of wastewater characteristics to flow ...

  13. HYDRAULIC CHARACTERISTICS OF SEWER SEDIMENT GATE-FLUSHING TANKS: LABORATORY FLUME STUDIES

    EPA Science Inventory

    The objective of this study was to test the performance of gate-flushing tanks, simulated in a laboratory flume, to remove sediments from combined sewers and storage tanks. A significant amount of sediment/debris/sludge may accumulate at the bottom of a sewer during dry weather o...

  14. HYDRAULIC CHARACTERISTICS OF SEWER SEDIMENT GATE FLUSHING TANKS: LABORATORY FLUME STUDIES

    EPA Science Inventory

    The objective of this study was to test the performance of gate flushing tanks, simulated in a laboratory flume, to remove sediments from combined sewers and storage tanks. A significant amount of sediment/debris/sludge may accumulate at the bottom of a sewer during dry weather o...

  15. HYDRAULIC CHARACTERISTICS OF SEWER SEDIMENT GATE-FLUSHING TANKS: LABORATORY FLUME STUDIES

    EPA Science Inventory

    The objective of this study was to test the performance of gate-flushing tanks, simulated in a laboratory flume, to remove sediments from combined sewers and storage tanks. A significant amount of sediment/debris/sludge may accumulate at the bottom of a sewer during dry weather o...

  16. HYDRAULIC CHARACTERISTICS OF SEWER SEDIMENT GATE FLUSHING TANKS: LABORATORY FLUME STUDIES

    EPA Science Inventory

    The objective of this study was to test the performance of gate flushing tanks, simulated in a laboratory flume, to remove sediments from combined sewers and storage tanks. A significant amount of sediment/debris/sludge may accumulate at the bottom of a sewer during dry weather o...

  17. Focused Field Investigations for Sewer Condition Assessment with EPA SSOAP Toolbox

    EPA Science Inventory

    The Nation’s sanitary sewer infrastructure is aging, and it is currently one of the top national water program priorities, and is one of the top priorities of the U.S. Conference of Mayors. The U.S. Environmental Protection Agency (EPA) developed the Sanitary Sewer Overflow Anal...

  18. Understanding the Spatial Formation and Accumulation of Fats, Oils & Grease Deposits in the Sewer Collection System

    USDA-ARS?s Scientific Manuscript database

    Sanitary sewer overflows are caused by the accumulation of insoluble calcium salts of fatty acids, which are formed by the reaction between fats, oils and grease (FOG) and calcium found in wastewaters. Different sewer structural configurations (i.e., manholes, pipes, wet wells), which vary spatially...

  19. STORM-SEWER FLOW MEASUREMENT AND RECORDING SYSTEM.

    USGS Publications Warehouse

    Kilpatrick, Frederick A.; Kaehrle, William R.

    1986-01-01

    A comprehensive study and development of instruments and techniques for measuring all components of flow in a storm-sewer drainage system were undertaken by the U. S. Geological Survey under the sponsorship of FHWA. The study involved laboratory and field calibration and testing of measuring flumes, pipe insert meters, weirs, and electromagnetic velocity meters as well as the development and calibration of pneumatic bubbler and pressure transducer head-measuring systems. Tracer dilution and acoustic-flowmeter measurements were used in field verification tests. A single micrologger was used to record data from all the instruments and also to activate on command the electromagnetic velocity meter and tracer dilution systems.

  20. Comparison of core sampling and visual inspection for assessment of concrete sewer pipe condition.

    PubMed

    Stanić, N; de Haan, C; Tirion, M; Langeveld, J G; Clemens, F H L R

    2013-01-01

    Sewer systems are costly to construct and even more costly to replace, requiring proper asset management. Sewer asset management relies to a large extent on available information. In sewer systems where pipe corrosion is the dominant failure mechanism, visual inspection by closed circuit television (CCTV) and core sampling are among the methods mostly applied to assess sewer pipe condition. This paper compares visual inspection and drill core analysis in order to enhance further understanding of the limitations and potentials of both methods. Both methods have been applied on a selected sewer reach in the city of The Hague, which was reportedly subject to pipe corrosion. Results show that both methods, visual inspection and core sampling, are associated with large uncertainties and that there is no obvious correlation between results of visual inspection and results of drill core analysis.

  1. Prioritizing sewer rehabilitation projects using AHP-PROMETHEE II ranking method.

    PubMed

    Kessili, Abdelhak; Benmamar, Saadia

    2016-01-01

    The aim of this paper is to develop a methodology for the prioritization of sewer rehabilitation projects for Algiers (Algeria) sewer networks to support the National Sanitation Office in its challenge to make decisions on prioritization of sewer rehabilitation projects. The methodology applies multiple-criteria decision making. The study includes 47 projects (collectors) and 12 criteria to evaluate them. These criteria represent the different issues considered in the prioritization of the projects, which are structural, hydraulic, environmental, financial, social and technical. The analytic hierarchy process (AHP) is used to determine weights of the criteria and the Preference Ranking Organization Method for Enrichment Evaluations (PROMETHEE II) method is used to obtain the final ranking of the projects. The model was verified using the sewer data of Algiers. The results have shown that the method can be used for prioritizing sewer rehabilitation projects.

  2. Simulation of sulfide buildup in wastewater and atmosphere of sewer networks.

    PubMed

    Nielsen, A H; Yongsiri, C; Hvitved-Jacobsen, T; Vollertsen, J

    2005-01-01

    A model concept for prediction of sulfide buildup in sewer networks is presented. The model concept is an extension to--and a further development of--the WATS model (Wastewater Aerobic-anaerobic Transformations in Sewers), which has been developed by Hvitved-Jacobsen and co-workers at Aalborg University. In addition to the sulfur cycle, the WATS model simulates changes in dissolved oxygen and carbon fractions of different biodegradability. The sulfur cycle was introduced via six processes: 1. sulfide production taking place in the biofilm covering the permanently wetted sewer walls; 2. biological sulfide oxidation in the permanently wetted biofilm; 3. chemical and biological sulfide oxidation in the water phase; 4. sulfide precipitation with metals present in the wastewater; 5. emission of hydrogen sulfide to the sewer atmosphere and 6. adsorption and oxidation of hydrogen sulfide on the moist sewer walls where concrete corrosion may take place.

  3. Modelling the impacts of Combined Sewer Overflows on the river Seine water quality.

    PubMed

    Even, Stéphanie; Mouchel, Jean-Marie; Servais, Pierre; Flipo, Nicolas; Poulin, Michel; Blanc, Stéphanie; Chabanel, Matthieu; Paffoni, Catherine

    2007-04-01

    To achieve the objectives of the European Water Framework Directive (EWFD), the Seine basin Water Authority has constructed a number of prospective scenarios forecasting the impact of planned investments in water quality. Paris and its suburbs were given special attention because of their impact on the river Seine. Paris sewer system and overflow control is of major concern in future management plans. The composition and fate of the urban effluents have been characterized through numerous in situ samplings, laboratory experiments and modelling studies. The PROSE model was especially designed to simulate the impact on the river of both permanent dry-weather effluents and of highly transient Combined Sewer Overflow (CSO). It was also used to represent the impact of Paris at large spatial and temporal scales. In addition to immediate effects on oxygen levels, heavy particulate organic matter loads that settle downstream of the outlets contribute to permanent oxygen consumption. Until the late 90s, the 50 km long reach of the Seine inside Paris was permanently affected by high oxygen consumption accounting for 112% of the flux upstream of the city. 20% of this demand resulted from CSO. However, the oxygenation of the system is strong due to high phytoplankton activity. As expected, the model results predict a reduction of both permanent dry-weather effluents and CSOs in the future that will greatly improve the oxygen levels (concentrations higher than 7.3 mgO(2) L(-1), 90% of the time instead of 4.0 mgO(2) L(-1) in the late 90s). The main conclusion is that, given the spatial and temporal extent of the impact of many CSOs, water quality models should take into account the CSOs in order to be reliable.

  4. DC Water and Sewer Authority and lead in drinking water: a case study in environmental health risk management.

    PubMed

    Guidotti, Tee L; Moses, Marina S; Goldsmith, David F; Ragain, Lisa

    2008-01-01

    In 2001, following a change in disinfection agent in anticipation of the Environment Protection Agency Disinfection Byproduct Rule, lead levels began rising in drinking water in Washington, District of Columbia, and in 2002, the DC Water and Sewer Authority was found to have exceeded the Environment Protection Agency lead action level, requiring compliance with a series of measures under the Lead and Copper Rule. In 2004, the issue became a public concern, drawing considerable media attention. The problem was eventually resolved through the application of orthophosphate but while it played out, the utility was forced to respond to a novel public health issue with few risk management options. This case study examines the lessons learned.

  5. Detention storage volume for combined sewer overflow into a river.

    PubMed

    Temprano, J; Tejero, I

    2002-06-01

    This article discusses the storage volume needed in a combined sewer system tank in order to preserve the water quality. There are a lot of design criteria which do not take into account the conditions of the receiving water, and as a result are inappropriate. A model was used to simulate the performance of a theoretical combined sewer system where a tank was located downstream. Results were obtained from the overflows produced by the rain recorded in Santander (Spain) for 11 years, with several combinations of storage volume and treatment capacity in the wastewater treatment plant. Quality criteria were also proposed for faecal coliforms, BOD, and total nitrogen to evaluate the effects from the overflows in the river water quality. Equations have been obtained which relate the number of overflows, the storage volume and the treatment plant capacity. The bacteriological pollution, quantified by means of faecal coliforms, was the analytical parameter which produced the most adverse effects in the river, so that more storage volume is needed (45 to 180 m3 ha(-1) net) than with other simulated pollutants (5 to 50 m3 ha(-1) net for BOD, and less than 4 m3 ha(-1) net for the total nitrogen). The increase in the treatment plant's capacity, from two to three times the flow in dry weather, reduces the impact on the river water in a more effective way, allowing a reduction of up to 65% in the number of overflows rather than increasing the storage volume.

  6. Dissolved methane in the influent of three Australian wastewater treatment plants fed by gravity sewers.

    PubMed

    Short, Michael D; Daikeler, Alexander; Wallis, Kirsten; Peirson, William L; Peters, Gregory M

    2017-12-01

    Methane (CH4) is an important anthropogenic greenhouse gas and a by-product of urban sewage management. In recent years and contrary to international (IPCC) consensus, pressurised (anaerobic) sewers were identified as important CH4 sources, yet relatively little remains known regarding the role of gravity sewers in CH4 production and conveyance. Here we provide the results of a nine month study assessing dissolved CH4 levels in the raw influent of three large Australian wastewater treatment plants (WWTPs) fed by gravity sewers. Similar to recent international research and contrary to IPCC guidance, results show that gravity sewered wastewater contains moderate levels of CH4 (≈1mgL(-1)). Dissolved CH4 concentration correlated negatively with daily sewage flow rate (i.e. inversely proportional to sewer hydraulic residence time), with daily CH4 mass loads on average some two-fold greater under low flow (dry weather) conditions. Along with sewage hydraulic residence time, sewer sediments are thought to interact with sewage flow rate and are considered to play a key role in gravity sewer CH4 production. A per capita load of 78gCH4person(-1)y(-1) is offered for gravity sewered wastewater entering WWTPs, with a corresponding emission estimate of up to 62gCH4person(-1)y(-1), assuming 80% water-to-air transfer of inflowing CH4 in WWTPs with combined preliminary-primary plus secondary treatment. Results here support the emerging consensus view that hydraulic operation (i.e. gravity versus pressurised, sewage flow rate) is a key factor in determining sewer CH4 production, with gravity sewer segments likely to play a dominant role in total CH4 production potential for large metropolitan sewer networks. Further work is warranted to assess the scale and temporal dynamics of CH4 production in gravity sewers elsewhere, with more work needed to adequately capture and assess the scale of diffuse sewer network CH4 emissions from sprawling urban settlements globally. Copyright

  7. Online load measurement in combined sewer systems--possibilities of an integrated management of waste water transportation and treatment.

    PubMed

    Häck, M; Lorenz, U

    2002-01-01

    To obtain a further appreciable reduction of discharges in the area of sewage disposal, besides waste water purification at our treatment plants, discharge of wastewater through the sewer system has to be taken into account. Today, control strategies pursuing this aim are mainly based on hydraulic conditions like level or flow rate. They all neglect the wastewater organic load as an essential parameter. The main reasons are the expensive methods used to continuously measure traditional organic sum parameters like COD or TOC. A meaningful alternative to those parameters is the spectral absorption coefficient at lambda = 254 nm (SAC), defined in DIN 38402 by the German Institute for Standardisation. As a purely physical parameter, the SAC shows a good correlation to organic sum parameters like COD and TOC, especially if municipal wastewater is considered. By using an UV-process probe, it is possible to measure the SAC and infer the organic load of raw wastewater continuously without any sample pre-treatment. By the use of this instrument numerous possibilities arise, in order to control the sewers discharge load depend.

  8. Factors that influence properties of FOG deposits and their formation in sewer collection systems.

    PubMed

    Iasmin, Mahbuba; Dean, Lisa O; Lappi, Simon E; Ducoste, Joel J

    2014-02-01

    Understanding the formation of Fat, Oil, and Grease (FOG) deposits in sewer systems is critical to the sustainability of sewer collection systems since they have been implicated in causing sewerage blockages that leads to sanitary sewer overflows (SSOs). Recently, FOG deposits in sewer systems displayed strong similarities with calcium-based fatty acid salts as a result of a saponification reaction. The objective of this study was to quantify the factors that may affect the formation of FOG deposits and their chemical and rheological properties. These factors included the types of fats used in FSEs, environmental conditions (i.e. pH and temperature), and the source of calcium in sewer systems. The results of this study showed that calcium content in the calcium based salts seemed to depend on the solubility limit of the calcium source and influenced by pH and temperature conditions. The fatty acid profile of the calcium-based fatty acid salts produced under alkali driven hydrolysis were identical to the profile of the fat source and did not match the profile of field FOG deposits, which displayed a high fraction of palmitic, a long chain saturated fatty acid. It is hypothesized that selective microbial metabolism of fats and/or biologically induced hydrogenation may contribute to the FOG deposit makeup in sewer system. Therefore, selective removal of palmitic in pretreatment processes may be necessary prior to the discharge of FSE wastes into the sewer collection system. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Modeling Sulfides, pH and Hydrogen Sulfide Gas in the Sewers of San Francisco.

    PubMed

    Vollertsen, Jes; Revilla, Nohemy; Hvitved-Jacobsen, Thorkild; Nielsen, Asbjørn Haaning

    2015-11-01

    An extensive measuring campaign targeted on sewer odor problems was undertaken in San Francisco. It was assessed whether a conceptual sewer process model could reproduce the measured concentrations of total sulfide in the wastewater and H2S gas in the sewer atmosphere, and to which degree such simulations have potential for further improving odor and sulfide management. The campaign covered measurement of wastewater sulfide by grab sampling and diurnal sampling, and H2S gas in the sewer atmosphere was logged. The tested model was based on the Wastewater Aerobic/Anaerobic Transformations in Sewers (WATS) sewer process concept, which never had been calibrated to such an extensive dataset. The study showed that the model was capable of reproducing the general levels of wastewater sulfide, wastewater pH, and sewer H2S gas. It could also reproduce the general variability of these parameters, albeit with some uncertainty. It was concluded that the model could be applied for the purpose in mind.

  10. The effect of extended in-sewer storage on wastewater treatment plant performance.

    PubMed

    Ashley, R M; Dudley, J; Vollertsen, J; Saul, A J; Jack, A; Blanksby, J R

    2002-01-01

    A project funded by UKWIR is under way in the UK to develop a relatively simple methodology whereby the effects of the introduction of extended in-sewer storage at CSOs on downstream sewerage and treatment can be assessed. Recent legislation (UK and European) has compelled many sewer system operators to introduce systems which increase in-sewer retention times, and also retain more flow and load within sewer networks. The project has reviewed existing knowledge about the interaction between in-sewer flow and treatment plants, together with available models. The study is utilising a "benchmark" of 3 configurations of treatment plant and dynamic simulation using the WRc STOAT software, with minor modifications to ensure that effects on odour generation and nutrient removal processes are adequately modelled. As no existing sewer flow quality model can represent the range of conditions possible in sewer networks, a combined application of the Hydroworks model and a new model developed at Aalborg University is being used for this part of the study.

  11. Risk assessment model to prioritize sewer pipes inspection in wastewater collection networks.

    PubMed

    Anbari, Mohammad Javad; Tabesh, Massoud; Roozbahani, Abbas

    2017-04-01

    In wastewater systems as one of the most important urban infrastructures, the adverse consequences and effects of unsuitable performance and failure event can sometimes lead to disrupt part of a city functioning. By identifying high failure risk areas, inspections can be implemented based on the system status and thus can significantly increase the sewer network performance. In this study, a new risk assessment model is developed to prioritize sewer pipes inspection using Bayesian Networks (BNs) as a probabilistic approach for computing probability of failure and weighted average method to calculate the consequences of failure values. Finally to consider uncertainties, risk of a sewer pipe is obtained from integration of probability and consequences of failure values using a fuzzy inference system (FIS). As a case study, sewer pipes of a local wastewater collection network in Iran are prioritized to inspect based on their criticality. Results show that majority of sewers (about 62%) has moderate risk, but 12%of sewers are in a critical situation. Regarding the budgetary constraints, the proposed model and resultant risk values are expected to assist wastewater agencies to repair or replace risky sewer pipelines especially in dealing with incomplete and uncertain datasets.

  12. Main features of meiosis

    SciTech Connect

    1993-12-31

    Chapter 17, outlines the main features of meiosis, beginning with its significance and proceeding through the meiotic stages. Meiosis is the most important modification of mitosis because it is the reduction division that gives rise to the haploid generation in the life cycle. 17 refs., 6 figs.

  13. The Ecology of Acidophilic Microorganisms in the Corroding Concrete Sewer Environment

    PubMed Central

    Li, Xuan; Kappler, Ulrike; Jiang, Guangming; Bond, Philip L.

    2017-01-01

    Concrete corrosion is one of the most significant problems affecting valuable sewer infrastructure on a global scale. This problem occurs in the aerobic zone of the sewer, where a layer of surface corrosion develops on the exposed concrete and the surface pH is typically lowered from around 11–10 (pristine concrete) to pH 2–4. Acidophilic microorganisms become established as biofilms within the concrete corrosion layer and enhance the loss of concrete mass. Until recently, the acidophilic community was considered to comprise relatively few species of microorganisms, however, the biodiversity of the corrosion community is now recognized as being extensive and varying from different sewer environmental conditions. The diversity of acidophiles in the corrosion communities includes chemolithoautotrophs, chemolithoheterotrophs, and chemoorganoheterotrophs. The activity of these microorganisms is strongly affected by H2S levels in the sewer gas phase, although CO2, organic matter, and iron in the corrosion layer influence this acidic ecosystem. This paper briefly presents the conditions within the sewer that lead to the development of concrete corrosion in that environment. The review focuses on the acidophilic microorganisms detected in sewer corrosion environments, and then summarizes their proposed functions and physiology, especially in relation to the corrosion process. To our knowledge, this is the first review of acidophilic corrosion microbial communities, in which, the ecology and the environmental conditions (when available) are considered. Ecological studies of sewer corrosion are limited, however, where possible, we summarize the important metabolic functions of the different acidophilic species detected in sewer concrete corrosion layers. It is evident that microbial functions in the acidic sewer corrosion environment can be linked to those occurring in the analogous acidic environments of acid mine drainage and bioleaching. PMID:28473816

  14. The Ecology of Acidophilic Microorganisms in the Corroding Concrete Sewer Environment.

    PubMed

    Li, Xuan; Kappler, Ulrike; Jiang, Guangming; Bond, Philip L

    2017-01-01

    Concrete corrosion is one of the most significant problems affecting valuable sewer infrastructure on a global scale. This problem occurs in the aerobic zone of the sewer, where a layer of surface corrosion develops on the exposed concrete and the surface pH is typically lowered from around 11-10 (pristine concrete) to pH 2-4. Acidophilic microorganisms become established as biofilms within the concrete corrosion layer and enhance the loss of concrete mass. Until recently, the acidophilic community was considered to comprise relatively few species of microorganisms, however, the biodiversity of the corrosion community is now recognized as being extensive and varying from different sewer environmental conditions. The diversity of acidophiles in the corrosion communities includes chemolithoautotrophs, chemolithoheterotrophs, and chemoorganoheterotrophs. The activity of these microorganisms is strongly affected by H2S levels in the sewer gas phase, although CO2, organic matter, and iron in the corrosion layer influence this acidic ecosystem. This paper briefly presents the conditions within the sewer that lead to the development of concrete corrosion in that environment. The review focuses on the acidophilic microorganisms detected in sewer corrosion environments, and then summarizes their proposed functions and physiology, especially in relation to the corrosion process. To our knowledge, this is the first review of acidophilic corrosion microbial communities, in which, the ecology and the environmental conditions (when available) are considered. Ecological studies of sewer corrosion are limited, however, where possible, we summarize the important metabolic functions of the different acidophilic species detected in sewer concrete corrosion layers. It is evident that microbial functions in the acidic sewer corrosion environment can be linked to those occurring in the analogous acidic environments of acid mine drainage and bioleaching.

  15. Parsimonious hydrological modeling of urban sewer and river catchments

    NASA Astrophysics Data System (ADS)

    Coutu, Sylvain; Del Giudice, Dario; Rossi, Luca; Barry, D. A.

    2012-09-01

    SummaryA parsimonious model of flow capable of simulating flow in natural/engineered catchments and at WWTP (Wastewater Treatment Plant) inlets was developed. The model considers three interacting, dynamic storages that account for transfer of water within the system. One storage describes the “flashy” response of impervious surfaces, another pervious areas and finally one storage describes subsurface flow. The sewerage pipe network is considered as an impervious surface and is thus included in the impervious surface storage. In addition, the model assumes that water discharged from several CSOs (combined sewer overflows) can be accounted for using a single, characteristic CSO. The model was calibrated on, and validated for, the Vidy Bay WWTP, which receives effluent from Lausanne, Switzerland (population about 200,000), as well as for an overlapping urban river basin. The results indicate that a relatively simple approach is suitable for predicting the responses of interacting engineered and natural hydrosystems.

  16. Gamma and beta logging of underground sewer and process lines

    SciTech Connect

    Rangel, M.J.; Martz, D.E.; Langner, G.H. Jr.

    1989-11-01

    The GammaSnake can be useful for locating uranium mill tailings used as backfill for sewer lines or storm drains where the lines can be readily accessed from a cleanout access port or other opening. The time required to determine if contamination is present using the GammaSnake method is considerably less than when using the delta gamma or drilling methods. There is, also, less potential hazard to the equipment operators when using the GammaSnake method. The GammaSnake method is generally limited to a distance of 100 feet or less. Used with the MAC-51B line locator, the GammaSnake method can provide useful information without extensive drilling or surveying. 7 figs., 2 tabs.

  17. ENVIRONMENTAL FOOTPRINT OF PHARMACEUTICALS - THE SIGNIFICANCE OF FACTORS BEYOND DIRECT EXCRETION TO SEWERS

    EPA Science Inventory

    The combined excretion of active pharmaceutical ingredients (APIs) via urine and feces is considered the primary route by which APIs from human pharmaceuticals enter the environment. Disposal of unwanted, leftover medications by flushing into sewers has been considered a secondar...

  18. Demonstration of an Innovative Large-Diameter Sewer Rehabilitation Technology in Houston, Texas - slides

    EPA Science Inventory

    While sewer renewal technologies currently being used for the repair, replacement and/or rehabilitation of deteriorating wastewater collection systems are generally effective, there is still room for improvement of existing technologies and for the development of new technologies...

  19. Demonstration of an Innovative Large-Diameter Sewer Rehabilitation Technology in Houston, Texas

    EPA Science Inventory

    While sewer renewal technologies currently being used for the repair, replacement and/or rehabilitation of deteriorating wastewater collection systems are generally effective, there is still room for improvement of existing technologies and for the development of new technologies...

  20. Final Storm Sewer General Permit Issued for 260 Massachusetts Municipalities to Help Keep Local Waters Clean

    EPA Pesticide Factsheets

    BOSTON - Today, EPA issued final general permits updating requirements for small Municipal Separate Storm Sewer Systems (MS4) located in Massachusetts. The new permits will update stormwater management efforts across Massachusetts, better protecti

  1. Status of Civil Judicial Consent Decrees Addressing Combined Sewer Systems (CSOs)

    EPA Pesticide Factsheets

    Tracking table of civil consent decrees for combined sewer systems (CSOs). This supports the National Enforcement Initiative (NEI) for Keeping Raw Sewage and Contaminated Stormwater Out of Our Nation's Waters.

  2. ANFIS-based approach for predicting sediment transport in clean sewer

    PubMed Central

    Azamathulla, H. Md.; Ab. Ghani, Aminuddin; Fei, Seow Yen

    2012-01-01

    The necessity of sewers to carry sediment has been recognized for many years. Typically, old sewage systems were designated based on self-cleansing concept where there is no deposition in sewer. These codes were applicable to non-cohesive sediments (typically storm sewers). This study presents adaptive neuro-fuzzy inference system (ANFIS), which is a combination of neural network and fuzzy logic, as an alternative approach to predict the functional relationships of sediment transport in sewer pipe systems. The proposed relationship can be applied to different boundaries with partially full flow. The present ANFIS approach gives satisfactory results (r2 = 0.98 and RMSE = 0.002431) compared to the existing predictor. PMID:22389640

  3. District of Columbia Municipal Separate Storm Sewer System (MS4) NPDES Permit Reissuance

    EPA Pesticide Factsheets

    Public Notice of Draft Permit and Opportunity for Public Comment under the Clean Water Act to the Government of the District of Columbia for discharges of stormwater from its Municipal Separate Storm Sewer System.

  4. RTC simulations on large branched sewer systems with SmaRTControl.

    PubMed

    de Korte, Kees; van Beest, Dick; van der Plaat, Marcel; de Graaf, Erno; Schaart, Niels

    2009-01-01

    In The Netherlands many large branched sewer systems exist. RTC can improve the performance of these systems. The objective of the universal algorithm of SmaRTControl is to improve the performance of the sewer system and the WWTP. The effect of RTC under rain weather flow conditions is simulated using a hydrological model with 19 drainage districts. The system related inefficiency coefficient (SIC) is introduced for assessment of the performance of sewer systems. The performance can be improved by RTC in combination with increased pumping capacities in the drainage districts, but without increasing the flow to the WWTP. Under dry weather flow conditions the flow to the WWTP can be equalized by storage of wastewater in the sewer system. It is concluded that SmaRTControl can improve the performance, that simulations are necessary and that SIC is an excellent parameter for assessment of the performance.

  5. Demonstration of an Innovative Large-Diameter Sewer Rehabilitation Technology in Houston, Texas

    EPA Science Inventory

    While sewer renewal technologies currently being used for the repair, replacement and/or rehabilitation of deteriorating wastewater collection systems are generally effective, there is still room for improvement of existing technologies and for the development of new technologies...

  6. Statistical evidence on the effectiveness of sewering to protect groundwater from VOC contamination

    NASA Astrophysics Data System (ADS)

    Willis, Cleve E.; Sacheti, Sandeep

    1996-03-01

    Volatile organic compounds (VOCs) are an important source of contamination of groundwater supplies in Massachusetts and many parts of the United States. One local response is to require sewering in wellhead protection areas as an easily enforceable policy designed to reduce the probability of VOC contamination of groundwater. Data were collected for 238 wellhead protection areas in Massachusetts on VOC contamination levels and the sewered and unsewered land uses in those aquifer recharge areas. Logistic regression procedures were used to see whether sewering had any statistical effect on likelihood of contamination of well water. The results provided limited, but not overpowering, support for the idea that requiring commercial and industrial land uses to use sewers would reduce the chance of VOC contamination.

  7. Demonstration of an Innovative Large-Diameter Sewer Rehabilitation Technology in Houston, Texas - slides

    EPA Science Inventory

    While sewer renewal technologies currently being used for the repair, replacement and/or rehabilitation of deteriorating wastewater collection systems are generally effective, there is still room for improvement of existing technologies and for the development of new technologies...

  8. Effect of environmental conditions on the erosional resistance of cohesive sediment deposits in sewers.

    PubMed

    Tai, S J; Marion, A; Camuffo, G

    2003-01-01

    The potential to adjust sewer network operation in order to control the level of transported sediment in sewage so as to enhance the performance of end-of-pipe treatment works is now being investigated. However for this to become a practical management option there is a need to be able to understand the processes which control the movement of sediments that are found in many combined sewers. Crucial to this understanding is an ability to predict how sediments from in-sewer deposits, are released by the action of vigorous flows. This paper reports on a laboratory investigation that aimed to investigate the effect that the environmental conditions during deposit formation can have on the ability of fine-grained organic sediment within in-sewer deposits to resist erosion and subsequent release into transport.

  9. USING VISUAL PLUMES PREDICTIONS TO MODULATE COMBINED SEWER OVERFLOW (CSO) RATES

    EPA Science Inventory

    High concentrations of pathogens and toxic residues in creeks and rivers can pose risks to human health and ecological systems. Combined Sewer Overflows (CSOs) discharging into these watercourses often contribute significantly to elevating pollutant concentrations during wet weat...

  10. The utilisation of engineered invert traps in the management of near bed solids in sewer networks.

    PubMed

    Ashley, R M; Tait, S J; Stovin, V R; Burrows, R; Framer, A; Buxton, A P; Blackwood, D J; Saul, A J; Blanksby, J R

    2003-01-01

    Large existing sewers are considerable assets which wastewater utilities will require to operate for the foreseeable future to maintain health and the quality of life in cities. Despite their existence for more than a century there is surprisingly little guidance available to manage these systems to minimise problems associated with in-sewer solids. A joint study has been undertaken in the UK, to refine and utilise new knowledge gained from field data, laboratory results and Computational Fluid Dynamics (CFD) simulations to devise cost beneficial engineering tools for the application of small invert traps to localise the deposition of sediments in sewers at accessible points for collection. New guidance has been produced for trap siting and this has been linked to a risk-cost-effectiveness assessment procedure to enable system operators to approach in-sewer sediment management pro-actively rather than reactively as currently happens.

  11. ENVIRONMENTAL FOOTPRINT OF PHARMACEUTICALS - THE SIGNIFICANCE OF FACTORS BEYOND DIRECT EXCRETION TO SEWERS

    EPA Science Inventory

    The combined excretion of active pharmaceutical ingredients (APIs) via urine and feces is considered the primary route by which APIs from human pharmaceuticals enter the environment. Disposal of unwanted, leftover medications by flushing into sewers has been considered a secondar...

  12. USING VISUAL PLUMES PREDICTIONS TO MODULATE COMBINED SEWER OVERFLOW (CSO) RATES

    EPA Science Inventory

    High concentrations of pathogens and toxic residues in creeks and rivers can pose risks to human health and ecological systems. Combined Sewer Overflows (CSOs) discharging into these watercourses often contribute significantly to elevating pollutant concentrations during wet weat...

  13. Condition Assessment of Wastewater Collection Systems Using the Sanitary Sewer Overflow Analysis and Planning (SSOAP) Toolbox

    EPA Science Inventory

    The Sanitary Sewer Overflow Analysis and Planning (SSOAP) Toolbox can serve as the foundation of wastewater collection system infrastructure research, among several applications, for analyzing monitored flow data to prioritize where to inspect, monitor, and to assess the performa...

  14. Predicting the Probability of Failure of Cementitious Sewer Pipes Using Stochastic Finite Element Method.

    PubMed

    Alani, Amir M; Faramarzi, Asaad

    2015-06-10

    In this paper, a stochastic finite element method (SFEM) is employed to investigate the probability of failure of cementitious buried sewer pipes subjected to combined effect of corrosion and stresses. A non-linear time-dependant model is used to determine the extent of concrete corrosion. Using the SFEM, the effects of different random variables, including loads, pipe material, and corrosion on the remaining safe life of the cementitious sewer pipes are explored. A numerical example is presented to demonstrate the merit of the proposed SFEM in evaluating the effects of the contributing parameters upon the probability of failure of cementitious sewer pipes. The developed SFEM offers many advantages over traditional probabilistic techniques since it does not use any empirical equations in order to determine failure of pipes. The results of the SFEM can help the concerning industry (e.g., water companies) to better plan their resources by providing accurate prediction for the remaining safe life of cementitious sewer pipes.

  15. Optimization of the central automatic control of a small Dutch sewer system

    NASA Astrophysics Data System (ADS)

    Kolechkina, A. G.; Hoes, O. A. C.

    2012-04-01

    A sewer control system was developed in the context of a subsidized project aiming at improvement of surface water quality by control of sewer systems and surface water systems. The project was coordinated by the local water board, "Waterschap Hollandse Delta". Other participants were Delft University of Technology, Deltares and the municipalities Strijen, Cromstrijen, Westmaas, Oud Beijerland and Piershil. As part of the project there were two pilot implementations where a central automatic controller was coupled to the existing SCADA system. For these two pilots the system is now operational. A Dutch urban area in the western part of the Netherlands is usually part of a polder, which is effectively an artificially drained catchment. The urban area itself is split into small subcatchments that manage runoff in different ways. In all cases a large fraction goes into the natural hydrological cycle, but, depending on the design of the local sewer system, a larger or smaller part finds its way into the sewer system. Proper control of this flow is necessary to control surface water quality and to avoid health risks from flow from the sewer into the streets. At each time step the controller switches pumps to distribute the remaining water in the system at the end of the time step over the different subcatchments. The distribution is created based on expert judgment of the relative vulnerability and subcatchment sewer system water quality. It is implemented in terms curves of total system stored volume versus subcatchment stored volume. We describe the process of the adaptation of a controller to two different sewer systems and the understanding of the artificial part of the catchment we gained during this process. In the process of adaptation the type of sewer system (combined foul water and storm water transport or separate foul water and storm water transport) played a major role.

  16. Indirect sulfur reduction via polysulfide contributes to serious odor problem in a sewer receiving nitrate dosage.

    PubMed

    Liang, Shuang; Zhang, Liang; Jiang, Feng

    2016-09-01

    Nitrate dosing is commonly used to control hydrogen sulfide production in sewer systems. However, quick rebound of the sulfide concentration after nitrate depletion has been observed and results in more serious odor and corrosion problem. To investigate the mechanism of sulfide regeneration in the nitrate-free period, a laboratory-scale sewer reactor was run for 30 days to simulate sulfide production and oxidation with intermittent nitrate addition. The results show that nitrate addition substantially reduced the sulfide concentration, but the produced elemental sulfur was then quickly reduced back to sulfide in nitrate-free periods. This induced more and more sulfide production in the sewer reactor. Elemental sulfur and polysulfide reductions were found in the sewage in nitrate-free periods, showing their contributions to the sulfide regeneration. Through batch tests, polysulfide was confirmed as the key intermediate for accelerating sulfur reduction during the nitrate-free period in the sewer. Sulfide production rates significantly increased by 65% and 59% in the presences of tetrasulfide and sulfur with sulfide, respectively, at the beginning of the test. While polysulfide formation was prevented by the ferrous chloride addition, the sulfur reduction rate remarkably decreased from 12.8 mgS/L-h to 1.8 mgS/L-h. This indicates that direct sulfur reduction was significantly slower than the indirect sulfur reduction via polysulfide; the latter process could be the cause for the quick rebound of the sulfide concentration in the sewer with intermittent nitrate dosing. Thus, the pathways of sulfur transformations in a sewer, both in the presence and absence of nitrate, were proposed. Microbial community analysis results reveal that some common sulfate-reducing bacteria (SRB) genera in sewer sediment were possible sulfur reducers. According to this finding, the effect and strategy of nitrate dosing for hydrogen sulfide control in sewers should be re-evaluated and re

  17. The rising risks of rising tides

    SciTech Connect

    Hanson, H.; Lindh, G.

    1996-12-31

    The erosion of beaches, flooding of agricultural land, and intrusion of saltwater into coastal streams could become a reality if temperatures climb. Over the past century, sea levels have risen 4 to 6 inches. Now, the Intergovernmental panel on Climate Change (IPCC) predicts that sea levels will rise between 8 and 28 inches by 2070, say Hans Hanson, associate professor emeritus in the Department of Water Resources Engineering at the University of Lund in Sweden. Coastal communities, which harbor more than half the world`s population, are poorly equipped to combat the threat of encroaching waters. {open_quotes}Few public officials have developed comprehensive strategies to address the potential consequences of sea-level rise,{close_quotes} the authors say. In response to the lack of long-term strategies to address the potential consequences of sea-level rise,{close_quotes} the authors say. In response to the lack of long-term strategies, the IPCC has recommended that coastal nations implement coastal-zone management plans by 2000. {open_quotes}Low-lying islands and high-use, developed coastal areas... face an urgent need to develop strategies for coping with sea-level rise,{close_quotes} the authors conclude.

  18. Design of self-cleansing sanitary sewer systems with the use of flushing devices.

    PubMed

    Goormans, T; Engelen, D; Bouteligier, R; Willems, P; Berlamont, J

    2009-01-01

    Many European countries tend to shift from constructing combined sewer systems to separate ones, in order to optimise wastewater treatment efficiency and reduce CSO impact on surface waters. An economic design minimises maintenance requirements by aiming at self-cleansing pipes. However, providing the necessary slopes for self-cleansing sanitary sewer pipes often is unfeasible in flat regions, resulting in an increased risk of loss of hydraulic capacity or blocking. To reduce these risks, flushing tanks can be installed in the sewer system. Where most other researchers contribute to a better understanding of the hydraulics of flushing, this paper rather tries to formulate a methodology to design and test flushing devices in sanitary sewer systems using standards and hydrodynamic simulations. Therefore, several aspects that require consideration when incorporating flushing devices into a sanitary sewer system are discussed. For instance, when flushing sanitary sewers the increase in discharge has to be explicitly considered. A Belgian case study is used to investigate the suitability of the developed methodology. Although the pipe slopes in the methodology are derived assuming uniform flow, the simulation results comply with it. Furthermore, pressurisation of the conduits due to multiple flushing waves remains within acceptable limits.

  19. Assessment of erosion and sedimentation dynamic in a combined sewer network using online turbidity monitoring.

    PubMed

    Bersinger, T; Le Hécho, I; Bareille, G; Pigot, T

    2015-01-01

    Eroded sewer sediments are a significant source of organic matter discharge by combined sewer overflows. Many authors have studied the erosion and sedimentation processes at the scale of a section of sewer pipe and over short time periods. The objective of this study was to assess these processes at the scale of an entire sewer network and over 1 month, to understand whether phenomena observed on a small scale of space and time are still valid on a larger scale. To achieve this objective the continuous monitoring of turbidity was used. First, the study of successive rain events allows observation of the reduction of the available sediment and highlights the widely different erosion resistance for the different sediment layers. Secondly, calculation of daily chemical oxygen demand (COD) fluxes during the entire month was performed showing that sediment storage in the sewer pipe after a rain period is important and stops after 5 days. Nevertheless, during rainfall events, the eroded fluxes are more important than the whole sewer sediment accumulated during a dry weather period. This means that the COD fluxes promoted by runoff are substantial. This work confirms, with online monitoring, most of the conclusions from other studies on a smaller scale.

  20. Acronical Risings and Settings

    NASA Astrophysics Data System (ADS)

    Hockey, Thomas A.

    2012-01-01

    A concept found in historical primary sources, and useful in contemporary historiography, is the acronical rising and setting of stars (or planets). Topocentric terms, they provide information about a star's relationship to the Sun and thus its visibility in the sky. Yet there remains ambiguity as to what these two phrases actually mean. "Acronical” is said to have come from the Greek akros ("point,” "summit,” or "extremity") and nux ("night"). While all sources agree that the word is originally Greek, there are alternate etymologies for it. A more serious difficulty with acronical rising and setting is that there are two competing definitions. One I call the Poetical Definition. Acronical rising (or setting) is one of the three Poetical Risings (or Settings) known to classicists. (The other two are cosmical rising/setting, discussed below, and the more familiar helical rising/setting.) The term "poetical" refers to these words use in classical poetry, e. g., that of Columella, Hesiod, Ovid, Pliny the Younger, and Virgil. The Poetical Definition of "acronical” usually is meant in this context. The Poetical Definition of "acronical” is as follows: When a star rises as the Sun sets, it rises acronically. When a star sets as the Sun sets, it sets acronically. In contrast with the Poetical Definition, there also is what I call the Astronomical Definition. The Astronomical Definition is somewhat more likely to appear in astronomical, mathematical, or navigational works. When the Astronomical Definition is recorded in dictionaries, it is often with the protasis "In astronomy, . . . ." The Astronomical Definition of "acronical” is as follows: When a star rises as the Sun sets, it rises acronically. When a star sets as the Sun rises, it sets acronically. I will attempt to sort this all out in my talk.

  1. Succession of sulfur-oxidizing bacteria in the microbial community on corroding concrete in sewer systems.

    PubMed

    Okabe, Satoshi; Odagiri, Mitsunori; Ito, Tsukasa; Satoh, Hisashi

    2007-02-01

    Microbially induced concrete corrosion (MICC) in sewer systems has been a serious problem for a long time. A better understanding of the succession of microbial community members responsible for the production of sulfuric acid is essential for the efficient control of MICC. In this study, the succession of sulfur-oxidizing bacteria (SOB) in the bacterial community on corroding concrete in a sewer system in situ was investigated over 1 year by culture-independent 16S rRNA gene-based molecular techniques. Results revealed that at least six phylotypes of SOB species were involved in the MICC process, and the predominant SOB species shifted in the following order: Thiothrix sp., Thiobacillus plumbophilus, Thiomonas intermedia, Halothiobacillus neapolitanus, Acidiphilium acidophilum, and Acidithiobacillus thiooxidans. A. thiooxidans, a hyperacidophilic SOB, was the most dominant (accounting for 70% of EUB338-mixed probe-hybridized cells) in the heavily corroded concrete after 1 year. This succession of SOB species could be dependent on the pH of the concrete surface as well as on trophic properties (e.g., autotrophic or mixotrophic) and on the ability of the SOB to utilize different sulfur compounds (e.g., H2S, S0, and S2O3(2-)). In addition, diverse heterotrophic bacterial species (e.g., halo-tolerant, neutrophilic, and acidophilic bacteria) were associated with these SOB. The microbial succession of these microorganisms was involved in the colonization of the concrete and the production of sulfuric acid. Furthermore, the vertical distribution of microbial community members revealed that A. thiooxidans was the most dominant throughout the heavily corroded concrete (gypsum) layer and that A. thiooxidans was most abundant at the highest surface (1.5-mm) layer and decreased logarithmically with depth because of oxygen and H2S transport limitations. This suggested that the production of sulfuric acid by A. thiooxidans occurred mainly on the concrete surface and the

  2. Characterization of microflora and transformation of organic matters in urban sewer system.

    PubMed

    Jin, Pengkang; Wang, Bin; Jiao, Ding; Sun, Guangxi; Wang, Baobao; Wang, Xiaochang C

    2015-11-01

    A study was conducted using a pilot sewer system consisting of 35 sequential sections, totalling 1200 m of gravity pipe. Urban sewage flowed into the sewer system at a constant flow rate until it reached physical and microbiological steady states. Microflora in the biofilm that attached to the inner surface along the pipe length were analysed. The organic compositions in both the liquid and gaseous phases of the sewer system were monitored. The results showed that typical fermentation bacteria, such as bacteroidetes and bacillus, were abundant in the system, indicating that the anoxic environment (DO = 0.3 mg/L) was suitable for fermentative bacterial growth. This resulted in a substantial reduction of the chemical oxygen demand (COD) along the pipe length and an increase of the biodegradable oxygen demand/chemical oxygen demand (BOD/COD) ratio from 0.68 at the beginning of the sewer system to 0.84 at the end of the sewer system; this was an indication of a transformation of organic matters from less-biodegradable to more-biodegradable products. Via molecular weight (MW) analysis, it was further identified that the larger organic molecules (MW > 10,000 Da) were transformed into products with smaller molecular weights. Regarding the fermentation products, the concentrations of the volatile fatty acids (VFAs) increased dramatically in the initial 600-m sections and then remained constant for the later sections except for the end section of the sewer; acetic acid was found to be the primary product of the VFAs. Gaseous carbon dioxide (CO2) and methane (CH4) were found to increase along the length of the sewer system, whereas the concentrations of ethanol, lactic acid, and hydrogen (H2) were high at the beginning of the sewer and then decreased in the rear sections of the sewer system. It could thus be concluded that in an urban wastewater sewer system, fermentative microflora could perform important roles in contributing to organic matter removal and

  3. [Transport and sources of runoff pollution from urban area with combined sewer system].

    PubMed

    Li, Li-Qing; Yin, Cheng-Qing

    2009-02-15

    Sampling and monitoring of runoff and sewage water in Wuhan urban area with combined sewer system were carried out during the period from 2003 to 2006, to study the transport and sources of runoff pollution at the catchment scale coupled with environmental geochemistry method. The results showed a change in quality between the runoff entering the sewer network and the combined storm water flow at the sewer's outlet. A significant increase was observed in the concentrations of total suspended solids (TSS), volatile suspended solids (VSS), COD, TN, and TP, and in the proportion of COD linked to particles. During the runoff production and transport, the concentrations of TSS and COD increased from 18.7 mg/L and 37.0 mg/L in roof runoff, to 225.3 mg/L and 176.5 mg/L in street runoff, and to 449.7 mg/L and 359.9 mg/L in combined storm water flow, respectively. The proportion of COD linked to particles was increased by 18%. In addition, the total phosphorus (P) and iron (Fe) contents in urban ground dust, storm drain sediment, sewage sewer sediment and combined sewer sediment were measured to identify the potential sources of suspended solids in the combined flow. The urban ground dust andstorm drain sediment wererich in Fe, whereas the sewage sewer sediment was rich in P. The P/Fe ratios in these groups were significantly distinct and able to differentiate them. A calculation of the two storm events based on the P/Fe rations showed that 56% +/- 26% of suspended solids in combined flow came from urban ground and storm drain. The rest wer e originated from the sewage sewer sediments which deposited in combined sewer on the dry weather days and were eroded on the wet weather days. The combined sewer network not only acts as a transport system, but also constitutes a physicochemical reactor that degrades the quality of urban water. Reducing the in-sewer pollution stocks would effectively control urban runoff pollution.

  4. Source tracking of leaky sewers: a novel approach combining fecal indicators in water and sediments.

    PubMed

    Guérineau, Hélène; Dorner, Sarah; Carrière, Annie; McQuaid, Natasha; Sauvé, Sébastien; Aboulfadl, Khadija; Hajj-Mohamad, Mariam; Prévost, Michèle

    2014-07-01

    In highly urbanized areas, surface water and groundwater are particularly vulnerable to sewer exfiltration. In this study, as an alternative to Microbial Source Tracking (MST) methods, we propose a new method combining microbial and chemical fecal indicators (Escherichia coli (E. coli)) and wastewater micropollutants (WWMPs) analysis both in water and sediment samples and under different meteorological conditions. To illustrate the use of this method, wastewater exfiltration and subsequent infiltration were identified and quantified by a three-year field study in an urban canal. The gradients of concentrations observed suggest that several sources of fecal contamination of varying intensity may be present along the canal, including feces from resident animal populations, contaminated surface run-off along the banks and under bridge crossings, release from contaminated banks, entrainment of contaminated sediments, and most importantly sewage exfiltration. Calculated exfiltration-infiltration volumes varied between 0.6 and 15.7 m(3)/d per kilometer during dry weather, and between 1.1 and 19.5 m(3)/d per kilometer during wet weather. WWMPs were mainly diluted and degraded below detection limits in water. E. coli remains the best exfiltration indicator given a large volume of dilution and a high abundance in the wastewater source. WWMPs are effective for detecting cumulated contamination in sediments from a small volume source and are particularly important because E. coli on its own does not allow source tracking. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Biocides used in building materials and their leaching behavior to sewer systems.

    PubMed

    Burkhardt, M; Kupper, T; Hean, S; Haag, R; Schmid, P; Kohler, M; Boller, M

    2007-01-01

    There is increasing concern about diffuse pollution of aquatic systems by biocides used in urban areas. We investigated sources and pathways of biocides significant for the pollution of storm water runoff. Main sources seem to be building envelopes, i.e. facades (paints, plasters) and roof sealing membranes. First results from a defined urban catchment drained by a separated sewer system without any agricultural activities reveal a substantial occurrence. Even after the first flush, concentrations of terbutryn, carbendazim, mecoprop as well as Irgarol 1051 and its metabolite exceeded the Swiss water quality standard of 0.1 microg/L. In laboratory experiments, leaching of mecoprop used as a root protection agent in bitumen sheets for roof waterproofing was determined. The concentrations differed in 16 different sheets two orders of magnitude, depending on the product composition. Using optimized products, it is expected to be the most efficient and sustainable way to reduce the environmental impact. To understand transport dynamics and environmental risk, further storm water events will be analyzed. Based on the ongoing project URBIC, first measures will be proposed to limit the release to surface and ground water.

  6. Combined Sewer Overflows as a Source of Hormones to Surface Water

    NASA Astrophysics Data System (ADS)

    Phillips, P.; Chalmers, A.; Gray, J. L.; Foreman, W.; Kolpin, D. W.; Wall, G.; Esposito, K.

    2009-12-01

    Some sources of hormones to surface water, such as wastewater-treatment-plant (WWTP) effluent, have been well documented, but other sources, particularly wet-weather discharges from combined-sewer-overflows (CSOs), are not well characterized. Flow-weighted composite samples of secondarily treated WWTP effluent and untreated sewage discharges from WWTP inflows and CSO discharges were collected during 12 storms and 6 non-storm conditions from November 2007-December 2008 at the main Burlington Vermont WWTP. Concentrations of many androgens and estrogens were highest in samples from untreated sewage, and lower in samples from treated sewage. For example, concentrations of estriol in CSO samples ranged from 5 to over 100 ng/L (nanograms per liter), but were generally less than 1 ng/L in treated sewage. Many androgens were detected in CSO discharge samples in concentrations ranging from 1 to over 1000 ng/L, but were not detected above 1 ng/L in treated samples. For many of the hormones, including androgens and estriol, CSO discharges comprised over half of the total load discharged by the WWTP, even though annual CSO discharge is less than 10% of the treated plant discharge. These results indicate that untreated discharges during CSO events can be a major source of some hormones and other wastewater compounds to the environment.

  7. Seasonality of antibiotic prescriptions for outpatients and resistance genes in sewers and wastewater treatment plant outflow.

    PubMed

    Caucci, Serena; Karkman, Antti; Cacace, Damiano; Rybicki, Marcus; Timpel, Patrick; Voolaid, Veiko; Gurke, Robert; Virta, Marko; Berendonk, Thomas U

    2016-05-01

    To test the hypothesis of a seasonal relationship of antibiotic prescriptions for outpatients and the abundance of antibiotic resistance genes (ARGs) in the wastewater, we investigated the distribution of prescriptions and different ARGs in the Dresden sewer system and wastewater treatment plant during a two-year sampling campaign. Based on quantitative PCR (qPCR), our results show a clear seasonal pattern for relative ARGs abundances. The higher ARGs levels in autumn and winter coincide with the higher rates of overall antibiotic prescriptions. While no significant differences of relative abundances were observed before and after the wastewater treatment for most of the relative ARGs, the treatment clearly influenced the microbial community composition and abundance. This indicates that the ARGs are probably not part of the dominant bacterial taxa, which are mainly influenced by the wastewater treatment processes, or that plasmid carrying bacteria remain constant, while plasmid free bacteria decrease. An exception was vancomycin (vanA), showing higher relative abundance in treated wastewater. It is likely that a positive selection or community changes during wastewater treatment lead to an enrichment of vanA. Our results demonstrate that in a medium-term study the combination of qPCR and next generation sequencing corroborated by drug-related health data is a suitable approach to characterize seasonal changes of ARGs in wastewater and treated wastewater. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  8. Assessment of pollutants and gaseous emissions in sewer network in NCT of Delhi.

    PubMed

    Aswale, P; Rao, N N; Karthik, M; Dhodapkar, R; Patkar, G; Nandy, T

    2012-04-01

    The NCT of Delhi in India handles domestic sewage through a long sewerage networks. The network is into eight divisions. The aim of the present study is to arrive at a correlation between sewage quality and gas emissions in the sewer network of various divisions. This will aid in forewarning the sewer workers about the safety precautions. The health effects due to toxic sewer gases exposure and assessment of hazardous conditions and hazard potential are discussed. The study areas were broadly classified as residential, commercial, industrial and mix (combination of residential & commercial) for comparison. Sewage samples were collected from 1020 sites and analyzed for 10 different physicochemical parameters. The analytical data revealed wide variation in the chemical composition of sewage flowing at various sewerage network sites. Based on comparison with the regulatory standard for discharge in sewers, 89 sites with higher values of BOD and sulphate were marked as critical sites. Subsequently, the concentrations of CH4 and H2S in sewer emissions were determined for the 89 critical sites through onsite monitoring. Samples from 22 sites had significantly higher concentration of CH4 than the LEL and those from 40 sites showed concentrations higher than the LFL. On the other hand, samples from 38 locations showed significantly high H2S concentration, more than permissible limit of 10 ppm. The sewer workers in North East, North West and West region of the metropolis were exposed to hazards from excessive CH4 and H2S emissions, whereas those under South and South West regions were more vulnerable to H2S related risks. The sewer network under North, Central and South poses relatively less hazard with regard to gaseous emissions.

  9. Multi-objective evolutionary optimization for greywater reuse in municipal sewer systems.

    PubMed

    Penn, Roni; Friedler, Eran; Ostfeld, Avi

    2013-10-01

    Sustainable design and implementation of greywater reuse (GWR) has to achieve an optimum compromise between costs and potable water demand reduction. Studies show that GWR is an efficient tool for reducing potable water demand. This study presents a multi-objective optimization model for estimating the optimal distribution of different types of GWR homes in an existing municipal sewer system. Six types of GWR homes were examined. The model constrains the momentary wastewater (WW) velocity in the sewer pipes (which is responsible for solids movement). The objective functions in the optimization model are the total WW flow at the outlet of the neighborhoods sewer system and the cost of the on-site GWR treatment system. The optimization routing was achieved by an evolutionary multi-objective optimization coupled with hydrodynamic simulations of a representative sewer system of a neighborhood located at the coast of Israel. The two non-dominated best solutions selected were the ones having either the smallest WW flow discharged at the outlet of the neighborhood sewer system or the lowest daily cost. In both solutions most of the GWR types chosen were the types resulting with the smallest water usage. This lead to only a small difference between the two best solutions, regarding the diurnal patterns of the WW flows at the outlet of the neighborhood sewer system. However, in the upstream link a substantial difference was depicted between the diurnal patterns. This difference occurred since to the upstream links only few homes, implementing the same type of GWR, discharge their WW, and in each solution a different type of GWR was implemented in these upstream homes. To the best of our knowledge this is the first multi-objective optimization model aimed at quantitatively trading off the cost of local/onsite GW spatially distributed reuse treatments, and the total amount of WW flow discharged into the municipal sewer system under unsteady flow conditions. Copyright © 2013

  10. Maine Ingredients

    ERIC Educational Resources Information Center

    Waters, John K.

    2009-01-01

    This article features Maine Learning Technology Initiative (MLTI), the nation's first-ever statewide 1-to-1 laptop program which marks its seventh birthday by expanding into high schools, providing an occasion to celebrate--and to examine the components of its success. The plan to put laptops into the hands of every teacher and student in grades 7…

  11. Sewer Lateral Electro Scan Field Verification Pilot (WERF ...

    EPA Pesticide Factsheets

    Abstract:WERF selected a proposed research project to field test an emerging technology for inspecting sanitary sewer lateral pipes. The technology is called Electro Scan and is used to find defects in laterals that allow the infiltration of groundwater into the lateral. Electro Scan testing involves passing an electrical probe through a pipe filled with water. The probe emits a focused electrical beam that is able to pass through the pipe wall into the surrounding soil, ultimately to complete an electrical circuit with a ground rod. The significance of the electrical signal suggests the significance of the infiltration defect. Over 100 laterals were tested in the City of Wauwatosa, Wisconsin, as a pilot project partially funded by the Milwaukee Metropolitan Sewerage District (MMSD). These tests were then compared to additional information concerning the condition of the laterals, including internal television inspection, infiltration rates produced in a rainfall simulation test, and water exfiltration rates. The results of these comparisons, lessons learned, and costs related to the testing are presented in this report, suggesting that while less expensive than a CCTV inspection, Electro Scan is best when performed with CCTV. [NOTE: For link (url) below – click on “sign in”; sign in or create new account; return to home page; enter project number in “search” box; and click on report title.] Benefits: • Demonstrates the effectiveness of Electro Sca

  12. Fractal analysis of urban environment: land use and sewer system

    NASA Astrophysics Data System (ADS)

    Gires, A.; Ochoa Rodriguez, S.; Van Assel, J.; Bruni, G.; Murla Tulys, D.; Wang, L.; Pina, R.; Richard, J.; Ichiba, A.; Willems, P.; Tchiguirinskaia, I.; ten Veldhuis, M. C.; Schertzer, D. J. M.

    2014-12-01

    Land use distribution are usually obtained by automatic processing of satellite and airborne pictures. The complexity of the obtained patterns which are furthermore scale dependent is enhanced in urban environment. This scale dependency is even more visible in a rasterized representation where only a unique class is affected to each pixel. A parameter commonly analysed in urban hydrology is the coefficient of imperviousness, which reflects the proportion of rainfall that will be immediately active in the catchment response. This coefficient is strongly scale dependent with a rasterized representation. This complex behaviour is well grasped with the help of the scale invariant notion of fractal dimension which enables to quantify the space occupied by a geometrical set (here the impervious areas) not only at a single scale but across all scales. This fractal dimension is also compared to the ones computed on the representation of the catchments with the help of operational semi-distributed models. Fractal dimensions of the corresponding sewer systems are also computed and compared with values found in the literature for natural river networks. This methodology is tested on 7 pilot sites of the European NWE Interreg IV RainGain project located in France, Belgium, Netherlands, United-Kingdom and Portugal. Results are compared between all the case study which exhibit different physical features (slope, level of urbanisation, population density...).

  13. Adaptation of sewer networks using integrated rehabilitation management.

    PubMed

    Tscheikner-Gratl, Franz; Mikovits, Christian; Rauch, Wolfgang; Kleidorfer, Manfred

    2014-01-01

    The urban water structure is aging and in need of rehabilitation. Further, the need to address future challenges (climate change, urban development) also arise lines. This study investigates if it is possible to combine rehabilitation and adaptation measures. To do so, we combined an urban development model, an urban drainage model and a rehabilitation model. A case study of a medium-sized alpine city with a sewer length of 228 km and a population of 125,431 was used to develop and apply this method. A priority model to pinpoint the structures in need of replacement was used. This model considered a deterioration model, vulnerability estimation and other influences. Further different rehabilitation rates and methods were examined. The urban development model used is a simplistic approach specifically tailored for the field of urban infrastructure management. Climate change is considered in terms of climate change factors. All these different influences together create scenarios for which the construction costs and the flooding volume are estimated and compared. Consequently the aim of this paper was to test to which degree it is possible to reduce urban flooding by adapting those parts of the network which require rehabilitation anyway. In our case study it could be reduced by 5%.

  14. EPA Region 2 NPDES Combined Sewer Outfall (CSO) GIS Layer

    EPA Pesticide Factsheets

    This ArcGIS 10.3 point feature class contains identification, location, and outfall attributes including outfall size and receiving water body, class, and contributor information for New York City combined sewer outfalls (CSOs). The information is provided by New York City in their draft SPDES Permit with NYSDEC. This information layer and all R2 GIS layers are maintained in a SQLServer 2012 geodatabase. The National Pollutant Discharge Elimination System (NPDES) program is implemented by NYSDEC via the compliance and enforcement elements of the State Pollutant Discharge Elimination System (SPDES) permit program.This GIS layer supports an ArcGIS relationship class with the attribute table titled EPA_FACILITIES_R2_RELATE_NPDES_CSO_DSCH. This table provides information about outfall events in terms of size (million gallons/year) and number of events per year for select CSOs. The National Pollutant Discharge Elimination System (NPDES) permit program is authorized by the Clean Water Act. The Integrated Compliance Information System (ICIS) for NPDES data exchange allows Partners to provide ICIS-NPDES data to EPA in an XML format and provides processing results to assist Partners with correcting common errors that may occur with their submissions.

  15. Sewer and drain swabbing as a means of investigating salmonellosis

    PubMed Central

    Harvey, R. W. S.; Price, T. H.

    1970-01-01

    The use of gauze swabs in drains or sewers to clarify the path followed by a salmonella from source to human host has been reviewed in the light of experience gained in Cardiff over 15 years. This period has seen a marked change in attitudes to salmonella epidemiology in that infected food is now regarded as of greater importance than infected food handlers. In these 15 years, butchers, abattoirs and knackers' yards, markets and bakehouses have been monitored. In the bakehouse survey the existence of staff infection was demonstrated by sewage examination. Sewage investigation has also been used to show frequent entry of salmonellas into households in a residential estate. The estate was carefully chosen to exclude salmonellas from industrial sources and shops. The frequent finding of infection in this sewage implies that a commonly consumed heavily infected food item is involved. The wide range of serotypes isolated suggests an animal usually fed on infected animal feed. Poultry and pigs are put forward as animals liable to spread salmonellosis to man. It is hoped that clarification of the salmonella pathway may eventually lead to measures likely to prevent the transmission of infection to man. It is also suggested that swabs placed in abattoir drains serve as an economical method of obtaining warning of a persistent build-up of contamination. The persistence of a serotype in an abattoir is not infrequently followed by human infection. PMID:5276333

  16. Remaining Sites Verification Package for the 100-B-14:1 Process Sewer, Waste Site Reclassification Form 2004-005

    SciTech Connect

    L. M. Dittmer

    2007-02-22

    The 100-B-14:1 subsite encompasses the former process sewer main associated with the 105-B Reactor Building, 108-B Chemical Pumphouse and Tritium Separation Facility, 184-B Boiler House and the 100-B water treatment facilities, as well as the feeder lines associated with the 108-B facility, formerly discharging to the 116-B-7 Outfall Structure. The subsite has been remediated to achieve the remedial action objectives specified in the Remaining Sites ROD. The results of verification sampling demonstrated that residual contaminant concentrations do not preclude any future uses and allow for unrestricted use of shallow zone soils. The results also showed that residual contaminant concentrations are protective of groundwater and the Columbia River.

  17. Tharsis Rise Graben

    NASA Image and Video Library

    2002-06-17

    This image of Tharsis Rise from NASA Mars Odyssey shows a series of linear features called graben, which are associated with crustal extension resulting in up and down blocks of crust that run perpendicular to the direction of the extension.

  18. Extreme Precipitation and Emergency Room Visits for Gastrointestinal Illness in Areas With and Without Combined Sewer Systems: An Analysis of Massachusetts Data, 2003-2007

    EPA Science Inventory

    Background: Combined sewer overflows (CSOs) occur in combined sewer systems when sewage and stormwater runoff discharge into waterbodies potentially contaminating water sources. CSOs are often caused by heavy precipitation and are expected to increase with increasing extreme pre...

  19. Extreme Precipitation and Emergency Room Visits for Gastrointestinal Illness in Areas With and Without Combined Sewer Systems: An Analysis of Massachusetts Data, 2003-2007

    EPA Science Inventory

    Background: Combined sewer overflows (CSOs) occur in combined sewer systems when sewage and stormwater runoff discharge into waterbodies potentially contaminating water sources. CSOs are often caused by heavy precipitation and are expected to increase with increasing extreme pre...

  20. Sewer Gas: An Indoor Air Source of PCE to Consider During Vapor Intrusion Investigations

    PubMed Central

    Pennell, Kelly G.; Scammell, Madeleine Kangsen; McClean, Michael D.; Ames, Jennifer; Weldon, Brittany; Friguglietti, Leigh; Suuberg, Eric M.; Shen, Rui; Indeglia, Paul A.; Heiger-Bernays, Wendy J.

    2013-01-01

    The United States Environmental Protection Agency (USEPA) is finalizing its vapor intrusion guidelines. One of the important issues related to vapor intrusion is background concentrations of volatile organic chemicals (VOCs) in indoor air, typically attributed to consumer products and building materials. Background concentrations can exist even in the absence of vapor intrusion and are an important consideration when conducting site assessments. In addition, the development of accurate conceptual models that depict pathways for vapor entry into buildings is important during vapor intrusion site assessments. Sewer gas, either as a contributor to background concentrations or as part of the site conceptual model, is not routinely evaluated during vapor intrusion site assessments. The research described herein identifies an instance where vapors emanating directly from a sanitary sewer pipe within a residence were determined to be a source of tetrachloroethylene (PCE) detected in indoor air. Concentrations of PCE in the bathroom range from 2.1 to 190 ug/m3 and exceed typical indoor air concentrations by orders of magnitude resulting in human health risk classified as an “Imminent Hazard” condition. The results suggest that infiltration of sewer gas resulted in PCE concentrations in indoor air that were nearly two-orders of magnitude higher as compared to when infiltration of sewer gas was not known to be occurring. This previously understudied pathway whereby sewers serve as sources of PCE (and potentially other VOC) vapors is highlighted. Implications for vapor intrusion investigations are also discussed. PMID:23950637

  1. Biogenic acids produced on epoxy linings installed in sewer crown and tidal zones.

    PubMed

    Valix, M; Shanmugarajah, K

    2015-09-01

    In this study the biogenic acids generated by microbes on the surface of Bisphenol A epoxy mortar coupons were investigated for up to 30 months. The epoxy coupons were installed in six sewers in three city locations, Sydney, Melbourne and Perth. Coupons were installed in both the crown and the tidal zones of the sewers to capture the effect of location within the pipe on acid production. The coupons were retrieved approximately every 6 months to provide a dynamic analysis of the biogenic acid production. Our results reveal the colonisation of epoxy mortar by the more aggressive acidophilic bacteria occurred within six months to two years of their installation in the sewer pipes. Biogenic acid generation appear to occur homogeneously from the tidal zone to the crown of the sewer pipes. The reduction in the surface pH of the epoxy lining was supported by the successive growth of microbes beginning with fungi followed be neutrophilic and heterotrophic bacteria and finally by the acidophilic bacteria and the corresponding accumulation of organic and sulphuric acids attributed to these organisms. This study also revealed the potential inhibiting effects on the microbes induced by the accumulation of metabolic products on the epoxy surface. The accumulation of organic acids and H2S coincided with the growth and metabolism inhibition of fungi and acidophilic bacteria. These results provide insights into the microbial interaction and biogenic acids production that contribute to lining degradation and corrosion of concrete in sewer pipes. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. A mathematical model to predict the effect of heat recovery on the wastewater temperature in sewers.

    PubMed

    Dürrenmatt, David J; Wanner, Oskar

    2014-01-01

    Raw wastewater contains considerable amounts of energy that can be recovered by means of a heat pump and a heat exchanger installed in the sewer. The technique is well established, and there are approximately 50 facilities in Switzerland, many of which have been successfully using this technique for years. The planning of new facilities requires predictions of the effect of heat recovery on the wastewater temperature in the sewer because altered wastewater temperatures may cause problems for the biological processes used in wastewater treatment plants and receiving waters. A mathematical model is presented that calculates the discharge in a sewer conduit and the spatial profiles and dynamics of the temperature in the wastewater, sewer headspace, pipe, and surrounding soil. The model was implemented in the simulation program TEMPEST and was used to evaluate measured time series of discharge and temperatures. It was found that the model adequately reproduces the measured data and that the temperature and thermal conductivity of the soil and the distance between the sewer pipe and undisturbed soil are the most sensitive model parameters. The temporary storage of heat in the pipe wall and the exchange of heat between wastewater and the pipe wall are the most important processes for heat transfer. The model can be used as a tool to determine the optimal site for heat recovery and the maximal amount of extractable heat. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. A risk-based approach to sanitary sewer pipe asset management.

    PubMed

    Baah, Kelly; Dubey, Brajesh; Harvey, Richard; McBean, Edward

    2015-02-01

    Wastewater collection systems are an important component of proper management of wastewater to prevent environmental and human health implications from mismanagement of anthropogenic waste. Due to aging and inadequate asset management practices, the wastewater collection assets of many cities around the globe are in a state of rapid decline and in need of urgent attention. Risk management is a tool which can help prioritize resources to better manage and rehabilitate wastewater collection systems. In this study, a risk matrix and a weighted sum multi-criteria decision-matrix are used to assess the consequence and risk of sewer pipe failure for a mid-sized city, using ArcGIS. The methodology shows that six percent of the uninspected sewer pipe assets of the case study have a high consequence of failure while four percent of the assets have a high risk of failure and hence provide priorities for inspection. A map incorporating risk of sewer pipe failure and consequence is developed to facilitate future planning, rehabilitation and maintenance programs. The consequence of failure assessment also includes a novel failure impact factor which captures the effect of structurally defective stormwater pipes on the failure assessment. The methodology recommended in this study can serve as a basis for future planning and decision making and has the potential to be universally applied by municipal sewer pipe asset managers globally to effectively manage the sanitary sewer pipe infrastructure within their jurisdiction. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Effect of detached/re-suspended solids from sewer sediment on the sewage phase bacterial activity.

    PubMed

    Leung, H D; Chen, G; Sharma, K

    2005-01-01

    This study was conducted to make an assessment of the effects of the detached/re-suspended solids on the bacterial activity in the sewage phase of a gravity sewer. A physical sewer-model was used to simulate two extreme conditions: sewage flow without the presence of sewer sediment, and filtered sewage flow with the sediment. The first scenario was to evaluate the effect of the settling of solids on the bacterial activity, while the second scenario was to examine the effect of purely re-suspended or detached solids. The water media were aerated to obtain an initial DO level at about 6 mg/L, and the bacterial activity was monitored at a regular time interval during each operation. Two bacterial cell staining techniques, one using 4', 6-diamidino-2-phenyl indole (DAPI), and another using 5-cyano 2, 3-ditoyl tetrazolium chloride (CTC), were employed to measure the amount of total and respiring bacteria, respectively. Both the DAPI and CTC counts decreased with time in the first case, while that increased with time in the second case. The bacterial activity in a sewer phase was observed to be contributed by smaller sized particles. Also, the solids originated from the sewer sediment through re-suspension or detachment demonstrated a higher bacterial activity than the solids originally present in the sewage.

  5. Groundwater infiltration, surface water inflow and sewerage exfiltration considering hydrodynamic conditions in sewer systems.

    PubMed

    Karpf, Christian; Hoeft, Stefan; Scheffer, Claudia; Fuchs, Lothar; Krebs, Peter

    2011-01-01

    Sewer systems are closely interlinked with groundwater and surface water. Due to leaks and regular openings in the sewer system (e.g. combined sewer overflow structures with sometimes reverse pressure conditions), groundwater infiltration and surface water inflow as well as exfiltration of sewage take place and cannot be avoided. In the paper a new hydrodynamic sewer network modelling approach will be presented, which includes--besides precipitation--hydrographs of groundwater and surface water as essential boundary conditions. The concept of the modelling approach and the models to describe the infiltration, inflow and exfiltration fluxes are described. The model application to the sewerage system of the City of Dresden during a flood event with complex conditions shows that the processes of infiltration, exfiltration and surface water inflows can be described with a higher reliability and accuracy, showing that surface water inflow causes a pronounced system reaction. Further, according to the simulation results, a high sensitivity of exfiltration rates on the in-sewer water levels and a relatively low influence of the dynamic conditions on the infiltration rates were found.

  6. Evidence for fat, oil, and grease (FOG) deposit formation mechanisms in sewer lines.

    PubMed

    He, Xia; Iasmin, Mahbuba; Dean, Lisa O; Lappi, Simon E; Ducoste, Joel J; de los Reyes, Francis L

    2011-05-15

    The presence of hardened and insoluble fats, oil, and grease (FOG) deposits in sewer lines is a major cause of line blockages leading to sanitary sewer overflows (SSOs). Despite the central role that FOG deposits play in SSOs, little is known about the mechanisms of FOG deposit formation in sanitary sewers. In this study, FOG deposits were formed under laboratory conditions from the reaction between free fatty acids and calcium chloride. The calcium and fatty acid profile analysis showed that the laboratory-produced FOG deposit displayed similar characteristics to FOG deposits collected from sanitary sewer lines. Results of FTIR analysis showed that the FOG deposits are metallic salts of fatty acid as revealed by comparisons with FOG deposits collected from sewer lines and pure calcium soaps. Based on the data, we propose that the formation of FOG deposits occurs from the aggregation of excess calcium compressing the double layer of free fatty acid micelles and a saponification reaction between aggregated calcium and free fatty acids.

  7. The distribution dynamics and desorption behaviour of mobile pharmaceuticals and caffeine to combined sewer sediments.

    PubMed

    Hajj-Mohamad, M; Darwano, H; Duy, S Vo; Sauvé, S; Prévost, M; Arp, H P H; Dorner, S

    2017-01-01

    Pharmaceuticals are discharged to the environment from wastewater resource recovery facilities, sewer overflows, and illicit sewer connections. To understand the fate of pharmaceuticals, there is a need to better understand their sorption dynamics to suspended sediments (SS) and settled sediments (StS) in sewer systems. In this study, such sorption dynamics to both SS and StS were assessed using a batch equilibrium method under both static and dynamic conditions. Experiments were performed with natively occurring and artificially modified concentrations of sewer pharmaceuticals (acetaminophen, theophylline, carbamazepine, and a metabolite of carbamazepine) and caffeine. Differences in apparent distribution coefficients, Kd,app, between SS and StS were related to differences in their organic carbon (OC) content, and the practice of artificially modifying the concentration. Kd,app values of modified contaminant concentrations and high OC sediments were substantially higher. Pseudo-second order desorption rates for these mobile compounds were also quantified. Successive flushing events to simulate the addition of stormwater to sewer networks revealed that aqueous concentrations would not necessarily decrease, because the added water will rapidly return to equilibrium concentrations with the sediments. Sorption and desorption kinetics must be considered in addition to dilution, to avoid underestimating the influence of dilution on concentrations of pharmaceuticals discharged to the environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Improving the benefits of sewer condition deterioration modelling through information content analysis.

    PubMed

    Rokstad, M M; Ugarelli, R M

    2016-11-01

    As urban sewer infrastructures age, it becomes increasingly important to make effective decisions to maintain the structural condition of the sewers at an acceptable level. To support the decision-making process, the utility manager can apply sewer deterioration models. However, the quality of the decision support from such models is dependent on the accuracy and reliability of the predictions, and previous research has shown that sewer deterioration predictions can be unreliable. In this paper it is shown, by numerical experiment and analysis of information content, how the accuracy of sewer deterioration models is inhibited by data heterogeneity. The data heterogeneity arises when the condition class is used as a response variable, because the condition class is an aggregation of different failure modes, and contains information that does not describe structural deterioration. Based on these findings, the paper suggests changes to be implemented in the condition classification standard, which can mitigate heterogeneity and improve prediction reliability. The suggestions for improvement include distinguishing between structural and functional defect codes, defining new condition metrics better suited for deterioration modelling, and registration of detailed defect codes to allow distinction of different failure mechanisms.

  9. Wastewater compounds in urban shallow groundwater wells correspond to exfiltration probabilities of nearby sewers.

    PubMed

    Lee, Do Gyun; Roehrdanz, Patrick R; Feraud, Marina; Ervin, Jared; Anumol, Tarun; Jia, Ai; Park, Minkyu; Tamez, Carlos; Morelius, Erving W; Gardea-Torresdey, Jorge L; Izbicki, John; Means, Jay C; Snyder, Shane A; Holden, Patricia A

    2015-11-15

    Wastewater compounds are frequently detected in urban shallow groundwater. Sources include sewage or reclaimed wastewater, but origins are often unknown. In a prior study, wastewater compounds were quantified in waters sampled from shallow groundwater wells in a small coastal California city. Here, we resampled those wells and expanded sample analyses to include sewage- or reclaimed water-specific indicators, i.e. pharmaceutical and personal care product chemicals or disinfection byproducts. Also, we developed a geographic information system (GIS)-based model of sanitary sewer exfiltration probability--combining a published pipe failure model accounting for sewer pipe size, age, materials of construction, with interpolated depths to groundwater--to determine if sewer system attributes relate to wastewater compounds in urban shallow groundwater. Across the wells, groundwater samples contained varying wastewater compounds, including acesulfame, sucralose, bisphenol A, 4-tert-octylphenol, estrone and perfluorobutanesulfonic acid (PFBS). Fecal indicator bacterial concentrations and toxicological bioactivities were less than known benchmarks. However, the reclaimed water in this study was positive for all bioactivity tested. Excluding one well intruded by seawater, the similarity of groundwater to sewage, based on multiple indicators, increased with increasing sanitary sewer exfiltration probability (modeled from infrastructure within ca. 300 m of each well). In the absence of direct exfiltration or defect measurements, sewer exfiltration probabilities modeled from the collection system's physical data can indicate potential locations where urban shallow groundwater is contaminated by sewage.

  10. A different approach for predicting H(2)S((g)) emission rates in gravity sewers.

    PubMed

    Lahav, Ori; Sagiv, Amitai; Friedler, Eran

    2006-01-01

    All detrimental phenomena (mal odors, metal corrosion, concrete disintegration, health hazard) associated with hydrogen sulfide in gravity sewers depend on the rate of H(2)S emission from the aqueous phase to the gas phase of the pipe. In this paper a different approach for predicting H(2)S((g)) emission rates from gravity sewers is presented, using concepts adapted from mixing theory. The mean velocity gradient (G=gamma SV/micro; S is the slope, V the mean velocity), representing mixing conditions in gravity flow, was used to quantify the rate of H(2)S((g)) emission in part-full gravity sewers. Based on this approach an emission equation was developed. The equation was verified and calibrated by performing 20 experiments in a 27-m gravity-flow experimental-sewer (D=0.16 m) at various hydraulic conditions. Results indicate a clear dependency of the sulfide stripping-rate on G(1) (R(2)=0.94) with the following overall emission equation: where S(T) is the total sulfide concentration in the aqueous phase, mg/L; w the flow surface width, m; A(cs) the cross-sectional area, m(2); T the temperature, degrees C; K(H) the Henry's constant, molL(-1)atm(-1); and P(pH2S) the partial pressure of H(2)S((g)) in the sewer atmosphere, atm.

  11. Glaciers and Sea Level Rise

    NASA Image and Video Library

    2017-09-28

    Peripheral glaciers and ice caps (isolated from the main ice sheet, which is seen in the upper right section of the image) in eastern Greenland. To learn about the contributions of glaciers to sea level rise, visit: www.nasa.gov/topics/earth/features/glacier-sea-rise.html Credit: Frank Paul, University of Zurich NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

  12. 78 FR 27964 - Draft Small Municipal Separate Storm Sewer System NPDES General Permit-New Hampshire; Extension...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-13

    ... From the Federal Register Online via the Government Publishing Office ENVIRONMENTAL PROTECTION AGENCY Draft Small Municipal Separate Storm Sewer System NPDES General Permit--New Hampshire; Extension... period. SUMMARY: EPA issued a Notice of Availability of the draft Small Municipal Separate Storm Sewer...

  13. Relationships between rainfall and Combined Sewer Overflow (CSO) occurrences

    NASA Astrophysics Data System (ADS)

    Mailhot, A.; Talbot, G.; Lavallée, B.

    2015-04-01

    Combined Sewer Overflow (CSO) has been recognized as a major environmental issue in many countries. In Canada, the proposed reinforcement of the CSO frequency regulations will result in new constraints on municipal development. Municipalities will have to demonstrate that new developments do not increase CSO frequency above a reference level based on historical CSO records. Governmental agencies will also have to define a framework to assess the impact of new developments on CSO frequency and the efficiency of the various proposed measures to maintain CSO frequency at its historic level. In such a context, it is important to correctly assess the average number of days with CSO and to define relationships between CSO frequency and rainfall characteristics. This paper investigates such relationships using available CSO and rainfall datasets for Quebec. CSO records for 4285 overflow structures (OS) were analyzed. A simple model based on rainfall thresholds was developed to forecast the occurrence of CSO on a given day based on daily rainfall values. The estimated probability of days with CSO have been used to estimate the rainfall threshold value at each OS by imposing that the probability of exceeding this rainfall value for a given day be equal to the estimated probability of days with CSO. The forecast skill of this model was assessed for 3437 OS using contingency tables. The statistical significance of the forecast skill could be assessed for 64.2% of these OS. The threshold model has demonstrated significant forecast skill for 91.3% of these OS confirming that for most OS a simple threshold model can be used to assess the occurrence of CSO.

  14. Evaluating Cryptosporidium and Giardia concentrations in combined sewer overflow.

    PubMed

    Arnone, Russell D; Walling, Joyce Perdek

    2006-06-01

    Since the first identified Cryptosporidium outbreaks occurred in the 1980s and the massive 1993 Milwaukee, WI outbreak affected more than 400,000 people, the concern over the public health risks linked to protozoan pathogens Cryptosporidium and Giardia has grown. Cryptosporidium and Giardia, found in streams, rivers, groundwater, and soil, form hardy, disinfection-resistant oocysts and cysts. Both organisms are recognized causative agents of gastrointestinal illnesses linked to the consumption of contaminated surface or groundwater. This study, the first in a planned series to estimate the urban contribution to the total Cryptosporidium and Giardia receiving-water loads, focused on combined sewer overflow (CSO). CSOs are discharges of mixed untreated sewage and stormwater released directly into receiving waters during rainfall. This engineered relief is necessary to accommodate hydraulic strain when the combined rain and sanitary flows exceed the system capacity. Limited comprehensive data are available assessing the CSO discharge contribution as a source of these two pathogens. Works by States et al. and Gibson et al. each found Cryptosporidium and much greater Giardia concentrations in CSOs draining parts of Pittsburgh, PA. This project estimated the relative detection frequency and concentration of Cryptosporidium and Giardia in CSO. Analytical results were obtained using a modification of Method 1623, originally developed for much cleaner environmental samples. These data are useful for drinking water treatment plants located downstream of CSOs. It is also significant in determining the potential concentrations of parasites at treatment plant intakes and for assessing health risks for water contact and fishing activities. Commonly monitored indicator organisms (total coliform, fecal coliform, E. coli, Enterococcus, and fecal streptococcus), endospores, and selected physical and chemical parameters were analyzed to further describe the samples. CSO from urban

  15. Application of morphological segmentation to leaking defect detection in sewer pipelines.

    PubMed

    Su, Tung-Ching; Yang, Ming-Der

    2014-05-16

    As one of major underground pipelines, sewerage is an important infrastructure in any modern city. The most common problem occurring in sewerage is leaking, whose position and failure level is typically identified through closed circuit television (CCTV) inspection in order to facilitate rehabilitation process. This paper proposes a novel method of computer vision, morphological segmentation based on edge detection (MSED), to assist inspectors in detecting pipeline defects in CCTV inspection images. In addition to MSED, other mathematical morphology-based image segmentation methods, including opening top-hat operation (OTHO) and closing bottom-hat operation (CBHO), were also applied to the defect detection in vitrified clay sewer pipelines. The CCTV inspection images of the sewer system in the 9th district, Taichung City, Taiwan were selected as the experimental materials. The segmentation results demonstrate that MSED and OTHO are useful for the detection of cracks and open joints, respectively, which are the typical leakage defects found in sewer pipelines.

  16. Flow measurements in sewers based on image analysis: automatic flow velocity algorithm.

    PubMed

    Jeanbourquin, D; Sage, D; Nguyen, L; Schaeli, B; Kayal, S; Barry, D A; Rossi, L

    2011-01-01

    Discharges of combined sewer overflows (CSOs) and stormwater are recognized as an important source of environmental contamination. However, the harsh sewer environment and particular hydraulic conditions during rain events reduce the reliability of traditional flow measurement probes. An in situ system for sewer water flow monitoring based on video images was evaluated. Algorithms to determine water velocities were developed based on image-processing techniques. The image-based water velocity algorithm identifies surface features and measures their positions with respect to real world coordinates. A web-based user interface and a three-tier system architecture enable remote configuration of the cameras and the image-processing algorithms in order to calculate automatically flow velocity on-line. Results of investigations conducted in a CSO are presented. The system was found to measure reliably water velocities, thereby providing the means to understand particular hydraulic behaviors.

  17. The role of iron in sulfide induced corrosion of sewer concrete.

    PubMed

    Jiang, Guangming; Wightman, Elaine; Donose, Bogdan C; Yuan, Zhiguo; Bond, Philip L; Keller, Jurg

    2014-02-01

    The sulfide-induced corrosion of concrete sewer is a widespread and expensive problem for water utilities worldwide. Fundamental knowledge of the initiation and propagation of sewer corrosion, especially the interactions between chemical reactions and physical structure changes, is still largely unknown. Advanced mineral analytical techniques were applied to identify the distribution of corrosion products and the micro-cracking that developed along the corrosion boundary. It was found that sewer concrete corrosion caused by reactions with sulfuric acid progressed uniformly in the cement of concrete. In contrast to conventional knowledge, iron rust rather than gypsum and ettringite was likely the factor responsible for cracking ahead of the corrosion front. The analysis also allowed quantitative determination of the major corrosion products, i.e., gypsum and ettringite, with the latter found closer to the corrosion front. The conceptual model based on these findings clearly demonstrated the complex interactions among different chemical reactions, diffusion, and micro-structure changes.

  18. Application of Morphological Segmentation to Leaking Defect Detection in Sewer Pipelines

    PubMed Central

    Su, Tung-Ching; Yang, Ming-Der

    2014-01-01

    As one of major underground pipelines, sewerage is an important infrastructure in any modern city. The most common problem occurring in sewerage is leaking, whose position and failure level is typically idengified through closed circuit television (CCTV) inspection in order to facilitate rehabilitation process. This paper proposes a novel method of computer vision, morphological segmentation based on edge detection (MSED), to assist inspectors in detecting pipeline defects in CCTV inspection images. In addition to MSED, other mathematical morphology-based image segmentation methods, including opening top-hat operation (OTHO) and closing bottom-hat operation (CBHO), were also applied to the defect detection in vitrified clay sewer pipelines. The CCTV inspection images of the sewer system in the 9th district, Taichung City, Taiwan were selected as the experimental materials. The segmentation results demonstrate that MSED and OTHO are useful for the detection of cracks and open joints, respectively, which are the typical leakage defects found in sewer pipelines. PMID:24841247

  19. Coordinated management of combined sewer overflows by means of environmental decision support systems.

    PubMed

    Murla, Damian; Gutierrez, Oriol; Martinez, Montse; Suñer, David; Malgrat, Pere; Poch, Manel

    2016-04-15

    During heavy rainfall, the capacity of sewer systems and wastewater treatment plants may be surcharged producing uncontrolled wastewater discharges and a depletion of the environmental quality. Therefore there is a need of advanced management tools to tackle with these complex problems. In this paper an environmental decision support system (EDSS), based on the integration of mathematical modeling and knowledge-based systems, has been developed for the coordinated management of urban wastewater systems (UWS) to control and minimize uncontrolled wastewater spills. Effectiveness of the EDSS has been tested in a specially designed virtual UWS, including two sewers systems, two WWTP and one river subjected to typical Mediterranean rain conditions. Results show that sewer systems, retention tanks and wastewater treatment plants improve their performance under wet weather conditions and that EDSS can be very effective tools to improve the management and prevent the system from possible uncontrolled wastewater discharges.

  20. The search for an alternative to piped water and sewer systems in the Alaskan Arctic.

    PubMed

    Hickel, Korie A; Dotson, Aaron; Thomas, Timothy K; Heavener, Mia; Hébert, Jack; Warren, John A

    2017-03-29

    Forty-two communities in rural Alaska are considered unserved or underserved with water and sewer infrastructure. Many challenges exist to provide centralized piped water and sewer infrastructure to the homes, and they are exacerbated by decreasing capital funding. Unserved communities in rural Alaska experience higher rates of disease, supporting the recommendation that sanitation infrastructure should be provided. Organizations are pursuing alternative solutions to conventional piped water and sewer in order to maximize water use and reuse for public health. This paper reviews initiatives led by the State of Alaska, the Alaska Native Tribal Health Consortium, and the Yukon Kuskokwim Health Corporation to identify and develop potential long-term solutions appropriate and acceptable to rural communities. Future developments will likely evolve based on the lessons learned from the initiatives. Recommendations include Alaska-specific research needs, increased end-user participation in the design process, and integrated monitoring, evaluation, and information dissemination in future efforts.

  1. Effect of flow rate on growth and oxygen consumption of biofilm in gravity sewer.

    PubMed

    Xu, Jingwei; Li, Muzhi; He, Qiang; Sun, Xingfu; Zhou, Xiangren; Su, Zhenping; Ai, Hainan

    2017-01-01

    The function of sewer as reactors must rely on the biofilm in it. In this paper, the formation, structure, oxygen transfer, and activity of the biofilm under different hydraulic conditions were studied by the microelectrode technology, oxygen uptake rate (OUR) technology, and 454 high-throughput pyrosequencing technology. Results showed that when the wall-shear stresses were 1.12, 1.29, and 1.45 Pa, the porosity of the steady-state biofilm were 69.1, 64.4, and 55.1 %, respectively. The maximum values of OUR were 0.033, 0.027, and 0.022 mg/(L*s), respectively, and the COD removal efficiency in the sewers reached 40, 35, and 32 %, respectively. The research findings had an important significance on how to improve the treatment efficiency of the sewers. Fig. a Graphical Abstract.

  2. Hydraulic Modeling and Evolutionary Optimization for Enhanced Real-Time Decision Support of Combined Sewer Overflows

    NASA Astrophysics Data System (ADS)

    Zimmer, A. L.; Minsker, B. S.; Schmidt, A. R.; Ostfeld, A.

    2011-12-01

    Real-time mitigation of combined sewer overflows (CSOs) requires evaluation of multiple operational strategies during rapidly changing rainfall events. Simulation models for hydraulically complex systems can effectively provide decision support for short time intervals when coupled with efficient optimization. This work seeks to reduce CSOs for a test case roughly based on the North Branch of the Chicago Tunnel and Reservoir Plan (TARP), which is operated by the Metropolitan Water Reclamation District of Greater Chicago (MWRDGC). The North Branch tunnel flows to a junction with the main TARP system. The Chicago combined sewer system alleviates potential CSOs by directing high interceptor flows through sluice gates and dropshafts to a deep tunnel. Decision variables to control CSOs consist of sluice gate positions that control water flow to the tunnel as well as a treatment plant pumping rate that lowers interceptor water levels. A physics-based numerical model is used to simulate the hydraulic effects of changes in the decision variables. The numerical model is step-wise steady and conserves water mass and momentum at each time step by iterating through a series of look-up tables. The look-up tables are constructed offline to avoid extensive real-time calculations, and describe conduit storage and water elevations as a function of flow. A genetic algorithm (GA) is used to minimize CSOs at each time interval within a moving horizon framework. Decision variables are coded at 15-minute increments and GA solutions are two hours in duration. At each 15-minute interval, the algorithm identifies a good solution for a two-hour rainfall forecast. Three GA modifications help reduce optimization time. The first adjustment reduces the search alphabet by eliminating sluice gate positions that do not influence overflow volume. The second GA retains knowledge of the best decision at the previous interval by shifting the genes in the best previous sequence to initialize search at

  3. Sewers as a source and sink of chlorinated-solvent groundwater contamination, Marine Corps Recruit Depot, Parris Island, South Carolina

    USGS Publications Warehouse

    Vroblesky, D.A.; Petkewich, M.D.; Lowery, M.A.; Landmeyer, J.E.

    2011-01-01

    Groundwater contamination by tetrachloroethene and its dechlorination products is present in two partially intermingled plumes in the surficial aquifer near a former dry-cleaning facility at Site 45, Marine Corps Recruit Depot, Parris Island, South Carolina. The northern plume originates from the vicinity of former above-ground storage tanks. Free-phase tetrachloroethene from activities in this area entered the groundwater. The southern plume originates at a nearby, new dry-cleaning facility, but probably was the result of contamination released to the aquifer from a leaking sanitary sewer line from the former dry-cleaning facility. Discharge of dissolved groundwater contamination is primarily to leaking storm sewers below the water table. The strong influence of sanitary sewers on source distribution and of storm sewers on plume orientation and discharge at this site indicates that groundwater-contamination investigators should consider the potential influence of sewer systems at their sites. ?? 2011, National Ground Water Association.

  4. Critical review on the stability of illicit drugs in sewers and wastewater samples.

    PubMed

    McCall, Ann-Kathrin; Bade, Richard; Kinyua, Juliet; Lai, Foon Yin; Thai, Phong K; Covaci, Adrian; Bijlsma, Lubertus; van Nuijs, Alexander L N; Ort, Christoph

    2016-01-01

    Wastewater-based epidemiology (WBE) applies advanced analytical methods to quantify drug residues in wastewater with the aim to estimate illicit drug use at the population level. Transformation processes during transport in sewers (chemical and biological reactors) and storage of wastewater samples before analysis are expected to change concentrations of different drugs to varying degrees. Ignoring transformation for drugs with low to medium stability will lead to an unknown degree of systematic under- or overestimation of drug use, which should be avoided. This review aims to summarize the current knowledge related to the stability of commonly investigated drugs and, furthermore, suggest a more effective approach to future experiments. From over 100 WBE studies, around 50 mentioned the importance of stability and 24 included tests in wastewater. Most focused on in-sample stability (i.e., sample preparation, preservation and storage) and some extrapolated to in-sewer stability (i.e., during transport in real sewers). While consistent results were reported for rather stable compounds (e.g., MDMA and methamphetamine), a varying range of stability under different or similar conditions was observed for other compounds (e.g., cocaine, amphetamine and morphine). Wastewater composition can vary considerably over time, and different conditions prevail in different sewer systems. In summary, this indicates that more systematic studies are needed to: i) cover the range of possible conditions in sewers and ii) compare results more objectively. To facilitate the latter, we propose a set of parameters that should be reported for in-sewer stability experiments. Finally, a best practice of sample collection, preservation, and preparation before analysis is suggested in order to minimize transformation during these steps. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Fat, oil and grease deposits in sewers: characterisation of deposits and formation mechanisms.

    PubMed

    Williams, J B; Clarkson, C; Mant, C; Drinkwater, A; May, E

    2012-12-01

    Fat, oil and grease deposits (FOG) in sewers are a major problem and can cause sewer overflows, resulting in environmental damage and health risks. Often simplistically portrayed as cooling of fats, recent research has suggested that saponification may be involved in FOG formation. However there are still questions about the mechanisms effecting transformations in sewers and the role and source of metal cations involved in saponification. This study characterises FOG deposits from pumping stations, sewers and sewage works from different water hardness zones across the UK. The sites all had previous problems with FOG and most catchments contained catering and food preparation establishments. The FOG deposits were highly variable with moisture content ranging from 15 to 95% and oil content from 0 to 548 mg/g. Generally the pumping stations had lower moisture content and higher fat content, followed by the sewers then the sewage works. The water in contact with the FOG had high levels of oil (mean of about 800 mg/L) and this may indicate poor kitchen FOG management practices. FOG fatty acid profiles showed a transformation from unsaturated to saturated forms compared to typical cooking oils. This seems to relate to ageing in the sewer network or the mechanism of formation, as samples from pumping stations had higher proportions of C18:1 compared to C16. This may be due to microbial transformations by bacteria such as Clostridium sp. in a similar process to adipocere formation. There was an association between water hardness and increased Ca levels in FOG along with harder deposits and higher melting points. A link between FOG properties and water hardness has not been previously reported for field samples. This may also be due to microbial processes, such as biocalcification. By developing the understanding of these mechanisms it may be possible to more effectively control FOG deposits, especially when combined with promotion of behavioural change.

  6. Quantitative and qualitative assessment of the impact of climate change on a combined sewer overflow and its receiving water body.

    PubMed

    Bi, Eustache Gooré; Monette, Frédéric; Gachon, Philippe; Gaspéri, Johnny; Perrodin, Yves

    2015-08-01

    Projections from the Canadian Regional Climate Model (CRCM) for the southern part of the province of Québec, Canada, suggest an increase in extreme precipitation events for the 2050 horizon (2041-2070). The main goal of this study consisted in a quantitative and qualitative assessment of the impact of the 20 % increase in rainfall intensity that led, in the summer of 2013, to overflows in the "Rolland-Therrien" combined sewer system in the city of Longueuil, Canada. The PCSWMM 2013 model was used to assess the sensitivity of this overflow under current (2013) and future (2050) climate conditions. The simulated quantitative variables (peak flow, Q(CSO), and volume discharged, VD) served as the basis for deriving ecotoxicological risk indices and event fluxes (EFs) transported to the St. Lawrence (SL) River. Results highlighted 15 to 500% increases in VD and 13 to 148% increases in Q(CSO) by 2050 (compared to 2013), based on eight rainfall events measured from May to October. These results show that (i) the relationships between precipitation and combined sewer overflow variables are not linear and (ii) the design criteria for current hydraulic infrastructure must be revised to account for the impact of climate change (CC) arising from changes in precipitation regimes. EFs discharged into the SL River will be 2.24 times larger in the future than they are now (2013) due to large VDs resulting from CC. This will, in turn, lead to excessive inputs of total suspended solids (TSSs) and tracers for numerous urban pollutants (organic matter and nutrients, metals) into the receiving water body. Ecotoxicological risk indices will increase by more than 100% by 2050 compared to 2013. Given that substantial VDs are at play, and although CC scenarios have many sources of uncertainty, strategies to adapt this drainage network to the effects of CC will have to be developed.

  7. Post-rehabilitation evaluation of the sanitary sewer system at Lawrence Livermore National Laboratory

    SciTech Connect

    Royal, D.

    1995-11-01

    We are updating a CH2M Hill study which found that the sanitary sewer system is sufficient to transport peak dry weather flow. However, under peak wet weather conditions, the system has insufficient capacity to transport the projected flows for existing and future development. This is due to the amount of infiltration/inflow (I/I) that enters the sewer system when it rains. Our goal is to examine the existing system to determine its adequacy to accommodate present and future peak flows, and also to further update and improve the CH2M Hill study. A set of alternatives was also developed to address deficiencies of the existing system.

  8. Removal of the organic surface layer in combined sewer sediment using a flushing gate.

    PubMed

    Laplace, D; Oms, C; Ahyerre, M; Chebbo, O; Lemasson, J; Felouzis, L

    2003-01-01

    Recent research identified the different sources of pollution of wet weather Combined Sewers Overflows (CSOs): it appeared that the deposits in sewers, and especially an organic layer situated at the water-sediment interface, may contribute 40-70% to the total pollution load of CSOs. Using the cyclic flush Hydrass gate, we generated increased water flows during dry weather. The effects of flushing the deposits have been analysed: the eroded particles sampled during the first flush wave show pollutant characteristics similar to characteristics measured in the organic layer. The organic layer that has formed on the surface of deposits can thus be washed off before rainstorms occur using the cyclic flushing technique.

  9. A bottom-up approach to estimate dry weather flow in minor sewer networks.

    PubMed

    Elías-Maxil, J A; van der Hoek, Jan Peter; Hofman, Jan; Rietveld, Luuk

    2014-01-01

    In order to evaluate the feasibility of installing decentralised installations for wastewater reuse in cities, information about flows at specific spots of a sewer is needed. However, measuring intermittent flows in partially filled conduits is a technical task which is sometimes difficult to accomplish. This paper describes a method to model intermittent discharges in small sewers by linking a stochastic model for wastewater discharge to a hydraulic model to predict the attenuation of the discharges and its impact on the arrival time to a defined spot. The method was validated in a case study. The model estimated adequately the wastewater discharges on working days.

  10. Super Moon Rises

    NASA Image and Video Library

    2011-03-19

    The full moon is seen as it rises near the National Mall, Saturday, March 19, 2011, in Washington. The full moon tonight is called a "Super Moon" since it is at its closest to Earth. Photo Credit: (NASA/Paul E. Alers)

  11. Global sea level rise

    SciTech Connect

    Douglas, B.C. )

    1991-04-15

    Published values for the long-term, global mean sea level rise determined from tide gauge records exhibit considerable scatter, from about 1 mm to 3 mm/yr. This disparity is not attributable to instrument error; long-term trends computed at adjacent sites often agree to within a few tenths of a millimeter per year. Instead, the differing estimates of global sea level rise appear to be in large part due to authors' using data from gauges located at convergent tectonic plate boundaries, where changes of land elevation give fictitious sea level trends. In addition, virtually all gauges undergo subsidence or uplift due to postglacial rebound (PGR) from the last deglaciation at a rate comparable to or greater than the secular rise of sea level. Modeling PGR by the ICE-3G model of Tushingham and Peltier (1991) and avoiding tide gauge records in areas of converging tectonic plates produces a highly consistent set of long sea level records. The value for mean sea level rise obtained from a global set of 21 such stations in nine oceanic regions with an average record length of 76 years during the period 1880-1980 is 1.8 mm/yr {plus minus} 0.1. This result provides confidence that carefully selected long tide gauge records measure the same underlying trend of sea level and that many old tide gauge records are of very high quality.

  12. Temporal variability of combined sewer overflow contaminants: evaluation of wastewater micropollutants as tracers of fecal contamination.

    PubMed

    Madoux-Humery, Anne-Sophie; Dorner, Sarah; Sauvé, Sébastien; Aboulfadl, Khadija; Galarneau, Martine; Servais, Pierre; Prévost, Michèle

    2013-09-01

    A monitoring program was initiated for two sewage outfalls (OA and OB) with different land uses (mainly residential versus institutional) over the course of a year. Eleven CSO events resulting from fall and summer precipitations and a mixture of snowmelt and precipitation in late winter and early spring were monitored. Median concentrations measured in CSOs were 1.5 × 10(6)Escherichia coli/100 mL, 136.0 mg/L of Total Suspended Solids (TSS), 4599.0 ng/L of caffeine (CAF), 158.9 ng/L of carbamazepine (CBZ), in outfall OA and 5.1 × 10(4)E. coli/100 mL, 167.0 mg TSS/L, 300.8 ng CAF/L, 4.1 ng CBZ/L, in outfall OB. Concentration dynamics in CSOs were mostly related to the dilution by stormwater and the time of day of the onset of overflows. Snowmelt was identified as a critical period with regards to the protection of drinking water sources given the high contaminant concentrations and long duration of events in addition to a lack of restrictions on overflows during this period. Correlations among measured parameters reflected the origins and transport pathways of the contaminants, with E. coli being correlated with CBZ. TSS were not correlated with E. coli because E. coli was found to be mostly associated with raw sewage whereas TSS were additionally from the resuspension of in-sewer deposits and surface runoff. In receiving waters, E. coli remained the best indicator of fecal contamination in strongly diluted water samples as compared to WWMPs because WWMPs can be diluted to below their detection limits. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Main Report

    PubMed Central

    2006-01-01

    scientific literature. The criteria were distributed among three main categories for each condition: The availability and characteristics of the screening test;The availability and complexity of diagnostic services; andThe availability and efficacy of treatments related to the conditions. A survey process utilizing a data collection instrument was used to gather expert opinion on the conditions in the first tier of the assessment. The data collection format and survey provided the opportunity to quantify expert opinion and to obtain the views of a diverse set of interest groups (necessary due to the subjective nature of some of the criteria). Statistical analysis of data produced a score for each condition, which determined its ranking and initial placement in one of three categories (high scoring, moderately scoring, or low scoring/absence of a newborn screening test). In the second tier of these analyses, the evidence base related to each condition was assessed in depth (e.g., via systematic reviews of reference lists including MedLine, PubMed and others; books; Internet searches; professional guidelines; clinical evidence; and cost/economic evidence and modeling). The fact sheets reflecting these analyses were evaluated by at least two acknowledged experts for each condition. These experts assessed the data and the associated references related to each criterion and provided corrections where appropriate, assigned a value to the level of evidence and the quality of the studies that established the evidence base, and determined whether there were significant variances from the survey data. Survey results were subsequently realigned with the evidence obtained from the scientific literature during the second-tier analysis for all objective criteria, based on input from at least three acknowledged experts in each condition. The information from these two tiers of assessment was then considered with regard to the overriding principles and other technology or condition

  14. Green Infrastructure in the Mix to Reduce District of Columbia Sewer Overflows

    EPA Pesticide Factsheets

    District of Columbia's Long Term Control Plan to keep sewage out of the city’s rivers is being modified to include a substantial greening component for the first time, making it a dominant feature of 2 of the 3 drainage areas of the combined sewer system.

  15. Iron salts dosage for sulfide control in sewers induces chemical phosphorus removal during wastewater treatment.

    PubMed

    Gutierrez, Oriol; Park, Donghee; Sharma, Keshab R; Yuan, Zhiguo

    2010-06-01

    Chemical phosphorus (P) removal during aerobic wastewater treatment induced by iron salt addition in sewer systems for sulfide control is investigated. Aerobic batch tests with activated sludge fed with wastewater containing iron sulfide precipitates showed that iron sulfide was rapidly reoxidised in aerobic conditions, resulting in phosphate precipitation. The amount of P removed was proportional to the amount of iron salts added, and for the sludge used, ratios of 0.44 and 0.37 mgP/mgFe were obtained for ferric and ferrous dosages, respectively. The hydraulic retention time (HRT) of iron sulfide in sewers was found to have a crucial impact on the settling of iron sulfide precipitates during primary settling, with a shorter HRT resulting in a higher concentration of iron sulfide in the primary effluent and thus enabling higher P removal. A mathematical model was developed to describe iron sulfide oxidation in aerated activated sludge and the subsequent iron phosphate precipitation. The model was used to optimise FeCl(3) dosing in a real wastewater collection and treatment system. Simulation studies revealed that, by moving FeCl(3) dosing from the WWTP, which is the current practice, to a sewer location upstream of the plant, both sulfide control and phosphate removal could be achieved with the current ferric salt consumption. This work highlights the importance of integrated management of sewer networks and wastewater treatment plants. Copyright 2010 Elsevier Ltd. All rights reserved.

  16. Acoustic measurement and morphological features of organic sediment deposits in combined sewer networks.

    PubMed

    Carnacina, Iacopo; Larrarte, Frédérique; Leonardi, Nicoletta

    2017-04-01

    The performance of sewer networks has important consequences from an environmental and social point of view. Poor functioning can result in flood risk and pollution at a large scale. Sediment deposits forming in sewer trunks might severely compromise the sewer line by affecting the flow field, reducing cross-sectional areas, and increasing roughness coefficients. In spite of numerous efforts, the morphological features of these depositional environments remain poorly understood. The interface between water and sediment remains inefficiently identified and the estimation of the stock of deposit is frequently inaccurate. In part, this is due to technical issues connected to difficulties in collecting accurate field measurements without disrupting existing morphologies. In this paper, results from an extensive field campaign are presented; during the campaign a new survey methodology based on acoustic techniques has been tested. Furthermore, a new algorithm for the detection of the soil-water interface, and therefore for the correct esteem of sediment stocks is proposed. Finally, results in regard to bed topography, and morphological features at two different field sites are presented and reveal that a large variability in bed forms is present along sewer networks.

  17. HIGH-RATE DISINFECTION OF COMBINED SEWER OVERFLOW USING CHLORINE DIOXIDE

    EPA Science Inventory

    This presentation is a state-of-the-art review of chlorine dioxide (ClO2) used for high-rate disinfection of combined sewer overflow (CSO). The review includes bench-, pilot-, and fullscale studies on the use of ClO2 as a disinfecting agent for a variety of wastewaters. Specific ...

  18. A review of the Y-12 Plant discharge of enriched uranium to the sanitary sewer (DEUSS)

    SciTech Connect

    Not Available

    1991-09-01

    The Oak Ridge Y-12 Plant is situated adjacent to the Oak Ridge city limits and is operated by the United States Department of Energy (DOE). The Y-12 Plant is located on 4,860 acres, which is collectively referred to as the Y-12 Plant site. Among the missions for which the facility is in existence are producing nuclear weapons components, supporting weapon design laboratories, and processing special nuclear materials (SNM). The Y-12 Plant is under the regulatory guidance of DOE Order 5400.5 and has complied with the technical requirements governing SNM since its issue. However, an in-depth review with appropriate documentation had not been performed, prior to the effect presented herein, to substantiate this claim. As a result of the solid waste issue, it was determined that other types of waste should be formally reviewed for content with respect to SNM. Therefore, a project was formed to investigate the conveyance of SNM through the sanitary sewer system. It is emphasized that this project addresses only effluent from the sanitary sewer system and not the storm sewer system. The project reviewed sanitary sewer data both for the Y-12 Plant and the Y-12 Plant site.

  19. Assessment of the effects of greywater reuse on gross solids movement in sewer systems.

    PubMed

    Penn, R; Schütze, M; Friedler, E

    2014-01-01

    Onsite greywater reuse (GWR) and installation of water-efficient toilets (WETs) reduce urban freshwater demand and thus enhance urban water use sustainability. Research on GWR and WETs has generally overlooked their potential effects on municipal sewer systems: GWR and WETs affect the flow regime in sewers, and consequently also influence gross solids transport. To asses these impacts, a gross solids transport model was developed. The model is based on approaches found in the literature. Hydrodynamic calculations of sewage flow were performed using the SIMBA6 simulator and then used for the gross solid movement models. Flow characteristics in the up- and downstream sections of the sewer network differ. Therefore different approaches were used to model solids movement in each of these two parts. Each model determines whether a solid moves as a result of a momentary sewage flow, and if it moves, calculation of its velocity is possible. The paper shows the adoption and implementation of two gross solids transport models using SIMBA6 and depicts the results of the effects of various GWR and WET scenarios on gross solids movement in sewers for a real case study in Israel.

  20. Predicting the Probability of Failure of Cementitious Sewer Pipes Using Stochastic Finite Element Method

    PubMed Central

    Alani, Amir M.; Faramarzi, Asaad

    2015-01-01

    In this paper, a stochastic finite element method (SFEM) is employed to investigate the probability of failure of cementitious buried sewer pipes subjected to combined effect of corrosion and stresses. A non-linear time-dependant model is used to determine the extent of concrete corrosion. Using the SFEM, the effects of different random variables, including loads, pipe material, and corrosion on the remaining safe life of the cementitious sewer pipes are explored. A numerical example is presented to demonstrate the merit of the proposed SFEM in evaluating the effects of the contributing parameters upon the probability of failure of cementitious sewer pipes. The developed SFEM offers many advantages over traditional probabilistic techniques since it does not use any empirical equations in order to determine failure of pipes. The results of the SFEM can help the concerning industry (e.g., water companies) to better plan their resources by providing accurate prediction for the remaining safe life of cementitious sewer pipes. PMID:26068092

  1. REMOVAL OF TANK AND SEWER SEDIMENT BY GATE FLUSHING: COMPUTATIONAL FLUID DYNAMICS MODEL STUDIES

    EPA Science Inventory

    This presentation will discuss the application of a computational fluid dynamics 3D flow model to simulate gate flushing for removing tank/sewer sediments. The physical model of the flushing device was a tank fabricated and installed at the head-end of a hydraulic flume. The fl...

  2. Temporal asymmetry in precipitation time series and its influence on flow simulations in combined sewer systems

    NASA Astrophysics Data System (ADS)

    Müller, Thomas; Schütze, Manfred; Bárdossy, András

    2017-09-01

    A property of natural processes is temporal irreversibility. However, this property cannot be reflected by most statistics used to describe precipitation time series and, consequently, is not considered in most precipitation models. In this paper, a new statistic, the asymmetry measure, is introduced and applied to precipitation enabling to detect and quantify irreversibility. It is used to analyze two different data sets of Singapore and Germany. The data of both locations show a significant asymmetry for high temporal resolutions. The asymmetry is more pronounced for Singapore where the climate is dominated by convective precipitation events. The impact of irreversibility on applications is analyzed on two different hydrological sewer system models. The results show that the effect of the irreversibility can lead to biases in combined sewer overflow statistics. This bias is in the same order as the effect that can be achieved by real time control of sewer systems. Consequently, wrong conclusion can be drawn if synthetic time series are used for sewer systems if asymmetry is present, but not considered in precipitation modeling.

  3. Biodegradation of fat, oil and grease (FOG) deposits under various redox conditions relevant to sewer environment.

    PubMed

    He, Xia; Zhang, Qian; Cooney, Michael J; Yan, Tao

    2015-07-01

    Fat, oil and, grease (FOG) deposits are one primary cause of sanitary sewer overflows (SSOs). While numerous studies have examined the formation of FOG deposits in sewer pipes, little is known about their biodegradation under sewer environments. In this study, FOG deposit biodegradation potential was determined by studying the biodegradation of calcium palmitate in laboratory under aerobic, nitrate-reducing, sulfate-reducing, and methanogenic conditions. Over 110 days of observation, calcium palmitate was biodegraded to CO2 under aerobic and nitrate-reducing conditions. An approximate 13 times higher CO2 production rate was observed under aerobic condition than under nitrate-reducing condition. Under sulfate-reducing condition, calcium palmitate was recalcitrant to biodegradation as evidenced by small reduction in sulfate. No evidence was found to support calcium palmitate degradation under methanogenic condition in the simulated sewer environment. Dominant microbial populations in the aerobic and nitrate-reducing microcosms were identified by Illumina seqeuncing, which may contain the capability to degrade calcium palmitate under both aerobic and nitrate-reducing conditions. Further study on these populations and their functional genes could shed more light on this microbial process and eventually help develop engineering solutions for SSOs control in the future.

  4. Mechanisms of fat, oil and grease (FOG) deposit formation in sewer lines.

    PubMed

    He, Xia; de los Reyes, Francis L; Leming, Michael L; Dean, Lisa O; Lappi, Simon E; Ducoste, Joel J

    2013-09-01

    FOG deposits in sewer systems have recently been shown to be metallic salts of fatty acids. However, the fate and transport of FOG deposit reactant constituents and the complex interactions during the FOG deposit formation process are still largely unknown. In this study, batch tests were performed to elucidate the mechanisms of FOG deposit formation that lead to sanitary sewer overflows (SSOs). We report the first formation of FOG deposits on a concrete surface under laboratory conditions that mimic the formation of deposits in sewer systems. Results showed that calcium, the dominant metal in FOG deposits, can be released from concrete surfaces under low pH conditions and contribute to the formation process. Small amounts of additional oil to grease interceptor effluent substantially facilitated the air/water or pipe surface/water interfacial reaction between free fatty acids and calcium to produce surface FOG deposits. Tests of different fatty acids revealed that more viscous FOG deposit solids were formed on concrete surfaces, and concrete corrosion was accelerated, in the presence of unsaturated FFAs versus saturated FFAs. Based on all the data, a comprehensive model was proposed for the mechanisms of FOG deposit formation in sewer systems.

  5. Mechanisms of Fat, Oil and Grease (FOG) Deposit Formation in Sewer Lines

    USDA-ARS?s Scientific Manuscript database

    FOG deposits in sewer systems recently have been shown to be metallic salts of fatty acids. However, the fate and transport of FOG deposit reactant constituents and the complex interactions during the FOG deposit formation process are still largely unknown. Batch tests were performed to elucidate ...

  6. A sewer process model as planning and management tool--hydrogen sulfide simulation at catchment scale.

    PubMed

    Vollertsen, J; Nielsen, L; Blicher, T D; Hvitved-Jacobsen, T; Nielsen, A H

    2011-01-01

    The collection system of a major city at the Persian Gulf was simulated for bulk water hydrogen sulfide and the release of sewer gas to the urban atmosphere. Geometry data on 870 km of sanitary sewer and data on dry weather flow entering all nodes in the catchment was exported from a Mike Urban database and imported to the sewer process model WATS. The process model then routed sewage and sewer gas through the system and simulated relevant physical, chemical and biological processes. In its non-calibrated state, the model was used as a planning tool to identify problem areas and to identify locations to install monitoring equipment and make preliminary choices for control strategies in terms of dosing of nitrate and iron salts. The monitoring equipment consisted of flow meters, level gauges, UV-Vis spectroscopes, and H2S gas sensors. Data from the first set of installed monitoring equipment were applied to calibrate and validate the model. It was illustrated how the calibrated model can be applied to assess compliance with quantitative formulated service levels and to design control strategies in terms of dosing of iron and nitrate salts.

  7. MODELS TO ESTIMATE VOLATILE ORGANIC HAZARDOUS AIR POLLUTANT EMISSIONS FROM MUNICIPAL SEWER SYSTEMS

    EPA Science Inventory

    Emissions from municipal sewers are usually omitted from hazardous air pollutant (HAP) emission inventories. This omission may result from a lack of appreciation for the potential emission impact and/or from inadequate emission estimation procedures. This paper presents an analys...

  8. AN ASSESSMENT OF AUTOMATIC SEWER FLOW SAMPLERS (EPA/600/2-75/065)

    EPA Science Inventory

    A brief review of the characteristics of storm and combined sewer flows is given followed by a general discussion of the purposes for and requirements of a sampling program. The desirable characteristics of automatic sampling equipment are set forth and problem areas are outlined...

  9. Event-driven model predictive control of sewage pumping stations for sulfide mitigation in sewer networks.

    PubMed

    Liu, Yiqi; Ganigué, Ramon; Sharma, Keshab; Yuan, Zhiguo

    2016-07-01

    Chemicals such as Mg(OH)2 and iron salts are widely dosed to sewage for mitigating sulfide-induced corrosion and odour problems in sewer networks. The chemical dosing rate is usually not automatically controlled but profiled based on experience of operators, often resulting in over- or under-dosing. Even though on-line control algorithms for chemical dosing in single pipes have been developed recently, network-wide control algorithms are currently not available. The key challenge is that a sewer network is typically wide-spread comprising many interconnected sewer pipes and pumping stations, making network-wide sulfide mitigation with a relatively limited number of dosing points challenging. In this paper, we propose and demonstrate an Event-driven Model Predictive Control (EMPC) methodology, which controls the flows of sewage streams containing the dosed chemical to ensure desirable distribution of the dosed chemical throughout the pipe sections of interests. First of all, a network-state model is proposed to predict the chemical concentration in a network. An EMPC algorithm is then designed to coordinate sewage pumping station operations to ensure desirable chemical distribution in the network. The performance of the proposed control methodology is demonstrated by applying the designed algorithm to a real sewer network simulated with the well-established SeweX model using real sewage flow and characteristics data. The EMPC strategy significantly improved the sulfide mitigation performance with the same chemical consumption, compared to the current practice. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Demonstration of Green/Gray Infrastructure for Combined Sewer Overflow Control

    EPA Science Inventory

    This project is a major national demonstration of the integration of green and gray infrastructure for combined sewer overflow (CSO) control in a cost-effective and environmentally friendly manner. It will use Kansas City, MO, as a case example. The project will have a major in...

  11. Demonstration of Green/Gray Infrastructure for Combined Sewer Overflow Control

    EPA Science Inventory

    This project is a major national demonstration of the integration of green and gray infrastructure for combined sewer overflow (CSO) control in a cost-effective and environmentally friendly manner. It will use Kansas City, MO, as a case example. The project will have a major in...

  12. THE CHOICE OF REAL-TIME CONTROL STRATEGY FOR COMBINED SEWER OVERFLOW CONTROL

    EPA Science Inventory

    This paper focuses on the strategies used to operate a collection system in real-time control (RTC) in order to optimize use of system capacity and to reduce the cost of long-term combined sewer overflow (CSO) control. Three RTC strategies were developed and analyzed based on the...

  13. Sewer Lateral Electro Scan Field Verification Pilot (WERF Report INFR4R12)

    EPA Science Inventory

    Abstract:WERF selected a proposed research project to field test an emerging technology for inspecting sanitary sewer lateral pipes. The technology is called Electro Scan and is used to find defects in laterals that allow the infiltration of groundwater into the lateral. Electro ...

  14. High-throughput amplicon sequencing reveals distinct communities within a corroding concrete sewer system.

    PubMed

    Cayford, Barry I; Dennis, Paul G; Keller, Jurg; Tyson, Gene W; Bond, Philip L

    2012-10-01

    Microbially induced concrete corrosion (MICC) is an important problem in sewers. Here, small-subunit (SSU) rRNA gene amplicon pyrosequencing was used to characterize MICC communities. Microbial community composition differed between wall- and ceiling-associated MICC layers. Acidithiobacillus spp. were present at low abundances, and the communities were dominated by other sulfur-oxidizing-associated lineages.

  15. Corrosion of concrete sewers--the kinetics of hydrogen sulfide oxidation.

    PubMed

    Vollertsen, Jes; Nielsen, Asbjørn Haaning; Jensen, Henriette Stokbro; Wium-Andersen, Tove; Hvitved-Jacobsen, Thorkild

    2008-05-01

    Hydrogen sulfide absorption and oxidation by corroding concrete surfaces was quantified in a test rig consisting of 6 concrete pipes operated under sewer conditions. The test rig was placed in an underground sewer monitoring station with access to fresh wastewater. Hydrogen sulfide gas was injected into the pipe every 2nd hour to peak concentrations around 1000 ppm. After some months of operation, the hydrogen sulfide became rapidly oxidized by the corroding concrete surfaces. At hydrogen sulfide concentrations of 1000 ppm, oxidation rates as high as 1 mg S m(-2) s(-1) were observed. The oxidation process followed simple nth order kinetics with a process order of 0.45-0.75. Extrapolating the results to gravity sewer systems showed that hydrogen sulfide oxidation by corroding concrete is a fast process compared to the release of hydrogen sulfide from the bulk water, resulting in low gas concentrations compared with equilibrium. Balancing hydrogen sulfide release with hydrogen sulfide oxidation at steady state conditions demonstrated that significant corrosion rates--several millimeters of concrete per year--can potentially occur at hydrogen sulfide gas phase concentrations well below 5-10 ppm. The results obtained in the study advances the knowledge on prediction of sewer concrete corrosion and the extent of odor problems.

  16. Research of trace metals as markers of entry pathways in combined sewers.

    PubMed

    Gounou, C; Varrault, G; Amedzro, K; Gasperi, J; Moilleron, R; Garnaud, S; Chebbo, G

    2011-01-01

    Combined sewers receive high toxic trace metal loads emitted by various sources, such as traffic, industry, urban heating and building materials. During heavy rain events, Combined Sewer Overflows (CSO) can occur and, if so, are discharged directly into the aquatic system and therefore could have an acute impact on receiving waters. In this study, the concentrations of 18 metals have been measured in 89 samples drawn from the three pollutant Entry Pathways in Combined Sewers (EPCS): i) roof runoff, ii) street runoff, and iii) industrial and domestic effluents and also drawn from sewer deposits (SD). The aim of this research is to identify metallic markers for each EPCS; the data matrix was submitted to principal component analysis in order to determine metallic markers for the three EPCS and SD. This study highlights the fact that metallic content variability across samples from different EPCS and SD exceeds the spatio-temporal variability of samples from the same EPCS. In the catchment studied here, the most valuable EPCS and SD markers are lead, sodium, boron, antimony and zinc; these markers could be used in future studies to identify the contributions of each EPCS to CSO metallic loads.

  17. Trace element carriers in combined sewer during dry and wet weather: an electron microscope investigation.

    PubMed

    El Samrani, A G; Lartiges, B S; Ghanbaja, J; Yvon, J; Kohler, A

    2004-04-01

    The nature of trace element carriers contained in sewage and combined sewer overflow (CSO) was investigated by TEM-EDX-Electron diffraction and SEM-EDX. During dry weather, chalcophile elements were found to accumulate in sewer sediments as early diagenetic sulfide phases. The sulfurization of some metal alloys was also evidenced. Other heavy metal carriers detected in sewage include metal alloys, some iron oxihydroxide phases and neoformed phosphate minerals such as anapaite. During rain events, the detailed characterization of individual mineral species allowed to differentiate the contributions from various specific sources. Metal plating particles, barite from automobile brake, or rare earth oxides from catalytic exhaust pipes, originate from road runoff, whereas PbSn alloys and lead carbonates are attributed to zinc-works from roofs and paint from building siding. Soil contribution can be traced by the presence of clay minerals, iron oxihydroxides, zircons and rare earth phosphates. However, the most abundant heavy metal carriers in CSO samples were the sulfide particles eroded from sewer sediments. The evolution of relative abundances of trace element carriers during a single storm event, suggests that the pollution due to the "first flush" effect principally results from the sewer stock of sulfides and previously deposited metal alloys, rather than from urban surface runoff.

  18. Assessment of pollutant load emission from combined sewer overflows based on the online monitoring.

    PubMed

    Brzezińska, Agnieszka; Zawilski, Marek; Sakson, Grażyna

    2016-09-01

    Cities equipped with combined sewer systems discharge during wet weather a lot of pollutants into receiving waters by combined storm overflows (CSOs). According to the Polish legislation, CSOs should be activated no more than ten times per year, but in Lodz, most of the 18 existing CSOs operate much more frequently. To assess the pollutant load emitted by one of the existing CSOs, the sensors for measuring the concentration of total suspended solids (SOLITAX sc) and dissolved chemical oxygen demand (UVAS plus) installed in the overflow chamber as well as two flowmeters placed in the outflow sewer were used. In order to check the data from sensors, laboratory tests of combined wastewater quality were conducted simultaneously. For the analysis of the total pollutant load emitted from the overflow, the raw data was denoised using the Savitzky-Golay method. Comparing the load calculated from the analytical results to online smoothed measurements, negligible differences were found, which confirms the usefulness of applying the sensors in the combined sewer system. Online monitoring of the quantity and quality of wastewater emitted by the combined sewer overflows to water receivers, provides a considerable amount of data very useful for combined sewerage upgrading based on computer modelling, and allows for a significant reduction of laboratory analysis.

  19. SeWeR: a customizable and integrated dynamic HTML interface to bioinformatics services.

    PubMed

    Basu, M K

    2001-06-01

    Sequence analysis using Web Resources (SeWeR) is an integrated, Dynamic HTML (DHTML) interface to commonly used bioinformatics services available on the World Wide Web. It is highly customizable, extendable, platform neutral, completely server-independent and can be hosted as a web page as well as being used as stand-alone software running within a web browser.

  20. Sewer Lateral Electro Scan Field Verification Pilot (WERF Report INFR4R12)

    EPA Science Inventory

    Abstract:WERF selected a proposed research project to field test an emerging technology for inspecting sanitary sewer lateral pipes. The technology is called Electro Scan and is used to find defects in laterals that allow the infiltration of groundwater into the lateral. Electro ...

  1. Impact of dry weather discharges on annual pollution from a separate storm sewer in Toulouse, France.

    PubMed

    Deffontis, S; Breton, A; Vialle, C; Montréjaud-Vignoles, M; Vignoles, C; Sablayrolles, C

    2013-05-01

    The city of Toulouse with its separate sewer system is ideal for studying stormwater. However, during dry weather, the storm sewer also discharges water into the environment, and it is the impact of these discharges on annual pollution from storm sewer that is the object of this study. Samples have been taken from the outlets of two storm drains located in heavily and moderately urbanized areas. Sampling has been undertaken during wet weather and during dry weather between January 2010 and February 2011. Three dry weather and two wet weather samples have been taken every three months and from each outlet. The overall pollution parameters have been analyzed (chemical oxygen demand, biological oxygen demand, total nitrogen, ammonium, nitrate, total phosphorus, suspended solid matter, volatile suspended matter, pH, conductivity, turbidity). Characterization has been completed by analysis of trace organic compounds: polycyclic aromatic hydrocarbons, total hydrocarbons, methyl tert-butyl ether, diethylhexylphthalate, nonylphenols, hormones (estradiol, ethinylestradiol). For certain parameters, the results obtained did not conform to legislative requirements concerning discharge into the natural environment. Correlations between these parameters have been studied, and identified between several of them using principal component analysis. The most important correlation observed was between conductivity and concentration in total phosphorus for one of the outlet. Results showed that dry weather had an impact on annual pollution load from separate storm sewer and that level of urbanization was also a factor. The effect of season has been studied but no significant impact was found.

  2. High-Rate Disinfection Techniques for Combined Sewer Overflow (Proceedings Paper)

    EPA Science Inventory

    This paper presents high-rate disinfection technologies for combined sewer overflow (CSO). The high-rate disinfection technologies of interest are: chlorination/dechlorination, ultraviolet light irradiation (UV), chlorine dioxide (ClO2 ), ozone (O3), peracetic acid (CH3COOOH ), a...

  3. Measuring Flow Reductions in a Combined Sewer System Using Green Infrastructure

    EPA Science Inventory

    A green infrastructure (GI) design approach was used in CSO Basin #130, a 17-acre sewershed in the Butchertown section of Louisville, Kentucky, to reduce combined sewer overflows (CSOs). For the design year, the modeled design was expected to reduce the CSO frequency from 34 to ...

  4. Phosphate dynamics in an urban sewer: a case study of Nancy, France.

    PubMed

    Houhou, J; Lartiges, B S; Hofmann, A; Frappier, G; Ghanbaja, J; Temgoua, A

    2009-03-01

    The nature of phosphate phases present in suspended matter, biofilm, and sediment of Greater Nancy sewer system was investigated over a period of two years. The phosphate speciation was determined by two approaches: a direct identification of phosphorus mineral phases was conducted by Transmission Electron Microscopy (TEM) coupled with energy-dispersive X-ray spectroscopy (EDXS), whereas a chemical extraction of samples provided an estimate of phosphorus pools defined by the fractionation scheme. Quantitative analysis of 1340 individual particles by TEM-EDXS allowed to draw a picture of phosphate species distributions along the sewer system and over time. Amorphous Ca-phosphates (brushite, whitlockite, octacalcium phosphate, Mg-brushite, hydroxyapatite and carbapatite) were ubiquitous although brushite dominated upstream, and octacalcium phosphate and apatite prevailed downstream and in sediments. Al-Ca-phosphate minerals such as foggite, bearthite, gatumbaite, and crandallite appeared downstream and in biofilms. Ca-phosphate phase assemblages in the different locations of the sewer system were dependent on phase transformations from brushite to hydroxyapatite that were shown to be kinetically driven. The restriction of Al-Ca-phosphates to downstream of the sewer system was most probably related to the lower pHs measured at these sites. The pH dependency was confirmed by stability calculations. Chemical extractions were not reliable. TEM examination of extraction residues revealed the presence of neoformed Al-Ca-phosphate species that invalidated the fractionation scheme. Nonetheless, it confirmed that phosphate phases may undergo significant geochemical changes over a short time scale.

  5. Measuring Flow Reductions in a Combined Sewer System Using Green Infrastructure

    EPA Science Inventory

    A green infrastructure (GI) design approach was used in CSO Basin #130, a 17-acre sewershed in the Butchertown section of Louisville, Kentucky, to reduce combined sewer overflows (CSOs). For the design year, the modeled design was expected to reduce the CSO frequency from 34 to ...

  6. AN ASSESSMENT OF AUTOMATIC SEWER FLOW SAMPLERS (EPA/600/2-75/065)

    EPA Science Inventory

    A brief review of the characteristics of storm and combined sewer flows is given followed by a general discussion of the purposes for and requirements of a sampling program. The desirable characteristics of automatic sampling equipment are set forth and problem areas are outlined...

  7. Controlling chemical dosing for sulfide mitigation in sewer networks using a hybrid automata control strategy.

    PubMed

    Liu, Yiqi; Ganigué, Ramon; Sharma, Keshab; Yuan, Zhiguo

    2013-01-01

    Chemicals such as magnesium hydroxide (Mg(OH)2) and iron salts are widely used to control sulfide-induced corrosion in sewer networks composed of interconnected sewer pipe lines and pumping stations. Chemical dosing control is usually non-automatic and based on experience, thus often resulting in sewage reaching the discharge point receiving inadequate or even no chemical dosing. Moreover, intermittent operation of pumping stations makes traditional control theory inadequate. A hybrid automata-based (HA-based) control method is proposed in this paper to coordinate sewage pumping station operations by considering their states, thereby ensuring suitable chemical concentrations in the network discharge. The performance of the proposed control method was validated through a simulation study of a real sewer network using real sewage flow data. The physical, chemical and biological processes were simulated using the well-established SeweX model. The results suggested that the HA-based control strategy significantly improved chemical dosing control performance and sulfide mitigation in sewer networks, compared to the current common practice.

  8. Reduced sulfur compounds in the atmosphere of sewer networks in Australia: geographic (and seasonal) variations.

    PubMed

    Wang, B; Sivret, E C; Parcsi, G; Le, N M; Kenny, S; Bustamante, H; Stuetz, R M

    2014-01-01

    The management of odorous emissions from sewer networks has become an important issue for sewer system operators resulting in the need to better understand the composition of reduced sulfur compounds (RSCs). Gaseous RSCs including hydrogen sulfide (H2S), methanethiol (MeSH), dimethyl sulfide (DMS), carbon disulfide (CS2), dimethyl disulfide (DMDS) and dimethyl trisulfide (DMTS) were measured in the atmosphere of selected sewer networks in two major Australian cities (Sydney and Melbourne) during 2011-2012. The RSC concentrations in the sewer air were detected in a highly variable range. H2S and MeSH were found at the highest concentrations, followed by DMS (39.2-94.0 μg/m(3)), CS2 (18.3-19.6 μg/m(3)), DMDS (7.8-49.6 μg/m(3)) and DMTS (10.4-35.3 μg/m(3)). Temporal trends in the occurrence of targeted RSCs were observed and the highest sulfur concentration occurred either in summer or spring, which are typically regarded as the warmer seasons. Statistical significant difference in the magnitude of targeted RSCs was found between samples collected in Sydney and Melbourne.

  9. COMPUTER MODEL ANALYSIS FOR MITIGATION PLANNING OF SANITARY-SEWER OVERFLOWS

    EPA Science Inventory

    Sanitary sewer overflows (SSOs) are generally difficult to witness or document as they usually occur during rain events when people are indoors or out of sight. To anser where and when an SSO may occur, it is necessary to know the flow conveyance capacity at various parts of the ...

  10. Identification of sewer pipes to be cleaned for reduction of CSO pollutant load.

    PubMed

    Nagaiwa, Akihiro; Settsu, Katsushi; Nakajima, Fumiyuki; Furumai, Hiroaki

    2007-01-01

    To reduce the CSO (Combined Sewer Overflow) pollutant discharge, one of the effective options is cleaning of sewer pipes before rainfall events. To maximize the efficiency, identification of pipes to be cleaned is necessary. In this study, we discussed the location of pipe deposit in dry weather in a combined sewer system using a distributed model and investigated the effect of pipe cleaning to reduce the pollutant load from the CSO. First we simulated the dry weather flow in a combined sewer system. The pipe deposit distribution in the network was estimated after 3 days of dry weather period. Several specific pipes with structural defect and upper end pipes tend to have an accumulation of deposit. Wet weather simulations were conducted with and without pipe cleaning in rainfall events with different patterns. The SS loads in CSO with and without the pipe cleaning were compared. The difference in the estimated loads was interpreted as the contribution of wash-off in the cleaned pipe. The effect of pipe cleaning on reduction of the CSO pollutant load was quantitatively evaluated (e.g. the cleaning of one specific pipe could reduce 22% of total CSO load). The CSO simulations containing pipe cleaning options revealed that identification of pipes with accumulated deposit using the distributed model is very useful and informative to evaluate the applicability of pipe cleaning option for CSO pollutant reduction.

  11. High-Rate Disinfection Techniques for Combined Sewer Overflow (Proceedings Paper)

    EPA Science Inventory

    This paper presents high-rate disinfection technologies for combined sewer overflow (CSO). The high-rate disinfection technologies of interest are: chlorination/dechlorination, ultraviolet light irradiation (UV), chlorine dioxide (ClO2 ), ozone (O3), peracetic acid (CH3COOOH ), a...

  12. Effects of climate and sewer condition on virus transport to groundwater

    USDA-ARS?s Scientific Manuscript database

    Pathogen contamination from leaky sanitary sewers poses a threat to groundwater quality in urban areas, yet the spatial and temporal dimensions of this contamination are not well understood. In this study, 16 monitoring wells and six municipal wells were repeatedly sampled for human enteric viruses....

  13. Identifying pathways for sanitary sewer pathogens to reach deep water supply wells in Madison, Wisconsin

    USDA-ARS?s Scientific Manuscript database

    Previous work conducted by the Wisconsin Geological and Natural History Survey indicated that human enteric viruses from leaking sewers are present in several municipal wells in Madison, WI. These wells are the drinking water source for the City of Madison, are typically 700 to 900 feet deep, and pe...

  14. Spatial Models of Sewer Pipe Leakage Predict the Occurrence of Wastewater Indicators in Shallow Urban Groundwater.

    PubMed

    Roehrdanz, Patrick R; Feraud, Marina; Lee, Do Gyun; Means, Jay C; Snyder, Shane A; Holden, Patricia A

    2017-02-07

    Twentieth century municipal wastewater infrastructure greatly improved U.S. urban public health and water quality. However, sewer pipes deteriorate, and their accumulated structural defects may release untreated wastewater to the environment via acute breaks or insidious exfiltration. Exfiltrated wastewater constitutes a loss of potentially reusable water and delivers a complex and variable mix of contaminants to urban shallow groundwater. Yet, predicting where deteriorated sewers impinge on shallow groundwater has been challenging. Here we develop and test a spatially explicit model of exfiltration probability based on pipe attributes and groundwater elevation without prior knowledge of exfiltrating defect locations. We find that models of exfiltration probability can predict the probable occurrence in underlying shallow groundwater of established wastewater indicators including the artificial sweetener acesulfame, tryptophan-like fluorescent dissolved organic matter, nitrate, and a stable isotope of water (δ(18)O). The strength of the association between exfiltration probability and indicators of wastewater increased when multiple pipe attributes, distance weighting, and groundwater flow direction were considered in the model. The results prove that available sanitary sewer databases and groundwater digital elevation data can be analyzed to predict where pipes are likely leaking and contaminating groundwater. Such understanding could direct sewer infrastructure reinvestment toward water resource protection.

  15. High-Throughput Amplicon Sequencing Reveals Distinct Communities within a Corroding Concrete Sewer System

    PubMed Central

    Dennis, Paul G.; Keller, Jurg; Tyson, Gene W.

    2012-01-01

    Microbially induced concrete corrosion (MICC) is an important problem in sewers. Here, small-subunit (SSU) rRNA gene amplicon pyrosequencing was used to characterize MICC communities. Microbial community composition differed between wall- and ceiling-associated MICC layers. Acidithiobacillus spp. were present at low abundances, and the communities were dominated by other sulfur-oxidizing-associated lineages. PMID:22843532

  16. HIGH-RATE DISINFECTION OF COMBINED SEWER OVERFLOW USING CHLORINE DIOXIDE

    EPA Science Inventory

    This presentation is a state-of-the-art review of chlorine dioxide (ClO2) used for high-rate disinfection of combined sewer overflow (CSO). The review includes bench-, pilot-, and fullscale studies on the use of ClO2 as a disinfecting agent for a variety of wastewaters. Specific ...

  17. COMPUTER MODEL ANALYSIS FOR MITIGATION PLANNING OF SANITARY-SEWER OVERFLOWS

    EPA Science Inventory

    Sanitary sewer overflows (SSOs) are generally difficult to witness or document as they usually occur during rain events when people are indoors or out of sight. To anser where and when an SSO may occur, it is necessary to know the flow conveyance capacity at various parts of the ...

  18. Modelling sewer sediment deposition, erosion, and transport processes to predict acute influent and reduce combined sewer overflows and CO(2) emissions.

    PubMed

    Mouri, Goro; Oki, Taikan

    2010-01-01

    Understanding of solids deposition, erosion, and transport processes in sewer systems has improved considerably in the past decade. This has provided guidance for controlling sewer solids and associated acute pollutants to protect the environment and improve the operation of wastewater systems. Although measures to decrease combined sewer overflow (CSO) events have reduced the amount of discharged pollution, overflows continue to occur during rainy weather in combined sewer systems. The solution lies in the amount of water allotted to various processes in an effluent treatment system, in impact evaluation of water quality and prediction technology, and in stressing the importance of developing a control technology. Extremely contaminated inflow has been a serious research subject, especially in connection with the influence of rainy weather on nitrogen and organic matter removal efficiency in wastewater treatment plants (WWTP). An intensive investigation of an extremely polluted inflow load to WWTP during rainy weather was conducted in the city of Matsuyama, the region used for the present research on total suspended solid (TSS) concentration. Since the inflow during rainy weather can be as much as 400 times that in dry weather, almost all sewers are unsettled and overflowing when a rain event is more than moderate. Another concern is the energy consumed by wastewater treatment; this problem has become important from the viewpoint of reducing CO(2) emissions and overall costs. Therefore, while establishing a prediction technology for the inflow water quality characteristics of a sewage disposal plant is an important priority, the development of a management/control method for an effluent treatment system that minimises energy consumption and CO(2) emissions due to water disposal is also a pressing research topic with regards to the quality of treated water. The procedure to improve water quality must make use of not only water quality and biotic criteria, but also

  19. Nutrient Input and Dynamics in a Restored Urban Stream Impacted by Mixed Sewer Systems

    NASA Astrophysics Data System (ADS)

    Sikora, M. T.; Elliott, E. M.; Bain, D. J.

    2008-12-01

    Export and retention of nutrients in urban watersheds remains poorly constrained. Available data is often based on studies conducted on large-scale, forested and mixed use watersheds rather than small urbanized systems. Additionally, there is a lack of data on the amount and impact of nutrients introduced into urban waterways as the result of stream-sewer interactions and a varied flow regime. In order to address this knowledge gap, water was sampled during baseflow (bi-weekly from April 2007 to present) and stormflow from a restored urban stream in Pittsburgh, Pennsylvania (USA) impacted by both Sanitary Sewer and Combined Sewer Overflow (SSO and CSO, respectively) networks. Nine Mile Run (NMR), a restored urban stream, drains a 1600 hectare urban watershed characterized as 38% impervious. Analysis of post-restoration water quality data suggests that atmospheric deposition and sewage both contribute nutrient pollution to the stream. We estimate input of atmospheric nitrate deposition to the watershed is 18.96 kg NO3- ha-1yr-1, yet a preliminary nitrogen budget suggests that nitrate export from the basin is consistently higher (~30 kg NO3- ha-1yr-1). Mean baseflow nitrate concentrations are substantially higher during the wetter portions of 2008 (12.07 mg NO3 -/L) as compared to the drier 2007 year (7.3 mg NO3 -/L). This suggests increased stream/sewer interactions during wetter periods. These results document the effect of Sanitary Sewer systems on an urban stream and highlight the challenges inherent in improving urban water quality through physical stream restorations.

  20. Getting the max out of past investments in sewer systems by using RTC

    NASA Astrophysics Data System (ADS)

    van Heeringen, Klaas-Jan; van Loenen, Arnejan; van Leeuwen, Elgard; van Nooyen, Ronald; van Velzen, Edwin

    2013-04-01

    We discuss a project in which water quality improvements of surface waters are realised by replacing local control of sewer pumps by central control. The paper focuses on the effect of implementation of real-time control in a specific group of sewer systems in the Netherlands, namely the systems that have been upgraded in the past as a result of new standards. Since these upgrades were often solely based on straightforward so-called upgrade rules and theoretical simulation studies, a thorough analysis of the real life systems by means of measurements to study the system performance or calibrate the models was rarely performed. As a result the potential of many systems is not used to the full. Because of the structure of these systems, (suboptimal distribution of storage and pump capacities) the effect of RTC is much larger than would be expected in the case of a completely new design. But because of implementation of RTC, it was required to do this thorough analysis of the sewer systems. This study focuses on the estimation of this additional RTC effect. RTC both improves the return on past investments and provides the benefits of central information and control. The project considered the sewer systems in the Hoeksche Waard area, south of Rotterdam, the Netherlands. Three RTC improvements have been implemented whereby the abovementioned effects have been achieved. There were many technological challenges to overcome during the project, such as relatively high rates of data communication needed for in systems with relatively small storage capacities, connections to multiple types of SCADA and information systems, the integration of meteo forecasts and the RTC backup architecture based on the use of multiple control modes. The potential of the RTC has been proved as such in the HoekscheWaard area. On the basis of this implementation in a typical dutch sewer system, we expect RTC to have the same potential at a national scale.

  1. Use of iron salts to control dissolved sulfide in trunk sewers

    SciTech Connect

    Padival, N.A.; Kimbell, W.A.; Redner, J.A.

    1995-11-01

    Sewer headspace H{sub 2}S reduction by precipitating dissolved sulfide in wastewater was investigated using iron salt (FeCl{sub 3} and FeCl{sub 2}). Full-scale experiments were conducted in a 40-km (25 mi) sewer with an average flow of 8.7 m{sup 3}/s (200 mgd). Results were sensitive to total Fe dosages and Fe(III)/Fe(II) blend ratios injected. A concentration of 16 mg/L total Fe and a blend ratio of 1.9:1 [Fe(III):Fe(II)] reduced dissolved sulfide levels by 97%. Total sulfide and headspace H{sub 2}S were reduced by 63% and 79%, respectively. Liquid and gas-phase sulfide reductions were largely due to the effective precipitation of sulfide with Fe(III) and Fe(II) and the limited volatilization of H{sub 2}S, respectively. Oxidation of sulfide in the presence of Fe(II) and minute amounts of O{sub 2} may have occurred. A combination of Fe(III) and Fe(II) proved more effective than either salt alone. By using excess Fe(III), dissolved sulfide can be reduced to undetectable levels. No specific relation between the concentration of Fe or Fe(III)/Fe(II) blend ratio and sewer crown pH was inferred. Iron salts may retard crown corrosion rates by precipitating free sulfide and reducing its release to the sewer headspace as H{sub 2}S. A mechanism to inhibit certain responsible bacteria was not established in the 40-km (25 mi) sewer.

  2. Rise of the Andes.

    PubMed

    Garzione, Carmala N; Hoke, Gregory D; Libarkin, Julie C; Withers, Saunia; MacFadden, Bruce; Eiler, John; Ghosh, Prosenjit; Mulch, Andreas

    2008-06-06

    The surface uplift of mountain belts is generally assumed to reflect progressive shortening and crustal thickening, leading to their gradual rise. Recent studies of the Andes indicate that their elevation remained relatively stable for long periods (tens of millions of years), separated by rapid (1 to 4 million years) changes of 1.5 kilometers or more. Periodic punctuated surface uplift of mountain belts probably reflects the rapid removal of unstable, dense lower lithosphere after long-term thickening of the crust and lithospheric mantle.

  3. RATES OF GASTROINTESTINAL ILLNESS AMONG AREAS IMPACTED BY COMBINED SEWER FACILITIES: ANALYSIS OF MASSACHUSETTS DATA, 2003-2007

    EPA Science Inventory

    Previous studies have reported a temporal association between heavy rainfall and gastrointestinal infection (GI). Combined sewer systems (CSSs), which are present in many urban areas in the US, were designed to collect rainwater runoff, domestic sewage, and industrial wastewater ...

  4. A generic methodology for the optimisation of sewer systems using stochastic programming and self-optimizing control.

    PubMed

    Mauricio-Iglesias, Miguel; Montero-Castro, Ignacio; Mollerup, Ane L; Sin, Gürkan

    2015-05-15

    The design of sewer system control is a complex task given the large size of the sewer networks, the transient dynamics of the water flow and the stochastic nature of rainfall. This contribution presents a generic methodology for the design of a self-optimising controller in sewer systems. Such controller is aimed at keeping the system close to the optimal performance, thanks to an optimal selection of controlled variables. The definition of an optimal performance was carried out by a two-stage optimisation (stochastic and deterministic) to take into account both the overflow during the current rain event as well as the expected overflow given the probability of a future rain event. The methodology is successfully applied to design an optimising control strategy for a subcatchment area in Copenhagen. The results are promising and expected to contribute to the advance of the operation and control problem of sewer systems.

  5. Association between Gastrointestinal Illness and Precipitation in Areas Impacted by Combined Sewer Facilities: Analysis of Massachusetts Data, 2003-2007

    EPA Science Inventory

    Background: Combined sewer systems (CSS) collect rainwater runoff, sewage, and industrial wastewater for transit to treatment facilities. With heavy precipitation, volumes can exceed capacity of treatment facilities, and wastewater discharges directly to receiving waters. These c...

  6. RATES OF GASTROINTESTINAL ILLNESS AMONG AREAS IMPACTED BY COMBINED SEWER FACILITIES: ANALYSIS OF MASSACHUSETTS DATA, 2003-2007

    EPA Science Inventory

    Previous studies have reported a temporal association between heavy rainfall and gastrointestinal infection (GI). Combined sewer systems (CSSs), which are present in many urban areas in the US, were designed to collect rainwater runoff, domestic sewage, and industrial wastewater ...

  7. Association between Gastrointestinal Illness and Precipitation in Areas Impacted by Combined Sewer Facilities: Analysis of Massachusetts Data, 2003-2007

    EPA Science Inventory

    Background: Combined sewer systems (CSS) collect rainwater runoff, sewage, and industrial wastewater for transit to treatment facilities. With heavy precipitation, volumes can exceed capacity of treatment facilities, and wastewater discharges directly to receiving waters. These c...

  8. Assessment of the ecotoxicological risk of combined sewer overflows for an aquatic system using a coupled "substance and bioassay" approach.

    PubMed

    Gooré Bi, Eustache; Monette, Frederic; Gasperi, Johnny; Perrodin, Yves

    2015-03-01

    Very few tools are available for assessing the impact of combined sewer overflows (CSOs) on receiving aquatic environments. The main goal of the study was to assess the ecotoxicological risk of CSOs for a surface aquatic ecosystem using a coupled "substance and bioassay" approach. Wastewater samples from the city of Longueuil, Canada CSO were collected for various rainfall events during one summer season and analyzed for a large panel of substances (n = 116). Four bioassays were also conducted on representative organisms of surface aquatic systems (Pimephales promelas, Ceriodaphnia dubia, Daphnia magna, and Oncorhynchus mykiss). The analytical data did not reveal any ecotoxicological risk for St. Lawrence River organisms, mainly due to strong effluent dilution. However, the substance approach showed that, because of their contribution to the ecotoxicological hazard posed by the effluent, total phosphorus (Ptot), aluminum (Al), total residual chlorine, chromium (Cr), copper (Cu), pyrene, ammonia (N-NH4 (+)), lead (Pb), and zinc (Zn) require more targeted monitoring. While chronic ecotoxicity tests revealed a potential impact of CSO discharges on P. promelas and C. dubia, acute toxicity tests did not show any effect on D. magna or O. mykiss, thus underscoring the importance of chronic toxicity tests as part of efforts aimed at characterizing effluent toxicity. Ultimately, the study leads to the conclusion that the coupled "substance and bioassay" approach is a reliable and robust method for assessing the ecotoxicological risk associated with complex discharges such as CSOs.

  9. A vision-based tool for the control of hydraulic structures in sewer systems

    NASA Astrophysics Data System (ADS)

    Nguyen, L.; Sage, D.; Kayal, S.; Jeanbourquin, D.; Rossi, L.

    2009-04-01

    During rain events, the total amount of the wastewater/storm-water mixture cannot be treated in the wastewater treatment plant; the overflowed water goes directly into the environment (lakes, rivers, streams) via devices called combined sewers overflows (CSOs). This water is untreated and is recognized as an important source of pollution. In most cases, the quantity of overflowed water is unknown due to high hydraulic turbulences during rain events; this quantity is often significant. For this reason, the monitoring of the water flow and the water level is of crucial environmental importance. Robust monitoring of sewer systems is a challenging task to achieve. Indeed, the environment inside sewers systems is inherently harsh and hostile: constant humidity of 100%, fast and large water level changes, corrosive atmosphere, presence of gas, difficult access, solid debris inside the flow. A flow monitoring based on traditional probes placed inside the water (such as Doppler flow meter) is difficult to conduct because of the solid material transported by the flow. Probes placed outside the flow such as ultrasonic water level probes are often used; however the measurement is generally done on only one particular point. Experience has shown that the water level in CSOs during rain events is far from being constant due to hydraulic turbulences. Thus, such probes output uncertain information. Moreover, a check of the data reliability is impossible to achieve. The HydroPix system proposes a novel approach to the monitoring of sewers based on video images, without contact with the water flow. The goal of this system is to provide a monitoring tool for wastewater system managers (end-users). The hardware was chosen in order to suit the harsh conditions of sewers system: Cameras are 100% waterproof and corrosion-resistant; Infra-red LED illumination systems are used (waterproof, low power consumption); A waterproof case contains the registration and communication system. The

  10. Identification of controlling factors for the initiation of corrosion of fresh concrete sewers.

    PubMed

    Jiang, Guangming; Sun, Xiaoyan; Keller, Jurg; Bond, Philip L

    2015-09-01

    The development of concrete corrosion in new sewer pipes undergoes an initiation process before reaching an active corrosion stage. This initiation period is assumed to last several months to years but the key factors affecting the process, and its duration, are not well understood. This study is therefore focused on this initial stage of the corrosion process and the effect of key environmental factors. Such knowledge is important for the effective management of corrosion in new sewers, as every year of life extension of such systems has a very high financial benefit. This long-term (4.5 year) study has been conducted in purpose-built corrosion chambers that closely simulated the sewer environment, but with control of three key environmental factors being hydrogen sulfide (H2S) gas phase concentration, relative humidity and air temperature. Fresh concrete coupons, cut from an industry-standard sewer pipe, were exposed to the corrosive conditions in the chambers, both in the gas phase and partially submerged in wastewater. A total of 36 exposure conditions were investigated to determine the controlling factors by regular retrieval of concrete coupons for detailed analysis of surface pH, sulfur compounds (elemental sulfur and sulfate) and concrete mass loss. Corrosion initiation times were thus determined for different exposure conditions. It was found that the corrosion initiation time of both gas-phase and partially-submerged coupons was positively correlated with the gas phase H2S concentration, but only at levels of 10 ppm or below, indicating that sulfide oxidation rate rather than the H2S concentration was the limiting factor during the initiation stage. Relative humidity also played a role for the corrosion initiation of the gas-phase coupons. However, the partially-submerged coupons were not affected by humidity as these coupons were in direct contact with the sewage and hence did have sufficient moisture to enable the microbial processes to proceed. The

  11. Bayesian experimental design of tracer studies to monitor wastewater leakage from sewer networks

    NASA Astrophysics Data System (ADS)

    Rieckermann, J.; Borsuk, M. E.; Sydler, D.; Gujer, W.; Reichert, P.

    2010-08-01

    Despite more than a decade of research, the magnitude of wastewater leakage from defective sewer systems into groundwater supplies is still largely unknown, partly because reliable measurement methods are lacking. Although recently suggested in-sewer tracer studies present a promising solution, it is unclear how to optimally design such studies in network settings. In this study we present a formal experimental design procedure, which uses Bayesian data analysis to improve the diagnosis of sewer leakage by combining tracer test data with prior knowledge on network topology and condition. From a simulation study, we show that (1) if a single sewer section is expected to have high leakage, that section should be distinguished in measurement layouts through isolated tests or appropriate overlapping of multiple tests; (2) if multiple sections are expected to have high leakage, layouts with tests that cover more than one high-leakage section should be avoided; and (3) if a robust experimental design is desired, a balanced layout of tests that overlap multiple sections of high leakage, yet minimizes stretch length, should be chosen. This design will have the additional benefit of inducing covariance in the posterior distribution of exfiltration estimates, which can be used to advantage in subsequent studies. We apply these guidelines to a case study of a catchment in Zurich, Switzerland, and find that optimal layout design can improve the anticipated gain of information substantially relative to designs based on practical considerations alone. Remaining concerns regarding the procedure include (1) the generally poor understanding of the mechanisms governing sewer leakage, which can hamper reliable prior information on exfiltration; (2) the currently low measurement precision of sewer tracer studies, which might only allow for the detection of large leaks; and (3) the need for numerical implementation of the Bayesian inference procedure, which requires careful tuning and

  12. Capillary rise of superspreaders.

    PubMed

    Radulovic, Jovana; Sefiane, Khellil; Shanahan, Martin E R

    2011-09-15

    Trisiloxane surfactants, known as 'superspreaders', are commonly employed in numerous applications where enhanced wetting is of the utmost importance. The underlying mechanisms of superspreader wetting have been a focus of scientific interest for ca. 2 decades, and a number of mechanisms have been proposed to explain the unique trisiloxane dynamics. We have studied trisiloxane behaviour in thin capillaries to get further insight into their interfacial activity. Additionally, our knowledge of the capillary rise of superspreaders is surprisingly limited, and the effect of this extraordinary group of surfactants on capillary phenomena has been largely overlooked. Diffusion was confirmed to be the limiting factor of trisiloxane behaviour. A tentative theoretical explanation for the phenomenon studied and an appropriate mathematical model are presented. It is concluded that the enhancement of wetting due to surfactant addition is also a function of geometry: the effect is clear for a sessile drop, but more complex and less beneficial in a capillary.

  13. Ground potential rise monitor

    DOEpatents

    Allen, Zachery Warren; Zevenbergen, Gary Allen

    2012-07-17

    A device and method for detecting ground potential rise (GPR) comprising a first electrode, a second electrode, and a voltage attenuator. The first electrode and the second electrode are both electrically connected to the voltage attenuator. A means for determining the presence of a dangerous ground potential is connected to the voltage attenuator. The device and method further comprises a means for enabling one or more alarms upon the detection of the dangerous ground potential. Preferably, a first transmitter/receiver is connected to the means for enabling one or more alarms. Preferably, a second transmitter/receiver, comprising a button, is electromagnetically connected to the first transmitter/receiver. Preferably, the means for determining the presence of a dangerous ground potential comprises a means for determining the true RMS voltage at the output of the voltage attenuator, a transient detector connected to the output of the voltage attenuator, or a combination thereof.

  14. Ground potential rise monitor

    DOEpatents

    Allen, Zachery W [Mandan, ND; Zevenbergen, Gary A [Arvada, CO

    2012-04-03

    A device and method for detecting ground potential rise (GPR) comprising positioning a first electrode and a second electrode at a distance from each other into the earth. The voltage of the first electrode and second electrode is attenuated by an attenuation factor creating an attenuated voltage. The true RMS voltage of the attenuated voltage is determined creating an attenuated true RMS voltage. The attenuated true RMS voltage is then multiplied by the attenuation factor creating a calculated true RMS voltage. If the calculated true RMS voltage is greater than a first predetermined voltage threshold, a first alarm is enabled at a local location. If user input is received at a remote location acknowledging the first alarm, a first alarm acknowledgment signal is transmitted. The first alarm acknowledgment signal is then received at which time the first alarm is disabled.

  15. Anoxic transformations of wastewater organic matter in sewers--process kinetics, model concept and wastewater treatment potential.

    PubMed

    Abdul-Talib, S; Hvitved-Jacobsen, T; Vollertsen, J; Ujang, Z

    2002-01-01

    The sewer is an integral part of the urban wastewater system: the sewer, the wastewater treatment plant and the local receiving waters. The sewer is a reactor for microbial changes of the wastewater during transport, affecting the quality of the wastewater and thereby the successive treatment processes or receiving water impacts during combined sewer overflows. This paper presents the results of studies on anoxic processes, namely denitrification, in the bulk water phase of wastewater as it occurs in sewers. Experiments conducted on 12 different wastewater samples have shown that the denitrification process in the bulk wastewater can be simplified by the reduction of nitrate to nitrogen with significant accumulation of nitrite in the water phase. Utilization of nitrate was observed not to be limited by nitrate for concentrations above 5 gNO3-N/m3. The denitrification rates, under conditions of excess substrate and electron acceptor, were found to be in the range of 0.8-2.0 g NO3-N/(m3h). A discussion on the interaction of the sewer processes and the effects on a downstream located wastewater treatment plant (WWTP) is provided.

  16. Estimation of Biological Oxygen Demand and Chemical Oxygen Demand for Combined Sewer Systems Using Synchronous Fluorescence Spectra

    PubMed Central

    Hur, Jin; Lee, Bo-Mi; Lee, Tae-Hwan; Park, Dae-Hee

    2010-01-01

    Real-time monitoring of water quality for sewer system is required for efficient sewer network design because it provides information on the precise loading of pollutant to wastewater treatment facilities and the impact of loading on receiving water. In this study, synchronous fluorescence spectra and its first derivatives were investigated using a number of wastewater samples collected in sewer systems in urban and non-urban areas, and the optimum fluorescence feature was explored for the estimation of biochemical oxygen demand (BOD) and chemical oxygen demand (COD) concentrations of sewer samples. The temporal variations in BOD and COD showed a regular pattern for urban areas whereas they were relatively irregular for non-urban areas. Irrespective of the sewer pipes and the types of the areas, two distinct peaks were identified from the synchronous fluorescence spectra, which correspond to protein-like fluorescence (PLF) and humic-like fluorescence (HLF), respectively. HLF in sewer samples appears to be associated with fluorescent whitening agents. Five fluorescence characteristics were selected from the synchronous spectra and the first-derivatives. Among the selected fluorescence indices, a peak in the PLF region (i.e., Index I) showed the highest correlation coefficient with both BOD and COD. A multiple regression approach based on suspended solid (SS) and Index I used to compensate for the contribution of SS to BOD and COD revealed an improvement in the estimation capability, showing good correlation coefficients of 0.92 and 0.94 for BOD and COD, respectively. PMID:22319257

  17. Estimation of biological oxygen demand and chemical oxygen demand for combined sewer systems using synchronous fluorescence spectra.

    PubMed

    Hur, Jin; Lee, Bo-Mi; Lee, Tae-Hwan; Park, Dae-Hee

    2010-01-01

    Real-time monitoring of water quality for sewer system is required for efficient sewer network design because it provides information on the precise loading of pollutant to wastewater treatment facilities and the impact of loading on receiving water. In this study, synchronous fluorescence spectra and its first derivatives were investigated using a number of wastewater samples collected in sewer systems in urban and non-urban areas, and the optimum fluorescence feature was explored for the estimation of biochemical oxygen demand (BOD) and chemical oxygen demand (COD) concentrations of sewer samples. The temporal variations in BOD and COD showed a regular pattern for urban areas whereas they were relatively irregular for non-urban areas. Irrespective of the sewer pipes and the types of the areas, two distinct peaks were identified from the synchronous fluorescence spectra, which correspond to protein-like fluorescence (PLF) and humic-like fluorescence (HLF), respectively. HLF in sewer samples appears to be associated with fluorescent whitening agents. Five fluorescence characteristics were selected from the synchronous spectra and the first-derivatives. Among the selected fluorescence indices, a peak in the PLF region (i.e., Index I) showed the highest correlation coefficient with both BOD and COD. A multiple regression approach based on suspended solid (SS) and Index I used to compensate for the contribution of SS to BOD and COD revealed an improvement in the estimation capability, showing good correlation coefficients of 0.92 and 0.94 for BOD and COD, respectively.

  18. Septic systems, but not sanitary sewer lines, are associated with elevated estradiol in male frog metamorphs from suburban ponds.

    PubMed

    Lambert, Max R; Giller, Geoffrey S J; Skelly, David K; Bribiescas, Richard G

    2016-06-01

    Suburban neighborhoods are a dominant type of human land use. Many housing regions globally rely on septic systems, rather than sanitary sewers, for wastewater management. There is evidence that septic systems may contaminate waterbodies more than sewer lines. There is also mounting evidence that human activities contaminate waterways with endocrine-disrupting chemicals (EDCs), which alter wildlife sexual development. While endocrine disruption is often associated with intense activities such as agriculture or wastewater treatment plant discharges, recent evidence indicates that endocrine disruption is pervasive in frogs from suburban neighborhoods. In conjunction with other putative EDC sources, one hypothesis is that wastewater is contaminating suburban waterways with EDCs derived from pharmaceuticals or personal care products. Here, we measure estradiol (E2) in metamorphosing green frogs (Rana clamitans) from forested ponds and suburban ponds adjacent to either septic tanks or sanitary sewers. We show that E2 is highest in male frogs from septic neighborhoods and that E2 concentrations are significantly lower in male frogs from forested ponds and from ponds near sewers. These results indicate that septic tanks may be contaminating aquatic ecosystems differently than sewer lines. This pattern contrasts prior work showing no difference in EDC contamination or morphological endocrine disruption between septic and sewer neighborhoods, implying that suburbanization may have varying effects at multiple biological scales like physiology and anatomy. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Estimation of combined sewer overflow discharge: a software sensor approach based on local water level measurements.

    PubMed

    Ahm, Malte; Thorndahl, Søren; Nielsen, Jesper E; Rasmussen, Michael R

    2016-12-01

    Combined sewer overflow (CSO) structures are constructed to effectively discharge excess water during heavy rainfall, to protect the urban drainage system from hydraulic overload. Consequently, most CSO structures are not constructed according to basic hydraulic principles for ideal measurement weirs. It can, therefore, be a challenge to quantify the discharges from CSOs. Quantification of CSO discharges are important in relation to the increased environmental awareness of the receiving water bodies. Furthermore, CSO discharge quantification is essential for closing the rainfall-runoff mass-balance in combined sewer catchments. A closed mass-balance is an advantage for calibration of all urban drainage models based on mass-balance principles. This study presents three different software sensor concepts based on local water level sensors, which can be used to estimate CSO discharge volumes from hydraulic complex CSO structures. The three concepts were tested and verified under real practical conditions. All three concepts were accurate when compared to electromagnetic flow measurements.

  20. Case study of a fast propagating bacteriogenically induced concrete corrosion in an Austrian sewer system

    NASA Astrophysics Data System (ADS)

    Grengg, Cyrill; Mittermayr, Florian; Baldermann, Andre; Böttcher, Michael; Leis, Albrecht; Koraimann, Günther; Dietzel, Martin

    2015-04-01

    Reaction mechanisms leading to microbially induced concrete corrosion (MICC) are highly complex and often not fully understood. The aim of the present case study is to contribute to a deeper understanding of reaction paths, environmental controls, and corrosion rates related to MICC in a modern Austrian sewer system by introducing an advanced multi proxy approach that comprises gaseous, hydro-geochemical, bacteriological, and mineralogical analyses. Various crucial parameters for detecting alteration features were determined in the field and laboratory, including (i) temperature, pH, alkalinity, chemical compositions of the solutions, (ii) chemical and mineralogical composition of solids, (iii) bacterial analysis, and (iv) concentrations of gaseous H2S, CH4 and CO2 within the sewer pipe atmosphere. An overview of the field site and analytical results, focusing on reaction mechanisms causing the corrosion, as well as possible remediation strategies will be presented.

  1. PID and PLC units for the real-time control of sewer systems.

    PubMed

    Campisano, A; Modica, C

    2002-01-01

    Moveable gates for the real-time control (RTC) of sewer systems storage capacities are usually operated by controllers which, on the basis of local water level or flow velocity measurements, calculate the regulation errors of the monitored variables, determining the necessary regulator movements to lead the flow conditions to the desired set point. In this paper the results of an investigation on the influence of proportional-integral-derivative (PID) controllers and programmable logic controllers (PLC) for the RTC of moveable sluice gates positioned into sewer systems are presented. The analysis of response time, damping and regulation errors provided information on the PID parameter calibration values and on the PLC control function performances. A comparison between the two kind of controllers has also been carried out.

  2. Tharsis Rise Graben

    NASA Technical Reports Server (NTRS)

    2002-01-01

    (Released 22 May 2002) The Science This image is located in the northwestern portion of the Tharsis Rise at about 12 N and 125 W (235 E). What is immediately noticeable in this image is the series of linear features that are called graben. These features are associated with crustal extension which results in a series of up and down blocks of crust that run perpendicular to the direction of the extension. Images of Mars have shown a large number of these tectonic features concentrated on or near the Tharsis region. The Tharsis region is an enormous bulge that causes major tectonic disruptions across the planet when it tries to settle down from its height and reach equilibrium with the rest of the planet. The graben in this image display a number of preferential directions indicating that the crustal stresses that caused the graben have changed over time. By examining the cross-cutting relationships between the features, it is possible to reassemble the history of the area. The Story Now, if you thought that Mars was almost perfectly round, think again! The red planet has a large bulge sticking out from it called Tharsis. Almost 3,000 miles across, this enormous region rises almost four miles above the average radius of the planet. That's quite a bulge! Since Tharsis the land of the largest volcanoes in the solar system, it may have been formed by both the uplift of land from tectonic action and the build-up of lava flows. Tharsis can cause some pretty major tectonic disruptions across the planet when it tries to settle down from its height and reach a better equilibrium with the rest of the planet. In this image, located in the northwestern portion of the Tharsis Rise, a whole lot of lowered features stripe the landscape. They are called grabens, and formed when the crust of the planet was stretched tectonically. This kind of crustal extension (or stretching) tends to form a series of up-and-down blocks of crust that run perpendicular to the direction of the crustal

  3. Tharsis Rise Graben

    NASA Technical Reports Server (NTRS)

    2002-01-01

    (Released 22 May 2002) The Science This image is located in the northwestern portion of the Tharsis Rise at about 12 N and 125 W (235 E). What is immediately noticeable in this image is the series of linear features that are called graben. These features are associated with crustal extension which results in a series of up and down blocks of crust that run perpendicular to the direction of the extension. Images of Mars have shown a large number of these tectonic features concentrated on or near the Tharsis region. The Tharsis region is an enormous bulge that causes major tectonic disruptions across the planet when it tries to settle down from its height and reach equilibrium with the rest of the planet. The graben in this image display a number of preferential directions indicating that the crustal stresses that caused the graben have changed over time. By examining the cross-cutting relationships between the features, it is possible to reassemble the history of the area. The Story Now, if you thought that Mars was almost perfectly round, think again! The red planet has a large bulge sticking out from it called Tharsis. Almost 3,000 miles across, this enormous region rises almost four miles above the average radius of the planet. That's quite a bulge! Since Tharsis the land of the largest volcanoes in the solar system, it may have been formed by both the uplift of land from tectonic action and the build-up of lava flows. Tharsis can cause some pretty major tectonic disruptions across the planet when it tries to settle down from its height and reach a better equilibrium with the rest of the planet. In this image, located in the northwestern portion of the Tharsis Rise, a whole lot of lowered features stripe the landscape. They are called grabens, and formed when the crust of the planet was stretched tectonically. This kind of crustal extension (or stretching) tends to form a series of up-and-down blocks of crust that run perpendicular to the direction of the crustal

  4. Biodegradation of nonionic and anionic surfactants in domestic wastewater under simulated sewer conditions.

    PubMed

    Menzies, Jennifer Z; McDonough, Kathleen; McAvoy, Drew; Federle, Thomas W

    2017-02-01

    The ultimate disposition of chemicals discarded down the drain can be substantially impacted by their fate in the sewer, but to date limited data have been published on the biodegradability of chemicals in sewer systems. The recently established OECD 314 guideline (Simulation tests to assess the biodegradability of chemicals discharged in wastewater, 2008) contains a simulation method (314A) for evaluating the biodegradation of chemicals in sewage under simulated sewer conditions. This research used the OECD 314A method to evaluate the rates and pathways of primary and ultimate biodegradation of a suite of (14)C-labeled homologues representing four classes of high volume surfactants including nonionic alkyl ethoxylates (AE), and anionic alkyl ethoxysulfates (AES), alkyl sulfate (AS) and linear alkyl benzene sulfonate (LAS). All the tested homologues exhibited >97 % loss of parent, formation of metabolites, and some level (16-94 %) of CO2 production after being incubated 96-100 h in raw domestic wastewater. Comparison of C12E3, C14E3, and C16E3 showed that the first order biodegradation rate was affected by alkyl chain length with rates ranging from 6.8 h(-1) for C12E3 to 0.49 h(-1) for C16E3. Conversely, comparison of C14E1, C14E3, and C14E9 showed that the number of ethoxy units did not impact the biodegradation rate. AES and AS degraded quickly with first order kinetic rates of 1.9-3.7 and 41 h(-1) respectively. LAS did not exhibit first order decay kinetics and primary degradation was slow. Biodegradation pathways were also determined. This work shows that biodegradation in the sewer has a substantial impact on levels of surfactants and surfactant metabolites that ultimately reach wastewater treatment plants.

  5. Population ecology and movement of the American cockroach (Dictyoptera: Blattidae) in sewers.

    PubMed

    Tee, Hui-Siang; Saad, Ahmad Ramli; Lee, Chow-Yang

    2011-07-01

    The population size, age-class structure, and movement of the American cockroach, Periplaneta americana (L.) (Dictyoptera: Blattidae), were studied in three sewers in Penang, Malaysia, from September 2008 to October 2009. Eighteen to 20 glass-jar traps (two per manhole) were deployed for a 24-h period during each sampling occasion at each sewer. Adults and nymphs were active throughout the study period, with an average monthly trap catch of 57-97 adults and 79-99 nymphs. The mean proportions of adults and nymphs at the three sewers ranged from 0.47 to 0.57. Of the 2177 male and 2717 female cockroaches marked and released over the three sewers, recapture rates were 29.4-45.8 and 30.8-47.0%, respectively. The proportion of marked males and females did not differ significantly from the proportion of recaptured marked males and females. However, the mean number of times a marked female was recaptured was significantly greater than that of males. Of the 783 males and 1,030 females that were marked and recaptured, 19.4 and 24.7%, respectively, had moved between manholes, and significantly more females than males moved between manholes. Of the 406 recaptured marked adults that moved between manholes, 90.4% moved a distance of 2-20 m from their initial release site; one male moved 192 m, the longest distance recorded. Trap catch on each sampling occasion was positively correlated with daily mean temperature. The number of cockroach movements between manholes also was correlated with the mean daily minimum temperature.

  6. Tracking artificial sweeteners and pharmaceuticals introduced into urban groundwater by leaking sewer networks.

    PubMed

    Wolf, Leif; Zwiener, Christian; Zemann, Moritz

    2012-07-15

    There is little quantitative information on the temporal trends of pharmaceuticals and other emerging compounds, including artificial sweeteners, in urban groundwater and their suitability as tracers to inform urban water management. In this study, pharmaceuticals and artificial sweeteners were monitored over 6 years in a shallow urban groundwater body along with a range of conventional sewage tracers in a network of observation wells that were specifically constructed to assess sewer leakage. Out of the 71 substances screened, 24 were detected at above the analytical detection limit. The most frequent compounds were the iodinated X-ray contrast medium amidotrizoic acid (35.3%), the anticonvulsant carbamazepine (33.3%) and the artificial sweetener acesulfame (27.5%), while all other substances occurred in less than 10% of the screened wells. The results from the group of specifically constructed focus wells within 10 m of defective sewers confirmed sewer leaks as being a major entrance pathway into the groundwater. The spatial distribution of pharmaceuticals and artificial sweeteners corresponds well with predictions by pipeline leakage models, which operate on optical sewer condition monitoring data and hydraulic information. Correlations between the concentrations of carbamazepine, iodinated X-ray contrast media and artificial sweeteners were weak to non-existent. Peak concentrations of up to 4130 ng/l of amidotrizoic acid were found in the groundwater downstream of the local hospital. The analysis of 168 samples for amidotrizoic acid, taken at 5 different occasions, did not show significant temporal trends for the years 2002-2008, despite changed recommendations in the medical usage of amidotrizoic acid. The detailed results show that the current mass balance approaches for urban groundwater bodies must be adapted to reflect the spatially distributed leaks and the variable wastewater composition in addition to the lateral and horizontal groundwater fluxes.

  7. Proposed Decision Document for the Sanitary Sewer System, Interim Response Action at Rocky Mountain Arsenal.

    DTIC Science & Technology

    1989-01-01

    INTERIM RESPONSE ACTION. IS TO PREVENT THE POTENTIAL SPREAD OF CONTAMINATION VIA THE SANITARY SEWER SYSTEM. THE SOURCES OF STHIS POTENTIAL...Standards for Visible Pollutants ": a. No person will emit or cause to be emitted into the atmosphere from any diesel-powered vehicle any air contaminant , for...Distribution I Availability Codes Dist " Avail andIor SDist Special Prepared for: U.S. Army Program Manager’s Office for Rocky Mountain Arsenal Contamination

  8. Contamination Assessment Report Sanitary Sewer - Railyard and Administration Areas Version 3.2

    DTIC Science & Technology

    1988-08-01

    MANAGER’S OFFICE FOR ROCKY MOUNTAIN ARSENAL CONTAMINATION CLEANUP THE INFORMATION AND CONCLUSIONS PRESENTED IN THIS REPORT REFRESENT THE OFFICIAL POSITION...attributed to solvent contamination in the laboratory. Lead and arsenic were each detected once within their indicator ranges in the manhole borings and were...for additional contaminant sources in the vicinity of the sanitary sewer in this area, the presence of these chemicals in the wells downgradient from

  9. Succession of Sulfur-Oxidizing Bacteria in the Microbial Community on Corroding Concrete in Sewer Systems† ▿

    PubMed Central

    Okabe, Satoshi; Odagiri, Mitsunori; Ito, Tsukasa; Satoh, Hisashi

    2007-01-01

    Microbially induced concrete corrosion (MICC) in sewer systems has been a serious problem for a long time. A better understanding of the succession of microbial community members responsible for the production of sulfuric acid is essential for the efficient control of MICC. In this study, the succession of sulfur-oxidizing bacteria (SOB) in the bacterial community on corroding concrete in a sewer system in situ was investigated over 1 year by culture-independent 16S rRNA gene-based molecular techniques. Results revealed that at least six phylotypes of SOB species were involved in the MICC process, and the predominant SOB species shifted in the following order: Thiothrix sp., Thiobacillus plumbophilus, Thiomonas intermedia, Halothiobacillus neapolitanus, Acidiphilium acidophilum, and Acidithiobacillus thiooxidans. A. thiooxidans, a hyperacidophilic SOB, was the most dominant (accounting for 70% of EUB338-mixed probe-hybridized cells) in the heavily corroded concrete after 1 year. This succession of SOB species could be dependent on the pH of the concrete surface as well as on trophic properties (e.g., autotrophic or mixotrophic) and on the ability of the SOB to utilize different sulfur compounds (e.g., H2S, S0, and S2O32−). In addition, diverse heterotrophic bacterial species (e.g., halo-tolerant, neutrophilic, and acidophilic bacteria) were associated with these SOB. The microbial succession of these microorganisms was involved in the colonization of the concrete and the production of sulfuric acid. Furthermore, the vertical distribution of microbial community members revealed that A. thiooxidans was the most dominant throughout the heavily corroded concrete (gypsum) layer and that A. thiooxidans was most abundant at the highest surface (1.5-mm) layer and decreased logarithmically with depth because of oxygen and H2S transport limitations. This suggested that the production of sulfuric acid by A. thiooxidans occurred mainly on the concrete surface and the

  10. Sedimentology, stratigraphy and chronology of a decantation tank in the sewer network of Orléans (France).

    NASA Astrophysics Data System (ADS)

    Jacob, Jérémy; Thibault, Alexandre; Simonneau, Anaëlle; Le Milbeau, Claude; DiGiovanni, Christian; Sabatier, Pierre; Reyss, Jean-Louis; Ardito, Luigi; Morio, Cédric

    2017-04-01

    Current debates on the status of the Anthropocene convey geologists and palaeoenvironmentalists toward new spatial and temporal targets. One of the most emblematic socio-ecosystem of the Anthropocene is urban areas in which the dynamics of materials are mainly controlled by human activities. This brings unprecedented elemental, molecular and isotopic concentrations and distributions that lead Norra (2009) to propose a new geological sphere: the Astysphere. Here we propose that sediments accumulated in sewer networks can provide original, integrated, and multi-thematic archives for the recent history of cities by considering urban systems as any catchment where materials are produced, transported and sedimented. The study site is a decantation tank that collects stormwater and wastewater from the north of Orléans city, upstream wastewater plants in Orléans. Sediments accumulated since 1942 over 17 m depth and were never cleaned out until 2015. Two sedimentary cores of 70 (A) and 250 cm long (B) were collected before clean out and then a third of 150 cm (C) after. Sediments are organized into layers constituted by sands and gravels alternating with silts and organic layers. Sharp contacts between those layers indicate evenemential sedimentation, as expected in sewer networks. We formulate the hypothesis that organic/mineral alternations result from a seasonal dynamic. 7Be presence in topmost sample from core A confirms it was deposited within the last 6 months. In core C, only the upper half core, mostly mineral, displays significant 7Be levels whereas 7Be is absent from the lower half, which is mostly organic. This would confirm that our hypothesis of a seasonal alternation, with organic facies deposited during spring- summer and mineral facies deposited during fall-winter. 30 14C dates measured on cores A and B by postbomb method are logically distributed with depth, the most ancient (beginning of the eighties) being recorder at 2.5m depth. This study shows that

  11. A database and model to support proactive management of sediment-related sewer blockages.

    PubMed

    Rodríguez, Juan Pablo; McIntyre, Neil; Díaz-Granados, Mario; Maksimović, Cedo

    2012-10-01

    Due to increasing customer and political pressures, and more stringent environmental regulations, sediment and other blockage issues are now a high priority when assessing sewer system operational performance. Blockages caused by sediment deposits reduce sewer system reliability and demand remedial action at considerable operational cost. Consequently, procedures are required for identifying which parts of the sewer system are in most need of proactive removal of sediments. This paper presents an exceptionally long (7.5 years) and spatially detailed (9658 grid squares--0.03 km² each--covering a population of nearly 7.5 million) data set obtained from a customer complaints database in Bogotá (Colombia). The sediment-related blockage data are modelled using homogeneous and non-homogeneous Poisson process models. In most of the analysed areas the inter-arrival time between blockages can be represented by the homogeneous process, but there are a considerable number of areas (up to 34%) for which there is strong evidence of non-stationarity. In most of these cases, the mean blockage rate increases over time, signifying a continual deterioration of the system despite repairs, this being particularly marked for pipe and gully pot related blockages. The physical properties of the system (mean pipe slope, diameter and pipe length) have a clear but weak influence on observed blockage rates. The Bogotá case study illustrates the potential value of customer complaints databases and formal analysis frameworks for proactive sewerage maintenance scheduling in large cities.

  12. Evaluation of exposure pathways to man from disposal of radioactive materials into sanitary sewer systems

    SciTech Connect

    Kennedy, W.E. Jr.; Parkhurst, M.A.; Aaberg, R.L.; Rhoads, K.C.; Hill, R.L.; Martin, J.B.

    1992-05-01

    In accordance with 10 CFR 20, the US Nuclear Regulatory Commission (NRC) regulates licensees` discharges of small quantities of radioactive materials into sanitary sewer systems. This generic study was initiated to examine the potential radiological hazard to the public resulting from exposure to radionuclides in sewage sludge during its treatment and disposal. Eleven scenarios were developed to characterize potential exposures to radioactive materials during sewer system operations and sewage sludge treatment and disposal activities and during the extended time frame following sewage sludge disposal. Two sets of deterministic dose calculations were performed; one to evaluate potential doses based on the radionuclides and quantities associated with documented case histories of sewer system contamination and a second, somewhat more conservative set, based on theoretical discharges at the maximum allowable levels for a more comprehensive list of 63 radionuclides. The results of the stochastic uncertainty and sensitivity analysis were also used to develop a collective dose estimate. The collective doses for the various radionuclides and scenarios range from 0.4 person-rem for {sup 137}Cs in Scenario No. 5 (sludge incinerator effluent) to 420 person-rem for {sup 137}Cs in Scenario No. 3 (sewage treatment plant liquid effluent). None of the 22 scenario/radionuclide combinations considered have collective doses greater than 1000 person-rem/yr. However, the total collective dose from these 22 combinations was found to be about 2100 person-rem.

  13. Analysis of the microbial communities on corroded concrete sewer pipes--a case study.

    PubMed

    Vincke, E; Boon, N; Verstraete, W

    2001-12-01

    Conventional as well as molecular techniques have been used to determine the microbial communities present on the concrete walls of sewer pipes. The genetic fingerprint of the microbiota on corroded concrete sewer pipes was obtained by means of denaturing gradient gel electrophoresis (DGGE) of 16S rRNA gene fragments. The DGGE profiles of the bacterial communities present on the concrete surface changed as observed by shifts occurring at the level of the dominance of bands from non-corroded places to the most severely corroded places. By means of statistical tools, it was possible to distinguish two different groups, corresponding to the microbial communities on corroded and non-corroded surfaces, respectively. Characterization of the microbial communities indicated that the sequences of typical bands showed the highest level of identity to sequences from the bacterial strains Thiobacillus thiooxidans, Acidithiobacillus sp., Mycobacterium sp. and different heterotrophs belonging to the alpha-, beta- and gamma-Proteobacteria, Acidobacteria and Actinobacteria. In addition, the presence of N-acyl-homoserine lactone signal molecules was shown by two bio-assays of the biofilm on the concrete under the water level and at the most severely corroded places on the concrete surface of the sewer pipe.

  14. Predictive optimal control of sewer networks using CORAL tool: application to Riera Blanca catchment in Barcelona.

    PubMed

    Puig, V; Cembrano, G; Romera, J; Quevedo, J; Aznar, B; Ramón, G; Cabot, J

    2009-01-01

    This paper deals with the global control of the Riera Blanca catchment in the Barcelona sewer network using a predictive optimal control approach. This catchment has been modelled using a conceptual modelling approach based on decomposing the catchments in subcatchments and representing them as virtual tanks. This conceptual modelling approach allows real-time model calibration and control of the sewer network. The global control problem of the Riera Blanca catchment is solved using a optimal/predictive control algorithm. To implement the predictive optimal control of the Riera Blanca catchment, a software tool named CORAL is used. The on-line control is simulated by interfacing CORAL with a high fidelity simulator of sewer networks (MOUSE). CORAL interchanges readings from the limnimeters and gate commands with MOUSE as if it was connected with the real SCADA system. Finally, the global control results obtained using the predictive optimal control are presented and compared against the results obtained using current local control system. The results obtained using the global control are very satisfactory compared to those obtained using the local control.

  15. Update summary of the 1991 discharge of enriched uranium to the sanitary sewer (DEUSS) report

    SciTech Connect

    1995-04-01

    Since the 1991 Y-12 Plant report, a flow study of the Y-12 Plant sanitary sewer collection system has been completed by the Y-12 Plant staff (Hanzelka and Maguire, 1993). Additional data has been obtained by the Y-12 Plant and the City of Oak Ridge (COR, 1994). COR developed limits on radionuclide concentrations in sludges used for land application (Stetar, 1993). Martin Marietta Energy Systems has provided recommendations to the Department of Energy (DOE) regarding the impacts of sludge land farming operations on the ORR (Frye, 1992). The DOE Office of Nuclear Safety (USDOE, 1993) completed an audit of activities related to radiological contamination of the COR sewer system due to DOE operations. In addition COR is currently developing limits on radionuclide releases for all industrial customers to be applied through the permitting process. In 1994, a new sanitary sewer monitoring station was installed and began operation at the Y-12 Plant to determine releases specifically from the Y-12 Plant. Previously, estimates were based on mass balance calculations using data from the City Monitoring Station which monitors Union Valley and Y-12 Plant releases. The purpose of this report is to update the 1991 Y-12 Plant study taking into account current data and information.

  16. Is H2S a suitable process indicator for odour abatement performance of sewer odours?

    PubMed

    Wang, B; Sivret, E C; Parcsi, G; Wang, X; Le, N M; Kenny, S; Bustamante, H; Stuetz, R M

    2014-01-01

    Odour abatement units are typically designed and maintained on H(2)S concentrations, but operational failures are reported in terms of overall odour removal, suggesting a wide range of malodorous compounds emitted from sewers that may not be efficiently removed by existing odour abatement processes. Towards providing greater insight into this issue, several activated carbon filters and biofilters treating odorous emissions from sewer systems in Sydney (Australia) were monitored by collecting and analysing gas samples before and after treatment. The monitoring studies were conducted by both olfactometric measurements and gas-chromatography-based chemical analysis. Single H(2)S assessment often failed to indicate the odour abatement performance for treatment systems in the abatement units studied, particularly when the incoming H(2)S concentrations were in the sub-ppm range (i.e. below H(2)S odour threshold). Chemical analysis indicated that some non-H(2)S odorous compounds were not removed efficiently during odour treatment. Additionally, when odour eliminations were correlated with the removal of individual compounds (Pearson's correlations) it was observed that the correlation (with a coefficient of 0.79) was best when the overall removal of all the measured odorous compounds that exceeded their odour threshold values was used for the analysis. These findings may help to further advance the design and operation of odour abatement processes to address the treatment of sewer odour emissions.

  17. A different approach for predicting reaeration rates in gravity sewers and completely mixed tanks.

    PubMed

    Lahav, Ori; Binder, Assaf; Friedler, Eran

    2006-07-01

    A new semiempirical approach is presented for predicting air-to-water oxygen transfer rates in mixed tanks and gravity sewers, using methods adopted from mixing theory. First, a flocculation unit was used to impart selected mean velocity gradients (G) into a completely mixed tank, from which oxygen was first removed, and dissolved oxygen concentrations were measured with time. Regression analysis was used to fit the rate of oxygen transfer equation against G. The reaeration rate in completely mixed reactors was found to be proportional to G2 (R2 = 0.987). Subsequently, G was linked to headloss in sewers, and the equation was calibrated using a slope-adjustable, 27-m-long, gravity-flow, experimental sewer (internal diameter, D = 0.16 m). Here, the reaeration rate was proportional to G1 (R2 = 0.981). The equation was compared with existing oxygen transfer models and validated against experimental data from the literature, to which the overall mass transfer coefficient for oxygen, K(L)a, derived by the new approach, conformed well.

  18. The rise of graphene

    NASA Astrophysics Data System (ADS)

    Geim, A. K.; Novoselov, K. S.

    2007-03-01

    Graphene is a rapidly rising star on the horizon of materials science and condensed-matter physics. This strictly two-dimensional material exhibits exceptionally high crystal and electronic quality, and, despite its short history, has already revealed a cornucopia of new physics and potential applications, which are briefly discussed here. Whereas one can be certain of the realness of applications only when commercial products appear, graphene no longer requires any further proof of its importance in terms of fundamental physics. Owing to its unusual electronic spectrum, graphene has led to the emergence of a new paradigm of 'relativistic' condensed-matter physics, where quantum relativistic phenomena, some of which are unobservable in high-energy physics, can now be mimicked and tested in table-top experiments. More generally, graphene represents a conceptually new class of materials that are only one atom thick, and, on this basis, offers new inroads into low-dimensional physics that has never ceased to surprise and continues to provide a fertile ground for applications.

  19. Cost-effective solutions for water quality improvement in the Dommel River supported by sewer-WWTP-river integrated modelling.

    PubMed

    Benedetti, Lorenzo; Langeveld, Jeroen; van Nieuwenhuijzen, Arjen F; de Jonge, Jarno; de Klein, Jeroen; Flameling, Tony; Nopens, Ingmar; van Zanten, Oscar; Weijers, Stefan

    2013-01-01

    This project aims at finding cost-efficient sets of measures to meet the Water Framework Directive (WFD) derived goals for the Dommel River (The Netherlands). Within the project, both acute and long-term impacts of the urban wastewater system on the chemical and ecological quality of the river are studied with a monitoring campaign in the urban wastewater system (wastewater treatment plant and sewers) and in the receiving surface water system. An integrated model, which proved to be a powerful tool to analyse the interactions within the integrated urban wastewater system, was first used to evaluate measures in the urban wastewater system using the existing infrastructure and new real-time control strategies. As the latter resulted to be beneficial but not sufficient, this paper investigated the use of additional infrastructural measures to improve the system cost-effectively and have it meet the Directive's goals. Finally, an uncertainty analysis was conducted to investigate the impact of uncertainty in the main model assumptions and model parameters on the performance robustness of the selected set of measures. Apart from some extreme worst-case scenarios, the proposed set of measures turned out to be sufficiently robust. Due to the substantial savings obtained with the results of this project, the pay-back time of the whole monitoring and modelling work proved to be less than 5 months. This illustrates the power of mathematical modelling for decision support in the context of complex urban water systems.

  20. Influence of sampling intake position on suspended solid measurements in sewers: two probability/time-series-based approaches.

    PubMed

    Sandoval, Santiago; Bertrand-Krajewski, Jean-Luc

    2016-06-01

    Total suspended solid (TSS) measurements in urban drainage systems are required for several reasons. Aiming to assess uncertainties in the mean TSS concentration due to the influence of sampling intake vertical position and vertical concentration gradients in a sewer pipe, two methods are proposed: a simplified method based on a theoretical vertical concentration profile (SM) and a time series grouping method (TSM). SM is based on flow rate and water depth time series. TSM requires additional TSS time series as input data. All time series are from the Chassieu urban catchment in Lyon, France (time series from 2007 with 2-min time step, 89 rainfall events). The probability of measuring a TSS value lower than the mean TSS along the vertical cross section (TSS underestimation) is about 0.88 with SM and about 0.64 with TSM. TSM shows more realistic TSS underestimation values (about 39 %) than SM (about 269 %). Interquartile ranges (IQR) over the probability values indicate that SM is more uncertain (IQR = 0.08) than TSM (IQR = 0.02). Differences between the two methods are mainly due to simplifications in SM (absence of TSS measurements). SM assumes a significant asymmetry of the TSS concentration profile along the vertical axis in the cross section. This is compatible with the distribution of TSS measurements found in the TSM approach. The methods provide insights towards an indicator of the measurement performance and representativeness for a TSS sampling protocol.