sewer evaluation Articles

  • Evaluating the role of deterioration models for condition assessment of sewers

    Ensuring reliable structural condition of sewers is an important criterion for sewer rehabilitation decisions. Deterioration models applied to sewer pipes support the rehabilitation planning by means of prioritising pipes according to their current and predicted structural status. There is a benefit in applying such models if sufficient inspection data for calibration, an appropriate ...


    By IWA Publishing

  • Evaluation of effectiveness of combined sewer overflow control measures by operational data

    The effect of combined sewer overflow (CSO) control measures should be validated during operation based on monitoring of CSO activity and subsequent comparison with (legal) requirements. However, most CSO monitoring programs have been started only recently and therefore no long-term data is available for reliable efficiency control. A method is proposed that focuses on rainfall data for ...


    By IWA Publishing

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

    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. ...


    By IWA Publishing

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

    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. ...


    By IWA Publishing

  • The evaluation of rainfall influence on combined sewer overflows characteristics: the Berlin case study

    The present study aims to explore the relationship between rainfall variables and water quality/quantity characteristics of combined sewer overflows (CSOs), by the use of multivariate statistical methods and online measurements at a principal CSO outlet in Berlin (Germany). Canonical correlation results showed that the maximum and average rainfall intensities are the most influential variables ...


    By IWA Publishing

  • Evaluating the success of sewer reconstruction by using carbamazepine as anthropogenic marker in groundwater

    The antiepileptic drug carbamazepine is a useful anthropogenic marker in groundwater to detect and quantify sewer exfiltration. In 2003 its application on a city wide scale enabled the identification of a trunk sewer in extremely bad structural status with an exfiltration (of wastewater into groundwater) rate in the adjacent area of around 5% compared to an average of approximately 1% in other ...


    By IWA Publishing

  • Model evaluation of faecal contamination in coastal areas affected by urban rivers receiving combined sewer overflows

    Odaiba seaside park is one of the most popular waterfronts in Tokyo Bay, but is easily affected by wet weather pollutant loads through combined sewer overflows (CSOs). The monitoring data of Escherichia coli clearly showed high faecal contamination after a rainfall event on 9–11 November 2007. We estimated the amounts of discharge volume and E. coli pollutant loads of ...


    By IWA Publishing

  • Estimating inflow to a combined sewer overflow structure with storage tank in real time: evaluation of different approaches

    The performance assessment of storage tanks and combined sewer overflow (CSO) structures in sewer systems requires knowledge of the total inflow from the catchment during rainfall events. Many structures are, however, only equipped with sensors to measure water level and/or outflows. Based on the geometry of the tank, expressed as a level-storage relationship, inflow can be calculated from these ...


    By IWA Publishing

  • Priority substances in combined sewer overflows: case study of the Paris sewer network

    This study was undertaken to supply data on both priority pollutant (PP) occurrence and concentrations in combined sewer overflows (CSOs). A single rain event was studied on 13 sites within the Paris sewer network. For each sample, a total of 66 substances, including metals, polycyclic aromatic hydrocarbons (PAHs), pesticides, organotins, volatile organic compounds, chlorobenzenes, phthalates and ...


    By IWA Publishing

  • Quantification of sewer leakage by a continuous tracer method

    Water authorities interested in the evaluation of the structural state of a sewer must quantify leakage to plan strategic intervention. However, the quantification of the exfiltration and the localisation of structural damage are challenging tasks that usually require expensive and time-consuming inspections. Herein, we report one of the first applications of the QUEST-C method to quantify the ...


    By IWA Publishing

  • Modelling the viability of heat recovery from combined sewers

    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 ...


    By IWA Publishing

  • Delivering an Enhanced Sewer Condition Prioritization Process

    SCREAM™ is a sewer and manhole condition assessment tool developed by CH2MHill. It has been built into Wallingford Software’s InfoNet asset management solution as one of the standard choices for sewer and manhole condition grading. There is emphasis across the collections systems industry worldwide for sewer condition prioritization methods and manhole condition ranking. Although currently the UK ...


    By Innovyze

  • Simplifying impact of urban development on sewer systems

    Linking urban development and urban drainage models is a more and more popular approach when impacts of pavement of urban areas on sewer system performance are evaluated. As such an approach is a difficult task, this is not a feasible procedure for everyday engineering practice. We propose an alternative method, based on a developed simple near-quadratic relationship, which directly translates ...


    By IWA Publishing

  • A sewer ventilation model applying conservation of momentum

    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 ...


    By IWA Publishing

  • Modelling sewer sediment deposition, erosion, and transport processes to predict acute influent and reduce combined sewer overflows and CO2 emissions

    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 ...


    By IWA Publishing

  • Nitrification toxicity evaluation using bench-scale testing

    The Camas Wastewater Treatment Facility experienced a prolonged period of poor ammonia removal (nitrification). A variety of “real-world” bench tests were developed and performed to determine if toxins were inhibiting the nitrification process. The focus of this paper is on the methodology used and conclusions drawn from the bench-testing. INTRODUCTIONTest were performed that compared ...

  • Alum creek large diameter sewer assessment case study

    The Challenge The City of Columbus, like many municipalities, must make hard decisions on where to spend their limited capital improvement dollars. In tight economic conditions, a municipality’s decision to monitor, rehabilitate, or replace their assets is not cut and dry. Deferred maintenance of non-critical assets in one department may give other departments the monetary resources ...


    By Chester Engineers

  • Flow measurements in sewers based on image analysis: automatic flow velocity algorithm

    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 ...


    By IWA Publishing

  • Pipeline infrastructure renewal at Miami-Dade Water & Sewer Department

    Abstract Various governmental, professional and private studies have shown that the replacement costs of underground pipeline infrastructure is excessive and that best practice approaches for infrastructure risk management promote condition assessment programs to understand the actual condition of individual pipe sections in order to best allocate limited capital replacement and ...


    By Pure Technologies

  • Constructed wetlands for combined sewer overflow treatment in a Mediterranean country, Portugal

    The use of constructed wetlands as a valuable and attractive method for combined sewer overflow (CSO) treatment has been demonstrated in several studies. In Portugal, a Mediterranean country having usually a long dry period, there are still no applications of this technology. The purpose of this research is to gather information and know-how required for the design and management of this type of ...


    By IWA Publishing

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