Sewer Pipelines Research Articles

Imaging and condition diagnosis of underground sewer liners via active and passive infrared thermography: A case study in Singapore

This paper presents a case study of customizing an in-house built In-pipe Infrared Thermographic System (IPITS), which makes use of thermo-images for imaging and diagnosis of pipe crown condition in underground sewer pipelines. Active and passive infrared thermography (IRT) were attempted in two gravity sewer pipes in Singapore in July 2017. The results show that images captured with active IRT (with heating) can image and reveal invisible lining defects not readily revealed by traditional visual inspection using CCTV. These defects include bubbles, wrinkling and delamination, or construction details (like anchor knobs in HDPE material), for which sizes were estimated using an image processing algorithm customized in an in-house program. While images captured by passive IRT (without heating) can be used to identify suspected water seeping points, this paper also reports the design of instrumentation and appropriate parameter settings. The results of this case study are believed to pave the way for parallel inspections using a combination of CCTV and infrared cameras.

Multi-Objective Optimization Model for Inspection Scheduling of Sewer Pipelines

AbstractInspection activities play an important role in the operation and maintenance (O&M) strategy in municipalities. Efficient O&M strategies can help in making informed decisions based on the a...

3D pipe reconstruction employing video information from mobile robots

The development of a virtual scenario is desirable in many hostile environments such as in mining or sewer pipelines to inspect its current condition and to identify possible failures. Obtaining a virtual image through the reconstruction of the mineshaft or the inner pipe is a valuable tool for assessment and fault detection. The approach presented in this paper uses a fuzzy controlled robot so that the video information can reliably be taken. The robot fuzzy control guarantees its motion in a straight line while taking the images from the pipe. The control algorithm therefore prevents the robot from overturning while moving inside the pipe. Results from our 3D reconstruction approach using the autonomous mobile robot is presented. The proposed method overcomes the limitations of different detectors by using a novel combination of DoG and Harris Laplace. Once the frame selection is made, then the regions with affine transformations are used to find image features as correspondences using image descriptors such as SIFT (Scale-Invariant Feature Transform). The correspondences are required to obtain the orientation and position of the camera and to obtain the scene structure leading to the creation of the 3D virtual environment. The 3D reconstruction method outperformed similar commercial software which highlights its potential.

Estimating life cycle emissions in managing practical sewer pipeline projects

The objectives of this paper are 1) to estimate emissions in managing a sewer pipeline project from a life cycle perspective; and 2) to develop methods that can be used to assist engineers and stakeholders in the estimation especially when data are limited. The motivation is to provide an approach that can be used readily in practice to evaluate emissions in managing a sewer pipeline or a general infrastructure system by using available data. The life cycle assessment tool is applied over the pipe material manufacturing, installation, and maintenance phases. In the material manufacturing and installation phase, this research routinely tends to collect and evaluate detailed inventories data. The results show that the manufacturing phase contributes the most emissions. Material transportation in the installation also generates great amounts which are highly impacted by the transportation distance of vehicles. Emissions from activities such as equipment use and architecture and engineering services are not negligible which need to be considered in practice. In the maintenance phase, the study develops methods to estimate emissions based on the Markov chains model. The developed methods make it possible to estimate emissions within a given duration conventionally and at a ‘steady state’ phase once a strategy is applied. The study also presents a method to conduct the model sensitivity analysis using simulating results from Matlab tools. The analysis shows that the model has decent robustness. In addition, the methodology proposed may be applied to estimate emissions in other infrastructure management as well.

Test on Noxious Gases in Urban Sewage Pipe Based on Odor Classification

Urban sewage pipes are filled with flammable, explosive, toxic and other noxious gases, which have brought hidden troubles during system maintenance and operation. To ease these threats to the urban sewage pipeline network, we should perform spot inspection and take some measures against safety risks that may occur on them. But of those, the test of noxious gases is the most challenging. Based on the odor classification method, we take an urban sewage pipe network in Chongqing as a study case for sample collection and spot inspection. The purpose of this paper is to classify and test the methane CH4 and hydrogen sulfide H2S by different methods. Data available from individual supervision spots are compared and analyzed in parallel, in order to explore how to measure these noxious gases and what’s the distribution and concentration change laws of them in urban sewage pipes, hoping to provide the clues to the early warning and safety operation of urban sewage pipeline network.

Development and study of hydromechanical method for cleaning sewage collectors from contamination

In connection with bad state of existing sewer headers, there is a great need for quick and high-quality cleaning for their further operation. To extend service life of distribution systems, new technologies for their repair and recovery are being developed which makes it possible to ensure their stable functioning and as a result, provision of continuous drinking water supply and sewer disposal to improve quality of life for population. From an economic point of view, extension of service life of distribution systems through development of alternative repair technologies is promising as it will ensure their sustainable operation in conditions of limited financing.The proposed bucket design for cleaning the sewer headers has made it possible to identify the best option when using one design in different conditions.A new design of the bucket was proposed which enables cleaning of the sewage headers either separately in a purely mechanical way or with additional use of the hydraulic method. Thanks to such combined method, it is possible to eliminate dirt which cannot be qualitatively done separately with each of the existing methods in various technical and economic conditions.Purposefulness of application of the proposed method for cleaning sewage headers using the bucket of new design providing a combined method of operation was presented and justified. Examples of application of the new method for cleaning the headers using the bucket of new design were given. The obtained indicators confirm quality of the sewage header cleaning when working in various conditions, both technical (diameter, length and type of the header material, degree, and nature of foulness) and economic (work duration, energy, and water costs).Thanks to the use of this method, 75...85 % dirt elimination in the sewage headers and pipelines have been achieved which confirms its effectiveness and possibility of reducing work duration as well as resource and energy saving in carrying out these works

Use of 3D Simulation to Design Theoretical and Real Pipe Inspection Mobile Robot Model

Abstract The main aim of the paper is to present the process of design pipe inspection mobile robot by using 3D simulations. Next methods and processes of making designed components was described. Finally, functional tests of a constructed real robot model such as speed tests, inclined pipe test was carried out. The robot was specifically designed to inspect sewer pipelines. The mobile robot is equipped with a vision system. The structure of the pipe inspection robot allows adjustments to the geometrical parameters of the robot to suit the sewer pipes diameters by using in the construction of a pneumatic system with an actuator.

Towards 3D Pipe Reconstruction Employing Affine Transformations from Video Information

The development of a virtual scenario is desirable in a number of hostile environments such as in mining, or sewer pipelines to inspect its current condition and to identify possible failures. Obtaining a virtual image through the reconstruction of the mineshaft or inner pipe is a valuable tool for assessment and fault detection. In this paper, we present results for our 3D reconstruction approach, which proposes to employ regions with affine transformations that are used as dense correspondences. These features are calculated through local correspondences, such as the SIFT (Scale-invariant feature transform) and SURF (Speeded Up Robust Features). The correspondences are required to obtain the orientation and position of the camera and to get the structure of the scene leading to the creation of the 3D environment. The algorithm is presented as well as its results, which highlights the potential of the method.

Defect- and component-based assessment model for manholes

Although manholes are significant assets in sewer networks, their assessment is receiving little attention compared to sewer pipelines. It was reported that more than three-million manholes in the United States (US) were structurally weak and prone to collapse. To avoid sudden failure, systematic manhole condition assessment model is required. Therefore, the primary objective of this study was to develop a component-based condition assessment model for sewer access holes. The methodology was based on integrating the Quality Function Deployment (QFD), Decision-Making Trial Evaluation Laboratory (DEMATEL) techniques to study the causality relationship between the defects in the nine identified components of the manhole. The relative importance weights of the components were found by deploying the Analytic Network Process (ANP) and were used to compute the overall condition of the asset. Based on the results, the roots were the highest influence power in many of the components. In addition, the wall, cone, cover and frame, and seals components were higher importance weights compared to the remaining components. This model was tested on an actual case study from the city of Edmonton in Canada and compared with actual values. The model produced an average validity percentage (AVP) of 76.24%. The developed model is expected to enhance the assessment of manholes and therefore provide robust conclusions. Besides, the model offers a backward analysis to pinpoint critical components in the manhole. Consequently, better decisions are made pertinent to maintenance, rehabilitation, and replacement interventions.

Influence of Soil Deformation Caused by Mining on Sewage Pipelines Built Using The Pipe Jacking Method

Abstract This paper discusses the issues associated with the influence of underground mining operations on sewage pipelines built using the pipe jacking method. At present, to build sewage pipelines, especially in urban areas and deep embedment, trenchless technologies are employed. Mainly in these technologies, pipes are jacked into a bored tunnel using hydraulic jacks. These methods are also applied in mining areas. The aim of this paper is to analyse the influence of ground deformation, caused by mining operations, on sewage pipelines built using the pipe jacking method. The type of pipelines discussed here is built with butted sections, which cannot compensate the influences of mining operations in pipe joints if horizontal compression occurs in the near-surface layer of soil. Pipelines embedded in trenches in the mining areas are secured against the influence of mining operations with expansion joints, which compensate for ground deformation. Hence, in the analysis of the influence of soil deformation caused by mining on sewage pipelines built using jacking method, special attention was paid to the performance of pipe joints. Pipelines of the type are subjected to additional loads and displacements, caused by soil deformations like horizontal strains, horizontal soil displacements and surface curvatures. We propose a way to consider the influence of mining operations on sewage pipelines built using the pipe jacking method.

The Mechanical Properties of High Strength Reinforced Cured-in-Place Pipe (CIPP) Liner Composites for Urban Water Infrastructure Rehabilitation

Most urban areas in the world have water infrastructure systems, including the buried sewer and water pipelines, which are assessed as in need of extensive rehabilitation. Deterioration by many other factors affects structural integrity. Trenchless technologies such as Cured-in-Place Pipe (CIPP) are now applied in numerous projects while minimizing disturbance in an urban environment. The main purpose of this study is to develop a high strength CIPP material using various composite materials (e.g., glass fiber, carbon fiber, polyester felt, unsaturated polyester resin, and others). Composite samples were made of the materials and tested using three-point bend apparatus to find mechanical properties, which include the flexural modulus, strength, and deflection. A composite combination with glass fibers with thin felt layers shows the best results in mechanical properties. Flexural modulus is a key factor for CIPP liner thickness design. Glass fiber composite yields between four and nine times higher values than the minimum value specified in the American Society for Testing and Materials (ASTM) F1216. This study provides a fundamental baseline for high strength CIPP liners that are capable of using conventional curing technologies.

Defect-Based ArcGIS Tool for Prioritizing Inspection of Sewer Pipelines

AbstractThis paper presents a defect-based model for assessing risk of failure for sewer pipelines. The proposed model deploys a Sugeno fuzzy inference system to create a risk index from which insp...

Reactive and Mixing Processes Governing Ammonium and Nitrate Coexistence in a Polluted Coastal Aquifer

A comprehensive hydrochemical, stable isotope and microbial analyses characterisation has been performed to evaluate the sources of groundwater, nitrogen pollution and degradation processes occurring in an industrial polluted coastal aquifer in the framework of a complex hydrodynamic system. The coexistence of ammonium and nitrate has been observed in almost all the investigated monitoring wells, reaching maximum values of 100 and 200 mg/L for both species. Chloride and potassium concentration coupled with groundwater stable isotopes data show the influence of local and urban recharge and the occurrence of seawater intrusion in areas near the coastline. δ15N–NH4+ values ranging between −4.9 and +14.9% suggest that different processes such as partial nitrification of ammonium, probably anammox activities and sorption, are occurring at the site. The isotope data for NH4+ also showed the existence of the remnant of an old fertilizer plume in the downgradient area. The nitrate isotope data ranging between +9 and +46% and +6 and +26% for δ15N–NO3− and δ18O–NO3−, respectively, suggest that nitrate content is attenuated by denitrification and probably annamox. The fast groundwater flow field is one of the reasons for the coexistence of NH4+ and NO3− in groundwater, since both compounds can penetrate the reducing zone of the aquifer. The influence of leakage of sewage pipelines on the aquifer cannot be discerned due to the complexities of the nitrogen attenuation processes, also influenced by pumping activities.

An integrated assessment approach to prevent risk of sewer exfiltration

Regular inspection, assessment, and rehabilitation are necessary to maintain the performance levels of sewer pipelines. The primary objective of this research is to develop a causality-based model by incorporating twenty-two sewer defects, including erosion voids. The Decision Making Trial Evaluation Laboratory (DEMATEL) was used to study the causality relationship between the defects, based on a designed questionnaire, to conclude the influencing and influenced distress. The results suggested that 59% of the sewer structural and operational defects were influencing ones. Besides, the existing state of the sewer pipelines was evaluated on a scale from 1 (Excellent) to 5 (Critical) by integrating the DEMATEL technique with the Quality Function Deployment (QFD) method. The QFD-DEMATEL model was implemented on a case study to compare the model’s classifications of the pipelines’ states with the actual ones. Based on the comparison, the average accuracy and true negative rate (TNR) of the classifications were 74% and 79% respectively. Also, the average invalidity percentage (AIP) was 41.32%, causing the validity percentage to exceed 50%. The integrated approach keeps decision-makers informed about their sewer pipelines to prioritize pipelines rehabilitation. Thus, defective sewers are reduced and so are the exfiltration cases.

Detection of Hazardous Gas Composition in Sewer Pipeline and to Identifying Safe Working Condition in Sewer Pipelines

Detection of Hazardous Gas Composition in Sewer Pipeline and to Identifying Safe Working Condition in Sewer Pipelines

INFLUENCES OF SUBWAY TUNNELING ON DISASTER OF OVERLYING RAINWATER AND SEWAGE PIPELINES

Tunneling can cause the disaster of surrounding pipelines, thereby inducing serious consequences, such as road collapse. Existing relevant studies mainly focus on small-diameter pressure pipelines, while explorations on disaster characteristics of large-diameter overlying rainwater and sewage pipelines (ORSP) with high rigidity and strength as well as socket are rare, and the research methods of disaster characteristics of small-diameter pressure pipelines are mostly a combination of theoretical and experimental analyses, or a combination of theoretical and finite element analyses. In order to study the disaster characteristics of large-diameter ORSP during tunneling, the settlement and stress features of pipelines were evaluated through a model experiment of the pipe-tunnel orthogonal program, and influences of tunneling on the disaster of ORSP were discussed. Then, nonlinear simulation of the model was performed by finite element analysis. Numerical results are compared with model experiment and theoretical calculation results, and main indexes that influence the disaster characteristics of ORSP were examined. The results demonstrate that the settlement curve of ORSP conforms to Gaussian distribution, and the height of subsider increases with the increase in excavation procedures and stabilization time, thereby reaching 19.5 mm. Stress on ORSP is symmetric around tunnel centerline. The bottom is pressed slightly, while the top is stretched locally. Reliability of numerical model and theoretical calculation is validated by the finite element analysis. Stress ranges between ?545-59kPa, indicating that most positions of top and bottom of ORSP bear low pressures. The settlement of ORSP according to parameter analysis decreases with the increase in pipe-tunnel net distance (l) and inner diameter of pipeline (d). The settlement of ORSP becomes stable When l/D>3 (D is tunnel diameter) and d/l>0.24. The stress of ORSP gradually decreases with the growth of l and d. Conclusions in this study can provide theoretical references for ORSP protection measures in subway tunnel constructions. Keywords: pipelines, model experiment, finite element, disaster characteristics, validate

An economic loss model for failure of sewer pipelines

Estimating the costs of failure for sewer pipelines is usually accompanied with uncertainties because of the difficulty in capturing the relationship between the physical and economical characteristics of failed pipelines. To reduce such uncertainties economic loss models are usually used to evaluate the consequences of failure. This paper presents a methodology to estimate economic loss as a result of sewer pipelines’ failure using cost benefit analysis approach. Costs of sewer pipelines’ failure in addition to costs resulting from avoiding such failures are identified and analysed. To validate the proposed methodology, actual costs from a real failure incident were compared with the proposed model outputs. The model could estimate the direct and indirect costs with a deviation ranging between 10–12% and 22–30%, respectively. By implementing the proposed methodology on two case studies, it was found that the indirect costs as a result of sewer pipelines’ failure represent a significant portion ranging between 89 and 94% of the total costs of failure. Also, it was found that costs related to environment, delays to work and traffic disruptions contribute by 12–35% to the indirect costs.

Automated defect detection tool for closed circuit television (cctv) inspected sewer pipelines

This publication was made possible by NPRP grant # ( NPRP6-357-2-150 ) from the Qatar National Research Fund (a member of The Qatar Foundation). The statements made herein are solely the responsibility of the authors. Also the authors would like to thank the public works authority of Qatar (ASHGAL) for their support in the data collection.

Condition assessment model for sewer pipelines using fuzzy-based evidential reasoning

A condition assessment model for gravity and pressurised sewer pipelines using Fuzzy Set Theory (FST), and Evidential Reasoning (ER) with the aid of Fuzzy Analytical Network Process (FANP) integrated with Monte-Carlo Simulation is presented in this paper. Seventeen factors were considered for gravity pipelines in addition to the operating pressure for pressurised pipelines. The model was developed using relative weights for the different factors affecting pipelines condition which were obtained using FANP integrated with Monte-Carlo Simulation based on the results of a questionnaire that was distributed to experts working in the field of infrastructures. FST was used to set thresholds for the different effect values of factors on the pipelines’ condition, whereas ER was used to determine the final condition assessment index for the pipeline by aggregating both the relative weights and effect values for the different affecting factors.

Investigation of the motion processes of wastewater in sewerage of high-rise buildings

When designing, constructing and operating sewage pipelines in high-rise buildings, issues of failure-free operation of a network arise. Investigation of the processes of wastewater moving allows identifying problem areas during operation, assessing the possibility of obstructions and breakdowns of plumbing traps on the gravity drainage sections of the pipeline. The article performs the schemes of the water outflow from the floor sewer into the riser, including the places where the riser is bent, of air delivery to the working riser under the change of the direction of drain movement with the dropout line set-up, with the installation of an automatic anti-vacuum valve, with the installation of the ventilation pipeline. Investigations of the process of sewage waste flow in a sewage riser were carried out, in order to select the appropriate structure. The authors consider structure features of some sections of sewerage in high-rise buildings. The exhaustion value in the riser is determined from the rarefactions that occur below the compressed cross-section of the riser and the loss of the air flow pressure coming from the atmosphere into the riser during the deflooding of the liquid. Preventing the formation of obstructions and breakdowns of plumbing traps is an integral part of sewage networks.