scholarly journals Steady air flow model for large sewer networks: a theoretical framework

2020 ◽  
Author(s):  
Qi Zhang ◽  
Weiyun Shao ◽  
David Z. Zhu ◽  
Weilin Xu
Keyword(s):  
Driving Forces ◽  
Air Flow ◽  
General Idea ◽  
Sewer System ◽  
Flow Models ◽  
Closed Networks ◽  
Sewer Systems ◽  
Air Movement ◽  
System Data ◽  
Sewer Networks

Abstract Modelling air movement in sewer networks is needed in order to address the issues related to sewer odour complaints and sewer corrosions due to hydrogen sulphide in sewers. Most of the existing air flow models can only be applied in small sewer networks or the trunk lines of sewer systems. The purpose of this paper is therefore to propose a theoretical approach to formulate a general governing equation set for modelling steady air movement in large sewer systems. This approach decomposes the sewer system of interest into its basic physical components as pipes and nodes, and builds local topology of each pipe and each node based on geographic information system data as the fundamentals of model formulation. It avoids manually identifying each branch of the sewer system, eliminates the effect of physically closed networks in sewer systems on the governing equations, and considers key sewer components and all known driving forces. The proposed approach was applied to a real sewer system with over 500 pipes. The results show that the proposed model is applicable in modelling air movement in a large sewer system and provides a general idea of sewer gases moving through the system and their emission.

Quantification of sewer system infiltration using δ18O hydrograph separation

2009 ◽  
Vol 60 (3) ◽  
pp. 727-735 ◽  
Author(s):  
V. Prigiobbe ◽  
M. Giulianelli
Keyword(s):  
Sampling Strategy ◽  
Infiltration Rate ◽  
Hydrograph Separation ◽  
Catchment Scale ◽  
Sewer System ◽  
Urban Catchment ◽  
Sewer Systems ◽  
Conservative Tracer ◽  
Effective Water ◽  
Sewer Networks

The infiltration of parasitical water into two sewer systems in Rome (Italy) was quantified during a dry weather period. Infiltration was estimated using the hydrograph separation method with two water components and δ18O as a conservative tracer. The two water components were groundwater, the possible source of parasitical water within the sewer, and drinking water discharged into the sewer system. This method was applied at an urban catchment scale in order to test the effective water-tightness of two different sewer networks. The sampling strategy was based on an uncertainty analysis and the errors have been propagated using Monte Carlo random sampling. Our field applications showed that the method can be applied easily and quickly, but the error in the estimated infiltration rate can be up to 20%. The estimated infiltration into the recent sewer in Torraccia is 14% and can be considered negligible given the precision of the method, while the old sewer in Infernetto has an estimated infiltration of 50%.

An agent-based approach for generating virtual sewer systems

2010 ◽  
Vol 62 (5) ◽  
pp. 1090-1097 ◽  
Author(s):  
C. Urich ◽  
R. Sitzenfrei ◽  
M. Möderl ◽  
W. Rauch
Keyword(s):  
Population Distribution ◽  
Automatic Generation ◽  
Data Sets ◽  
Urban Structure ◽  
Sewer System ◽  
Agent Based ◽  
Sewer Systems ◽  
Virtual Infrastructure ◽  
Sewer Networks

The application of artificial case studies is a well established technique in urban drainage to test measures, approaches or models. However, the preparation of a virtual case study for a sewer system is a tedious task. Several algorithms have been presented in the literature for an automatic generation of virtual sewer systems. Applying the approach of generating virtual cities by means of the software VIBe (Virtual Infrastructure Benchmarking) the urban structure (including elevation map, land use and population distribution) is generated firstly and the infrastructure is designed meeting the requirements of the urban structure. The aim of this paper is the development of an agent based approach for generating virtual sewer systems. This new algorithm functions as module of the software VIBe but can of course also be applied to a real city in order to get information on possible/optimal sewer placement. Here hundred virtual VIBe cities and for each twelve virtual sewer networks are generated and calibrated based on data of an alpine region. It is revealed that with the approach presented virtual sewer networks which are comparable with real world sewer networks can be generated. The agent based method provides data sets for benchmarking and allows case independent testing of new measures.

Origins and characteristics of urban wet weather pollution in combined sewer systems: the experimental urban catchment “Le Marais” in Paris

1998 ◽  
Vol 37 (1) ◽  
pp. 35-43 ◽  
Author(s):  
Marie-Christine Gromaire-Mertz ◽  
Ghassan Chebbo ◽  
Mohamed Saad
Keyword(s):  
Waste Water ◽  
Sewer System ◽  
Urban Catchment ◽  
Rainfall Events ◽  
Sources Of Pollution ◽  
Sewer Systems ◽  
Combined Sewer ◽  
Wet Weather ◽  
Wet Weather Flow ◽  
Different Sources

An experimental urban catchment has been created in the centre of Paris, in order to obtain a description of the pollution of urban wet weather flows at different levels of the combined sewer system, and to estimate the contribution of runoff, waste water and sewer sediments to this pollution. Twenty-two rainfall events were studied from May to October 1996. Dry weather flow was monitored for one week. Roof, street and yard runoff, total flow at the catchment outlet and waste water were analysed for SS, VSS, COD and BOD5, on both total and dissolved fraction. Results show an evolution in the characteristics of wet weather flow from up to downstream: concentrations increase from the catchment entry to the outlet, as well as the proportion of particle-bound pollutants and the part of organic matter. A first evaluation of the different sources of pollution establishes that a major part of wet weather flow pollution originates from inside the combined sewer, probably through erosion of sewer sediments.

Sediment transport under dry weather conditions in a small sewer system

1998 ◽  
Vol 37 (1) ◽  
pp. 155-162
Author(s):  
Flemming Schlütter ◽  
Kjeld Schaarup-Jensen
Keyword(s):  
Sediment Transport ◽  
Field Data ◽  
Field Measurements ◽  
Weather Conditions ◽  
Sewer System ◽  
Transport Models ◽  
Sewer Systems ◽  
Combined Sewer ◽  
Initial Results

Increased knowledge of the processes which govern the transport of solids in sewers is necessary in order to develop more reliable and applicable sediment transport models for sewer systems. Proper validation of these are essential. For that purpose thorough field measurements are imperative. This paper renders initial results obtained in an ongoing case study of a Danish combined sewer system in Frejlev, a small town southwest of Aalborg, Denmark. Field data are presented concerning estimation of the sediment transport during dry weather. Finally, considerations on how to approach numerical modelling is made based on numerical simulations using MOUSE TRAP (DHI 1993).

Sewer rehabilitation strategy in Berlin

2002 ◽  
Vol 46 (6-7) ◽  
pp. 379-387
Author(s):  
D. Jacobi ◽  
K.-J. Sympher
Keyword(s):  
Structural Integrity ◽  
Cost Benefit Analysis ◽  
Cost Benefit ◽  
Remaining Useful Life ◽  
Sewer System ◽  
Sewer Systems ◽  
Catchment Areas ◽  
Sewer Rehabilitation ◽  
Useful Life ◽  
Rehabilitation Strategy

Berlin Wasserbetriebe is in need of a significant and longterm investment in the rehabilitation of its 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.

Estimating rainfall-induced inflow and infiltration in a sanitary sewer system based on water quality modelling: which parameter to use?

2018 ◽  
Vol 4 (3) ◽  
pp. 385-393 ◽  
Author(s):  
Mingkai Zhang ◽  
Yanchen Liu ◽  
Qian Dong ◽  
Yi Hong ◽  
Xia Huang ◽  
...  
Keyword(s):  
Public Health ◽  
Water Quality ◽  
Water Quality Modelling ◽  
Sewer System ◽  
Sanitary Sewer ◽  
Sewer Systems ◽  
Management Issues

Rainfall-derived inflow and infiltration (RDII) of urban sanitary sewer systems poses serious challenges for public health and management issues.

Experimental investigation on the efficiency of a high side weir overflow

1999 ◽  
Vol 39 (2) ◽  
pp. 61-68 ◽  
Author(s):  
Gert Luyckx ◽  
Guido Vaes ◽  
Jean Berlamont
Keyword(s):  
Experimental Investigation ◽  
Settling Velocity ◽  
Scale Model ◽  
Flow Conditions ◽  
Sewer System ◽  
Side Weir ◽  
Sewer Systems ◽  
High Side ◽  
Sediment Fraction

Most of the overflow structures in Flanders are ‘high side weir overflows’. For the design of these structures British guidelines are used. However, the design conditions for sewer systems in the U.K. differ from the Flemish design conditions. In Flanders, pressurised flow is in common use in the pipes of the sewer system. That is why tests have been carried out on a scale model of a high side weir overflow. The optimal dimensions are determined, using different model sediments. Also efficiency relationships have been determined. For a particular chamber geometry and particular flow conditions, the efficiency of a certain sediment fraction is only determined by the settling velocity of this fraction.

scholarly journals Surface Air Movement: An Important Contributor to Ventilation of Isolated Subsurface Structures?

2019 ◽  
Vol 4 (2) ◽  
pp. 23 ◽  
Author(s):  
Thomas Neil McManus ◽  
Assed Haddad
Keyword(s):  
Air Flow ◽  
Helmholtz Resonator ◽  
Worker Safety ◽  
Time Base ◽  
Near Surface ◽  
Helmholtz Resonators ◽  
Subsurface Structures ◽  
Air Movement ◽  
Air Speed ◽  
Almost All

This study reports on near-surface airspeed measured using a fast-responding thermoanemometer during an investigation of ventilation of an isolated subsurface structure induced by natural forces. Air speed changes continuously, rapidly, and unpredictably when assessed on the time base of one or two seconds. Zero, the most common air speed, occurred in almost all tests throughout the year but especially during cool and cold months. The most probable non-zero air speed, 10.7 m/min (35 ft/min), occurred in all tests. This air speed is below the level of detection by the senses. The number of zero values and the height of the peak at 10.7 m/min follow a repetitive annual cycle. Isolated subsurface structures containing manhole covers share the characteristics of Helmholtz resonators. Grazing air flow across the opening to the exterior induces rotational air flow in the airspace of a Helmholtz resonator. Rotational flow in the airspace potentially influences the exchange of the confined atmosphere with the external one. Ventilation of the airspace occurs continuously and without cost and is potentially enhanced by the unique characteristics of the Helmholtz resonator excited by surface air movement. These results have immense importance and immediate applicability to worker safety.

Sex pheromones of Callosobruchus subinnotatus and C. maculatus (Coleoptera: Bruchidae): congeneric responses and role of air movement

2000 ◽  
Vol 90 (2) ◽  
pp. 147-154 ◽  
Author(s):  
G.N. Mbata ◽  
S. Shu ◽  
S.B. Ramaswamy
Keyword(s):  
Sex Pheromone ◽  
Pest Management ◽  
Sex Pheromones ◽  
Air Flow ◽  
Latency Period ◽  
Air Movement ◽  
Sex Pheromone Components ◽  
Pheromone Components ◽  
Callosobruchus Subinnotatus

Females of Callosobruchus spp. are known to produce sex pheromones that attract males. These sex pheromones cannot be adopted for use in pest management without first investigating the responses of the males in the windless conditions of storage environments. Consequently, behavioural bioassays of Callosobruchus subinnotatus Pic males were conducted in an olfactometer in the absence of air-flow. Under these conditions males were found to be able to follow odour trails to the source. However, the latency period was longer in diffusional bioassays than for insects in a Y-tube olfactometer that provided directional wind cues. The highest percentage of males reached the pheromone source when components of the pheromones, (E)-3-methyl-2-heptenoic acid (E32A) and (Z)-3-methyl-2-heptenoic acid (Z32A), were formulated in a 50:50 or 25:75 ratio. Males of C. maculatus (Fabricius) responded to sex pheromone of C. subinnotatus, but males of C. subinnotatus did not respond to that of C. maculatus. The two sex pheromone components of C. subinnotatus are also constituents of C. maculatus sex pheromone. These two components may be potentially useful in monitoring the populations of both species in stored beans. It is postulated that (Z)-3-methyl-3-heptenoic acid (Z33A), the major component of the sex pheromone of C. maculatus, must have acted as an antagonist inhibiting response of C. subinnotatus to the sex pheromone of C. maculatus.

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