Sedimentation in Large Combined Sewage Systems: Perspectives of an Operator / La Sédimentation dans les Réseaux Unitaires Visitables: le Point de Vue d'un Exploitant

Riochet, Bertrand (2008). Sedimentation in Large Combined Sewage Systems: Perspectives of an Operator / La Sédimentation dans les Réseaux Unitaires Visitables: le Point de Vue d'un Exploitant. In: Frédérique Larrarte and Hubert Chanson, Experiences and Challenges in Sewers: Measurements and Hydrodynamics. International Meeting on Measurements and Hydraulics of Sewers IMMHS'08, Summer School GEMCEA/LCPC, Bouguenais, France, (11-19). 19-21 August 2008.

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Author Riochet, Bertrand
Title of paper Sedimentation in Large Combined Sewage Systems: Perspectives of an Operator / La Sédimentation dans les Réseaux Unitaires Visitables: le Point de Vue d'un Exploitant
Conference name International Meeting on Measurements and Hydraulics of Sewers IMMHS'08, Summer School GEMCEA/LCPC
Conference location Bouguenais, France
Conference dates 19-21 August 2008
Convener Frédérique Larrarte
Proceedings title Experiences and Challenges in Sewers: Measurements and Hydrodynamics
Place of Publication Brisbane QLD, Australia
Publisher Department of Civil Engineering at The University of Queensland
Publication Year 2008
Year available 2008
Sub-type Fully published paper
ISBN 9781864999280
Editor Frédérique Larrarte
Hubert Chanson
Start page 11
End page 19
Total pages 9
Collection year 2008
Language fre
eng
Abstract/Summary Combined sewers are designed to convey waste waters to a treatment plant. When the flow conditions do not allow the solid matters to be maintained suspension, the sediments deposit along the sewer system. The managers and operators of a network have to clean those sediment deposits. The operations require a lot of human and material resources, and efforts must aim to minimise the length of the cleansing operation because it is difficult task for the workforce that generates some nuisance (noises, odours, ...) for the neighbourhood. This paper presents the case study of the Nantes Métropole Sewer Authority (France). The man-entry part of the sewer network is located in the central area of Nantes city. This man-entry part represents about 120 km of the combined sewer channels with internal heights greater than 1.2 m. Current cleaning methods are presented including the sewer cleaning truck and the Hydrass floodgate. The truck technique has been improved to use the sewer channel water rather than tap water. The floodgate Hydrass is designed to create a surge by alternating closure and rapid opening (Fig. 3 & 4). After closure, the water behind the gate rises until a defined level, when the gate tilts. The rapid opening creates a surge wave flushing the downstream deposits. One limitations of the self-opening gate is its fixed location and its limited influence, typically about 150 m downstream of the gate. To avoid such limitations, Nantes Métropole Sewer Authority developed a new self cleaning, unmanned tool (Fig. 5 & 7). The key design principle is to reduce the flow cross section, increasing locally the velocity to scour the sediment deposits. This new carriage tool is pushed by the flow itself and it is self-cleaning. While human resources are required to install and remove the carriage, its advance and operation within the sewer channel does not require any human operator. It can be used to clean a fairly long section of channel, and its operation requires simply that the cross section remains constant. / Les ouvrages de décantation répartis sur le réseau unitaire visitable ne suffisent pas à piéger l’ensemble des matières solides transportées par les effluents. Certains collecteurs ont une pente très faible pouvant faire apparaître la formation de dépôts. Les opérations de curage du réseau unitaire visitable nécessitent souvent la mise en œuvre de moyens humains et matériels conséquents. Un des objectifs recherchés par l’Opérateur Public d’Assainissement est de limiter la durée de ces interventions souvent pénibles pour le personnel et source de nuisances pour les riverains (bruit, odeurs…). Cet article présente les outils actuellement utilisés et les travaux effectués pour améliorer les techniques de curage des collecteurs visitables.
Subjects 290000 Engineering and Technology
290800 Civil Engineering
290802 Water and Sanitary Engineering
Keyword exploitant
dépôts sédimentaires
développement d’outil
curage
assainissement
sewers
sewer management
sediment deposit
tool development
sedimentation
cleansing
self-cleaning unmanned carriage
Q-Index Code E1
Q-Index Status Provisional Code
Institutional Status Unknown
Additional Notes The full bibliographic details are : RIOCHET, B. (2008). "La Sédimentation dans les Réseaux Unitaires Visitables: le Point de Vue d'un Exploitant." ('Sedimentation in Large Combined Sewage Systems: Perspectives of an Operator.') Proceedings of the International Meeting on Measurements and Hydraulics of Sewers IMMHS'08, Summer School GEMCEA/LCPC, 19-21 Aug. 2008, Bouguenais, Frédérique LARRARTE and Hubert CHANSON Eds., Hydraulic Model Report No. CH70/08, Div. of Civil Engineering, The University of Queensland, Brisbane, Australia, Dec., pp. 11-19 (ISBN 9781864999280).

Document type: Conference Paper
Collection: School of Civil Engineering Publications
 
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Created: Fri, 28 Nov 2008, 14:35:55 EST by Hubert Chanson on behalf of School of Civil Engineering