Assessment of Human Stability in Sewer Systems during Dry Weather Conditions

Beniamino Russo,Alejandro Acero Oliete,Oscar Ruiz,Luca Locatelli,Daniel Yubero

doi:10.3390/w13212954

Abstract

Inspection and maintenance tasks are essential to guarantee the correct operation of sewer drainage networks. In combined sewers, these tasks are generally carried out during dry periods when only wastewater flow circulates in the system. When the sewer is big enough to allow the access of people, this inspection is done in person with consequent potential exposure to several hazards such as the presence of toxic gases, the possibility to fall or the loss of stability due to the presence of a continuous wastewater flow. In this context, this paper presents a methodology to assess hazard conditions related to human stability in sewer systems during dry weather periods. Hazard assessment has been performed by applying several hazard criteria to the results of a 1D sewer model simulations regarding a real network in Spain. Results show that the influence of the selection of hazard criteria is relevant, although only a small part of the whole system can be classified as high hazard. Regardless, the proposed method is highly effective to detect these kinds of pipes and we consider them as critical point to improve health and safety procedures during maintenance and inspection tasks.

Highlights

The inspection and maintenance of sewers pipes are necessary tasks to achieve the correct operation of sewer drainage networks
This paper presents results regarding human stability in combined sewer systems during dry weather conditions for a real case in Badalona (Spain), applying specific hazard criteria in visitable pipes of the existing sewer network of the city and using the flow results provided by a calibrated 1D sewer model [15,16]
This paper presents a methodology to assess hazard conditions related to human stability in sewer systems during dry weather periods

Summary

Introduction

The inspection and maintenance of sewers pipes are necessary tasks to achieve the correct operation of sewer drainage networks. Inspections of sewers are performed as part of the network maintenance or because of an emergency. In the case of a combined network, inspections are carried out in dry time and maintenance is performed when an emergency appears. In general, the lifespan of collectors is very long, hundreds of years in some cases [1] and multiple causes require inspection [2,3]. The sewers gather discharges from different origins that can have a negative impact on the pipes, mainly if the discharges are industrial [2]. Runoff can carry a multitude of elements that can hinder the water transport capacity of the network. External loads can break the walls of the pipeline, and so on

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