characteristics of flow entering the network, where infiltrated flows are warmer
than the flows already within the network, to using acoustic waves technologies
employed in a number of techniques that can be deployed externally or internally to
the pipeline, to measure comparative pipe condition to see if the assets are deteriorating. Together with CCTV surveys and the utilisation of more advanced techniques
such as pattern recognition, these methods can be used to identify possible areas of
infiltration in gravity sewers, or potential for bursts in rising mains [18].
The most recent innovation for inspection is passive untethered platforms including free-swimming solutions (which advect with the ambient pipe velocity) that can
complete long inspections in a single deployment. There is increased interest in the
utilisation of robotics. A comprehensive journal review [19] of robots for pipeline
inspection revealed that robots currently available are mainly laboratory prototypes
designed for large diameter pipes, human-controlled, heavy (tens or hundreds of kg)
single devices suitable for a single short-duration intervention. The last major area of
monitoring within the wastewater network is at the combined sewer overflow (CSO),
and this was driven in the UK by a strategic government decision under Ministerial
Direction in July 2013, to monitor the vast majority of CSO’s within the water
industry with event duration monitors (EDMs). This decision was made in order to
protect the environment from discharges to water courses through CSOs and other
discharges to the environment, including pumping station overflows and storm tank
overflows, when they either shouldn’t be taking place or are happening more often
than is reasonable.
A risk-based approach to the EDM programme was taken by the Environment
Agency looking at CSO’s in areas where the amenity or economic value is high, and
where an overflow is suspected to be a potential problem given the highest priority.
This goes all the way to the other end of the spectrum where an overflow is of
low amenity or economic value and is known not to overflow and hence is given
the lowest priority. The philosophy of the programme was to discover where all the
overflows were, and to monitor when and for how long they overflow to the
environment. With the highest-risk areas requiring much more detailed monitoring,
this effectively maps the exact area of impact that the sewerage network has on the
wider aquatic environment. In the programme, only low amenity overflows with less
than 20 spills per year were excluded, and, in practice, many of the water companies
will have 100% coverage before 2025.
As with all of these initiatives, in practice, they have a much greater operational
benefit than the project initially envisaged, and, as part of a “smart” wastewater
network, the EDM programme has the potential to be used to measure network
performance. It can also identify areas where the network is stressed and where
investment is required in order to provide further capacity, either through reduction
of the basal flow through infiltration reduction, increasing the capacity of the
wastewater network, or potentially increasing the monitoring and control of the
network to relieve periods when the wastewater network is having capacity issues
and is under stress.
124
O. Grievson
than the flows already within the network, to using acoustic waves technologies
employed in a number of techniques that can be deployed externally or internally to
the pipeline, to measure comparative pipe condition to see if the assets are deteriorating. Together with CCTV surveys and the utilisation of more advanced techniques
such as pattern recognition, these methods can be used to identify possible areas of
infiltration in gravity sewers, or potential for bursts in rising mains [18].
The most recent innovation for inspection is passive untethered platforms including free-swimming solutions (which advect with the ambient pipe velocity) that can
complete long inspections in a single deployment. There is increased interest in the
utilisation of robotics. A comprehensive journal review [19] of robots for pipeline
inspection revealed that robots currently available are mainly laboratory prototypes
designed for large diameter pipes, human-controlled, heavy (tens or hundreds of kg)
single devices suitable for a single short-duration intervention. The last major area of
monitoring within the wastewater network is at the combined sewer overflow (CSO),
and this was driven in the UK by a strategic government decision under Ministerial
Direction in July 2013, to monitor the vast majority of CSO’s within the water
industry with event duration monitors (EDMs). This decision was made in order to
protect the environment from discharges to water courses through CSOs and other
discharges to the environment, including pumping station overflows and storm tank
overflows, when they either shouldn’t be taking place or are happening more often
than is reasonable.
A risk-based approach to the EDM programme was taken by the Environment
Agency looking at CSO’s in areas where the amenity or economic value is high, and
where an overflow is suspected to be a potential problem given the highest priority.
This goes all the way to the other end of the spectrum where an overflow is of
low amenity or economic value and is known not to overflow and hence is given
the lowest priority. The philosophy of the programme was to discover where all the
overflows were, and to monitor when and for how long they overflow to the
environment. With the highest-risk areas requiring much more detailed monitoring,
this effectively maps the exact area of impact that the sewerage network has on the
wider aquatic environment. In the programme, only low amenity overflows with less
than 20 spills per year were excluded, and, in practice, many of the water companies
will have 100% coverage before 2025.
As with all of these initiatives, in practice, they have a much greater operational
benefit than the project initially envisaged, and, as part of a “smart” wastewater
network, the EDM programme has the potential to be used to measure network
performance. It can also identify areas where the network is stressed and where
investment is required in order to provide further capacity, either through reduction
of the basal flow through infiltration reduction, increasing the capacity of the
wastewater network, or potentially increasing the monitoring and control of the
network to relieve periods when the wastewater network is having capacity issues
and is under stress.
124
O. Grievson