installation of a flow meter in the rising main can provide a secondary verification of
this, which is especially useful on large pumping stations. It can also be used to allow
for visualisation of what is happening at a pumping station and inform how to react
to alarms that are raised on particular asset. Imagine a scenario where it is raining, all
of the pumps available are running, and the maximum output of the pumping station
is being pumped; and yet there is a high-level alarm. In this situation everything
possible is being done, but the sheer volume of flow is overwhelming the pumping
station. The same situation without a flow monitor would mean it would have to be
visited to assess the situation, whereas a flow meter would definitively confirm the
actual situation.
More recently there has been work with pressure monitoring on the rising main
aspect of the wastewater network. This uses high-resolution pressure monitoring to
predict when the rising main is going to fail, which is working along the same lines
as pressure transient monitoring in the potable water distribution network. The full
understanding of the methodology of using pressure monitoring to predict pipe
failure is not fully understood, but it is currently being studied.
On the pumped wastewater network, the ultimate aim is for it to work with the
gravity network with the main control point being the inlet of the wastewater works.
This provides flows to the treatment works that are, as far as possible, equalised
across a 24 h period with the ability to react to a model-based approach to reduce the
amount of wastewater discharged straight to the environment through storm overflows in wet weather.
The gravity network needs to work in conjunction with the pumped wastewater
network although it behaves in a completely different way, and the monitoring of the
gravity wastewater network has different challenges.
In the gravity network, the main question is what to measure, and where, within
the network. There is a school of thought that believes that level monitoring of the
sewerage system can be used in its entirety to monitor the situation in the network
and allow the required element of situational awareness. Another perspective is that
the use of flow monitoring in the wastewater network also adds another dimensional
element. As there aren’t many measurement technologies that will measure part full
pipes, flow measurement within the sewer is limited to Doppler style area-velocity
devices that can either be submerged in the flow (and are at risk of damage due to
fouling) or are remote from the flow (which have limitations over where they can be
installed and need a minimum size of pipe). There are technologies that are currently
being researched, looking into measuring the surface patterns of the flow inside the
pipe to measure the flow rate [15].
What value do each of the measuring techniques bring to the wastewater network? Level within the wastewater network can be used to simply indicate how full
the sewer is. This is a very powerful tool as it can indicate the current available
capacity within the network and, together with a wastewater network model and
meteorological detection methodologies, can be used to calculate whether there is
sufficient capacity within the network to manage a potential storm event that is
happening in the next few hours. This is a crucial element of a smart wastewater
network. Level, when measured at several different points, can also indicate where
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this, which is especially useful on large pumping stations. It can also be used to allow
for visualisation of what is happening at a pumping station and inform how to react
to alarms that are raised on particular asset. Imagine a scenario where it is raining, all
of the pumps available are running, and the maximum output of the pumping station
is being pumped; and yet there is a high-level alarm. In this situation everything
possible is being done, but the sheer volume of flow is overwhelming the pumping
station. The same situation without a flow monitor would mean it would have to be
visited to assess the situation, whereas a flow meter would definitively confirm the
actual situation.
More recently there has been work with pressure monitoring on the rising main
aspect of the wastewater network. This uses high-resolution pressure monitoring to
predict when the rising main is going to fail, which is working along the same lines
as pressure transient monitoring in the potable water distribution network. The full
understanding of the methodology of using pressure monitoring to predict pipe
failure is not fully understood, but it is currently being studied.
On the pumped wastewater network, the ultimate aim is for it to work with the
gravity network with the main control point being the inlet of the wastewater works.
This provides flows to the treatment works that are, as far as possible, equalised
across a 24 h period with the ability to react to a model-based approach to reduce the
amount of wastewater discharged straight to the environment through storm overflows in wet weather.
The gravity network needs to work in conjunction with the pumped wastewater
network although it behaves in a completely different way, and the monitoring of the
gravity wastewater network has different challenges.
In the gravity network, the main question is what to measure, and where, within
the network. There is a school of thought that believes that level monitoring of the
sewerage system can be used in its entirety to monitor the situation in the network
and allow the required element of situational awareness. Another perspective is that
the use of flow monitoring in the wastewater network also adds another dimensional
element. As there aren’t many measurement technologies that will measure part full
pipes, flow measurement within the sewer is limited to Doppler style area-velocity
devices that can either be submerged in the flow (and are at risk of damage due to
fouling) or are remote from the flow (which have limitations over where they can be
installed and need a minimum size of pipe). There are technologies that are currently
being researched, looking into measuring the surface patterns of the flow inside the
pipe to measure the flow rate [15].
What value do each of the measuring techniques bring to the wastewater network? Level within the wastewater network can be used to simply indicate how full
the sewer is. This is a very powerful tool as it can indicate the current available
capacity within the network and, together with a wastewater network model and
meteorological detection methodologies, can be used to calculate whether there is
sufficient capacity within the network to manage a potential storm event that is
happening in the next few hours. This is a crucial element of a smart wastewater
network. Level, when measured at several different points, can also indicate where
122
O. Grievson