This philosophy is changing, and a more systematic approach is being taken. At
the WTW this is designed based upon the philosophy of the resource factory and
treating the outputs from the WwTW as a product. In Fig. 1 we see the wastewater
treatment system in its entirety.
Looking at it from a systematic approach, and from a monitoring and control
point of view, the inputs into the system are not currently monitored due to the
difficulty in practically monitoring the inputs into the system. In the main, the
wastewater discharged is a calculated factor based upon the proportion of water
used if the customer is metered. If not, it is an estimated use depending upon the per
capita consumption. As the use of universal smart metering proliferates, then this
situation will improve (and is less of a problem in areas of the world with a much
higher roll out of smart metering). Inputs into the system from industrial customers
are monitored as they form the fundamental basis of the amount the industrial
customer is charged. The cost is based upon both the flow and concentration that
is being discharged utilising the Mogden formula. The last input into the system is
rainfall and runoff, which by its very nature cannot be measured but can be
monitored and predicted. This is where developments in both sensing technology
and modelling approaches can be used to predict what the inputs into the system
are [1].
There is one other “input” into the system that is even more difficult to monitor
(i.e. almost impossible to directly monitor) and that is infiltration into the gravity
system. As the wastewater collection network deteriorates, cracks or weaknesses
around joins in the pipes or manholes develop, and these allow infiltration into the
network. At its most serious, infiltration has been known to make up more flow into
the system than all of the other inputs even within dry weather flow, as underlying
soil conditions mean that, in wet weather, the soil fills and can take several months to
release the stored water into the sewer environment.
All of this has to be taken into account when looking to monitor and control the
wastewater system, and looking at it as a whole, it is important to look at the strategy
of how the wastewater system needs to be monitored and controlled. There is
underlying philosophy to a smart wastewater system and that is:
To manage the system by monitoring and control where there is a defined need, and to have
enough information to manage the system where there is not a defined need.
The ultimate aim for the wastewater system is for it to manage all of the flows that
should enter the network whilst detecting flows that should not be entering and to
convey them as optimally as possible to the WwTW in a balanced fashion. This
allows stability within, what in essence will become, the effluent factory producing
products such as water, nutrients (including biosolids) and energy.
We can achieve this by looking at the system holistically. In the rest of this
chapter, we will look at the different elements of the system as a whole and look at
the philosophy of operation that a smart system would put in place and the measurement and control needs.
Monitoring and Controlling a Smarter Wastewater Treatment System: A UK. . .
113
the WTW this is designed based upon the philosophy of the resource factory and
treating the outputs from the WwTW as a product. In Fig. 1 we see the wastewater
treatment system in its entirety.
Looking at it from a systematic approach, and from a monitoring and control
point of view, the inputs into the system are not currently monitored due to the
difficulty in practically monitoring the inputs into the system. In the main, the
wastewater discharged is a calculated factor based upon the proportion of water
used if the customer is metered. If not, it is an estimated use depending upon the per
capita consumption. As the use of universal smart metering proliferates, then this
situation will improve (and is less of a problem in areas of the world with a much
higher roll out of smart metering). Inputs into the system from industrial customers
are monitored as they form the fundamental basis of the amount the industrial
customer is charged. The cost is based upon both the flow and concentration that
is being discharged utilising the Mogden formula. The last input into the system is
rainfall and runoff, which by its very nature cannot be measured but can be
monitored and predicted. This is where developments in both sensing technology
and modelling approaches can be used to predict what the inputs into the system
are [1].
There is one other “input” into the system that is even more difficult to monitor
(i.e. almost impossible to directly monitor) and that is infiltration into the gravity
system. As the wastewater collection network deteriorates, cracks or weaknesses
around joins in the pipes or manholes develop, and these allow infiltration into the
network. At its most serious, infiltration has been known to make up more flow into
the system than all of the other inputs even within dry weather flow, as underlying
soil conditions mean that, in wet weather, the soil fills and can take several months to
release the stored water into the sewer environment.
All of this has to be taken into account when looking to monitor and control the
wastewater system, and looking at it as a whole, it is important to look at the strategy
of how the wastewater system needs to be monitored and controlled. There is
underlying philosophy to a smart wastewater system and that is:
To manage the system by monitoring and control where there is a defined need, and to have
enough information to manage the system where there is not a defined need.
The ultimate aim for the wastewater system is for it to manage all of the flows that
should enter the network whilst detecting flows that should not be entering and to
convey them as optimally as possible to the WwTW in a balanced fashion. This
allows stability within, what in essence will become, the effluent factory producing
products such as water, nutrients (including biosolids) and energy.
We can achieve this by looking at the system holistically. In the rest of this
chapter, we will look at the different elements of the system as a whole and look at
the philosophy of operation that a smart system would put in place and the measurement and control needs.
Monitoring and Controlling a Smarter Wastewater Treatment System: A UK. . .
113