Maintaining Chlorine Residuals in Your Reticulation Network.
The Current Situation:
Many utilities around Australia use flushing or scouring of water mains to achieve acceptable chlorine residuals in their reticulation network. But this practice does not correlate well with the water conservation message that the utilities face. To address this problem these utilities have been installing time-based flushing systems that work at night and are out of the eye of the public.
Why flush! At the end zones of reticulation networks, water consumption can be quite low and the chlorine has been consumed by the time it reaches customers at the end of the network. Some utilities will re-chlorinate secondary reservoirs to try an overcome this problem. But this approach will not work in most regional areas that have a large geographic network and a low amount of customer connections.
The Water Quality Vs Water Conservation Nexus!
With water utilities having a remit to achieve 0.2mg/L of free chlorine at the customer connection point as per the Australian Drinking Water Guidelines (v3.5 August 2018). There is often a tradeoff and that is water conservation to achieve water quality.
The Solution:
To achieve both water conservation and water quality (Chlorine residual and pH), SAFEgroup Automation (SGA) was engaged by a Western NSW council to provide an Automated Flushing System (AFS). The AFS uses a chlorine analyser (ATi Q46) with a user-defined working range set in ClearSCADA to operate a motorised valve to maintain targeted chlorine residual in the network. The AFS also has a smart meter connected to account for the non-revenue water (NRW) that is being flushed. The flushed water drains to a sewer pump station which feeds the water back to the STP which has a water reclamation system, so the water is reused.
To keep costs down we also used the existing SCADA Pack 334E at the pumping station to run the AFS. The analyser is connected to the SCADApack via hardwired I/O and operates the motorised valve based on high and low setpoints sent down from ClearSCADA. This being said, the ATiQ46 is also capable of communicating via Modbus TCP, which gives us the ability to integrate this system into an existing installation where physical I/O and real-estate is limited.
We also have the option to supply this system as a standalone telemetry site (mains powered or solar-powered). Whether it be via the local 4G/5G network, via an existing UHF radio network or even a point-to-point link to an existing telemetry site, we can supply a turn-key solution that sees the AFS up and running, ready to talk to your existing SCADA system in no time.
If you’re interested in finding out more about our Automated Flushing System solutions and how it can benefit your operations, contact our Smart Utilities Product Manager, Adam Simpson or get in touch with the SGA team today!