CSO Overflow Reduction & Check Valves 3. The RDNET 1000 CSO monitoring system has been designed to deliver advanced warning of rising levels at CSOs or sewers that could lead to spills. Operating using a combination of low power radio and smart antenna technology the system has a number of advantages over comparable GSM/GPRS based systems and overcomes one of their biggest issues that of unpredictable battery life. Operating similar to a warning beacon, the RDNET has a battery life of typically 10-years. Transmission reliability is very predictable and there are no running costs or SIM cards to forget to renew/top up. In locations near to existing infrastructure such as SWT and pumping stations it is possible to create a direct link between the CSO and the infrastructures existing telemetry outstation. In locations where the distance is greater we have a range of compact pole mounted remote telemetry units (RTU) that can be configured to act as Repeaters. In isolated locations the direct link or repeater can be replaced with a cellular or satellite gateway. From our experience dealing with the rail industry we can testify that locating the cellular device at the top of a pole increases the signal by some million fold, making it far more likely for a reliable connection to the network established. We offer a wide choice of transducers to monitor the level within the CSO. These can include float switches, conductivity probes or pendulum flow sticks. Aside from just raising an alarm - the messages generated by the RDNET CSO monitoring system can be used to close a FlapstopperTM pollution containment valve fitted to CSO outlet. The decision for closure could be qualified locally by taking a feed from a local rain gauge (distrometer) to determine if the excessive level is attributable to rainfall or a blockage etc. Hence, the valve could be closed whenever a non-consented discharge is likely to occur and a simultaneous message sent to summon emergency sewer unblocking teams.
The first idea involves the dynamic control of the catchment area to reduce the peak flow by strategically introducing FlapstoppersTM at some of the stormwater entry points to the network. Opinion is that only a relatively small percentage reduction in stormwater levels entering the combined sewer could be enough to have a significant impact on the number of spill incidents at certain locations. Dry spill incidents could be contained by using a Flapstopper on the CSO outflow. The FlapstopperTM would be closed off and locked whenever the CSO is about to dry spill. A
dry spill would be detected using a combination of local rain gauges and CSO level sensors. Due to the FlapstoppersTM ultra low power requirement it is now practical to install CSO spill mitigation in areas without power, something previously thought impossible. To find out more about CSO discharge technology or to book a trial please call our Southern UK office on +44(0)1279 600 440