Water Online

JUL 2017

Water Innovations gives Water and Wastewater Engineers and end-users a venue to find project solutions and source valuable product information. We aim to educate the engineering and operations community on important issues and trends.

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that warns of rising levels in areas of known problems so that issues can be dealt with according to priority, to systems that stop pump blockages and warn of problems via pump-reversing, monitoring of pump currents, and using flow meters to give a true picture of what is happening. The strategic direction is looking at the much wider, more- encompassing systems, and the advantage here is to limit the capital build of detention tanks in the network and storm tanks within the treatment works. The best case of this was in Barcelona, where a smart wastewater network was constructed for the Olympics in 1992. The alternative was a vast detention tank under the center of the city, and the smart wastewater network approach was the considerably cheaper option. From a holistic point of view, the treatment works must be brought into the equation too, and it is at this point of bringing together two aspects of the industry — network and treatment, where the real savings can be made by controlling the flow of water through the whole system and limiting the environmental impact of the wastewater systems — that we can truly get more for less. So, what does this wastewater system of the future look like? In normal day-to-day conditions, the smart wastewater network of the future controls flows, flattening out the flows that are received at the wastewater treatment works. It monitors how much time sewage spends in the network, aiming for a completely flat flow profile at the treatment works with regular, automated flushing cycles to ensure that the sewer stays as debris-free as possible, controlled by sewer level monitors to pick up unusual levels that might highlight blockages starting to develop. Various tools are used to keep the problems at bay, such as pump-reversing and flow monitoring to ensure that the flows keep moving and pumps don't block. Where problems are starting to appear and hot spots start to develop, an alert is triggered to look into potential sewer misuse. CSOs from the system are dry. Flows pass forward to the treatment system, where the relatively uniform flows enable efficiency of treatment and virtually eliminate the need for treating peak flows. This enables a uniform production through the process, which further improves the treatment efficiency. The intelligence of the system kicks in with the prediction of rainfall events. If the system were to predict that the sewer in its current state can't manage all of the flows within a six-hour period, it could recalculate and ramp up flows so that the required capacity of the sewer is available with an appropriate safety margin. The flows are managed and held within the sewers. The CSOs are still dry. If the rainstorm continues longer than predicted and causes a potential problem at a customer's premises, an alert is triggered in the control center, and a team is allocated to resolve the issue for the customer so that an incident is mitigated or avoided. This is a fictional, potential system of the future, but what we have heard at the various workshops and conferences is that this is a future that in reality isn't that far away. The technology exists, from sewer alarms and pump-reversing systems to the potential for network flow monitoring, event-duration monitoring, and customer flood- protection alarms. Taking a step up in complexity, weather radar systems, network model, and active control systems also exist. Finally, analytics and visualization systems exist as well, enabling the vast amount of data that is inevitably produced to be shown in a way that can be understood and acted upon. It's a system that is starting to be developed by some water companies, and more recently we have seen the development of the factory approach famously mentioned in a STOWA (Dutch acronym for the Foundation for Applied Water Research) report on wastewater treatment works of 2030. "Production efficiency monitoring systems" have worked out fantastically well for energy, water, and nutrient factories, and the extension of this approach to the wastewater network is just another step to a "smart industry" future. n 26 wateronline.com n Water Innovations INSTRUMENTATION Oliver Grievson is the wastewater flow and quality instrumentation specialist at the Foundation for Water Research, the director of the Sensors for Water Interest Group, a member of the ICA special inter- est group of the International Water Association, and founder of the LinkedIn Group "Water Industry Process Automation & Control" — all in addition to his duties as a flow compliance and regulatory efficiency manager. About The Author The impact of weather radars, coupled with data from rain gauges, will allow for predictive models to determine how the "smart network" can help the industry manage flows.

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