Future-proofing utilities' networks with smart sewer technology

How a growing number of utilities are turning to ‘smart sewer’ technology and smart hardware, like pumps or sensors, to optimize sewer networks while avoiding the need to build new infrastructure and reaping huge operational and environmental benefits in the process.

Nicole Pasch is a client solutions manager for Xylem Inc. where she works in the Great Lakes region of the US.
Nicole Pasch is a client solutions manager for Xylem Inc. where she works in the Great Lakes region of the US.

Around the world, increasingly erratic weather events and evolving populations are pushing aging sewer systems to the brink, resulting in billions of gallons of combined sewage being dumped into waterways each year or costly programs to mitigate the environmental impact. A growing number of utilities are turning to ‘smart sewer’ technology and smart hardware, like pumps or sensors, to optimize sewer networks while avoiding the need to build new infrastructure. The results are impressive; huge operational and environmental benefits are unlocked by upgrading existing systems and “turning on the lights” underground. 

Actionable insights
As water challenges intensify, utilities are realizing that conventional approaches to water infrastructure are not enough to solve challenges like affordability and resilience to climate change. Building bigger is not usually the most sustainable solution for a community. Digital solutions, combined with smart hardware, are helping to improve network visibility, empowering water managers to tackle critical issues more affordably and delivering major water, energy, and cost efficiencies. But often, digital solutions and software are “one-size-fits-all”, delivering data and information that does not take account of full operational and situational information. Similarly, hydraulic models themselves don’t tell the whole story for system operators. The result is that data-rich utilities can struggle to unlock useful operational visibility and guidance at scale. Utilities need actionable insights based on live, dynamic conditions – a must for driving greater efficiency and improved outcomes in a wastewater network.

Enter smart sewer technology. Using a combination of sensors and a variety of asset and situational data, together with digital twin technology to generate highly accurate predictions, wastewater network optimization technology enables unprecedented visibility and opportunity for coordinated control. These solutions are currently helping utilities around the world to drastically reduce sewer overflows, detect sewer blockages, minimize flooding events, identify sources of infiltration and inflow, and optimize functionality to ensure regulatory compliance – all while minimizing energy consumption. Leveraging existing sewer network assets(smart pumps, actuators, sensors, etc.) and utility system data (SCADA, GIS, collection system models, operator knowledge, etc.), utilities are often able to reduce the need for costly gray infrastructure in the future.

Across the US, in particular, smart sewer technology is playing an increasingly important role in helping to futureproof the 540,000 miles of sewers that are over 60 years old.   

$950 million saved
The City of Grand Rapids, Michigan needed to get a better understanding of the infiltration and inflow into its newly separated sanitary sewers to ensure compliance with a local mandate. This mandate allowed them zero overflow events of any kind, except as part of a wet weather event of a magnitude in excess of a 24-hour, 25-year storm. The City needed analytic data to certify performance and understand how the system behaved during a wide variety of wet and dry weather conditions. Prior to gathering this information, the City was presented with a hydraulic report stating that areas of e community were experiencing excessive surcharging and flooding. They suspected otherwise but needed proof for regulators, as mitigation to eliminate the surcharging and flooding was estimated to cost much as $1 billion; a capital expense the city could ill afford.

Grand Rapids turned to Xylem to understand how their sewer separation behaved, with the goal of modeling the performance in a computer environment to better predict how the system would perform with less costly improvements to existing infrastructure. First, the City installed and commissioned the deployment of a sensor network comprised of 90 flow meters and 10 rain gauges to collect real-time data from the sanitary lines. This data was analyzed using the Xylem wastewater network optimization solution, which collected, organized, analyzed, and served the data via dashboards, giving operators visual cues to understand and regulate the operation of their sewer systems. Once built, the model was then compared against ongoing sensor data, generating a higher level of system intelligence which is continuously improving with each wet weather event.

Upon completion of the investigation, the City demonstrated to regulators that, by focusing on a few critical areas needing improvement, its infiltration and inflow problem could be solved for between $30-50 million as opposed to the original $1 billion estimate.

Since implementation, Grand Rapids has achieved the performance required by the long-term control plan and continues working towards final certification with the Michigan Department of Environment, Great Lakes and Energy. Encouraged by those results, Grand Rapids has subsequently expanded the sensor network by an additional 70 sensors, many of which are now delivering real-time data from the City’s stormwater network and, over the next few years, the City will also embark on a multi-phased program to improve sustainability and improve water quality for wildlife and recreational use in the Grand River.

CSOs cut by 450 million gallons
When the City of Buffalo was experiencing nearly two billion gallons of combined sewer overflows (CSOs) annually, leading to a consent decree requiring improvements to its collection system, it too turned to smart sewer technology.

Buffalo Sewer Authority (BSA) officials knew they could not continue operating their collection system the same way they had been since the 1950s, and costly investments in new gray infrastructure, like tunnels and storage tanks, were deemed equally infeasible. Xylem, alongside BSA’s team of engineers and consultants, worked together to determine how to evolve the sewer system. Sixteen sites were identified for inline storage and optimal conveyance throughout the city. BSA selected the sites based on maximum return of investment, with the first two sites chosen for implementation as a representative sample of all the sites.

What was once a network of open flow gravity sewers is now becoming a coordinated conveyance and inline storage system. What’s truly exciting is that by deploying our wastewater network optimization system, the City was able to reduce CSOs by 450 million gallons in the first 12 months and dramatically lower the budget for fulfilling the consent decree. And the City’s bold move has paid dividends for today, and tomorrow. BSA has already locked in $145 million in avoided future infrastructure spend and is optimistic more large-scale projects will be set aside as the program evolves.

These utilities, and many more like them, are reaping the rewards of next-level visualization and decision support to better manage, control and optimize their networks – and doing so affordably. While moving away from conventional approaches can be daunting, these experiences demonstrate that when it comes to increasing the resiliency of wastewater infrastructure, smart sewers can be a smart choice.