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Smart sewers: Smart cities "start eight feet below the ground"

Kansas City’s smart sewers could save over $1 billion.


Andy Shively knows sewage. As special assistant city manager for Kansas City, Missouri, he oversees smart sewer and stormwater management systems that are projected to save taxpayers nearly $1 billion in coming years.


The city’s approach is based not only on Internet of Things (IoT) sensors for controlling sewer and stormwater flows but also on deep data-sets (exceeding 5 terabytes in size) that have helped guide the co-ordinated replacement of 140-year-old water and sewer pipes that are prone to breaks and leaks.


Kansas City uses IoT sensors, as well as AI and deep data-sets, for controlling sewer and stormwater flows.


Many cities and counties neglect water, sewer and stormwater systems at their peril. Shively chooses to stay on top of things. “I tell other cities that a smart city starts eight feet below the ground and goes up from there,” he said.

Smart sewers


Kansas City is located in the geographic heart of America and boasts the world’s largest smart sewer sensor network. It includes nearly 300 sensors deployed on the underside of rugged manhole covers across a vast 2,800-mile sewer pipe network covering 318 square miles.


A real-time decision support system created by tech company EmNet will dynamically control the flow of water to help prevent combined sewage from entering the Missouri River.


The system uses in-line gates to maximise storage in the sewer system during heavy rains, much the same as smart traffic lights work during rush hour. The $1.2 million (£0.9 million) smart system will help prevent the construction of costly deep tunnels and pumping stations. “We’ll use what’s already built to hold the flow,” he said.


The sensors act as a type of flow metre that works like sonar, measuring the flow and depth of the water in any given spot. Shively met EmNet five years ago, after founder Luis Montestruque converted artificial intelligence (AI) technology that was originally used to help locate snipers firing on troops in combat and to track enemies in GPS-denied areas. It was based on collecting data from IoT devices, which were named ‘Smart Dust’. EmNet is now part of Xylem Inc., a global water technology company with 2017 revenues of $4.7 billion (£3.6 billion).



The stormwater approach


For smart stormwater management, Kansas City has embarked on a continuous monitoring and adaptive control (CMAC) system from tech company Opti that also relies on Microsoft Azure. The Azure cloud is used to analyse National Oceanographic and Atmospheric Administration weather forecasts and local conditions, including the depth of retention and detention basins, to predict when flow gates should be left open or closed. The results can easily be audited to share with lawmakers and the public.


Kansas City’s CMAC system is currently monitoring a 1.9-million-gallon stormwater detention basin on Gardner Avenue and will be deployed in up to 14 future locations. Previously, the facility was manually operated, with workers opening and closing stormwater gates to handle heavy rains. The automated approach is more precise.


The retrofit system cost was 2 cents a gallon of captured run-off, compared with upwards of $8 (£6) a gallon previously. About 92 per cent of all the stormwater run-off at the Gardner facility has been captured in the first year of operation. Previously, this would have contributed to combined sewer overflows.


KC’s Gardner Avenue stormwater detention basin uses a CMAC system
KC’s Gardner Avenue stormwater detention basin uses a CMAC system

“The results have been impressive,” Shively said. So far, for the two systems from Opti, the city has spent about $100,000.


Why smart matters


Kansas City is under the gun from the U.S. Department of Environmental Protection to prevent combined sewer water and stormwater from entering the Missouri River.


The “Muddy Missouri” is the longest river in North America, at 2,341 miles. After its start far to the northwest in the state of Montana, it cuts a broad swathe through the heart of Kansas City at the edge of a downtown undergoing an ambitious commercial growth spurt.


The city recently added a modern 2.2-mile streetcar line and free downtown Wi-Fi connected to information kiosks that serve tourists, businesses and residents interested in enjoying restaurants, museums and a major indoor auditorium. From Kansas City, the river traverses the width of the state of Missouri (about 240 miles) to join the Mississippi River at St. Louis.


It’s an understatement to say that Shively and the city’s elected and appointed officials take the EPA’s consent decree seriously. While the city is required to act, protecting the river is also an indirect investment in the downtown renaissance.


Since 2010, the city has spent $505 million to prevent combined sewer overflows from entering the Missouri.


Since 2010, the city has spent $505 million to prevent combined sewer overflows from entering the Missouri. In all, the city said in 2010 it expects to spend $2.5 (£1.9 billion) billion (or $4.5 billion/£3.4 billion with inflation) over 25 years to meet the EPA requirements under the Clean Water Act.


“We have 17 years to go to reach the goal of 88 per cent capture of combined sewer overflows,” Shively said. What originally was an estimated 6.4 billion gallons of annual overflow will be reduced to 1.4 billion gallons annually, he added.


Going mainstream


The city is betting its smart sewer and stormwater systems will further reduce overflows into the river. Kansas City’s success in avoiding future costs – estimated at $1 billion (£0.76 billion) – are a lesson to other cities that may be sitting on the fence about what IoT, AI and data mining technology can do.


“All these smart technologies are gaining momentum,” Shively said. “Once these systems are installed and prove their performance and cost-effectiveness, more people will look into these types of solutions.”


EmNet founder Montestruque said Kansas City’s smart sewer system is one of 25 utilities in different stages of implementation, including Los Angeles, San Francisco and Cincinnati, Ohio.


Water utilities are generally “slow” in adopting such new technology, he said.


“This comes from their risk aversion, which is understandable due to the sensitive nature of dealing with water… One thing that has helped accelerate the adoption process recently is the fact that IoT and AI are now household names.”

EmNet's smart manhole cover
EmNet's smart manhole cover

Lessons learned so far


Shively said the biggest lesson he and Kansas City have learned about maintaining large sewer and water and stormwater systems is the importance of gathering data and mining it for insights that will prepare the community for the next 50 to 100 years.


“The biggest challenge that wastewater utilities face is understanding how their system will operate years from now,” he said. “Knowing what you have in place is the starting point. That’s uber important.”


Kansas City has spent $35 million on “system characterisation" of its sewers.


In recent years, Kansas City has spent $35 million (£26.8 million) for what it calls “system characterisation,” a process of inspecting sewer pipes and manholes and recording the data on servers and cloud-based solutions. Closed-circuit TV has been used to inspect 2,000 of 2,800 miles of sewer mains, as well as 34,000 of 66,000 manholes.


Another 16,000 visual pipe inspections have been completed. In 2016, the city had 80 gigabytes of such data, which has mushroomed to 5 terabytes in 2018.


Using software from big data automation company Innovyze to analyse the inspection data, the city has developed decay prediction curves for the underground pipes and other materials. With that information, the city can prioritise which sewer line segments need to be rehabilitated first.


A similar approach has been applied to water mains replacement to reduce the city’s unaccounted losses of clean water.


Every year, the city replaces one per cent of its 2,800 miles of water mains with ductile iron pipes, based on the likelihood of business risk exposure. A dynamic software model is deployed that is updated annually to assess two factors: likelihood of failure and consequence of failure. That work has helped reduce 1,800 water main breaks in 2012 to about 700 breaks in 2017.


A challenge


In addition to the big data work, the city, under Shively’s direction, created an unusual challenge to area contractors in 2016 – to lower sewer and water construction costs in a decade by $1 billion (£0.76 billion). That challenge and other city efforts have also helped private-sector project managers better forecast the city’s needs and their preparedness.


Elected leaders in Kansas City have been “very supportive” of such efforts, Shively said. The ultimate goal of all the city’s work is to flatten the costs to citizens for water, sewer and stormwater management after years of double-digit rate hikes.


The average monthly bill for city residents is currently $102 (£78), with 60 percent going on sewers, 38 per cent on water and 2 per cent on stormwater.


“Bills won’t go down, but we hope to flatten the amount in the future,” Shively said. Given the city’s commitment to smart tech, the odds are good.

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