PhD student Chitta Behera: Photo: DTU Chemical Engineering

A Smart City without plans for water is not smart

Friday 11 Aug 17


Gürkan Sin
DTU Chemical Engineering
+45 45 25 29 80

Big cities around the world are growing and infrastructure is increasingly under pressure from the influx of new inhabitants. Part of the solution could be so-called “Smart Cities” with innovative plans for revolutionizing the energy, transportation and health sector. The question remains, can we call our plans for the Smart City “smart” if they fail to include how we treat our wastewater?

An ordinary morning routine in an ordinary big city apartment: We get up, go to the bathroom, wash hands, take a shower, brush your teeth, boil water for our coffee. Already in these early hours, water is central to our daily routine, but few of us are concerned with what happens to the water as it disappears down the drain. The 21st century has turned out to be an era of urbanization. WHO has projected that more than 70 % of the world population will be living in cities by 2050. This places pressure on the densely populated cities around the world and as a result of this, the concept of “the Smart City” has arisen. With the help of data and IT, the cities of the future are to solve the consequences of urbanization more effectively. The focus of these Smart Cities varies, but in Denmark, a survey conducted last year by the Danish consultancy company, Niras indicated that 9 out of 10 municipalities do not have a Smart City strategy. And for the ones that do, the focus is primarily on open data, public involvement along with traffic and mobility issues. Wastewater treatment is one of the least prioritized issues.

60 % of European cities are overexploiting the groundwater

Chitta Ranjan Behera, a PhD student from DTU Chemical Engineering, has zoomed into the facts and figures of the water challenges worldwide. He is currently working on a project named “Potential of Innovative Technologies to Improve Sustainability of Sewage Treatment Plants” in short called PIONEER_STP. As the name implies, the aim of the project is to develop solutions for sewage treatment plants in EU and around the world. According to the PhD student, there are plenty of reasons why water should be a top priority in urban development plans.

Already five years ago, a survey report from the European Commission showed that 60 % of the European cities are overexploiting their groundwater resources. According to the Ministry of Environment and Forests of India, the crowded nation treats only 30% of household wastewater, the rest is being discharged. At the same time, the World Economic Forum estimates that global demand for water will increase by 50% in 2040. This is exactly why building Smart Cities without smart sewage infrastructure is not smartf”, warns Behera.

In order to meet these challenges before it is too late, researchers from around the EU have joined in collaboration on the Pioneer_STP project. The project counts researchers from DTU Chemical Engineering, the University of Verona (UNIVR), University of Santiago de Compostela (USC), Royal Institute of Technology (KTH) and the water company FCC Aqualia.

A holistic approach to wastewater treatment has great potential

The current trends of research and innovation in developing new wastewater treatment technologies are going towards reversing the energy and investment cost equations. Researchers are redefining sewage treatment plants as wastewater bio-refineries where energy can be produced in the form biogas, where resources can be recovered in the form of cellulose, fertilizer, commodity chemicals, and last, treated water can be used for drinking purpose. A study by the Water Environment Research Foundation projects that the wastewater treatment plants in the US could meet 10% of the nation's electricity demand. Furthermore, in 2010, the Dutch water board (STOWA) proposed a roadmap for next generation wastewater treatment, which focuses on building and rebuilding wastewater treatment plants as energy-, nutrient- and water factories.

We can also count examples in Denmark that show the potential of smart wastewater treatment, Lynetten in Copenhagen and Ejby Mølle, a treatment plant in Odense, are examples of plants that incorporate smart technologies. At Ejby Mølle they have succeeded in achieving 110% self-sufficiency in electricity, meaning it produces more energy than it consumes. According to Chitta Behera, the key to effective wastewater treatment could lie within attacking the problem from a global and holistic perspective.

In the future, the primary role of sewage treatment plants will remain focused on cleaning wastewater, providing sanitation for public health and drinkable water. Secondly, we will become better and better at recovering important resources such as cellulose, alginate, phosphorus from the wastewater and find the right market for the recovered product”, says the PhD student says.

It is an expensive but necessary investment

The concept of building sewage treatment plants started in the mid-nineteenth century and has continuously evolved with the advancement of technology. Today, although we have made significant technological progress, the general perception of sewage treatment plants is still being depicted as an energy sink, an expensive process or the sewage water is merely regarded as a waste. Developed countries are also currently paying large amounts of money for their wastewater treatment, for instance the Swedish wastewater utilities consume about 600 GWh of electric power annually, which is approximately 0.5% of the total Swedish electricity consumption. Similarly, the national renewable energy laboratory in the US estimates the water and wastewater treatment system consumes 3-4% of the total U.S electricity consumption.

In addition to this, the investment to build new or to rebuild existing sewage treatment plant which incorporates the newest technologies - used in, for instance, Ejby Mølle - is a costly affair. But these investments need to be part of the strategy already now according to project manager of PIONEER_STP, Associate Professor at DTU Chemical Engineering, Gürkan Sin.

With the increasing focus on sustainable growth and creating value from water, EU member states have still to invest significant resources to upgrade their wastewater treatment infrastructure as required by the enforced regulations. For example, by 2017 the investments in European sewage treatment plants expected to reach EUR 37.6 billion. In such a market scenario, the scope for innovation in municipal sewage treatment plants is strategic indeed. Key barriers to exploitation of innovations in wastewater treatment sector are not only the lack of incentives, but also the risk aversion of water utilities. Understandably, the water utilities are resistant to the idea of moving from conventional to highly efficient new concepts with added benefits for recovery of resources”, says the Associate Professor who has been researching smart wastewater treatment for 20 years.

But the current perception of sewage treatment plants as too expensive or risky, should not stop us from developing and using new technologies.

We cannot afford to go on and do things as we have always done. The new technologies needed are already here and even better ones are being developed as we speak. And since experience shows us that the investment is usually recovered within 20 years, we should really instead consider the potential in exporting these new green and environmental technologies. What we need now in Denmark specifically, is for the government to start providing incentive mechanisms for Danish the water companies, utility companies and research institutions to research and bring new solutions and concepts for plants”, says Gürkan Sin.

Using Big Data to solve big treatment issues

According to the researchers at DTU Chemical Engineering, we need solutions on a whole new level. The smart water management for a Smart City means effectively planning, developing, distributing and optimizing the use of water resources. To do this, we need to know how to utilize Big Data analysis and intelligent tools while developing the Smart Cities. But all this requires more research into how we can create a synergy among The Process knowledge, Big Data and The Internet of Things in our existing treatment plants.

Sewage water treatment is one of the most influential ways in which we can materialize effective water management for creating societal and economic value. Also, it’s an important platform on which we can develop and demonstrate new emerging concepts such as ‘circular economy’ and ‘urban biocycle’. So, apart from being an essential part of the solution to overpopulation – one of the future global challenge, it may also prove to inspire new holistic technologies which can be used in other areas of the Smart City. But it requires a holistic approach from decision makers so that they don’t only focus on delivering lampposts that turn on as pedestrians walk by, while forgetting about the water resource running in the sewers beneath their feet”, says Gürkan Sin.

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