Communities would be better able to manage rainwater and wastewater using software developed at a university in Germany.

Around half of the world's population still lives without piped sewerage, and new urban areas are constantly being built without proper drainage. Now a start-up from the University Kaiserslautern-Landau in south-west Germany has developed a new software platform called Ziggurat, which can automatically plan and optimise drainage systems sustainably, helping build resilience in the face of increasingly unpredictable climates.

High income countries like Germany have well-developed infrastructure, with sewer networks and wastewater treatment plants, but the situation is different in some less developed countries. Informal settlements known as shantytowns or favelas, where corrugated iron huts stand close together, alongside piles of rubbish and stagnant sewage, exist in many areas of the world.

With Sustainable Development Goal 6, the United Nations has set a goal of providing access to clean water and sanitation for all. To achieve this, corresponding infrastructure is needed, but planning sewer networks for wastewater, rainwater or combined sewage is complex and requires a great deal of expertise.

As well as sewerage, the technology can take into account blue-green infrastructure - networks of natural and semi-natural areas that can deliver a wide range of environmental and social benefits. Blue-green infrastructure can be made available for potential water storage and, along with certain technical measures, can make infiltration and evaporation of rainwater possible close to where it falls.

"Various parameters play a role, such as layout, the degree of centralisation, sewer diameters and gradient, laying depths, pumping and storage facilities," says Timo Dilly, an engineer from the founding team.

"It is based, among other things, on linking a large number of generally applicable technical rules of civil engineering planning and mathematical methods that can be used to generate sensible solution variants. We have developed our own algorithms for this. All this is based on current findings from our own research in urban drainage and hydroinformatics."

Climate change also plays a role in the planning of such drainage systems, as Dilly explains, "Dealing with rainwater has to be completely rethought when you consider increasing weather extremes.

"We need ways to store rainwater, but also natural elements such as sufficient green spaces. This can improve the urban climate in hot summer months."

Blue-green infrastructure plays an increasingly important role in the planning of new urban drainage systems, and Dilly says Ziggurat has incorporated this. This makes the software suitable for any cities and municipalities that want to adapt their drainage systems in the future.

"With these measures, cities increase resilience to extremes, lower costs and reduce negative impacts on the environment," he says.

In the future, the research team at Kaiserslautern would like to create an online platform for Ziggurat, where interested parties can create an account for a fee. The team would also provides expertise and support in sewerage and drainage planning.

The company has been supported by EXIST grant from the Federal Ministry of Economics & Climate Protection and the European Social Fund for Business Start-ups from Science.