Stormwater, ie rainwater and snowmelt, was previously seen only as a problem that needs to be transported away - a problem that was solved by sewer systems built already in the 1800s. Unfortunately, these systems are unable to meet all present and future needs; among other things, climate change has led to greater amounts of water falling down in less time than before, leading to overloading of the sewer system which can result in both flooding and overflow of wastewater.
Another problem is that stormwater when running through our cities, rinses pollutants from impervious surfaces like e.g. metals, PAHs (polycyclic aromatic hydrocarbons), oils, bacteria and particles from roads, buildings, parking lots etc. Today, most of this water is transported via sewer systems to the receiving waters wihtout being treated. The EU Water Framework Directive does, however, require that the water quality in our lakes and streams may not deteriorate. This requires that stormwater is treated in a completely different way than is the case today.
GreenNano takes a holistic approach to stormwater issues, through the combination of green infrastructure (such as green roofs, rain gardens, constructed wetlands and ponds) and advanced purification technology. By using green infrastructure stormwater is taken care of on the spot of precipitation, in a more aesthetically appealing way than the sewer systems prevailing nowadays. This reduces the water volume for overflow and stormwater minimizing the risk of flooding. Furthermore, green infrastructure removes nutrients and particles from stormwater, ie it acts as a pre-treatment for further purification with advanced purification technology, which in turn takes care of the pollutants.