In her thesis work, Ronja has investigated how and to which extent rainwater can be used as a part of the water supply for a planned new housing area in the Stockholm archipelago. She has also investigated the risk of seawater intrusion into the groundwater aquifer and suggested a possible technique for infiltration of rainwater to the aquifers. Additionally, the likely influences of changing precipitation patterns caused by climate change to a potential system of rainwater harvesting were also investigated.
After finalizing her studies at Luleå University of Technology Ronja Eränen has started her new career as environmental consultant at Sweco in Stockholm. In her new position, she works with investigations of polluted soils and groundwater due to e.g. old industrial activities and remediation of soil in such areas.