The T&K-Environment investment project in the City of Mikkeli’s Hulevesi treatment project implements biocarbon hule and leachate treatment solutions for Mikkeli Pitkäjärvi and Ristiina. The project is a parallel project for Xamk and Mikkeli Development Company Oy, which implements a monitoring system for the storm water treatment system to be built in this project. Long-term work has been carried out in South Savo for the development and commercialisation of new bio-processed products, in particular biocoal. One of the most interesting new applications for biochar is the treatment of storm water. Biocarbon is very suitable for use in storm water structures, as biocarbon added to the soil improves the soil’s water retention capacity. Due to the increasing rainfall and rain intensity due to climate change, the treatment of storm water will play an increasingly important role in the management of water management within cities. Hulewater treatment is also important for water quality in water bodies. Projects include:1) Construction of the Hule Water Treatment System (City of Mikkeli)2) Monitoring of demonstration sites (Xamk)3) Activation of T&K activities and the assembly of operator networks to exploit the T&K environment (Miksei)4) Reporting and information (Xamk) The storm water treatment systems implemented as a result of the project package improve the quality of wastewater discharges into the Saimaa river basin. At the same time, the solutions function as a nationally significant research and development environment for storm water treatment, in which companies and research actors can develop and test new solutions and products. The projects further strengthen Mikkeli’s water know-how, support the objectives of the EcoSairila development platform and offer opportunities for companies to develop and test new storm water treatment solutions.