The aim is the development of a cost-effective and modular filtration system with a new selective, biodegradable textile filter as the last purification stage for rainwater runoff. The combination with porous sol-gel coatings should enable the separation of heavy metals (zinc and copper) before the water infiltrates the soil body. The system will be the first on the market to be equipped with a monitoring system that provides data on the state of contamination in a central cloud and optimizes cleaning and maintenance. After being loaded with heavy metals, the textile filters will first be cleaned of heavy metals by acid treatment and then disposed of. A biodegradable three-dimensional textile fabric made of cellulose forms the basis. Several processes take place in parallel: selective adsorption of the heavy metals zinc and copper, physical particle retention, biological growth with retention of various micro-pollutants. A new type of monitoring system with online monitoring enables efficient management. This saves considerable maintenance costs and ensures the quality of the effluent.