Controlling weeds on semi-paved surfaces is a labour-intensive job. The municipality of Pijnacker-Nootdorp has opted for greenSand semi -paving for the quay along the Speenkruid. This makes burning, steaming and treating the weeds with hot water superfluous. Olivine removes water and CO2 from the air through natural weathering. What comes out is a calcareous type of water containing dissolved CO2. The lime lowers the pH value (acidic) of the soil, makes weeds less likely and 60 tons of CO2 is cleaned up along the pacifier!