Water treatment plants as resource hubs: enabling circularity by maximizing recovery of iron coagulants, phosphorus, silicate materials and others with the Sahara process

Safe and efficient use of resources will be central in the transition to a circular economy. The sludge obtained after water treatment contains valuable resources (phosphorus, iron, aluminium etc.) that today unfortunately are not utilized. Incineration of this sludge offers an effective way of removing pathogens and organic contaminants, reduces transports and concentrates the valuable resources. This project will investigate a process named Sahara, which aims to maximize the recovery of the valuable resources in the sludge ash and at the same time detoxify the ash from heavy metals. Sahara allows complete recovery of iron as high purity coagulant, increases the recovery efficiency of other elements and produces iron-free silicate sand. Sahara can redefine the water treatment sector, enabling treatment plants to become real circular resource hubs and reduce greenhouse gas emissions.