Sewage sludge consists of valuable components such as nutrients as well as harmful substances, e.g. heavy metals. For sludge with a low concentration of pollutants, its utilization in agriculture is the best way of sludge reuse. Carbon recycling is also possible by using disintegration in combination with anaerobic degradation processes. The other important compound in sludge is phosphorus, which is a limited resource on earth. Recycling options for phosphorus are also described in the paper. A safe disposal of the residues can be achieved by using incineration.