Municipal sewage sludges are often highly polluted with organics, such as hormones, antibiotics, endocrine disruptors, persistent organic pollutants
(POPs), and inorganics such as heavy metals e.g. cadmium, chromium, copper, nickel, mercury and zinc. In the last couple of years, the agricultural application
of sewage sludge has decreased in the European Union, while the interest in alternative sludge disposal routes to protect farmland and human health has increased.
However, following this strategy, nutrients (most notably phosphorus) are irreversibly lost and the need for mineral fertiliser products will increase.
The scarce resource phosphorus could be recovered if a sound recycling strategy is developed and applied.