ExtraPhos® recovery of phosphorus from sewage sludge

Environmentally friendly extraction with CO2

municipal sewage plant © hansenn/iStock/Thinkstock
Municipal sewage plant
Phosphate mining in Morocco © Michael Link
Phosphate mining in Morocco - Phosphate deposits are limited to a few mining sites worldwide.
The ExtraPhos® pilot plant © Kilian Schwarz
The ExtraPhos® pilot plant

Phosphorus is an essential »building block« for all living things. As a fundamental element in plant growth it is thus a major component of mineral plant fertilizers. In the environment, phosphorus usually appears as phosphate. About 85 % of all raw phosphates extracted go to the fertilizer market. Estimates of how long  conventional deposits can continue to cover the demand for phosphates range between 300 and 400 years. However, phosphates are excreted by humans and animals, so that phosphates are also contained in farm manure and sewage sludge. About two million tons of dry sludge mass accumulates each year in Germany, containing about 60,000 tons of phosphorus. Sewage  sludge is thus a possible source for phosphorus recycling. With the DBU’s support, the Chemische Fabrik Budenheim KG developed the ExtraPhos®process. With this process, phosphorus is separated from sewage sludge and thereby recovered. Carbon dioxide under increased pressure is introduced into the watersludge mixture, is transformed into carbonic acid, reduces the pH value and separates the phosphates from the sludge. The phosphates are then recovered in the form of calcium phosphate. The goal is to recycle in this manner up to 50 % of the phosphorus contained in the sludge.

The ExtraPhos®-Pilot plant

A mobile pilot plant runs since 2017. With this mobile plant, the process can be tested at different waste water treatment plants. It is planed to use the recovered phosphates exclusively in agriculture. In plant experiments the fertilizing effect of recycled fertilizers was comparable to conventional phosphate fertilizers. To this extent phosphate recycling represents an efficient method of sparing natural phosphate reserves.


Project implementation:

Chemische Fabrik Budenheim KG
Rheinstr. 27
55257 Budenheim
Telefon: 06139 | 89-0
E-Mail: info@extraphos.com


AZ 31590