IFAT | Environmental Impact in Recovering Phosphorus

Sewage sludge collects pollutants, but also nutrients, energy and minerals. These also include phosphorus. This finite resource must be recovered and recycled. The new Sewage Sludge Ordinance stipulates that by 2029, for example, 50% of the phosphorus demand must be recovered from wastewater.

"Phosphorus is a very important element, especially for agriculture. There is no plant growth, and therefore no agriculture, without phosphorus fertilizer. And phosphorus cannot be replaced by any other element".

Until now Germany had to import phosphorus. But there are new ideas to protect resources worldwide, reduce C02 emissions and to be economically independent.

"It is drastic that we have no phosphate deposits in Europe. All phosphate deposits are in North Africa, in China".

And that makes Europe politically and economically dependent.
Phosphorus can be extracted directly from the dewatered sewage sludge or - after incineration - from the ash. The goal: a high recovery rate, energy efficiency and low use of chemicals. And that by 2029. The clock is ticking.

"Some try the wet-chemical route, others the thermo-chemical route. Everything has its advantages and disadvantages. It will take a massive effort to achieve our goal.“

The EU project "Phos4you" is tests recovery using innovative technologies. At the wastewater treatment plant "Emschermündung" in Dinslaken, a special thermo-chemical process removes phosphorus directly from the dewatered sewage sludge without prior incineration.

"The idea behind the EuPhoRe process, is to incinerate the sewage sludge and produce a phosphorus fertilizer in one step."

Two steps become one! The sewage sludge is transported to the rotary kiln.
This is hermetically sealed and heated to approximately 700°C, to predry and thermo-chemically decompose the sludge into its individual parts. Then everything is incinerated and the gases remove pollutants. The phosphorus fertilizer is ready.

"The difference is that by adding additives such as chlorides, magnesium chloride, etc., we get the heavy metals out of this ashtray and thus have a product that is low in heavy metals with a very high phosphorus availability.

The EuPhoRe process produces 12.5 kg of phosphorus-containing ash from 100 kg of dewatered sludge, per hour.

"Our vision is that in the future we will have such a plant, or similar, at all major sewage treatment plants in order to recover the phosphorus from the sewage sludge.“

IFAT is the place to be when new technologies are presented, and IFAT is also the right platform for presenting such a new process.