New Circular Economy Business Model for More Sustainable Urban Construction

Demo 1: Phosphorous extraction as a step in a cascading recycling of sewage sludge as SRM

Phosphorous extraction

Phosphorous (P) is one of 27 CRM in Europe for which supply security is at risk and economic importance is high. Therefore, its recovery is demanded and may create circular business opportunities also in the context of utilising waste streams generated by municipal services such as wastewater treatment for SRM-based construction products.
The main principle of circular economy is to maintain resource at the highest possible value in material flows as long as possible. CINDERELA will demonstrate how this principle can be applied on the example of phosphorus extraction from black water before it ends up in sewage sludge – a waste stream of use for manufacturing such SRM-based construction products as geotechnical composites.
Phosphorus together with other nutrients important for agriculture will be recovered directly from separated urine in the form of a liquid fertilizer.

The complete nutrient recovery (CNR) system is consisting of stabilization, purification and concentration of the urine. A CNR approach has a number of important advantages, such as:

  • nitrogen and valuable secondary nutrients (boron, iron, nickel, …) are recovered along with the phosphate;
  • the full waste is treated, with full removal of micropollutants, pathogens, and bad odour from urine;
  • a liquid high-grade organic fertilizer is produced, which can be directly used for hydroponics/urban farming, and distilled water is obtained as a valuable by-product.

After CNR process urine enters sewage path again where finally sewage sludge without the extracted phosphorus and other nutrients can still be recycled into SRM-based construction product generating value as input material. The modular and mobile unit for extraction of nutrients from urine will be tested in Amsterdam (The Netherlands) and in Maribor (Slovenia). To showcase the full cascading recycling approach, sewage sludge, after phosphorus extraction, will be applied for production of SRM-based construction material (geotechnical composite) at the Umag site demonstration pilot.