RE-Fertilize

A circular solution for nitrogen recovery

Nitrogen is essential to life and is among the nutrients consumed in the largest quantities by all agricultural crops. However, today’s linear flow of nutrients (nitrogen, phosphorus and potassium), from fertilizer manufacturing to wastewater treatment plant (WWTP) via food production and human consumption, is not sustainable. 

The demand on nitrogen removal at WWTPs is increasing and nitrogen-containing effluents overall should be viewed as a nitrogen resource. Water streams with high ammonium content, such as reject from sludge dewatering or landfill leachate, are suitable for nitrogen recovery. 

EasyMinings new patented innovation enables efficient removal and recovery of ammonium from aqueous flows. The unique solution uses chemical precipitation of ammonium, by adding an adsorption chemical to the waste water. As a second step the captured ammonium is recovered in a conversion plant to a fertilizer and the adsorption chemical is regenerated to be used again.  

EasyMining is now working in a project to demonstrate this new, innovative removal and recovery process for ammonium nitrogen which can be used for different ammonium containing liquids and enables production of different ammonium products (e.g. fertilizers). This is an EU project, funded by the LIFE programme.

Background

Nitrogen fertilizers are today produced in the Haber-Bosch cycle which is energy intensive and relies on hydrogen gas produced from natural gas. Nitrogen from the air is converted into ammonia which then can be used in fertilizer products. Via food and humans, the nitrogen ends up in WWTPs. The nitrogen is through biochemical processes converted from ammonium into nitrogen gas which is released into the air. Thus the nitrogen in the form which can be used as a fertilizer is destroyed. If the nitrogen could be removed from wastewater but kept in the ammonium form, there would be energy and emission savings when the recycled ammonium is used in fertilizer products. 

In the sludge dewatering of the WWTP, a reject with a high ammonium concentration is generated. The reject is fed back into the main flow to the WWTP giving an internal load of nitrogen. Due to the relatively small flow with high ammonium concentration, this stream is suitable for ammonium recovery. 

Landfill leacheate, as well as other ammonium containing waste waters can also be viewed as a source for ammonium recovery. 

Solution

The solution 

EasyMinings process helps lowering CO2-emissions and prevents eutrophication by lowering nitrogen content and thereby improving the quality of the effluent. The RE-fertilize project creates a circular flow with clean ammonium products made from the nitrogen removed from waste water. The benefits of this are:

  • Prevent eutrophication  
  • Energy efficiency 
  • Resource efficiency 
  • Greenhouse gas reduction 
  • Cost efficient 

The process consists of several successive chemical reactions performed at elevated temperature but atmospheric pressure. There is no need for pressurized vessels or for exceptional materials to be used for the equipment. The mass balance of the process is favourable, since most input chemicals becomes a part of the product. 

The main inputs of the process are: 

  • Ammonium containing water 
  • Sulfuric acid 
  • Ammonia 

EU LIFE RE-Fertilize project

EasyMining has been granted 19 MSEK from the EU-LIFE program to create a demonstration plant to treat reject water at Biofos WWTP in Copenhagen and landfill leachate at Ragn-Sells landfill Högbytorp outside Stockholm. The fertilizer product will be evaluated by Lantmännen. The project will run until mid 2022.