”An important breakthrough for circular nitrogen recovery”

Swedish environmental company Ragn-Sells, through its innovation subsidiary EasyMining,has been granted 1.8 million euros from the European Union. The project’s objective is to develop a patented circular method for recovering nitrogen from sewage water and allowing it to be used again as agricultural fertilizer.The method is an important breakthrough, not least from a climate perspective, says Swedish Water & Wastewater Association expert Anders Finnson.

– In the water and wastewater sector, we have sought solutions for recovering nitrogen from wastewater for a long time. If this project is successful, we are looking at a momentous breakthrough for nitrogen recovery, says Anders Finnson, Senior Environmental Advisor at Svenskt Vatten, the Swedish Water & Wastewater Association.

Mr. Finnson is also part of the reference group that will review Ragn-Sells' new method for circular nitrogen removal and recovery.Earlier this year, Ragn-Sells was granted 1.8 million euros from the EU's LIFE innovation funding program, allowing them to develop the method and eventually offer it to Swedish wastewater treatment plants.

– Nitrogen is the result every time we use the toilet. Today, wastewater treatment plants remove the nitrogen from the sewage water with the help of bacteria.The problem with this technique is that the nitrogen simply goes right back into the atmosphere. Then we use energy-intensive methods to extract new nitrogen from the air in order to produce one of the key nutrients in commercial fertilizers, says Anders Finnson.

Ragn-Sells' new method allows the nitrogen to be recovered directly at the plant.According to Anders Finnson, this would mean both large energy savings and a substantial reduction of emissions, such as the powerful greenhouse gas nitrous oxide (N2O).

The new method for circular nitrogen removal has been developed by EasyMining. This technique will now be further tested and verified in collaboration with Denmark’s largest wastewater treatment company BIOFOS, Lantmännen, and Ragn-Sells’ business area Treatment & Detox.

– We have high levels of ammonium in the so-called reject water or supernatant at the treatment plants; that’s the water which is produced when the residual sludge is dewatered.The reject water holds up to 20 percent of the total nitrogen quantities in the treatment plant.It is in the treatment of the reject water this new method will be tested, says Anders Finnson.

Mr. Finnson emphasizes that Ragn-Sells' method has the potential to double the proportion of nitrogen that is returned to agriculture. If the residual product from the wastewater treatment is of sufficient quality, it can be used as a nutrient directly on agricultural land, as it contains organic material, phosphorus and nitrogen.

– What ends up at the treatment plants is basically what we eat, so we should be able to bring these resources back to agriculture, says Anders Finnson.

If the tests at the wastewater treatment plant in Copenhagen are successful, Mr. Finnson envisions global potential for exporting the method.

– International exchange is of great importance in the water sector and Ragn-Sells' circular method for nitrogen recovery is of great global relevance. In other OECD countries, there are both treatment plants and tougher requirements for purification of wastewater, says Anders Finnson.

Almost 90 million people live around the Baltic Sea, almost an inland body of water sensitive to both phosphorus and nitrogen. For this reason, there are EU-requirements for phosphorus and nitrogen removal at wastewater treatment plants to which more than 10,000 people are connected.

– Environmental policy often imposes ambitious and long-term obligations, which makes it profitable for technology suppliers to develop new methods to reduce emissions. Since we have problems with eutrophication in the Baltic Sea, there will be increasingly stricter requirements to remove both phosphorus and nitrogen in the future, says Anders Finnson.

It will be up to the individual wastewater treatment plant to decide what method for nitrogen recovery to use.Therefore, Mr.Finnson emphasizes the importance of political governance in order to reduce emissions.

– A crucial step in increasing the return of nitrogen is that the government sets targets for how much nitrogen the wastewater treatment plants must recover.This, combined with demands for reduced emissions, would indicate a clear political direction for the treatment plants, says Anders Finnson.

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Fact sheet: The process
EasyMining’s nitrogen removal process is chemical in nature, as opposed to the bacterial methods commonly used in wastewater treatment plants in Sweden and Europe today. Water with a high nitrogen content, such as the water produced by the dehydration of sewage sludge, is treated with an adsorption agent, which causes the nitrogen to crystalize and precipitate. Next, the nitrogen is extracted from the crystals and may be used again, while the adsorption agent is circulated back into the process.

The method can be used on any water containing ammonium. The EU-backed project encompasses use in wastewater treatment facilities as well as runoff from Ragn-Sells landfills. Additional possible use includes treatment of manure and liquids from biogas production facilities.

Fact sheet: EasyMining
EasyMining is Ragn-Sells’ innovation company, focused on circular solutions for extracting resources from waste. So far, the company has commercialized three patented processes:

Ash2Phos, for extracting phosphorus and other resources from incinerated sewage sludge while separating out heavy metals and other toxins.

CleanMAP, a method for extracting ammonium phosphate from mining waste or other sources.

Ash2Salt, whereby potassium chloride, sodium chloride and calcium chloride are extracted from fly ash created by the filtering of smoke from waste incineration.

For more depth, please visit EasyMining’s web site.

Fact sheet: The European Union’s LIFE programme
The LIFE programme is the EU’s funding instrument for the environment and climate action. Founded in 1992, the programme has so far backed more than 4 500 projects. The 2014–2020 funding period has a budget of 3,4 billion euros.

More info can be found at the programme’s web site.

Fact sheet: Removing nitrogen from sewage water
Wastewater treatment facilities remove toxins from municipal sewage water, as well as nutrients such as nitrogen and phosphorus. In Sweden, towns of at least 10,000 people along large portions of the coast are required to remove nitrogen from their sewage water.

In order to combat eutrophication, the levels of nitrogen allowed in water passing from a treatment facility are subject to regulation. The nitrogen removal methods most commonly used today focus only on reducing nitrogen in release water, not on capturing the nutrient for use as an agricultural fertilizer component.