EasyMining´s Ash2Phos technology extracts phosphorus and other resources from incinerated sewage sludge.
The Ash2Phos process can transform the sludge ash into a raw material for phosphorus extraction and thereby be a part of a circular solution for phosphorus management. The process consists of three steps: a first acidic step, a second alkaline step (where intermediate products are produced), and finally a conversion step where the intermediates are processed into final products.
The main inputs of the process are
- Ash from incinerated sewage sludge
- Acid (hydrochloric acid, HCl)
The process consists of several successive chemical reactions undertaken at room temperature (though one process step may benefit from a temperature of 40°C). 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 all input chemicals become part of the products.
From sewage sludge ash to premium phosphates.
Phosphate rock is the primary raw material for phosphate production, but unfortunately mineable phosphate rock is a limited non-renewable resource that may only last an additional 100 years. Large amounts of phosphorus end up in manures and in urban waste, mainly in sewage sludge and slaughterhouse waste.
Today EU are countries re-circulating phosphorus by distributing 48% of the sludge back to farmland. The positive aspect is that phosphorus is re-circulated, but it’s not problem free. Sewage sludge can still contain viruses, heavy metals, and other substances that can be harmful to human health. Currently 27% of the sewage sludge is landfilled or used in other ways that rarely recover any phosphorus. 25% of the sludge is incinerated and the ash is mainly landfilled.
High concentration of phosphorus
Ash from mono-incinerated sewage sludge has high concentrations of phosphorus (7-10%), iron (10-15%), and aluminium (5-10%), but also contains unwanted heavy metals such as cadmium. The high content of metal has up until now created an obstacle for possible applications for the phosphate-rich ash.
As long as society exists, sewage will be produced. With the end of phosphate rock reserves in sight and continued need for phosphorus in our society, phosphorus recycling from sewage will be an inevitable part of our future society.
EasyMining is focused on creating circular material flows from waste. Phosphorus is an essential element for life and a key nutrient for agriculture. Via the food cycle, phosphorus ends up in sewage sludge. This sludge can be spread on agricultural land, used for soil production, put on landfills, or be incinerated. Incineration is today mainly used as a method to reduce the amount of waste to landfill, or destruction if the sludge quality is too low for other uses.
Ongoing upscaling process
The phosphorus content of ash from incinerated sewage sludge is high, and through our unique patented process, we can produce clean commercial phosphorus products from the ash. In addition to phosphorus, the Ash2Phos process can recover precipitation chemicals and at the same time remove heavy metals.
Easymining is currently working with COWI as an engineering partner in the development of the first Ash2Phos factory. Upscaling of the process is ongoing and a full-scale plant in southern Sweden is being planned. In parallel, several additional plants in Europe are currently being considered with different partners.