A challenge for a waste water treatment plant (WWTP) is to effectively separate phosphorus from the outgoing water, but also how to recycle the phosphorus that ends up in the sewage sludge. There are some developing and developed solutions out there today, but many of them offers only a small recycling potential for the phosphorus in the waste water/sewage sludge. In addition, the recovered phosphorus products are often not compatible with the requirements and needs of the farmers, i.e. not well known fertilizer products. The consequence is that it’s hard if not impossible to get a monetary value from the phosphorus in the sewage sludge.

EasyMining has a process called Ash2Phos that can extract phosphorus from ash of incinerated sewage sludge. The main advantage of the Ash2Phos process is that it produces well known products that today are commercially traded and accepted in agriculture. In addition, the process extracts more than 90% of the phosphorus from the sewage sludge ash and at the same time produce iron chloride and aluminium sulfate (precipitation chemicals). The catch is that the Ash2Phos process doesn’t directly use sludge but needs ash of incinerated sewage sludge for its process.The positive side is that almost all phosphorus in the sludge is recovered and that there is no need for new investment in the WWTP.

Incineration of sewage sludge is an effective way of reducing the residual mass from waste water treatment plants (WWTP) with around 90%. One problem is what to do with the ash from the incineration? EasyMining provides the perfect solution!

The Ash2Phos process requires ash that comes from incinerated sewage sludge. We estimate that a phosphorus content in the ash of at least 4 % is needed for the Ash2Phos process to be economically viable. The consequence and benefit is that the sewage sludge doesn’t necessarily need to be mono-incinerated (around 9% phosphorus content), but also can to some extent be co-incinerated with materials that produce low amount of ashes.

High energy consumption can be a hassle when producing water soluble MAP (mono-ammonium phosphate). The central part of the CleanMAP technology is to extract phosphorus from P streams in the form of pure, solid and water-soluble phosphate salts (MAP, DAP) in a cost-effective way. We promote three main benefits of the Clean MAP process:

Reduced capital costs
The CleanMAP technology renders entire plant sections to be unnecessary such as evaporators, steam distribution systems, condensation systems, effluent gas treatment systems, cooling water systems, and acid storage facilities. Capital costs for the new technology are lower than excluded plant sections.

Reduced operational and maintenance costs
Reduced operational costs are mainly due to exclusion of the need for steam for acid concentration, and no need for complex effluent gas treatment. Reduced maintenance cost is mainly achieved due to the absence of sludge and scale removal from evaporation systems.

Quality difference – technical grade vs. fertilizer grade
The CleanMAP technology enables direct production of MAP or DAP of technical grade. Separation of pollutants such as cadmium, uranium and fluorine is achieved. The products are well defined and completely water-soluble. Phosphorus concentration is about 20 percent higher than in ammonium phosphates of fertilizer grade.

We believe it’s important that fertilizers used for agriculture are safe to use when it comes to contents of heavy metals, pathogens and medical residue. Phosphate rock (raw material for phosphorus fertilizers) can contain impurities, such as, high levels of cadmium and uranium. Impurities are today not separated during the production process and end up in the phosphorus fertilizer products. A heavy metal, such as, cadmium that accompanies phosphorus fertilizers from for example phosphate-mines in Morocco (world’s largest deposits of phosphate rock) have proven to be toxic for human health and is one of six substances banned by the European Union’s Restriction on Hazardous Substances (RoHS) directive. Recent data from epidemiological studies suggest that intake of cadmium through diet are associated with a higher risk of developing endometrial, breast and prostate cancer as well as to osteoporosis in humans.

Our starting points when we created the Ash2Phos process was that our fertilizer products need to be:

  1. A product that agriculture want and use today
  2. Pure and safe to use
  3. Delivering high plant availability
  4. Able to be used for precision fertilizing

We have made a comparison between the Ash2Phos product and the products from competing technologies below.