Why recover phosphate from wastewater?
19 April 2018
“life can multiply until all phosphorus is gone, and then there is an inexorable halt which nothing can prevent…We may be able to substitute nuclear power for coal, and plastics for wood, and yeast for meat…but for phosphorus there is neither substitute nor replacement.” Isaac Asimov (1974)
Phosphorous is an essential, limited, non-renewable resource that is necessary in supporting global food production. It is critical for plant and animal life; a key component of fertilisers and hence modern agriculture relies on it.
Most of the phosphorous used in agricultural fertiliser comes from the mining of Apatite ores. Phosphorous is globally concentrated, with sources of phosphate rock (Apatite ore) limited to very few countries. In Europe we are fully dependent on importing phosphate for using in our fertilisers.
With an ever-increasing population and subsequent growing demand for fertiliser for food production, the supply of phosphate is becoming critical. And since Apatite ore is a limited resource it needs to be preserved. Additionally, the mining and processing of the ore is an energy-intensive process which causes pollution.
Since phosphates are used so abundantly and they are becoming recognised as a limited resource, more research is being conducted into how we can recover and recycle phosphate.
Recovering and Recycling Phosphate
A large amount of phosphate from food ends up in municipal wastewater and sewage. Several technologies aim to recover this phosphate from wastewater for use in fertilisers, most of which focus on recovering the phosphate in a form known as a struvite.
Many sewage plants are already set-up to remove phosphates from effluent, in an effort to reduce pollution of surface water. As we discussed in our previous blog, while phosphates are essential to plant and animal life, in excess they can cause a type of pollution known as eutrophication. It is therefore extremely important for wastewater treatment plants to control the level of phosphorous which is discharged to attempt to minimise this risk. You can read more about excess phosphorous and eutrophication in our previous blog here.
The extraction of phosphates from municipal wastewater involves the recovery of phosphorous and separation of phosphates from harmful substances. Then this recovered phosphate can be used for fertilisation.
Research shows that phosphate recovery from municipal wastewater has the potential to effectively alleviate the problem of the depletion of this valuable, limited resource.
Can you see the benefits in recovering phosphate from wastewater?