Phosphorus (P) is a finite, life-essential, element required for all living organisms. P is an important constituent of our food chain, present in fertilizers, animal feed stocks and our food: meat and dairy diets are P-intensive. P is also contained in household detergents and pharmaceuticals.
We should be concerned about the global supply of P for two main reasons:
- Firstly, natural rock-P reserves are limited and in decline. Current P supplies are mined from the ground as rock-P and are found in only a few countries, Morocco, China, USA and Russia. Ireland and Europe are therefore vulnerable to P scarcity.
- Secondly, the inefficient use and over exploitation of P has negative impacts for water quality, causes eutrophication, toxic algal blooms, lowers biodiversity and the loss of ecosystem services.
As such, it is essential that sustainable technologies are trialled, developed and implemented to not only remove P from waste, but recover it for future long-term use. Recycling of P from waste will help towards ensuring global food security and preventing further deterioration in water quality, given increasing population growth and agricultural intensification to meet global demands for food. Sustainable P management strategies driven by legislative controls, for industry and agriculture, are also a key driver for change.
The two main inputs of P to surface waters include:
- Point sources – e.g. wastewater treatment works; septic tanks; industry
- Diffuse sources – e.g. agriculture
Society must therefore seek to migrate from our current practice of being a ‘linear economy’ whereby we dispose of P in waste, to a ‘circular economy’ were we aim to recover, recycle and reuse P from waste. ‘Closing the loop for P’ is the primary ethos underpinning P-sustainability. Raising awareness of the issues surrounding P sustainability is also important when engaging stakeholders in the journey from P-unsustainable to P-sustainable practices.
The wastewater processing industry offers a unique opportunity to develop novel technologies to remove and recover P. Current P removal methods in wastewater treatment works include:
- Physical – e.g. incineration; gasification
- Chemical – e.g. precipitation with aluminium, iron & calcium salts; struvite; ion exchange media and resins
- Biological – e.g. constructed wetlands; enhanced biological phosphate removal (EBPR); polyphosphate
The successful adoption of emerging technologies for the recovery of P is driven by efficiency, economic viability, purity and/or bioavailability of the recovered product and legislation.
The overall aim of this EPA funded project is to investigate P sustainability within the wastewater sector in Ireland and develop innovative technologies to recover P from wastewaters.