Phosphorous (P) is an essential, indispensable, but non-renewable, nutrient used as a fertilizer for the growth of all crops. However, excessive use and potential discharge of P into the environment can lead to eutrophication, which results in algae blooms and dead zones. Therefore, recovering P from waste streams has become a major objective both to provide new sources of fertilisers and to prevent pollution.
The Phos4You project, funded by Interreg North-West Europe programme, specifically targets phosphorus recovery from municipal waste water treatment plants (WWTPs). Six different demonstrators of innovative P-recovery technologies will be constructed and operated in real life conditions for municipal sewage water.
Scotland is considered as 97% rural with around 1600 waste water treatment plants serving communities with less than 500 persons. In small waste water treatment plants such as these, nutrients are usually not recovered, potentially leading to eutrophication problems when the waste water is discharged. Recovering P from these decentralized small waste water treatment plants requires systems offering robustness, low maintenance and adapted to a high variability of P in wastewater.
Glasgow Caledonian University (GCU), as part of the Interreg North West Europe Phos4You project, is evaluating a microalgae phosphorous recovery technology as part of its focus on technologies adapted to remote, rural and island locations in Scotland. The extremophile microalgae Chlamydomonas acidophila, which grows at a pH of 2-3, is being tested in this context for its high phosphorus and nitrogen uptake rates (up to 90%) whilst operating at low light intensities.
The novel, internally illuminated Pandora PBR™ photobioreactor (PBR) designed, developed and built by ASLEE partner Xanthella, is being considered for scale-up testing of this nature-based technology.
GCU and Xanthella are in discussions about how algal production can be enhanced and how the species used in wastewater treatment can grow and recover nutrients in their manufactured systems.