Recovering a crucial and non-renewable resource from wastewater

Sara Abu-Obaid
Sara Abu-Obaid conducting research.

Phosphorous (P) is a critical component of biological processes. Yet, its over-enrichment in water bodies, known as eutrophication, can have detrimental effects on aquatic ecosystems. As a non-renewable resource with no known alternatives, it is important to recover P from wastewater. Sara Abu-Obaid (PhD candidate), supervised by Professor Ramin Farnood and Adjunct Professor Shahram Tabe, is looking to do just that.

“Eutrophication can lead to harmful algae blooms, which threaten the quality of drinking water and fish habitat. It also causes degradation of recreational opportunities and hypoxia, a state in which oxygen is so low in water that it kills fish, depletes valuable fisheries, disrupts the food chain, and the list goes on. However, phosphorous is essential for many industries, especially fertilizer production,” explains Abu-Obaid.

Her research project entitled, Fabricating Novel Mixed Matrix Membranes for Phosphorous Recovery from Domestic Wastewater, aims to contribute to a circular economy by recovering P. Unlike traditional P-removal methods normally employed in wastewater treatment plants, Abu-Obaid explains that membranes offer a chance to recover this valuable resource.

The use of membranes for P removal from water is normally avoided due to the high pressure and energy requirements of the process. This is because traditional membranes use size exclusion to ‘filter’ out the P. Since P is an ion, the membrane would have to be practically non-porous to achieve that, therefore requiring high pressure and energy. Abu-Obaid is fabricating low-pressure mixed matrix membranes to remove P from water and reducing its concentration to meet guidelines for environmental protection.

“The membranes I am using do not rely on size-exclusion, instead they utilize nanomaterials grown on the surface and inside the pores of the membrane to remove P from the water. This allows us to benefit from the use of nanomaterials without having to worry about separating them from the water after use. Using nanomaterials for water treatment remains a challenge due to fear of leaching and difficulties with separation after use. However, anchoring them on the surface of support materials, such as membranes, allows us to utilize their benefits without suffering from their possible drawbacks,” details Abu-Obaid.

The Fabricating Novel Mixed Matrix Membranes for Phosphorous Recovery from Domestic Wastewater project is funded by the University of Toronto, MITACS, and the Ontario Graduate Scholarship (OGS). Abu-Obaid hopes to publish her findings soon.