Phosphorus Recovery (031-DP-5)
Discussion Paper Summary
Phosphorus is an essential element for all living cells, and thus is essential for our existence. Used by humans as an agricultural fertilizer, food and animal feed, in detergents and industrial settings, phosphorus, mined from phosphate rock, is a non-renewable resource; a substitute is not available. Phosphate is present, however, in significant amounts in animal manure and in wastewater.
The CRD has investigated phosphorus recovery from wastewater biosolids in order to gain insight into recovery technologies and Core Area wastewater. Phosphorus can be harmful to lakes, streams and marine receiving environments; it can also damage wastewater treatment systems. It makes ecological and economic sense to consider phosphorus recovery when planning for wastewater treatment.
Phosphorus Recovery Technology
Technologies for the recovery of phosphorus from wastewater and wastewater sludge are still in the embryonic stages of development. All suffer from challenges that limit their practicality.
Crystallization is the most promising technology in phosphorus recovery, and is currently in trial operation at the Lulu Island wastewater treatment facility and at the City of Edmonton’s Gold Bar WWTF. Recovery of phosphorus through growth of crystals has resulted in between 0.6 and 0.9 kilograms of phosphorus per 100 cubic metres of raw wastewater. This recovered phosphorus is then sold to recover costs.
Phosphorus Recovery Potential in the CRD
Using conventional secondary wastewater treatment in the Core Area, about 210 tonnes of phosphorus could be recovered each year, rising to 355 tonnes by 2065. Phosphorus prices are expected to rise as this resource is depleted. Phosphorus is thus a resource which could be recovered and sold to reclaim operating and maintenance costs of the wastewater treatment process.
© Image courtesy of Evan Leeson