Recovery of Phosphate as Struvite from Wastewater Streams

Keywords: Phosphorus recovery, struvite, Pearl, WASSTRIP, Crystal Green.

Growing populations and changes in diet are resulting in increasing pressure on the phosphate cycle at a global scale; resulting both in increased dependence on mineral fertilisers for agricultural production yields, and in further pressure on aquatic environments from nutrient discharge at all points in the phosphate cycle. As a result there is a vital need to make more efficient use of the phosphate resources that are mined, and an increased focus on recovery and reuse of the phosphates found in various waste streams.

Over the past decade, recovery of struvite from various waste streams has been demonstrated to be an economically viable alternative that can address both of these objectives. This paper presents Ostara’s Pearl ^® nutrient recovery process, along with two case studies of its application to municipal wastewater and phosphoric acid industry process water. The improved nutrient use efficiency derived from the plant-activated citrate solubility of the recovered Crystal Green ^® fertiliser is also presented. These case studies along with additional opportunities for recovery and reuse of waste phosphates from manure, food and beverage industry and biofuels industries are revealing that significant improvements in the sustainability of the phosphate cycle are not only possible, they are already being implemented at a commercial scale.

Ahren Britton and F. Phillip Abrary, Ostara Nutrient Recovery Technologies Inc. Vancouver, Canada

16 pages, 6 figures, 2 tables, 8 references