Review on Phosphorus Recovery as Struvite from Wastewater

Wastewater treatment plants, particularly anaerobic digesters, face significant challenges related to the deposition of struvite, a mineral scale composed of magnesium ammonium phosphate hexahydrate. The formation and accumulation of struvite can lead to blockages in the treatment system, reducing flow rates and overall plant efficiency. This article explores the necessity of struvite removal for proper plant function and the potential for struvite recovery due to its rich nutrient content, specifically phosphorus and nitrogen, which can be repurposed in agriculture. Struvite recovery not only mitigates mineral deposition problems but also addresses the ecological risks associated with nutrient-rich effluents. The excess nutrients in wastewater effluent can contribute to water pollution, leading to eutrophication, algal blooms, and oxygen depletion, negatively impacting aquatic ecosystems and aquatic life. Furthermore, as the world's phosphorus reserves are finite and depleting, recovering phosphorus from wastewater aids in conserving this non-renewable resource. To facilitate efficient struvite recovery, it is crucial to control the formation of struvite crystals. Key factors affecting this process include pH, temperature, supersaturation, and mixing energy. Understanding the optimal conditions for these parameters is vital for maximizing phosphorus recovery. Various technologies such as chemical precipitation, biomineralization, seeding, ultrasound, and electrochemical are being studied to enhance struvite recovery, offering sustainable and innovative approaches to address this challenge. Overall, this review explores the various techniques and technologies utilized to recover phosphorus in struvite form which contributes to the efficient and sustainable management of wastewater treatment systems.