Recovery of phosphorus from aqueous media as vivianite by crystallization

Since phosphorus resources are limited, optimal management of available phosphorus (P) and phosphorus recovery is a vital issue for the entire world. Studies continue on more efficient and economical phosphorus recovery techniques from wastewater and sludge. Recovery of phosphorus as vivianite is a current issue worldwide and studies are ongoing. Vivianite is a valuable mineral used in some industrial facilities and agricultural activities. Therefore, recovery of P from wastewater based on vivianite formation not only contributes to the sustainable use of phosphorus but also provides potential economic opportunities. In this study, it was aimed to determine the recovery potential of phosphorus as vivianite and to evaluate the effects of operational conditions on phosphorus recovery. For this purpose, two types of lab-scale crystallizer, semibatch completely mixed and fluidized bed, were used. In experimental studies, the effects of operating parameters such as pH, Fe/P ratio, Fe feeding rate, and P concentration for vivianite crystallization were investigated. The highest phosphorus recovery was found at a Fe/P ratio of 1.8 and P removal efficiency of up to 69% was achieved by vivianite crystallization.