About vivianite we have a large literature on its natural occurrences in different environmental conditions. Rothe and coworkers, 2016, proposed a review of "the nature, occurrence and environmental relevance of" vivianite. As explained by Silva et al., 2024, vivianite is a "mineral that can be associated with biogeochemical processes. The mineral is found in freshwater and marine systems as a biogenic product while it can undergo oxidation caused by the action of neutrophilic or photoautotrophic microorganisms" . For a recent review, see In industrial environment, vivianite can be found in wastewater treatment plants. As noted in Prot et al., 2021, the presence in wastewater sludge of soluble iron and phosphorus can lead to vivianite formation, that is to the "vivianite scaling" problem. "Vivianite scaling is widely occurring in wastewater treatment plant even though it is rarely reported". "Iron reduction appears to be the cause of vivianite scaling in anaerobic equipment. … Solubility of vivianite decreases when T>32 °C, favoring scaling in heat exchangers. … [Vivianite] is usually present as a hard and blue deposit that can also be brown or black depending on its composition and location" . However, vivianite can be turned into an important resource; this can happen by means of methods for the phosphorus recovery .