APPLICATION OF CALCIUM HYDROXIDE AS A TECHNIQUE FOR MITIGATION OF EUTROPHICATION IN RESERVOIRS IN THE BRAZILIAN SEMI-ARID REGION
hydrated lime, calcium hydroxide, phosphorus, eutrophication, sorption, reservoirs, semiarid.
Eutrophication is a process of increased primary production caused by increased input of limiting nutrients and represents a serious threat to aquatic ecosystems. This study investigated the potential of hydrated lime used in construction as a phosphorus sorbent in reservoirs in the Brazilian semiarid region. Through laboratory experiments, the sorption capacity of hydrated lime in distilled water and in water samples from two reservoirs was evaluated. The results demonstrated that hydrated lime had a high phosphorus removal capacity, both in distilled water and in natural waters, through P sorption and calcium phosphate precipitation. In addition, hydrated lime was effective in removing humic substances, contributing to improving water quality. Despite its efficiency, the application of lime increased the pH of the medium, an aspect that requires attention when applying this substance to natural waters. It is concluded that hydrated lime used in civil construction presents itself as a promising and low-cost alternative for controlling eutrophication in reservoirs; however, additional studies are necessary to optimize its application and mitigate the effects of increased pH.