Accelerated reoxygenation of water bodies using hydrogen peroxide

This paper reports a laboratory study of an accelerated reoxygenation treatment of polluted water bodies, using hydrogen peroxide (H₂O₂): conditions such as the discharge of waters from domestic sewers or polluted storm-water resulting from intense rainfall that lead to a reduction in the level of dissolved oxygen (DO). We studied the water from rivers that make up the basin of the Lagoa Rodrigo de Freitas (LRF) lagoon, Rio de Janeiro, Brazil. When intense rainfall coincides with discharge from sewers, the polluted water may reach LRF. This has in the past led to episodes of critical deficit in DO in the waters of the lagoon, resulting in fish kill. To study this, we carried out experiments with water samples taken from the river feeding the lagoon. To study the accelerated reoxygenation of the river waters, we used different doses of H₂O₂. We concluded that the addition of H₂O₂ to the waters of the river during polluting events can prevent the level of DO in the lagoon going below a critical value. This treatment resulted in an immediate increase in DO that lasted hours and in the sustainability of the DO above the legal limit 5.0 mg L^?1, enough to avoid fish kill.