Effectiveness of Oxygen-Saturated Seawater Injections and Air Sparging Technologies in Remediation of Coastal Marine Sediments from Sludge

The occurrence of hypoxic muddy sediments on shallow beaches and other sheltered areas is a well-known environmental problem, which negatively affects coastal areas, tourism potential, the public use sediment biodiversity. usual solution limited to dredging removal sludge landfill site. In this study, laboratory-scale experiment was performed determine effectiveness two technologies: modification air sparging new approach based injecting oxygen-saturated seawater in (oxygen-saturated injections method), for remediating sediments, minimizing impact respect dredging. Our results showed that both technologies significantly increased dissolved oxygen content pore water, facilitating oxidation more than 90% organic matter, reduced inorganic compounds such as sulphide, with consequent increase sulphate concentration from 0.3 3.0 g·L?1. Moreover, rise redox potential ? 258 mV above 200 mV, dramatic drop chemical demand were also indicators oxic conditions had been restored. After 65 days, soft, black, high matter characteristic foul odour transformed into well-oxygenated sediment, low lost its initial shiny black colour odour. main difference between depth influenced by remediation; affected deeper clean pressurized injections.