Remediation of contaminated urban river sediment based to iron-rich substrate: A comparative study with chemical oxidants

Abstract

In situ sediment remediation is commonly used for controlling the release of pollutants (N, P, C and S) from polluted urban river sediments. The addition of oxidants can effectively solve the odour​ problem and control the conversion of sulphur in sediments. Laboratory experiments were established to explore the effect of improving contaminated urban river sediment quality with hydrogen peroxide, calcium nitrate, calcium hypochlorite and iron-based substrate (IRS). The results verified that the redox potential increased to 161 mV and 90 mV after 30 days of calcium hypochlorite and calcium nitrate treatment, respectively. The addition of calcium hypochlorite or calcium nitrate reached 97.9% and 94.8% high removal efficiency of acid volatile sulphide due to the oxidation. The addition of IRS decreased the ammonia and total organic carbon concentrations, indicating that the IRS were conducive to controlling the release of 73.2% of the total nitrogen (TN) from river sediment. The consequence also showed that compared with other oxidants, IRS had remarkable influences on the interstitial sulphate, iron and nitrate contents in the sediment, clearly showing comprehensive application prospects.