Effect of phosphatation and calcination on the environmental behaviour of sediments

Abstract

a b s t r a c tDredging operations produce considerable quantities of materials, to be managed and this opens an opportunity for valorization in civil engineering. However, the contamination of the dredged sediments has become a major problem to solve. The major contaminants are heavy metals and organic compounds. This study focuses on the use of phosphoric acid (H 3 PO 4 ) to stabilize heavy metals from sediments and destroy organic matter by calcination at 650 °C with a goal of using sediments in roadworks. Several studies have been conducted in this field. The stabilized materials obtained have been used in civil engineering. The main purpose of this work is to discuss the environmental behavior of marine sediment treated by phosphatation and calcination. Two types of phosphoric acids were used. The pH dependence leaching test has been used as the basic characterization to evaluate the effect of the type of phosphoric acid on the metals behavior in a valorization scenario. The standard leaching test and the Toxicity Characteristic Leaching Procedure (TCLP) were conducted as compliance tests. In regards of the obtained results, the environmental assessment has also shown a reduction in the availability of targeted heavy metals in alkaline environment whatever the type of acid used for treatment. This opens opportunities for co-valorization.

From dredged sediment to supplementary cementitious material: characterization, treatment, and reuse

“…Sieving raw sediments through 120 μm and calcination at 850°C for 1 hour (Dang et al, 2013) Sediment from the northern coast of Brittany Washing process to reduce the salinity, decantation, drying at 40°C, sieving at 200 μm then calcination at 650 or 850 °C for 5 hours (Laoufi et al, 2016) Mud dredged from the Algerian dam of Fergoug Calcination at different temperatures, i.e. 750, 850 and 950°C, for 3 hours (Dia et al, 2014(Dia et al, , 2019 Dredged sediment from Dunkirk Harbor (north of France)…”

Micropollutant content of Sargassum drifted ashore: arsenic and chlordecone threat assessment and management recommendations for the Caribbean

“…The overall sample quantity was grinded with a Grindomix GM 200 Retsch apparatus till (< 63 µm). After this rst grinding, dry matter and mineral matter were determined thanks to NF EN 12880 (Chiffre et al, 2015) and NF EN 15169 standard (Dia et al, 2019), respectively.…”