Study on enhanced bioremediation effect of oil-bearing dredging sediment

To solve the problem of difficult treatment of oil-bearing dredging sediment, the effects of three methods of microbial remediation, phytoremediation and combined bioremediation on the treatment of oily river dredging sediments were compared and studied, and the influence factors of microbial remediation were explored through static bacteria-fling tests. The results showed that the combined remediation method was better than the single biological method in treating bottom mud. The oil content of the treated sediment was 1.21g/kg, and the removal rate was 95.31%; the organic matter of the treated sediment was 72.30g/kg, and the degradation rate was 37.33. %, which can meet the requirements in the “Control Standards of Pollutants in Sludge for Agricultural Use (GB4284–2018)” and can be used for agricultural purposes.

Influence of calcined mud on the mechanical properties and shrinkage of self-compacting concrete

The use of SCC has a particular interest in terms of sustainable development. Indeed, their specific formulation leads to a greater volume of dough than for common concretes, thus, a larger quantity of cement. However, for economical, ecological and technical reasons, it is sought to limit their cement content [1]. It is therefore necessary to almost always use mineral additions as a partial replacement for cement because the technology of self-compacting concretes can consume large quantities of fines, in this case calcinated mud issued from dams dredging sediments that can give and/or ameliorate characteristics and performances of this type of concretes. Four SCCs had been formulated from the same composition where the only percentage of calcinated mud of Chorfa (west of Algeria) dam changed (0%, 10%, 20% and 30%). The effect of calcinated mud on characteristics at fresh state of SCC according to AFGC was quantified. Mechanical strengths and shrinkage deformation (total, autogenous, drying) were evaluated. The results show the possibility to make SCCs with different dosages of calcinated mud having strengths that can defy those of the control SCC. The analysis of free deformations indicates the beneficial impact of the mud by contributing to decrease the amplitudes of the shrinkage compared to those of the control SCC.