Optimized evaporation technique for leachate treatment: Small scale implementation.

This paper introduces an optimized evaporation technique for leachate treatment. For this purpose and in order to study the feasibility and measure the effectiveness of the forced evaporation, three cuboidal steel tubs were designed and implemented. The first control-tub was installed at the ground level to monitor natural evaporation. Similarly, the second and the third tub, models under investigation, were installed respectively at the ground level (equipped-tub 1) and out of the ground level (equipped-tub 2), and provided with special equipment to accelerate the evaporation process. The obtained results showed that the evaporation rate at the equipped-tubs was much accelerated with respect to the control-tub. It was accelerated five times in the winter period, where the evaporation rate was increased from a value of 0.37 mm/day to reach a value of 1.50 mm/day. In the summer period, the evaporation rate was accelerated more than three times and it increased from a value of 3.06 mm/day to reach a value of 10.25 mm/day. Overall, the optimized evaporation technique can be applied effectively either under electric or solar energy supply, and will accelerate the evaporation rate from three to five times whatever the season temperature.

Association between plasmid carrying an expanded-spectrum cephalosporin resistance and biofilm formation in Escherichia coli.

The formation of biofilm is a universal bacterial survival strategy. Biofilms occur on inert and living support in the natural environment and in industrial installations. This microenvironment leads to the horizontal transfer of genetic material between bacteria by physical contact. In order to evaluate the relationship between biofilm-forming capabilities, surface characteristics and plasmid content we purified from Salmonella a plasmid conferring resistance to cephalosporin and transferred it by electroporation to E.coli DH10B originally unable to form biofilm in inert surface. We demonstrated the association between a plasmid conferring resistance to expanded-spectrum cephalosporin and biofilm formation. We also noted that this plasmid influences the cell surface properties and cell motility.