Algerian Journal of Engineering Research
Volume 1, Numéro 2, Pages 14-23
2017-12-01

Experimental Evaluation Of Pharmaceutical Products Effect On Activated Sludge Activity: Case Of Amoxicillin

Authors : Mahfoud Sakhraoui . Mossaab Bencheikh-lehocine . Rania Zerdazi-zamouche . Abdeslam-hassen Meniai .

Abstract

The presence of biologically resistant substances, such as antibiotics which are considered inhibitors, in wastewater deteriorates biological treatment systems (activated sludge) by reducing microbial activity which in turn impacts negatively carbonaceous treatment, solid- liquid separation etc. In this work, activated sludge under different conditions were used to evaluate experimentally the Amoxicillin effect and they were as follows: not adapted biomasses of conventional WWTP, adapted biomasses to the binary substrate (acetate and ammonium), adapted biomasses to the Amoxicillin and binary substrate, finely the biomasses adapted to another organic substrate (other than acetate). The experiments were undertaken using continuous aeration respirometric technique. This is based on monitoring oxygen uptake rate, of samples containing Amoxicillin and others free of it, as well as soluble COD and Amoxicillin, consumption kinetics using UV-VISIBLE absorbance measurements. The inhibition level was evaluated using the effective concentration index (EC index). Two ranges of Amoxicillin concentrations of 3 mg/l to 26 mg/l and 5 mg/l to 150 mg/l were used. Inhibition starts to appear at a low concentration of less than 3 mg/l in non adapted biomasses and in activated sludge adapted to organic substrate other than acetate, EC attains 14.71 % at a concentration of 11.5 mg/l for, however, a low S0/X0 ratio. Furthermore, the adapted activated sludge appeared to resist to Amoxicillin with a high concentration. It should be underlined that the results can be considered as preliminary, because, the antibiotic Amoxicillin trihydrate remains a very complex molecule and represents a different stress effect on the purifying bacteria. Further work is needed in order to evaluate the exact concentration in the low concentration range, and to determine the resistant germs through their insulation as well as the application of these protocols to higher S0/X0 ratios.

Keywords

Activated Sludge, Adaptation, Amoxicillin, Inhibition, Respirometry.