LAUSR

This manuscript investigates the effect of silver nanoparticles of different doses and shapes on different gram reaction stain bacteria found in wastewater and to make a comparison between the chemical and physical analyses for some water samples before and after treatment with AgNPs. Two shapes (rod, cube) and four concentrations of 0, 100, 10 and $${1\,\mu{g/ml}}$$1μg/ml of AgNPs were used on Klebsiella pneumonia, Bacillus cereus and Gardnerella vaginalis. The effect of the interaction between the best AgNPs shape and concentration on tap water inoculated with bacterial species and physical and chemical analyses of water before and after treatment with silver nanoparticles were also investigated. Based on the analysis of variance for growth reduction data for the three bacteria, the models showed significance at $${\alpha = 0.05}$$α=0.05. Generally, rod shape with concentration of $${100\, \mu{g/ml}}$$100μg/ml showed the best reduction results compared to cube-shaped particles with mean values of $${-67.48, -100}$$-67.48,-100 and −73.354 for G. vaginalis, B. cereus and K. pneumonia, respectively. Treating tap water inoculated with the bacterial species by silver nanoparticles showed no growth for the bacteria after 1 or 3 days. In general, tap water chemical and physical analyses values before and after treating with AgNPs were increased after treating the sample with AgNPs except for the pH where it shifted from 8.3 to 6.65. However, these values are still within the Saudi maximum limit except the values of turbidity. These results are encouraging for scaling up a treatment process using AgNPs.