Microbiological Hazard Analysis of Car Wash Wastewater

Abstract

Wastewater from car washes may contain many pathogenic microorganisms that can pose a hazard to human health through inhalation of bioaerosols generated during car washing. The aim of this study was to investigate which types of bacteria are present in the wastewater. Over 30 types of bacteria were determined in the examined wastewater, with the cells number at the level 2.86-3.71x106 CFU/mL. The complete inhibition of bacterial growth was observed for D-cycloserine and for a mixture of antibiotics (polymyxin B sulfate, Ceftazidime and Acryflavine HCl). E. coli bacteria were used to determine how the composition of chemicals used to wash cars affects their survival. It was found that the foaming agents (surfactants) do not have an antibacterial effect, unlike the alkaline agents used to remove insects (Insect). The chemicals present in wastewater promote bacterial mutation in the adaptation process. As a result, despite increasing the concentration of Insect solution to 0.5% and extending the contact time to 30 min the amount of bacteria cells in the wastewater decreased only from 2.93x105 to 5.56x102 CFU/mL.