Ecological parameters and disinfection effect of low-temperature laundering in hospitals in Slovenia

The aim of this research was to determine the influence of laundering procedures on the ecological parameters of wastewater and the electric energy consumption. Laundering procedures were simulated in a laboratory washing machine and the parameters temperature, duration and concentration of disinfection agents were varied until the optimal conditions were found for low-temperature laundering while achieving an appropriate disinfection effect with peroxyacetic acid and minimal damages to the textiles. The disinfection effect was determined using standard bioindicators Enterococcus faecium, Staphylococcus aureus, Enterobacter aerogenes and Candida albicans. The optimal low-temperature laundering procedure at 40 °C was then evaluated according to the Slovenian regulations for wastewater reuse and the toxicity of the wastewater on activated sludge as well as the wastewater biodegradability were determined. It was found that an optimal low-temperature laundering procedure at 40 °C decreased the energy consumption while reaching an adequate disinfection effect with somewhat higher dosages of chemicals and with lower damages to the textiles due to lower washing temperatures. The wastewater was found to have a certain level of pollution and was biodegradable and can therefore be treated using biological treatment.