Effects of alkaline hydrolysis and autoclaving on inorganic components present in healthcare waste

Abstract

In this work, samples of components usually present in healthcare waste, such as cotton, diapers, transfusion tubes, surgical gloves, examination gloves, adhesives, surgical masks, urine bag collectors, serum bottles and syringes, were subjected to alkaline hydrolysis or autoclaving and the effects of these treatments were assessed. Both treatments were carried out at 135 A degrees C, and the weight loss and the carbon loss of the components as well as the total organic carbon and the chemical oxygen demand in the effluents were determined. The biodegradability of effluents was assessed by measuring the biochemical oxygen demand after 5 days. Alkaline hydrolysis caused appreciable degradation in most of the components, with the adhesives and the diapers having the highest weight losses and carbon losses. Components made with low-density polyethylene, high-density polyethylene and polypropylene showed good chemical resistance with 2 M NaOH solution. The effluents obtained after alkaline treatment of healthcare waste are hazardous due to their very high alkalinity. The effluent obtained after treatment of a mixture of all components using a 2 M NaOH solution was biodegradable with the following parameters: 6.5 g C/l of total organic carbon, 29.8 g O-2/l of chemical oxygen demand and 14.9 g O-2/l of biochemical oxygen demand after 5 days. Although the autoclaving treatment degraded the components much less than alkaline hydrolysis, the effluents obtained from some components showed an appreciable organic load.