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Effects of alkaline hydrolysis and autoclaving on inorganic components present in healthcare waste
Pinho, S.C.; Almeida, M.F. & Nunes, O.C.
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 °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 O2/l of chemical oxygen
demand and 14.9 g O2/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.
Keywords
Medical waste; Hospital waste; Wet treatment; Thermal analysis; Principal components analysis
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