The performance of a healthcare waste Pyrotec Model 8 incinerator at Muhimbili national referral hospital in Dar es Salaam - Tanzania was investigated using two different types of healthcare wastes namely sharps waste and other waste (mass/weight) and as fractions. The other independent factor used in the investigation was diesel oil consumption. The Pyrotec Model 8 incinerator performance was evaluated by determining how these factors affected the amount of ash residue, the percentage of weight reduction, incinerator capacity and efficiency. The numerical quantities used for independent variables were randomly selected which included low, mid and high levels. The Factorial method with Mixture Historical Data Design type of research methodology was selected for analysis because of its capability to allow for the investigation of the main and interactive effects between the independent variables and on the response The analysis tools included Design Expert Version 7.1 and SigmaPlot 10.0. Results showed that weight reduction increased with increase in sharps waste for all quantities of the fraction of sharps waste. It was concluded that the level of other waste charged had no significant effect (p > 0.05) on the percentage of weight reduction at quantities of total waste below 940 kg/weight but in the presence of high levels of total waste above 960 kg/weight there was a possible interactive effect that influenced the observed high percentage of weight reduction. Also, in order to realize high quantities of weight reduction during the incineration process, the sharps waste and diesel oil consumption quantities needed to be high. As a recommendation, it is better to operate the Pyrotec Model 8 incinerator in terms of weight of sharps waste than in terms of the fraction of sharps waste.
Keywords: Incinerator efficiency, healthcare waste incineration, ash residue, weight reduction, sharps waste.