Sharps waste is part of infectious waste generated in health facilities, management of which is critical. This study aimed at assessing the sharps waste management practices in a referral hospital. The study was conducted at Muhimbili National Hospital (MNH) in Dar es Salaam, Tanzania. Data on sharps waste containers (SWCs) management in generation rates was collected for 60 days, while waste incineration data was collected from 65 randomly selected days. This study gives a picture on how sharps wastes are managed from generation to final disposal. The average weight per used safety box observed in this study (1.54 kg/box) was far above the average weight of a normally filled safety box (0.79 kg/box) indicating that most of the safety boxes are overfilled at MNH. The overfilling of SWCs at MNH was at an average of 10.7% of all the SWCs collected, with a maximum value of 30%, indicating a problem in sharps waste management within the hospital. The sharps waste generation rate observed in a referral hospital (40.8 kg/day) was higher than values reported in district hospitals, but the sharps waste proportion in the infectious medical waste incinerated at MNH was low (at 4% on average). Increasing sharps waste proportion in the waste load increased the incinerator performance in terms of fuel effectiveness. The amount of ash collected from the incinerator per day was observed to be minimal compared to literature data. The final ashes were 5.4% of the total waste loaded, which indicates that the incinerator is more effective in weight reduction, rated at 94.6% efficient.

The aim of the study was to analyze the performance of large scale incinerator installed in a referral hospital. The study involved weighing and loading infectious waste of different composition (sharps and other waste), recording temperatures in the primary and secondary chamber with time, fuel used and collecting and weighing the bottom ash for 65 days. The analysis shows that the incinerator on average uses 362 L/day (45 L/h) to incinerate 945 kg of medical waste (40.8 kg/day of sharps waste and 904 kg/day of other waste), generating 51.2 kg of ash daily. The observed fuel consumption rate was too high necessitating corrective action. The average weight reduction was 94.6%. The study shows that the average sharps waste composition for medical waste incinerated was 4.3% and other waste was 95.7%. The incinerator capacity ranged between 100 and 130 kg/h. The fuel effectiveness ranged between 2.0 and 3.0 liters of diesel per kg of waste incinerated. The fuel effectiveness increased linearly with total waste incinerated and incinerator capacity, respectively, depending on the fuel consumption rate.

Temperature profiles and cycle times in a large-scale medical waste incinerator installed in a referral hospital were used to assess the performance and functionality of incinerator. The study was conducted using data collected from 8 cycles per days for 67 days. For proper combustion and destruction of toxic components in the primary chamber and destruction of pollutants and toxic components in the flue gas, it is desired to reach the maximum temperature in the chambers faster and maintain this maximum temperature for an extended time interval. The primary and secondary temperatures T1 and T2, respectively, were recorded at an interval of one minute for different cycles. Different amounts of wastes with varying proportions of sharps and other wastes were loaded into the incinerator and temperature profiles recorded. The analysis shows that the incinerator works at primary temperature less than the required recommended by manufacturer while the secondary chamber operates between 600 and above 950˚C, although higher temperatures up to 1020˚C were observed. The average load preparation time was observed to be 14.6 minutes, while the chamber preheating time before daily initial loading was 25.45 minutes. Both temperature profiles were observed to have similar shapes for all combustion cycles studied, except when incinerator malfunctioning occurred. The average cycle time was established to be 32.7 minutes and 28.97 minutes based on time to drop to 550˚C after the maximum temperature and loading time intervals, respectively, although longer cycle times were observed. Temperature drop in both combustion chambers as a result of waste charging was observed in the interval of 5 minutes. The chamber heating rate was observed to decrease exponentially with time during both preheating and incineration operation.