Abstract

Introduction: Medical wastes are among hazardous wastes and their disposal requires special methods prior to landfilling. Medical wastes are divided into infected and non-infected wastes and the infected wastes require treatment. Incineration is one of the oldest methods for treatment of medical wastes, but their usage have faced wide objections due to emission of hazardous gases such as CO2 and CO as well as Carcinogenic gases such as Dioxins and Furans which are generated as a result of incomplete combustion of compositions like PVCs. Autoclave is one the newest methods of medical wastes treatment which works based on wet disinfection. Methods: The statistical population in this descriptive, comparative study includes hospitals located in Isfahan city and the sample hospitals were selected randomly. To environmentally evaluate the Autoclave method, TST (time, steam, temperature) and Spore tests were used. Also, samples were made from incinerator’s stack gases and their analyses results were compared with WHO standards. Findings: TST and spore tests results were negative in all cases indicating the success of treatment process. The comparison of incinerator’s stack gases with WHO standards showed the high concentration of CO in some samples indicating the incomplete combustion. Also, the incineration efficiency in some cases was less than 99.5 percent, which is the efficiency criterion according to the administrative regulations of wastes management law of Iran. No needle stick was observed in Autoclave method during the compaction of bags containing wastes, and the handlers were facing no danger in this respect. The comparison of costs indicated that despite higher capital investment for purchasing autoclave, its current costs (e.g. maintenance, etc) are much less than the incineration method. Discussion: Totally, due to inappropriate operation of incinerators and lack of air pollution control devices, the use of incinerators doesn’t seem rational anymore. Yet, despite the inefficiency of autoclaves in treatment of bulky wastes such as Anatomical wastes, their usage seems logic considering the very low amounts of such wastes. Also, considering the amount of generated wastes in Isfahan hospitals, a combination of centralized and non-centralized autoclaves is recommended for treatment of infected wastes. Mobile autoclaves may also be considered according to technical and economical conditions. It must not be forgotten that the priority must be given to the establishment of waste management systems particularly to personnel training to produce less wastes and to well separate them.

Key words: Hospital Wastes, Infected wastes, Wastes Management, Incineration, Autoclave, TST Test, Spore Test.