Physical and chemical composition of hospital waste.

For selecting the most efficient treatment method of hospital waste, the composition analysis is generally considered to be the fundamental information. Currently, there are few studies regarding the characteristics of hospital waste. This study evaluated the physical and elemental composition of the hospital waste at the National Taiwan University Hospital (NTUH). The results should help us design an incinerator for the treatment of infectious waste, plastic syringes, pathological waste, and kitchen waste. During the study period, the estimated daily waste generation rate at NTUH was 4,600 kg/day, which consisted of 4,100 kg/day noninfectious refuse, 340 kg/day infectious waste, 70 kg/day kitchen waste, 50 kg/day pathological waste, and 40 kg/day plastic syringes. The NTUH waste consisted of 99.02% combustible wastes and 0.97% noncombustible wastes by mass. The combustible wastes constituted paper (16.17%), textiles (9.77%), cardboard, wood, and leaves (1.12%), food waste (21.51%), and plastics (50.45%). The noncombustible waste included 0.40% metal and 0.57% glass. Furthermore, the analysis indicated that the wastes contained 38% moisture, 4% ashes, and 58% solid with an average heat value of 3,400 kcal/kg. From the elemental analysis, the dominant elements were found to be carbon (34%) and oxygen (15%).