Case Study

Microwave MedWaste Disinfection Studied

Microwave MedWaste Disinfection Studied

A study conducted by Ontario Hydro Technologies* shows the Sanitec microwave system to surpass the required microbiological destruction requirements for infectious wastes specified by the Ontario Ministry of Environment. A study conducted by Ontario Hydro Technologies* shows the Sanitec microwave system to surpass the required microbiological destruction requirements for infectious wastes specified by the Ontario Ministry of Environment.

The report cited these performance attributes of the system:

  • Single-person operation made possible by the system's automated end-to-end handling system
  • An average sound level exterior to the unit during operation of 47 dBA (12 dBA less than the street traffic around the hospital)
  • Use of 0.147 liters (of moistening) water per kilogram of waste--with no wastewater discharged to the sewer system.
  • No (detected) microwave leakage during the one year demonstration
  • Acceptance of materials having high and low moisture content, sharps, and primarily microbiological waste.
  • Average energy costs of approximately Canadian $0.01 per kilogram.

During a two-and-a-half-month period of the year-long study at The Toronto Hospital, the system processed 67,585 kg of waste at an average energy consumption of 0.181 kWhr/kg (0.091 kWhr/lb). (This result is consistent with previous findings in a study by Southern California Edison.) The study's report notes that the system was somewhat underutilized in the demonstration and that electrical usage could drop to 0.13 kWhr/kg (0.065 kWhr/lb) at processing rates of 2000 kg/day.

O&M costs of the system, which operated at 1300 kg/day during the period that results for the report were demonstrated, were Canadian $0.16./kg (US $0.045 /lb. The costs are calculated to drop to Canadian $0.11/kg (US $0.033/lb) at 2000 kg/day.

The system reduced the amount of biomedical waste requiring incineration at a large Canadian hospital by 90-95 percent, with the remaining 5-10 percent consisting of recognizable anatomical and cytotoxic wastes. As with any waste-treatment system, proper preparation (including waste segregation and shredding) was important to successful processing.

Ontario Hydro's report recommends the microwave technology as appropriate for up to 95 percent of the biomedical waste currently being incinerated in Canada. The report concludes that microwave technology, compared with other alternative waste treatment technologies, provides effective, efficient treating of biomedical waste.

* In addition to Ontario Hydro Technologies, participating entities included the Ontario Ministries of Health and Environment and Energy, Sanitec, MEDispose (the Canadian supplier), The Toronto Hospital, The Hospital for Sick Children, and the Canadian Electrical Association. For a complete copy of the report, or more information, contact Joe Delloiacovo, Sanitec, Inc., 26 Fairfield Place, West Caldwell, NJ 07006. Tel: 201.227.8855; Fax: 201.227.9048.

Edited by Paul Hersch