CLASSIFICATION OF BIOMEDICAL WASTE
In India, MoEF, GoI (1998) has notified Bio-medical Waste (management & Handling) Rules -1998,which describes ten categories viz., Human Anatomical Waste; Animal Waste; Microbiology & Biotechnology Waste; Waste Sharps; Discarded Medicines and Cytotoxic Drugs; Solid Waste; Liquid Waste; Incineration Ash and Chemical Waste. Many regulatory definitions of regulated medical waste are based on ten broad categories defined in a guide on infectious waste management. The ten categories are: Cultures and Stocks; Anatomical Wastes (or Human Pathological Wastes); Human Blood, Blood Products, and Other Bodily Fluids; Sharps; Animal Wastes; Isolation Wastes; Contaminated Medical Equipment; Surgery Wastes; Laboratory Wastes; and Dialysis Wastes .
DISPOSAL IN 5 OUT OF 10 CATEGORIES OF SCHEDULE #1 OF BIO-MEDICAL WASTE (MANAGEMENT & HANDLING) RULES, 1998 RECOMMENDS INCINERATION
Process Description
Incineration is the process by which materials are burned, producing combustion gases and non-combustible ash residue. The combustion gases are either vented directly to the atmosphere, or to the atmosphere after treatment in air pollution control (APC) equipment. The non-combustible ash residue is removed from the incineration system or air pollution control equipment for disposal.
Medical waste incineration involves the burning of wastes produced by hospitals, veterinary facilities, and medical research facilities. These wastes include both infectious (“red bag”) medical wastes as well as non-infectious, general housekeeping wastes. The emission factors presented here represent emissions when both types of these wastes are combusted rather than just infectious wastes.
Three main types of incinerators are used: controlled air, excess air, and rotary kiln. Of the incinerators identified in this study, the majority (>95 percent) are controlled air units. A small percentage (<2 percent) are excess air. Less than 1 percent were identified as rotary kiln.
In general terms the Incineration process can be separated into the following key Steps
1. Waste preparation and storage;
2. Waste charging (i.e. transfer of waste and loading of wastes to incinerator);
3. Waste combustion (including use of supplementary fuel for start-up and maintaining combustion conditions);
4. Treatment of combustion gases and by products (ie APC equipment); and
5. Residue handling and disposal (this includes the handling and disposal of furnace bottom ash, material collected in air pollution control (APC) equipment, and other materials used/consumed in the process eg. Scrubber liquor).
Toxic pollutants from Medical waste incinerators
STANDARDS
- Combustion Efficiency – 99%
- Two chambers, primary between 750-850ºC, secondary between 1000-1100 ºC
- Gas residence time of 1 second in secondary chamber with minimum 3% O2 in stack gas
- Emissions (SPM < 150 mg/Nm3, NO2 < 450 mg/Nm3, HCl < 50 mg/Nm3) at 12% CO2 correction
- VOC in ash not more than 0.01%
- No chemical treatment with chlorinated disinfectants prior to incineration
- Only low sulphur fuel to be used
DESIRABLE FEATURES
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- INCINERATORS are designed to efficiently and safely burn waste at specified rates and temperatures, with the residium ash containing NO combustible material.
- Air and Fuel are mixed in correct proportion
- Instantaneous ignition of waste and gaseous components
- High Retention time for complete combustion
- Provide for creating Turbulence in Combustion Chamber
- High Temperature and Chemical resistant Refractory Lining
- Easy to install and simple to operate
- Satisfy and Exceed Pollution Control Norms
- Extremely LOW NOx level Emission: At times<1mg/Nm3
- LOW SO2 Emission due to LESS Fuel Consumption
- LOW SPM due to GREATER Turbulence
- BETTER Emission Values WITHOUT Downstream Equipment
- Very LOW Electrical Load: 1 ph <0. 5HP (up to 70 kg/hr capacity) against 3 ph 30 HP for other designs
- Drastic CUT in Fuel Consumption:
- Savings of Rs. 3 to 6 Lakhs/ year
- MINIMUM Maintenance
- No possibility of diesel misappropriation or maintaining
- secondary chamber temperature only during inspections