HI Disposal Systems, LLC (Indianapolis, Indiana) and PEAT, Inc. (Huntsville, Alabama) have developed HI’s Plasma-Based Pyrolysis/Vitrification (PBPV) System. This patented system uses plasma energy to treat medical and other specific waste streams, converting the waste into a low-BTU gas and a glassy slag, both of which can be reused. This treatment technology reduces the volume of the waste by 95-98% and the weight by 80-90%. HI’s PBPV Systems can handle from 1,000 (system-A) to 3,000 (system-B) pounds per hour.

Plasma energy is produced by energizing a highly ionized gas known as plasma. When electricity flows through plasma, the resistance of the ionized gas to electrical current creates extremely high temperatures. In HI’s PBPV System, a plasma arc torch is used to heat a waste processing chamber to about 3,000°F. The entire process is done in the absence of air (a process called pyrolysis) thus destroying the waste and forming stable gases. The product gases have a heating value of about 300 BTUs per SCF, and can be used to generate steam, electricity, or methanol. The only residue left at the end of the process is a non-leachable, vitrified (glassy) slag. If this slag is used as aggregate in concrete, roadbeds, decorative tiles, etc.; nothing remains to be landfilled.

The main components of HI’s PBPV System are: storage bin, waste feed handling, plasma heating system, waste processing chamber, product gas treatment, water treatment system, aggregate cooling and handling, and controls.

Generally, HI’s PBPV System can handle all types of medical waste including cytotoxic agents, sharps, and anatomical waste, except radioactive waste. This system is also used to treat incinerator ash, toxic material, explosives, and other hazardous waste.

Capacity: 1000 pounds per hour
Dimensions: 50' l x 30' w x 30' h
Weight: 60 tons
Electrical: 1150 KVA, 480V, 3-ph
Water: 3 gallons per minute
Steam: 315 pounds per hour
Natural gas: 45 SCF per hour

The product gases from HI’s PBPV System form a low-BTU fuel: mostly hydrogen, carbon monoxide, carbon dioxide, water, and methane. All gases pass through quench and scrubber systems. If the product gases are combusted in a small flare, the air emissions are equivalent to burning natural gas or propane.

Energy use for the system-B model is estimated at 1.22 kWh per pound of waste. The power demand of the plasma arc torch is about 3,000 kW.

HI’s PBPV System offers the following advantages:

Importantly, toxic air contaminants and other pollutants are markedly lower than emissions from incinerators or landfills. One disadvantage is the large capital investment and the high throughput rates required for economic operation. Hence, using plasma technology to treat medical waste is appropriate only for large hospitals or regional treatment facilities.

The cost of HI’s PBPV System depends on the amount and type of waste being treated. Initial capital cost for system-A processing 1,000 pounds per hour (up to 12 tons per day) is about $3.0 million including permitting, installation, and one year of selected spares and consumables. Costs for system-B (3,000 pounds per hour, up to 36 tons per day) are considerably higher; system-B is designed for a regional commercial processing facility.

The expected operating cost (including labor, power, consumables, operations, maintenance, and amortized capital cost) for system-A is between 17-19¢ per pound; operating cost for system-B is 12-14 ¢ per pound. Operator training is similar to that of incinerator operators.

The State of Indiana and City of Indianapolis have issued all permits and approvals for HI's PBPV System. The California Department of Health Services had earlier approved the system as an alternative medical waste treatment technology.

Technical feasibility of HI’s PBPV System has been demonstrated at PEAT's Huntsville facility for over five years. One PEAT system is being installed in Virginia to process military waste streams, another in Washington State for treating mixed low-level radwaste. The first regional waste disposal facility in the U.S. using the PBPV System to destroy medical and low-end hazardous waste will become operational in late 1998 in Indianapolis, Indiana.

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