Great amounts of municipal wastes that are generated daily, lack of safe storage and processing costs cause threats to our health, drain taxpayers money and destroy delicate natural balance. These wastes easily penetrate to ecosystem, contaminate soil, and ground water.
Conventional waste utilisation methods certainly do not solve problems, because the harmful residues such as ash, dust, gases left behind cannot be filtered off even with the usage of innovative technologies. Municipal waste problem is undoubtedly waiting for proper solutions.
The reasonable assumption is that even after we divert, compost, recycle, reuse and implement all the current waste diversion methods, Toronto will be stuck with 30- 40% of the waste. This includes 15 million chip bags, 10 million light bulbs, five million toothbrushes and 100,000 mattresses that Toronto sends to landfills each year.
The solution therefore is a modern and clean technology of plasma utilisation to incinerate all kinds of trash. Plasma technology is known for more than a half of century and was developed and used particularly in metallurgy for production of high-grade steel. Today, it is widely used for municipal waste utilisation. In Japan two converters are working already and transform 200 tonnes per day. Plasma technology is currently being developed in Italy, Spain and other European countries. In North America there are companies, which produce plasma converters that have mobile and stationary capabilities.
What is plasma technology?
Very hot plasma is formed by ionized gas (i.e. Oxygen, under normal pressure) in the strong electrical arc with the power ranging from two to 20 Mega Watts. Temperature of such plasma is very high, ranging from 2000-6000oCelsius. In such high temperature all waste constituents, including metals, toxic materials, silicon, etc., are totally melted forming nontoxic dross. Plastic, biological and chemical compounds, toxic gases yield complete dissociation (required minimal dissociation temperature is in the range of 1500°C) into simpler gases mainly H2 and CO2. Simpler gases, mainly H2 can be used as ecological fuel to generate heat energy and electrical energy decreasing significantly (even to zero) cost of plasma formation and waste utilisation. Regained metals from dissociation process can safely return to metallurgic industry, and slag can be used as an additive to road and construction materials.
The utilisation of municipal waste using this method does not cause the emission of foul odours and does not produce a harmful ash, which is something that normally takes place in an incinerating plant.
Advantages of Plasma Technology
2. Plasma waste utilisation method takes place in a close system, without releasing ashes, waste remnants, dusts and toxic gases into environment. Regained metals return to metallurgic industry and created slag is used as an additive to road construction materials. Non-toxic gases, which are created, are stored in special containers (gas cylinders) and used as fuel and energy creators.
3. The volumetric waste reduction for most solid wastes is approximately 300 to one. Conventional incineration ratio is in the range of 5 to one since large quantities of ash are produced.
4. Plasma technology allows converting large quantities of municipal waste in the range of 10 to 500 tonnes a day.
5. This method of waste reduction is the only method available to reduce electronic waste, which does not undergo biodegradation.
6. The costs of using plasma technology are significantly reduced from $40/tonne to ZERO as a result of creation of ecologic by-products. The costs of using conventional incineration are in the range of $100/tonne.
7. Contaminates in slag and gases created during plasma utilisation with elements such as mercury, cadmium, sulphur, SO2, HCL, dioxins, selenium, chromium, lead, barium, arsenic, radioactive elements are strictly controlled by usage of special water or dry scrubbers and filters. Using this method elements are considerably minimised below environmental standards. The remainder of the pollutants sink into glassy slag and can be treated further in close system, which is a major distinction to conventional incineration.
8. The ashes that are formed as a result of conventional incineration can be burned down to further using plasma technology to make them harmless.
9. Contemporary plasma converters are computer controlled, safe, quiet and can be stationary or mobile.
10. Plasma waste utilisation will improve public health and safely achieve “total and irreversible destruction of hazardous and toxic compounds”, “lethal viruses, bacteria and prions that are so dangerous to our health”. (Startech Environmental Corp.)
Dr Marian Kowalski Sebastian Kopinski, Toronto, Ontari