- Norway do not need any central destruction facility for

hazardous waste

Jan Erik Kaarø

- There is no need for Norway to build a central treatment plant for hazardous waste. The Norcem cement furnaces are quite adequate as a destruction facility, says senior scientist Kåre Helge Karstensen, group manager at SINTEF Industrial Chemistry in Oslo.

For the past two and a half years, Karstensen has been trying without success to identify any hazardous consequences of burning waste oil, paints, PCBs and other hazardous waste in cement furnaces. His results thus agree with those of several studies in other countries. In early June, Karstensen presented the preliminary results of his research at an environmental conference in The Netherlands. These also demonstrated that burning hazardous waste does not influence the environmental quality of the cement produced in the furnaces.

Central facilities unnecessary

Karstensen believes that his results ought to affect the decision to construct a central treatment plant for hazardous waste in Norway. No-one knows just how much waste material of this sort is produced. In 1993, 98,000 tons were collected in Norway, but estimates made by the Norwegian Hazardous Waste Company A/S (NORSAS) suggest that annual production of hazardous waste lies at around 150000 tons.

The semi-publicly owned company Norwegian Waste Treatment A/S (NOAH) is currently drawing up plans for a central treatment plant, which is expected t be fully operational by the end of July 1997. The plant would have an annual capacity of 31,000 tons of organic waste, and preliminary estimates suggest that it would at least cost NOK 500 million. A final decision on whether to build the facility is expected t made in the course of 1994.

Kåre Helge Karstensen claims that in both socioeconomic and environmental policy terms, a better solution would be to burn organic hazardous waste in Norcem´s cement furnaces in Brevik and Kjøpsvik. Inorganic waste such as batteries and metals can either be sent to Sweden to the SAKAB plant, which has spare capacity, or be dealt with at NOAH´s plant on Langøya in the Oslo Fjord.

Advantages

"This would be the best solution for several reasons. The most important is that combustion in a cement furnace is better than in a destruction plant. Temperatures are as high as 1,400 - 2,000oC, and the waste stays at these temperatures in adequate time. In the Brevik cement furnace the fuel rotates at these temperatures for a distance of 80 metres, guaranteeing complete combustion," Karstensen point out.

Another advantage of this technology is that the special waste is also a valuable fuel. The cement furnaces usually burn coal. If some of the coal can be replaced with hazardous waste that has to be destroyed anyway, total carbon dioxide emissions will be reduced.

Many aspects being evaluated

Ellen Hambro, a consultant in the Waste and Recycling Dept. at the Ministry of Environment, points out that the Norwegian Parliament has adopted an objective that Norway should have treatment facilities for all types of hazardous waste by 1996. Parliament set up NOAH in 1991.

"When we evaluate future solutions we need to take into consideration economic aspects, our desire to utilize the energy in the waste products and the EU proposals for a directive regarding combustion of hazardous waste. It is by no means certain that the end result will be either one thing or the other. One of the alternative outlined by NOAH is to locate the joint treatment plant in Brevik and coordinate part of its operations with the cement factory," says Hambro.

Large quantities of coal

Norcem buys about 180,000 tons of coal a year from abroad for its two plants. Since 1987, 5,000 tons of hazardous waste a year have been burnt at Brevik. The new permit issued by the State Pollution Control Authority is for 15,000 tons, but is only valid until 1997. Last spring, trialburn with of hazardous waste as a fuel were also carried out in Kjøpsvik. During these trials, SINTEF´s Division of Industrial Chemistry performed a complete environmental analysis of the operation in order to detect any hazardous emissions. Neither there nor in any other cement factory anywhere in the world have negative consequences for fuelling with "alternative fuels" been identified. Tor Færden, a senior engineer with the State Pollution Control Authority confirms that a large number of international studies show that combustion in cement furnaces does not increase the threat to the environment. In many countries, therefore, cement furnaces are used to get rid of everything from waste oil and used tyres to ground up vehicle scrap. Norcem´s Brevik plant is among the few that have also burnt PCBs. To do so the plant have to show a destruction and removal efficiency of 99.9999 % i.e. of 100 tons of PCBs that are fed into the furnace, less than 100 grams can emit with the exhaust gases. All the same, cement production is not completely pure and problem-free. For example, the plants release a certain amount of organic compounds, heavy metals and dust.

"However, the point is that all our measurements show that these contaminants do not increase when the furnaces are fuelled with hazardous waste."

The studies of waste combustion in cement furnaces have been financed by the Research Council of Norway.