CHLORINE INPUT AND DIOXIN EMISSIONS
"Sintering plants serve for recycling of dusts, scrap and abrasion from other processes of the metallurgical plant to recover the iron for further use in the blast furnace. But this reasonable waste management method is accompanied by the problem of introducing traces of chlorine and organic compounds responsible for the generation of PCDD/F (dioxin) within these plants."
Source: Greenpeace report 'Achieving Zero Dioxin' - July 1994 .
We have asked it at the Hoogovens iron and steel plants in The Netherlands: NO scrap recycling is done in sintering plants! Only the dust from the blast furnaces is recycled that way. Sintering is the reaction of iron ORE with coke and some other stuff (e.g. lime) to form hard pellets that can withstand the high static pressure of the blast furnace. Scrap metal has no use there, it is used in steel furnaces and reclamation plants. In fact no external industrial sources of chlorine are introduced, neither in the sintering process, nor in blast furnaces.
Where is chlorine to form dioxins while sintering then coming from? Simply from nature. All natural materials contain salt in small quantities. So it is in coal and thus in coke. In general this is already a million times more than necessary to form all dioxins you will form. Even ambient air contains a hundred to a thousandfold the quantity of natural chlorine, necessary to form the amount of dioxins found in the worst case of incineration... So you don't even need chlorine in the 'fuel' to form dioxins...
Because Greenpeace accuses the chlorine industry to be THE source of chlorine in incinerators and in all other cases of dioxin releases, it is interesting to see if the chlorine input is important to form dioxins:
Maximum chlorine content and measured/estimated dioxin release:
All figures expressed in µg I-TEQ to air per ton produced or incinerated.
|chlorine input and dioxin output of different processes|
|Incineration of hospital waste:||7||800||5000||1|
|Incineration of copper cable:||20||3.7||2280||5|
|Incineration of wood (with PCP):||1||25||500||6|
|Incineration of solid chemical waste:||6||3.6||310||1|
|Incineration of municipal waste:||0.5||7||277||1|
|Incineration of liq/gas. chemical waste:||5||4.4||222||1|
|Incineration of wood (painted):||1||5||100||6|
|Incineration of chlorinated waste:||69||2.7||93||1|
|Recycling of copper/brass/bronze:||?||5||35||1|
|Recycling of aluminiumscrap (dirty):||?||1.7||35||1|
|Incineration of wood (clean, dry):||1||13||28.5||6|
|High temp. processes (glass, cement):||?||0.3||8.7||7|
|Diesel motor of seaships (heavy fuel):||0.000011||3.2||6.5||2|
|Secundary steel (scrap recycling):||?||4.4||6||1|
|Incineration of waste lubricating oil:||?||5||1|
|Recycling of lead:||?||5||1|
|Incineration of sludge (municipal):||0.1||5||1|
|PVC at a warehouse fire:||57||4||1|
|Incineration of sludge (industrial):||?||3.2||4||1|
|Incineration of electromotors:||?||3.3||1|
|Incineration of clean wood (stove):||1||1||3.3||1|
|Incineration of VCM production waste:||69||2.7||8|
|Incineration of coal:||?||0.35||1.6||1|
|Carmotor on leaded gasoline:||0.000048||1.2||1|
|Incineration of biogas:||?||1.1||1|
|Dieselmotor Rhine barge (gasoil):||0.000001||1||2|
|Production of coke:||?||0.3||1|
|Primary iron/steel production:||?||0.13||4|
|Production of VCM:||57||0.1||1|
|Carmotor, unleaded gasoline, no catalist:||0.000001||0.06||1|
|Asphalt mixing installations:||?||0.05||1|
|Carmotor, unleaded gasoline, with catalist:||0.000001||0.01||1|
There is an enormous difference in amount of chlorine: from near zero to 69% of the incinerated material. As you can see, there is no correlation between the chlorine content of the 'fuel' and the amount of dioxin released. An incidental fire with lots of PVC gives less dioxin per ton as the fuel use of a seaship, although PVC contains at least 500,000 times more chlorine!
There are even enormous differences in releases of dioxin from incineration of the same type of waste: municipal waste gives amounts ranging from 7 to 277 µg per ton incinerated, due to differences in incinerators and circumstances.
The incineration of hospital waste gave the highest dioxin emission per ton. This was due to the lack of quality of the incinerators. All individual incinerators at hospitals are closed now and the waste is incinerated at one central facility which satisfies all strict rules on dioxin release (less than 0.1 ng I-TEQ/m3 off-gas), and should be below 1 µg per ton now.
The incineration of copper cable is now forbidden. Instead of incineration, cable is stripped.
There were no measurements on the use of pitch (the heaviest part of crude oil) as an energy source at refinaries. This makes it impossible to make comparisons between 100% oil based and partly salt based plastics in dioxin releases during production. Neither were there measurements at paper production and recycling plants, 'because they use no chlorine'. That is not a guarantee not to form dioxins, see Chlorine and paper bleaching.
The total amount of dioxins released to air is the most important source of dioxins in the environment. But with building new incinerators and renovation of existing ones, and the measures, taken in the metal industry, dioxin releases will firmly go down.
PVC waste provides about half the chlorine input of municipal incinerators and is therefore accused to be the main source of dioxin-emissions. To be right, there must be a direct correlation between chlorine/PVC input and dioxin output. In general, no such correlation exists.
The American Society of Mechanical Engineers conducted a study  of all available evidence about tests at different incinerators all over the world. 72 municipal incinerator facilities showed no relationship between chlorine input and dioxin output, even when near all chlorine input was omitted or the chlorine/PVC input was augmented to a fivefold. Neither could a change in composition of the dioxins ('the fingerprint') been detected. Eight facilities displayed decreasing dioxin concentrations with increasing chlorine and ten facilities displayed an increase. With other words, the chlorine content is not important for dioxin output. That is in fact normal, because in general only one millionth of the average chlorine input is needed to form all the dioxin found. What is important, is the conditions which makes dioxin. For the complete abstract and summary of this report, see The ASME Research Report summary.
To understand why there is no correlation between chlorine input and dioxin output, you have to know how dioxin is formed. That was investigated in a lot of experiments at different universities. Dioxin and a lot of other unpleasant materials are formed as a result of incomplete burning of any organic material. This happens mainly when the temperature is too low, especially between 200 and 600 °C. In incinerators, if there is enough air and the burning temperature is above 950 °C and the residence time is long enough, all dioxin and other organic stuff is effectively destroyed. What rests, is some fly ash, which contains carbon, chlorine (in form of salt) and trace metals. When the off-gases are cooling down, dioxin and other stuff are formed again, especially on the surface of the fly ash particles. The amount of dioxin relates directly to, in descending order:
With the above knowledge, an experiment was done at an incinerator in Flanders, which was nominated to be closed, because of too high dioxin emissions. The investigators changed the conditions of the incineration:
The results were far beyond expectations: the amount of dioxin released was reduced a ten- to hundredfold! The incinerator changed from one of the worst to one of the best, without any investment! You can compare this with the - theoretical - results of omitting most of the chlorine input, which results in a - theoretical - reduction to half the amount, still largely above the legal limits, but never seen in real circumstances.
The only incidental fire in the world where the amount of released dioxin was quantitatively measured, was a big fire at a warehouse in Sweden, where about 700 tonnes of PVC and PVC-containing material was burned. Due to weather conditions, all soot was settled on snow. So the amount of dioxin in soot and the total amount of soot could be measured. Because almost all dioxin formed is adhered at soot, the total amount could be calculated: about 3 mg I-TEQ was released, which gives an average of 4 µg I-TEQ dioxin per incinerated ton PVC/PVC containing material. This is less than the dioxin emmission per ton of heavy fuel, used by a seaship and less than burning clean, dry wood in open fireplaces...
An investigation of the German Firebrigades, on a lot of incidental fires, revealed that with all fires some very small amounts of dioxin are released. Even in the case of big fires with 'chlorine-free' materials like polyethylene and polypropylene, small quantities of dioxin are found in the soot. The concentrations found are about one quarter of those found in soot from PVC-fires, but no quantities of soot are known, so no quantitative comparations can be made.
Is dioxin release from incidental fires a threat for health? No, the German firemen themselves were tested for dioxin in their blood. The average was not higher than the average dioxin level of the general German population.
Is dioxin release from incidental fires an environmental problem? No, even in the worst cases measured, the amounts of dioxin in soot were so low, that you have to eat hundreds grams of soot (!) to reach the (WHO) daily allowable dose. Just by washing off the soot from vegetables and fruits or pealing them, the possible problem was over. In all cases (even from measurements, conducted by Greenpeace!) the dioxin content of upper soil was below the directives of the German UBA for industrial areas and in most cases for urban areas and agricultural use.
Higher amounts of dioxin were found in partly burned rests of fires, but not more than found in ashes of open fireplaces... These could easely been destroyed by burning in well equiped incinerators.
All alternatives for chlorinated chemicals, like PVC, give also dioxins during production, transport, recycling and/or incineration. In many cases, they give more dioxin releases than the production, transport, use, recycling, incineration and accidental fires of PVC or other chlorinated chemicals. See dioxin releases of materials during their life cycle.
Except for releases from the past, chlorine industry and chlorine products are among the least sources of dioxin today.
There is no reason to treat the release of dioxins from chlorine processes different from chlorine-free. And there is no reason at all to accuse the chlorine industry of today to be the main origin of large quantities of dioxins in the environment.
It is for 0.1% true that the chlorine- and PVC-industry is a source of dioxins, but it is for 99.9% a lie. And it is green fundamentalism to ask for a complete end of chlorine- and PVC-industry to 'solve' the dioxin problem, while much larger dioxin sources like domestic wood combustion and the metal industry are not attacked at all.
You are at level two of the Chlorophiles pages.
Created: April 8, 1996.
Last update: September 28, 1998.
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