Guest Comment
The facts behind the"Zero AOX"goals In pulp and paper mills By Doug Christie,P. Eng., Process Engineer,Hornby Island, B.C.
Responding to the article "Pulp
Mill regulation threatened, says BC Law Association" published in the June 2002
issue of Environmental Science &
Engine-ering, I wrote complaining that it was a sad misrepresentation of the technology and the facts, and was pleased to be invited to respond. At issue is the "Zero AOX" regula tion, which was to have come into
effect in BC at the end of this year. It has been known for ten years that this goal was not possible, and would even tually have to be rescinded. Now that the inevitable is occurring, there is a chorus of complaint from environmen tal groups that the provincial govern ment - they stress Liberal government - is making a gift to industry. There has been no discussion of the feasibility or the desirability of achieving zero AOX; it is the process which is being attacked. The plain fact is that zero AOX in effluent is not possible. The only way in which a mill can meet this target is to shut down. The regulation was a political statement when it was put into place in 1992, knowing that 2003 was a long way off. The environment min ister of the day, whose expertise is in religion, admitted he had no idea how it would be accomplished, but he "had faith". This regulation was doomed the day it was proclaimed. What is AOX? Absorbable organic halides, in effect chlorinated organics
uble lignin, and reducing the X com ponent, oxidative chlorine compounds. Both of these have been done, with the result that AOX in BC mills now aver
government as only engineers and a chemist. My first thought on reading the panel report was to wonder who in the environmental groups was fit to make this judgement. My explicit request for the names and qualifications of their experts has gone unanswered.
ages 0.47 kg/t, a reduction of 93% in the last 15 years. Less than half of the remaining AOX is derived from the bleaching chemicals. The incentives to bring this about have been firstly process changes to eliminate TCDD and TCDF (tetrachloro dibenzyl dioxins and furans), and secondly the insistence of mainly the Alberta government on the absolute best technology for new mills
to be based on a snapshot of the tech nology in 1998. It lacks the perspective of those who have lived through the development of effluent regulations and bleaching technology for the last 30 years, and can distinguish between facts and advertising fluff disguised as
there in the late 1980s.
technical articles.
AOX as a goal has appealed prima rily to governments because it is a sim ple number and has a nicer ring than tetrachloro dibenzyl-p-dioxin. A implies progress and X implies sinister mystery. However both Environment Canada and the US EPA have declined to set an AOX standard on the basis
that it is not specific to any definable environmental problem. The basic arguments of the environ mental groups are that BC mills are backward in pollution prevention, that only a zero AOX regulation is holding their feet to the fire, that an attractive market for TCP pulp is being ignored and that zero AOX could be achieved
by TCP bleaching and/or full mill clo sure. They also criticise the make-up of the Review Panel appointed by the BC
Their technical information seems
The fact is that the newer mills and the recent rebuilds in BC and Alberta
represent, and to some degree define, the new world standard. The average performance of older mills is at a high standard. TCDD/P has been eliminat
ed, AOX, for what it is worth, is reduced 93%, and all mills have spill control and secondary treatment. Those who have been to court over
alleged infractions do not feel that the enforcement is lax.
Furthermore, we have in Vancouver
a large infrastructure of pulp mill expertise, operating, engineering, research and academic, and we do not need to be lectured by amateurs. As one who has been responsible for defining the process for a new mill overseas, I can say that information on
in solution. AOX is a broadband test
procedure. It is not a narrow chemical group with a definable environmental impact. Many foodstuffs, cosmetics and pharmaceuticals test positively for AOX. The human body generates AOX. Unbleached pulp mills produce AOX. Pristine streams contain AOX. What is the source of AOX in kraft effluent? A small amount comes from the trees themselves. Chloride
is
&
essential to life, as witness the histori cal role of salt in trade. The rest comes
from bleaching with chlorine com pounds. There are two ways to reduce AOX: reducing the O component, sol
Norske Canada s Elk Falls mill, in Campbell River, British Columbia.
30 Environmental Science & Engineering, March 2003