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Article traduit
au français
par Claude Léger


Orimulsion:
Alimentant les centrales du
N-B

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"To summarize, orimulsion burning is fraught with danger. It can be burned safely and efficiently, but at times it seems that those conditions present very serious technological challenges."

 

 

 

 

 

 

       

Orimulsion:
An Environmentalist's Concerns

Mike Lushington
Environmentalist, teacher, farmer, writer
October 2000

 

rimulsion has been burned in the NB Power Generating Plant in Dalhousie since August of 1994. 


(photo: Mike Lushington)
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Dalhousie Thermal Generating Plant -
as seen from Eel River Bar
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To argue that it has been an environmental improvement over previous fuels, mainly coal, is a non-starter; no one would question it. One has only to recall the persistent filth of dust from the coal piles and soot from the smoke stacks, which would literally turn a snowfall black within a couple of days, to realize the improvements.

However, improvements, in themselves, do not signify acceptability. The burning of orimulsion creates environmental concerns in itself and these concerns are all the more serious because they are rather more insidious than were those associated with coal burning. These concerns break down into four groups. It is the purpose of this paper to take a brief, non-technical look at each of them.

Orimulsion is a bitumen and water mixture mined in Venezuela. It is shipped to Dalhousie in tankers and pumped ashore at the government wharf just to the west of the Bowater Pulp and Paper Mill. There are usually two shipments a month. NB Power officials monitor the off-loading and have, they say, a sophisticated monitoring system in place to detect any spills before they can become a problem. Furthermore, the company holds regular exercises designed to fine-tune its response in the event of a major spill.

The problem with orimulsion is that it does not behave like oil when it spills into open water.
Instead of floating on the surface, orimulsion drops some eight to ten feet (two-and-one- half to three meters) into the water column and disperses from there. The Bay of Chaleur does not have a high tide action in itself, but here, where the off-loading takes place, tides combine with the outflow from the Restigouche River to create a great deal of water action. It is very safe to say that any spill from the wharf will be dispersed over a large area of the Restigouche Estuary and the upper reaches of the Bay within a couple of tide cycles. Independent analyses of containment practices of orimulsion spills under similar circumstances in England have indicated major problems; one such report denounced the exercises as complete failures.


(photo: Mike Lushington)

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Just a few of the estimated 150 000 sea birds
that frequent the Upper Bay of Chaleur and
the Restigouche Estuary each spring
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The Restigouche Estuary is wide (ranging from one to six kilometers) but very shallow. It is a major spawning ground for blue mussels, clams, rock crabs and other sea life. One of the most important salmon runs in the entire Atlantic region passes through the estuary; smelt, sea trout, and mackerel are also present in large numbers at different times each year. As well, a major herring spawning ground is located just to the east of the river mouth. The estuary also hosts very large numbers of seaducks and other waterfowl. Indeed, the area has just been proclaimed an Important Bird Area by the Canadian Nature Federation, because of the huge concentrations of Black scoters (up to 120 000) each spring.

All of this would be in danger should a major spill occur. Despite assurances from local NB Power personnel, the very real problems associated with containment and recovery of this elusive substance in the event of a spill are cause for serious concern.

Once the fuel is ashore, environmental concerns shift to the burning itself. The three remaining concerns all have to do with this.

When orimulsion burns, it releases considerable amounts of sulphur dioxide (SO2) and sulphur trioxide (SO3). Containment of the former was a priority for NB Power from the start and, for the most part, has not been a major concern, apart from the costs associated with the maintaining of the proper equipment for that containment.


(photo: Mike Lushington)

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The Bon Ami Rocks - a sea bird colony situated
less than one kilometre from the Dalhousie plant and,
in the opposite direction, from the wharf where
Orimulsion is off-loaded
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Sulphur trioxide containment has been trickier. For the past few years, local people have complained about the periodic emission of a plume from the plant which quickly turned into a rather dark brown/purple haze. Under ideal weather conditions, the haze would spread for fifty kilometers or more, either up the Restigouche River Valley (with an east wind) or down over Charlo, Belledune and across to communities on the Quebec shore, with a west wind. Finally succumbing to pressure from local environmentalists and other citizens, NB Power installed a sophisticated new scrubber in its smoke stack in May of this year (2000); to date, there has been some improvement in the visual situation, although it must be noted that this improvement has not been one hundred percent effective. In fairness, too, it must be noted that environmental monitoring stations situated around the plant at distances of up to ten or fifteen kilometers have not recorded any unduly high emission of either SO2 or SO3 since the latest installations.

One of the major concerns of the burning of orimulsion is that the process releases extremely tiny particles of heavy metals. These particles are so small that they appear almost like gasses rather than solids. In this state, they are not trapped by conventional electrostatic precipitators; instead, they escape to pollute the surrounding landscape, particularly in areas downwind of the prevailing breezes. To my knowledge, no monitoring of these particles is carried out on any regular basis, by NB Power or by anyone else; nor has there been any systematic soil sampling in the "footprint" area of the smokestack. Whenever the question arises, we are assured that heavy metal particles are trapped by the superior precipitators with which this plant is equipped, but it would be a source of reassurance to see the results of an independent soil and water analysis.

On the issue of heavy metal particles, it is worth noting that a Kent Co., Britain, farmer sued the local power commission over contamination of his crops by heavy metal emissions from orimulsion burning. The contamination was serious enough that the power commission decided to settle out of court rather than risk having the evidence against it brought to public awareness.

The final concerns have to do with the phenols in orimulsion. Released into the environment, either through improper burning or by spillage, phenols have serious "gender-bender" side effects all up and down the food chain. Organisms poisoned by phenols have difficulty reproducing; they either suffer from sterility or produce defective offspring. Orimulsion also has something in common with many widely used pesticides; the emulsifying agents in the substance also have serious genetic implications, again, primarily in reproduction.


(photo: Mike Lushington)

======== Upper Restigouche Estuary ========

To summarize, orimulsion burning is fraught with danger. It can be burned safely and efficiently, but at times it seems that those conditions present very serious technological challenges. Like nuclear power, it can operate safely ninety-nine percent of the time, but a one- percent slip could cause disaster. I dread the consequences of a major spill into the Restigouche and every time I hear someone complaining of another asthma attack, brought on by another bad day at the plant itself, I wonder what we are breathing, or eating, or drinking by way of by-products from this process.