Dow Chemical Canada Inc., a C4 participant, with annual sales of $2.4 billion, is made up of about 2000 people producing and selling a wide variety of chemicals and plastics. About 28% of the chemicals and plastics manufactured in Canada are exported to 60 countries around the world. Headquartered in Sarnia, Ontario, it has manufacturing sites in Sarnia, Ontario; Varennes, Quebec; Fort Saskatchewan, Alberta, and a plant producing foam insulation in Weston, Ontario. Distribution terminals are located in Thunder Bay, Ontario, and North Vancouver, British Columbia.

Reducing Chlorinated Compounds in Effluent

At Dow Canada's manufacturing plants, a large volume of water is used every day with approximately 98% used for cooling purposes. This cooling water normally does not come into contact with chemicals and is returned to source, a nearby river. The greatest potential for contamination comes from the accidental release of process chemicals into the storm water drainage systems. Each manufacturing site is committed to eliminating harmful discharges and spills by reducing, reusing, recycling and treating both process and drainage water.

Since the 1980s, employees at Dow Canada's Sarnia Site have worked to reduce the release of priority pollutants in the water returned to the St. Clair River. The Site monitors 43 priority pollutants that could potentially be present. Many are chlorinated compounds. The primary source of emissions to water of organic chemicals has been residual contaminants in the ground in old sections of the plant site - especially in and around old sewers. Some are not intentionally manufactured, but are trace chemicals, such as hexachlorobenzene and octachlorostyrene, created during manufacturing processes. Others, such as propylene dichloride, are also present.

In 1986, water returned to the river contained an average of over 40 kilograms per day of these priority pollutants. By 1989, the Site had reduced this amount to 8 kilograms.

In 1989, in order to further reduce these emissions, Dow Canada publicly committed to a River Separation Project at the Sarnia Site. Estimated to take 10 years and cost $100 million, this major undertaking involved redesigning the flow of all of the water at the Site; including river water used in manufacturing processes, to cool the processes, as well as, any surface water resulting from rain or snow. One of the main components of the River Separation Project was to route the once-through-cooling water into new sewers and isolate, contain and shutdown the old, leaky, sewers leading to the River. Since 1989, four of these sewers have been shutdown, reducing the number of sewers from seven to three.

During 1995, work continued on the River Separation Project with approximately $2 million spent to install a drainage containment pond in an area surrounding four of the Site's manufacturing plants. The containment pond collects rain and run-off water from roads, parking lots and other surrounding areas through a network of sewers, drains and ditches.

Daily discharges of priority pollutants have been further reduced, with many virtually eliminated, from an average of 8 kilograms per day in 1989, to an average of 0.3 kilograms per day in 1995, a reduction of 96%.