Case Studies

These case studies illustrate how Alcoa is acting upon its commitment to sustainable development throughout the world. We are pleased with this progress, but look forward to achieving even more.

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2010 — Environment

Optimizing water use at the Bécancour Rod Plant: lower consumption = less wastewater = lower costs!

By automating the blow-off at the Bécancour Rod Plant’s casting pool, we reduced the amount of wastewater at the outflow by 50%. But that’s not all because less wastewater also means a smaller overall intake of water and savings in water treatment costs, both upstream and downstream of our process.
The casting pool is supplied with softened potable water to eliminate calcium and magnesium ions. In the past, the pool was blown off continuously, which meant that we had to frequently replenish our supply of softened water and use extensive amounts of water softener salts. The latter had to be disposed of by a specialized firm to ensure that we did not exceed the allowable salinity levels in our wastewater set in our Certificate of Authorization.
In 2009, we conducted a manual trial of a blow-off management approach based on conductivity, which was very effective on our cooling towers. Our tracking method enabled us to see the evolution of several water parameters – hardness, ph, bacterial content, chloride content, suspended solids, muddying – thereby eliminating the risks of losing control over the process or the release of non-compliant wastewater.
Following these conclusive trials, we began the automation of the blow-off in 2009 using a continuous conductivity reader. An additional parameter required by our Certificate of Authorization , namely continuous readings of oil and grease, as well as an automated control for our allowable aluminum content, serve as a cross-check before the blow-off is opened. As a result, the potential for release of non-compliant wastewater is reduced to a minimum.
  • The saltwater pond is emptied every 27 days rather than every 11 days. By extending this period by a factor of 2.5, and thereby reducing the number of times we are charged $2,020 for disposal of the saltwater, we have achieved yearly savings of over $36,000.
  • The reduction in demand for potable water, evaluated at 7,692 m3/year, also enables us to save close to $3,000 annually on water softeners.
  • In total, this environmentally responsible initiative will result in savings of close to $40,000 annually. Proof that respecting the environment can also translate into a financially leaner operation!