By Dave Christophersen, Veolia Water Technologies
The steel industry has historically presented challenges for effective water treatment because it is a high water user and the applications may involve high heat, critical noncontact cooling, direct contact cooling, high suspended solids waters, oil and grease contamination, and complicated cascading.
The first step in treating the cooling waters used in a steel mill or steel processing plant is to thoroughly understand the water characteristics, systems, contaminants loading, treatment systems used and their effectiveness, retention times, and water quality requirements. A mass balance around the water and the constituents helps to determine needs and opportunities.
A common goal is to reuse as much water as possible within the various water systems and work toward minimal discharge or zero liquid discharge. Veolia has been involved in many efforts to reach this goal and both mechanical and chemical strategies are typically needed to handle the stressed conditions created.