Even when not required by environmental regulations, the following best practices are recommended.
Maintenance Practices
- Maintain cooling towers to the manufacturer’s specifications by scheduling routine monitoring and maintenance activities.
- Include specific language in service contracts encouraging vendors to substitute less toxic chemicals where feasible.
- During repair or reconstruction of existing open recirculating tower systems, limit the use of copper-based materials.
Alternative Operational Practices
- Consider using electrically powered water conditioning units. For example, automatic bleed/feed controllers enables the facility to continuously monitor the concentration of dissolved material in the cooling water. When the concentration exceeds a preset level, the controller opens the bleed valve and activates the chemical feed pump, thereby keeping the tower at the optimal concentration at all times. Unintentional discharge of active chemicals is minimized in this manner.
- Consider magnetic water conditioning, which reduces the need for chemical additives.
- Determine optimal chemicals for the prevention of biological growth and corrosion. For example, chlorinated biocides are less toxic than brominated biocides, and polyphosphate and organophosphate inhibitors are less toxic than chromate corrosion inhibitors.
- Consider using ozone treatment in lieu of common biocide use. However, several documented disadvantages associated with this practice need to be weighed: 1) the potential for corrosion in cooling towers unless careful dosing is practices; 2) potential rapid fouling on high temperature surfaces in recirculating systems; and 3) health and safety issues related to potential worker exposure to ozone.
- Pretreat makeup water to reduce the chemical treatment requirements for scale and corrosion control and increases the ability to recycle the water.
- Consider using polyethylene, titanium, and stainless steel materials of construction for cooling tower equipment and piping instead of materials such as stainless steel because they requires less scale/corrosion inhibitors.