In every cooling tower there is a loss of water to the environment due to the evaporative cooling process. This evaporation is usually in the form of pure water vapor and presents no harm to the environment.
Drift, however, is the undesirable loss of liquid water to the environment via small droplets that become entrained in the leaving air stream. There, water droplets carry with them chemicals and minerals, thus impacting the surrounding environment.
Drift eliminators are designed to capture large water droplets caught in the cooling tower air stream. The eliminators prevent the water droplets and mist from escaping the cooling tower. Eliminators do this by causing the droplets to change direction and lose velocity at impact on the blade walls and fall back into the tower. Efficient drift eliminators will keep drift losses to less than .001% of the re-circulating water flow rate.