Protozoa are a diverse group of microorganisms that inhabit terrestrial and aquatic environments. They are present in every ecosystem and are generally much larger (0.01 mm to 1.0 mm in length) than bacteria or viruses, though most are visible only through a microscope. Most protozoa are not harmful to humans; however, those that are pathogenic, such as Giardia lamblia, are of great concern to the water industry.

Executive Tool Kit​