Passing a fecal coliform limit isn't luck — it's the predictable result of an operator who understands exactly what the contact tank, the dechlorination system, and the UV bank each need in order to do their job. This guide moves from why we disinfect effluent (covered in the Operator Fundamentals guide) into how to actually run and control the systems that make disinfection compliance happen day after day.
The Chlorine Contact Tank: Purpose and Design
The chlorine contact tank (or contact chamber) exists for one purpose: to give chlorine enough time in contact with the effluent to inactivate pathogens before the water is discharged. Contact time alone isn't the whole story, though — the way water moves through the tank matters just as much as how long it theoretically stays there.
Most contact tanks are built with a series of baffles arranged in a serpentine (over-and-under